From daf4cceab48b772ed8a3ff66958f71b35580f120 Mon Sep 17 00:00:00 2001
From: Martin Bonnin <martin@mbonnin.net>
Date: Tue, 24 Feb 2026 13:14:44 +0100
Subject: [PATCH 1/4] Add fragment-arguments

---
 libraries/apollo-ast/api/apollo-ast.api       |  16 +-
 libraries/apollo-ast/api/apollo-ast.klib.api  |  16 +-
 .../com/apollographql/apollo/ast/Issue.kt     |   2 +-
 .../com/apollographql/apollo/ast/api.kt       |  14 +-
 .../com/apollographql/apollo/ast/gql.kt       | 115 ++++++++--
 .../ast/internal/ExecutableValidationScope.kt | 135 ++++++++---
 .../apollo/ast/internal/Parser.kt             |  18 +-
 .../apollo/ast/internal/ValidationCommon.kt   |  24 +-
 .../apollo/ast/internal/fields_merging.kt     |  90 +++++++-
 .../ast/test/ExecutableValidationTest.kt      |   3 +-
 .../apollo/graphql/ast/test/fixtures.kt       |  10 +-
 .../parser/fragment-arguments-error.expected  |   2 +
 .../parser/fragment-arguments-error.graphql   |   7 +
 .../parser/fragment-arguments.expected        |   8 +
 .../parser/fragment-arguments.graphql         |   9 +
 .../executable/UnusedVariable.expected        |   2 +-
 .../default_value.expected}                   |   0
 .../fragment_arguments/default_value.graphql  |  12 +
 .../fragment_arguments/merge_error.expected   |  11 +
 .../fragment_arguments/merge_error.graphql    |  31 +++
 .../missing_required_argument.expected        |   2 +
 .../missing_required_argument.graphql         |  12 +
 .../operation_variable_passthrough.expected}  |   0
 .../operation_variable_passthrough.graphql    |  12 +
 .../fragment_arguments/schema.graphqls        |  29 +++
 .../fragment_arguments/type_mismatch.expected |   2 +
 .../fragment_arguments/type_mismatch.graphql  |  12 +
 .../unknown_argument.expected                 |   2 +
 .../unknown_argument.graphql                  |  12 +
 .../unused_fragment_variable.expected         |   2 +
 .../unused_fragment_variable.graphql          |  12 +
 .../valid_usage.expected}                     |   0
 .../fragment_arguments/valid_usage.graphql    |  12 +
 .../variable_scoping.expected}                |   0
 .../variable_scoping.graphql                  |  18 ++
 .../graphql-js/LICENSE                        |   0
 .../graphql-js/README.md                      |   0
 .../allows_different_order_of_args.expected   |   0
 .../allows_different_order_of_args.graphql    |   0
 .../field_merging_order}/schema.graphqls      |   0
 ...input_object_fields_in_arg_values.expected |   0
 ..._input_object_fields_in_arg_values.graphql |   0
 .../input_field_order}/schema.graphqls        |   0
 .../keywords}/schema.graphqls                 |   0
 ..._field_names_that_are_js_keywords.expected |   0
 ...r_field_names_that_are_js_keywords.graphql |   0
 .../known_directive/schema.graphqls           |  13 ++
 .../with_misplaced_directives.expected        |  29 +++
 .../with_misplaced_directives.graphql         |  10 +
 .../with_no_directive.expected}               |   0
 .../known_directive/with_no_directive.graphql |   8 +
 .../with_standard_directives.expected         |   2 +
 .../with_standard_directives.graphql          |   4 +
 .../with_unknown_directive.expected           |   5 +
 .../with_unknown_directive.graphql            |   3 +
 ...ot_unused_or_undefined_variables.expected} |   0
 ..._not_unused_or_undefined_variables.graphql |  12 +
 ...guments_are_not_unused_variables.expected} |   0
 ...ot_unused_or_undefined_variables.expected} |   0
 ..._not_unused_or_undefined_variables.graphql |  12 +
 ...variables_produce_multiple_errors.expected |  35 +++
 ..._variables_produce_multiple_errors.graphql |  24 ++
 ...ariables_in_fragments_not_defined.expected |   5 +
 ...variables_in_fragments_not_defined.graphql |  20 ++
 .../multiple_variables_not_defined.expected   |   5 +
 .../multiple_variables_not_defined.graphql    |   5 +
 .../multiple_variables_not_used.expected      |   5 +
 .../multiple_variables_not_used.graphql       |   5 +
 ...e_variables_not_used_in_fragments.expected |   5 +
 ...le_variables_not_used_in_fragments.graphql |  20 ++
 .../no_unused_variable.expected               |   2 +
 .../no_unused_variable.graphql                |   5 +
 .../schema.graphqls                           |   8 +
 ...ot_defined_by_multiple_operations.expected |   5 +
 ...not_defined_by_multiple_operations.graphql |  15 ++
 ...d_fragment_variables_are_reported.expected |   2 +
 ...ed_fragment_variables_are_reported.graphql |  12 +
 .../uses_all_variables_deeply.expected}       |   0
 .../uses_all_variables_deeply.graphql         |   9 +
 ...ables_deeply_in_inline_fragments.expected} |   0
 ...riables_deeply_in_inline_fragments.graphql |  13 ++
 .../uses_all_variables_in_fragments.expected} |   0
 .../uses_all_variables_in_fragments.graphql   |  20 ++
 ...fragment_not_defined_by_operation.expected |   2 +
 ..._fragment_not_defined_by_operation.graphql |  20 ++
 ...ment_not_defined_by_unnamed_query.expected |   5 +
 ...gment_not_defined_by_unnamed_query.graphql |  10 +
 ..._fragment_used_by_other_operation.expected |  11 +
 ...n_fragment_used_by_other_operation.graphql |  20 ++
 .../variable_not_defined.expected             |   2 +
 .../variable_not_defined.graphql              |   5 +
 ...le_not_defined_by_anonymous_query.expected |   5 +
 ...ble_not_defined_by_anonymous_query.graphql |   5 +
 .../variable_not_used.expected                |   5 +
 .../variable_not_used.graphql                 |   5 +
 ..._fragment_used_by_other_operation.expected |  11 +
 ...y_fragment_used_by_other_operation.graphql |  20 ++
 ...not_used_by_unreferenced_fragment.expected |   8 +
 ..._not_used_by_unreferenced_fragment.graphql |  15 ++
 .../variable_not_used_in_fragments.expected   |   2 +
 .../variable_not_used_in_fragments.graphql    |  20 ++
 ..._fragment_in_multiple_operations.expected} |   0
 ...by_fragment_in_multiple_operations.graphql |  20 ++
 ...riable_used_by_recursive_fragment.expected |   2 +
 ...ariable_used_by_recursive_fragment.graphql |  10 +
 ...ot_defined_by_multiple_operations.expected |   5 +
 ...not_defined_by_multiple_operations.graphql |  15 ++
 ...nts_are_still_undefined_variables.expected |   5 +
 ...ents_are_still_undefined_variables.graphql |  15 ++
 ...uments_may_be_undefined_variables.expected |   5 +
 ...guments_may_be_undefined_variables.graphql |  12 +
 ...fragments_without_type_condition.expected} |   0
 ...e_fragments_without_type_condition.graphql |   0
 ...non_conflicting_overlapping_types.expected |   0
 ..._non_conflicting_overlapping_types.graphql |   0
 ...ompares_deep_types_including_list.expected |   0
 ...compares_deep_types_including_list.graphql |   0
 ..._shapes_on_different_return_types.expected |   0
 ...n_shapes_on_different_return_types.graphql |   0
 ...n_types_which_potentially_overlap.expected |   0
 ...rn_types_which_potentially_overlap.graphql |   0
 ...p_return_types_despite_no_overlap.expected |   0
 ...ep_return_types_despite_no_overlap.graphql |   0
 ...rn_type_list_despite_no_overlap_1.expected |   0
 ...urn_type_list_despite_no_overlap_1.graphql |   0
 ...rn_type_list_despite_no_overlap_2.expected |   0
 ...urn_type_list_despite_no_overlap_2.graphql |   0
 ...pe_nullability_despite_no_overlap.expected |   0
 ...ype_nullability_despite_no_overlap.graphql |   0
 ...g_return_types_despite_no_overlap.expected |   0
 ...ng_return_types_despite_no_overlap.graphql |   0
 .../disallows_differing_subfields.expected    |   0
 .../disallows_differing_subfields.graphql     |   0
 .../ignores_unknown_types.expected            |   0
 .../ignores_unknown_types.graphql             |   0
 ...on_exclusive_follows_an_exclusive.expected |   0
 ...non_exclusive_follows_an_exclusive.graphql |   0
 .../same_wrapped_scalar_return_types.expected |   0
 .../same_wrapped_scalar_return_types.graphql  |   0
 .../same_response_shape}/schema.graphqls      |   0
 ...alias_masking_direct_field_access.expected |   0
 .../alias_masking_direct_field_access.graphql |   0
 ...rgs_where_no_conflict_is_possible.expected |   0
 ...args_where_no_conflict_is_possible.graphql |   0
 ..._fragment_without_arg_is_reported.expected |   5 +
 ...o_fragment_without_arg_is_reported.graphql |  10 +
 .../schema1/conflicting_arg_names.expected    |   0
 .../schema1/conflicting_arg_names.graphql     |   0
 .../schema1/conflicting_arg_values.expected   |   0
 .../schema1/conflicting_arg_values.graphql    |   0
 .../graphql-js/schema1/deep_conflict.expected |   0
 .../graphql-js/schema1/deep_conflict.graphql  |   0
 ...eep_conflict_with_multiple_issues.expected |   0
 ...deep_conflict_with_multiple_issues.graphql |   0
 ...rent_args_second_adds_an_argument.expected |   0
 ...erent_args_second_adds_an_argument.graphql |   0
 ...t_args_second_missing_an_argument.expected |   0
 ...nt_args_second_missing_an_argument.graphql |   0
 ...erent_args_with_different_aliases.expected |   0
 ...ferent_args_with_different_aliases.graphql |   0
 ...directives_with_different_aliases.expected |   0
 ..._directives_with_different_aliases.graphql |   0
 ..._skip_include_directives_accepted.expected |   0
 ...t_skip_include_directives_accepted.graphql |   0
 ...on_immediately_recursive_fragment.expected |   0
 ..._on_immediately_recursive_fragment.graphql |   0
 ...finite_loop_on_recursive_fragment.expected |   0
 ...nfinite_loop_on_recursive_fragment.graphql |   0
 ...with_a_field_named_after_fragment.expected |   0
 ..._with_a_field_named_after_fragment.graphql |   0
 ...ive_fragments_separated_by_fields.expected |   0
 ...sive_fragments_separated_by_fields.graphql |   0
 ...n_transitively_recursive_fragment.expected |   0
 ...on_transitively_recursive_fragment.graphql |   0
 .../encounters_conflict_in_fragments.expected |   0
 .../encounters_conflict_in_fragments.graphql  |   0
 ...s_conflict_in_fragments_with_args.expected |   8 +
 ...rs_conflict_in_fragments_with_args.graphql |   9 +
 ...th_immediately_recursive_fragment.expected |   0
 ...ith_immediately_recursive_fragment.graphql |   0
 ...n_with_field_named_after_fragment.expected |   0
 ...en_with_field_named_after_fragment.graphql |   0
 .../schema1/fragment_args_are_known.expected  |   2 +
 .../schema1/fragment_args_are_known.graphql   |  10 +
 .../schema1/identical_fields.expected         |   0
 .../schema1/identical_fields.graphql          |   0
 ...ntical_fields_with_identical_args.expected |   0
 ...entical_fields_with_identical_args.graphql |   0
 ..._fields_with_identical_directives.expected |   0
 ...l_fields_with_identical_directives.graphql |   0
 .../ignores_unknown_fragments.expected        |   0
 .../schema1/ignores_unknown_fragments.graphql |   0
 ...p_conflict_after_nested_fragments.expected |   0
 ...ep_conflict_after_nested_fragments.graphql |   0
 ...deep_conflict_in_nested_fragments.expected |   0
 ..._deep_conflict_in_nested_fragments.graphql |   0
 ...nflict_to_nearest_common_ancestor.expected |   0
 ...onflict_to_nearest_common_ancestor.graphql |   0
 ...rest_common_ancestor_in_fragments.expected |   0
 ...arest_common_ancestor_in_fragments.graphql |   0
 .../reports_each_conflict_once.expected       |   0
 .../reports_each_conflict_once.graphql        |   0
 ...allowed_on_non_overlapping_fields.expected |   0
 ..._allowed_on_non_overlapping_fields.graphql |   0
 ...ases_with_different_field_targets.expected |   0
 ...iases_with_different_field_targets.graphql |   0
 .../graphql-js/schema1/schema.graphqls        |   1 +
 .../graphql-js/schema1/unique_fields.expected |   0
 .../graphql-js/schema1/unique_fields.graphql  |   0
 .../unknown_args_amongst_known_args.expected  |   8 +
 .../unknown_args_amongst_known_args.graphql   |   7 +
 .../schema1/very_deep_conflict.expected       |   0
 .../schema1/very_deep_conflict.graphql        |   0
 .../mandatory_argument.expected               |   2 +-
 .../apollo-compiler/api/apollo-compiler.api   |   7 +-
 .../apollo/compiler/ApolloCompiler.kt         |   6 +-
 .../apollographql/apollo/compiler/Options.kt  |   6 +-
 .../apollo/compiler/ir/IrOperationsBuilder.kt |   2 +-
 .../apollo-execution/api/apollo-execution.api |   1 +
 .../api/apollo-execution.klib.api             |   1 +
 .../apollo/execution/ExecutableSchema.kt      |  16 +-
 .../execution/internal/OperationContext.kt    | 210 ++++++++++--------
 .../internal/coerceArgumentValues.kt          |  71 +++++-
 .../apollo/execution/internal/prepare.kt      |  15 +-
 .../kotlin/test/ExecutionTest.kt              | 132 ++++++++++-
 .../api/apollo-gradle-plugin-tasks.api        |   4 +-
 .../gradle/task/apolloGenerateOptions.kt      |   2 +
 .../api/apollo-gradle-plugin.api              |   3 +-
 .../apollo/gradle/api/Service.kt              |   7 +
 .../gradle/internal/DefaultApolloExtension.kt |   1 +
 tests/fragment-arguments/build.gradle.kts     |  24 ++
 .../src/main/graphql/operations.graphql       |   7 +
 .../src/main/graphql/schema.graphqls          |   3 +
 .../test/kotlin/test/FragmentArgumentsTest.kt |  39 ++++
 tests/settings.gradle.kts                     |   1 +
 235 files changed, 1647 insertions(+), 203 deletions(-)
 create mode 100644 libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/parser/fragment-arguments.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/parser/fragment-arguments.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.expected => fragment_arguments/default_value.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/different_args_with_different_aliases.expected => fragment_arguments/operation_variable_passthrough.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/schema.graphqls
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/different_directives_with_different_aliases.expected => fragment_arguments/valid_usage.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/different_skip_include_directives_accepted.expected => fragment_arguments/variable_scoping.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge => }/graphql-js/LICENSE (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge => }/graphql-js/README.md (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema2 => graphql-js/field_merging_order}/allows_different_order_of_args.expected (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema2 => graphql-js/field_merging_order}/allows_different_order_of_args.graphql (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema2 => graphql-js/field_merging_order}/schema.graphqls (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema3 => graphql-js/input_field_order}/allows_different_order_of_input_object_fields_in_arg_values.expected (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema3 => graphql-js/input_field_order}/allows_different_order_of_input_object_fields_in_arg_values.graphql (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema3 => graphql-js/input_field_order}/schema.graphqls (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema5 => graphql-js/keywords}/schema.graphqls (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema5 => graphql-js/keywords}/works_for_field_names_that_are_js_keywords.expected (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema5 => graphql-js/keywords}/works_for_field_names_that_are_js_keywords.graphql (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/schema.graphqls
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/identical_fields.expected => graphql-js/known_directive/with_no_directive.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_args.expected => graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_directives.expected => graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_variables.expected} (100%)
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.expected => graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/schema.graphqls
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.graphql
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema1/unique_fields.expected => graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.expected} (100%)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.graphql
 rename libraries/apollo-ast/test-fixtures/validation/executable/{fields_in_set_can_merge/graphql-js/schema4/allows_inline_fragments_without_type_condition.expected => graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.expected} (100%)
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diff --git a/libraries/apollo-ast/api/apollo-ast.api b/libraries/apollo-ast/api/apollo-ast.api
index fd83f840ad9..64e939c7af9 100644
--- a/libraries/apollo-ast/api/apollo-ast.api
+++ b/libraries/apollo-ast/api/apollo-ast.api
@@ -432,8 +432,12 @@ public final class com/apollographql/apollo/ast/GQLFloatValue : com/apollographq
 public final class com/apollographql/apollo/ast/GQLFragmentDefinition : com/apollographql/apollo/ast/GQLDescribed, com/apollographql/apollo/ast/GQLExecutableDefinition, com/apollographql/apollo/ast/GQLHasDirectives, com/apollographql/apollo/ast/GQLNamed {
 	public fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;)V
 	public synthetic fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;)V
+	public synthetic fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;)Lcom/apollographql/apollo/ast/GQLFragmentDefinition;
+	public final fun copy (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;)Lcom/apollographql/apollo/ast/GQLFragmentDefinition;
 	public static synthetic fun copy$default (Lcom/apollographql/apollo/ast/GQLFragmentDefinition;Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;ILjava/lang/Object;)Lcom/apollographql/apollo/ast/GQLFragmentDefinition;
+	public static synthetic fun copy$default (Lcom/apollographql/apollo/ast/GQLFragmentDefinition;Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lcom/apollographql/apollo/ast/GQLNamedType;Ljava/util/List;Ljava/lang/String;ILjava/lang/Object;)Lcom/apollographql/apollo/ast/GQLFragmentDefinition;
 	public fun copyWithNewChildrenInternal (Lcom/apollographql/apollo/ast/NodeContainer;)Lcom/apollographql/apollo/ast/GQLNode;
 	public fun getChildren ()Ljava/util/List;
 	public fun getDescription ()Ljava/lang/String;
@@ -443,15 +447,21 @@ public final class com/apollographql/apollo/ast/GQLFragmentDefinition : com/apol
 	public final fun getSelections ()Ljava/util/List;
 	public fun getSourceLocation ()Lcom/apollographql/apollo/ast/SourceLocation;
 	public final fun getTypeCondition ()Lcom/apollographql/apollo/ast/GQLNamedType;
+	public final fun getVariableDefinitions ()Ljava/util/List;
 	public fun writeInternal (Lcom/apollographql/apollo/ast/SDLWriter;)V
 }
 
 public final class com/apollographql/apollo/ast/GQLFragmentSpread : com/apollographql/apollo/ast/GQLSelection, com/apollographql/apollo/ast/GQLHasDirectives, com/apollographql/apollo/ast/GQLNamed {
 	public fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;)V
 	public synthetic fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;)V
+	public synthetic fun <init> (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;)Lcom/apollographql/apollo/ast/GQLFragmentSpread;
+	public final fun copy (Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;)Lcom/apollographql/apollo/ast/GQLFragmentSpread;
 	public static synthetic fun copy$default (Lcom/apollographql/apollo/ast/GQLFragmentSpread;Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;ILjava/lang/Object;)Lcom/apollographql/apollo/ast/GQLFragmentSpread;
+	public static synthetic fun copy$default (Lcom/apollographql/apollo/ast/GQLFragmentSpread;Lcom/apollographql/apollo/ast/SourceLocation;Ljava/lang/String;Ljava/util/List;Ljava/util/List;ILjava/lang/Object;)Lcom/apollographql/apollo/ast/GQLFragmentSpread;
 	public fun copyWithNewChildrenInternal (Lcom/apollographql/apollo/ast/NodeContainer;)Lcom/apollographql/apollo/ast/GQLNode;
+	public final fun getArguments ()Ljava/util/List;
 	public fun getChildren ()Ljava/util/List;
 	public fun getDirectives ()Ljava/util/List;
 	public fun getName ()Ljava/lang/String;
@@ -1134,9 +1144,10 @@ public final class com/apollographql/apollo/ast/OtherValidationIssue : com/apoll
 
 public final class com/apollographql/apollo/ast/ParserOptions {
 	public static final field Companion Lcom/apollographql/apollo/ast/ParserOptions$Companion;
-	public synthetic fun <init> (ZZZZLkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (ZZZZZLkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun getAllowDirectivesOnDirectives ()Z
 	public final fun getAllowEmptyDocuments ()Z
+	public final fun getAllowFragmentArguments ()Z
 	public final fun getAllowServiceCapabilities ()Z
 	public final fun getWithSourceLocation ()Z
 }
@@ -1145,14 +1156,17 @@ public final class com/apollographql/apollo/ast/ParserOptions$Builder {
 	public fun <init> ()V
 	public final fun allowDirectivesOnDirectives (Z)Lcom/apollographql/apollo/ast/ParserOptions$Builder;
 	public final fun allowEmptyDocuments (Z)Lcom/apollographql/apollo/ast/ParserOptions$Builder;
+	public final fun allowFragmentArguments (Z)Lcom/apollographql/apollo/ast/ParserOptions$Builder;
 	public final fun allowServiceCapabilities (Z)Lcom/apollographql/apollo/ast/ParserOptions$Builder;
 	public final fun build ()Lcom/apollographql/apollo/ast/ParserOptions;
 	public final fun getAllowDirectivesOnDirectives ()Z
 	public final fun getAllowEmptyDocuments ()Z
+	public final fun getAllowFragmentArguments ()Z
 	public final fun getAllowServiceCapabilities ()Z
 	public final fun getWithSourceLocation ()Z
 	public final fun setAllowDirectivesOnDirectives (Z)V
 	public final fun setAllowEmptyDocuments (Z)V
+	public final fun setAllowFragmentArguments (Z)V
 	public final fun setAllowServiceCapabilities (Z)V
 	public final fun setWithSourceLocation (Z)V
 	public final fun withSourceLocation (Z)Lcom/apollographql/apollo/ast/ParserOptions$Builder;
diff --git a/libraries/apollo-ast/api/apollo-ast.klib.api b/libraries/apollo-ast/api/apollo-ast.klib.api
index 6ad360e3171..52d0a8a074d 100644
--- a/libraries/apollo-ast/api/apollo-ast.klib.api
+++ b/libraries/apollo-ast/api/apollo-ast.klib.api
@@ -588,6 +588,7 @@ final class com.apollographql.apollo.ast/GQLFloatValue : com.apollographql.apoll
 
 final class com.apollographql.apollo.ast/GQLFragmentDefinition : com.apollographql.apollo.ast/GQLDescribed, com.apollographql.apollo.ast/GQLExecutableDefinition, com.apollographql.apollo.ast/GQLHasDirectives, com.apollographql.apollo.ast/GQLNamed { // com.apollographql.apollo.ast/GQLFragmentDefinition|null[0]
     constructor <init>(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String, kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective>, com.apollographql.apollo.ast/GQLNamedType, kotlin.collections/List<com.apollographql.apollo.ast/GQLSelection>, kotlin/String?) // com.apollographql.apollo.ast/GQLFragmentDefinition.<init>|<init>(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>;com.apollographql.apollo.ast.GQLNamedType;kotlin.collections.List<com.apollographql.apollo.ast.GQLSelection>;kotlin.String?){}[0]
+    constructor <init>(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String, kotlin.collections/List<com.apollographql.apollo.ast/GQLVariableDefinition>, kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective>, com.apollographql.apollo.ast/GQLNamedType, kotlin.collections/List<com.apollographql.apollo.ast/GQLSelection>, kotlin/String?) // com.apollographql.apollo.ast/GQLFragmentDefinition.<init>|<init>(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLVariableDefinition>;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>;com.apollographql.apollo.ast.GQLNamedType;kotlin.collections.List<com.apollographql.apollo.ast.GQLSelection>;kotlin.String?){}[0]
 
     final val children // com.apollographql.apollo.ast/GQLFragmentDefinition.children|{}children[0]
         final fun <get-children>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLNode> // com.apollographql.apollo.ast/GQLFragmentDefinition.children.<get-children>|<get-children>(){}[0]
@@ -605,17 +606,23 @@ final class com.apollographql.apollo.ast/GQLFragmentDefinition : com.apollograph
         final fun <get-sourceLocation>(): com.apollographql.apollo.ast/SourceLocation? // com.apollographql.apollo.ast/GQLFragmentDefinition.sourceLocation.<get-sourceLocation>|<get-sourceLocation>(){}[0]
     final val typeCondition // com.apollographql.apollo.ast/GQLFragmentDefinition.typeCondition|{}typeCondition[0]
         final fun <get-typeCondition>(): com.apollographql.apollo.ast/GQLNamedType // com.apollographql.apollo.ast/GQLFragmentDefinition.typeCondition.<get-typeCondition>|<get-typeCondition>(){}[0]
+    final val variableDefinitions // com.apollographql.apollo.ast/GQLFragmentDefinition.variableDefinitions|{}variableDefinitions[0]
+        final fun <get-variableDefinitions>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLVariableDefinition> // com.apollographql.apollo.ast/GQLFragmentDefinition.variableDefinitions.<get-variableDefinitions>|<get-variableDefinitions>(){}[0]
 
     final fun copy(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> = ..., com.apollographql.apollo.ast/GQLNamedType = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLSelection> = ..., kotlin/String? = ...): com.apollographql.apollo.ast/GQLFragmentDefinition // com.apollographql.apollo.ast/GQLFragmentDefinition.copy|copy(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>;com.apollographql.apollo.ast.GQLNamedType;kotlin.collections.List<com.apollographql.apollo.ast.GQLSelection>;kotlin.String?){}[0]
+    final fun copy(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLVariableDefinition> = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> = ..., com.apollographql.apollo.ast/GQLNamedType = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLSelection> = ..., kotlin/String? = ...): com.apollographql.apollo.ast/GQLFragmentDefinition // com.apollographql.apollo.ast/GQLFragmentDefinition.copy|copy(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLVariableDefinition>;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>;com.apollographql.apollo.ast.GQLNamedType;kotlin.collections.List<com.apollographql.apollo.ast.GQLSelection>;kotlin.String?){}[0]
     final fun copyWithNewChildrenInternal(com.apollographql.apollo.ast/NodeContainer): com.apollographql.apollo.ast/GQLNode // com.apollographql.apollo.ast/GQLFragmentDefinition.copyWithNewChildrenInternal|copyWithNewChildrenInternal(com.apollographql.apollo.ast.NodeContainer){}[0]
     final fun writeInternal(com.apollographql.apollo.ast/SDLWriter) // com.apollographql.apollo.ast/GQLFragmentDefinition.writeInternal|writeInternal(com.apollographql.apollo.ast.SDLWriter){}[0]
 }
 
 final class com.apollographql.apollo.ast/GQLFragmentSpread : com.apollographql.apollo.ast/GQLHasDirectives, com.apollographql.apollo.ast/GQLNamed, com.apollographql.apollo.ast/GQLSelection { // com.apollographql.apollo.ast/GQLFragmentSpread|null[0]
+    constructor <init>(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String, kotlin.collections/List<com.apollographql.apollo.ast/GQLArgument>, kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective>) // com.apollographql.apollo.ast/GQLFragmentSpread.<init>|<init>(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLArgument>;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>){}[0]
     constructor <init>(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String, kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective>) // com.apollographql.apollo.ast/GQLFragmentSpread.<init>|<init>(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>){}[0]
 
+    final val arguments // com.apollographql.apollo.ast/GQLFragmentSpread.arguments|{}arguments[0]
+        final fun <get-arguments>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLArgument> // com.apollographql.apollo.ast/GQLFragmentSpread.arguments.<get-arguments>|<get-arguments>(){}[0]
     final val children // com.apollographql.apollo.ast/GQLFragmentSpread.children|{}children[0]
-        final fun <get-children>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> // com.apollographql.apollo.ast/GQLFragmentSpread.children.<get-children>|<get-children>(){}[0]
+        final fun <get-children>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLNode> // com.apollographql.apollo.ast/GQLFragmentSpread.children.<get-children>|<get-children>(){}[0]
     final val directives // com.apollographql.apollo.ast/GQLFragmentSpread.directives|{}directives[0]
         final fun <get-directives>(): kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> // com.apollographql.apollo.ast/GQLFragmentSpread.directives.<get-directives>|<get-directives>(){}[0]
     final val name // com.apollographql.apollo.ast/GQLFragmentSpread.name|{}name[0]
@@ -623,6 +630,7 @@ final class com.apollographql.apollo.ast/GQLFragmentSpread : com.apollographql.a
     final val sourceLocation // com.apollographql.apollo.ast/GQLFragmentSpread.sourceLocation|{}sourceLocation[0]
         final fun <get-sourceLocation>(): com.apollographql.apollo.ast/SourceLocation? // com.apollographql.apollo.ast/GQLFragmentSpread.sourceLocation.<get-sourceLocation>|<get-sourceLocation>(){}[0]
 
+    final fun copy(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLArgument> = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> = ...): com.apollographql.apollo.ast/GQLFragmentSpread // com.apollographql.apollo.ast/GQLFragmentSpread.copy|copy(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLArgument>;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>){}[0]
     final fun copy(com.apollographql.apollo.ast/SourceLocation? = ..., kotlin/String = ..., kotlin.collections/List<com.apollographql.apollo.ast/GQLDirective> = ...): com.apollographql.apollo.ast/GQLFragmentSpread // com.apollographql.apollo.ast/GQLFragmentSpread.copy|copy(com.apollographql.apollo.ast.SourceLocation?;kotlin.String;kotlin.collections.List<com.apollographql.apollo.ast.GQLDirective>){}[0]
     final fun copyWithNewChildrenInternal(com.apollographql.apollo.ast/NodeContainer): com.apollographql.apollo.ast/GQLNode // com.apollographql.apollo.ast/GQLFragmentSpread.copyWithNewChildrenInternal|copyWithNewChildrenInternal(com.apollographql.apollo.ast.NodeContainer){}[0]
     final fun writeInternal(com.apollographql.apollo.ast/SDLWriter) // com.apollographql.apollo.ast/GQLFragmentSpread.writeInternal|writeInternal(com.apollographql.apollo.ast.SDLWriter){}[0]
@@ -1316,6 +1324,8 @@ final class com.apollographql.apollo.ast/ParserOptions { // com.apollographql.ap
         final fun <get-allowDirectivesOnDirectives>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.allowDirectivesOnDirectives.<get-allowDirectivesOnDirectives>|<get-allowDirectivesOnDirectives>(){}[0]
     final val allowEmptyDocuments // com.apollographql.apollo.ast/ParserOptions.allowEmptyDocuments|{}allowEmptyDocuments[0]
         final fun <get-allowEmptyDocuments>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.allowEmptyDocuments.<get-allowEmptyDocuments>|<get-allowEmptyDocuments>(){}[0]
+    final val allowFragmentArguments // com.apollographql.apollo.ast/ParserOptions.allowFragmentArguments|{}allowFragmentArguments[0]
+        final fun <get-allowFragmentArguments>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.allowFragmentArguments.<get-allowFragmentArguments>|<get-allowFragmentArguments>(){}[0]
     final val allowServiceCapabilities // com.apollographql.apollo.ast/ParserOptions.allowServiceCapabilities|{}allowServiceCapabilities[0]
         final fun <get-allowServiceCapabilities>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.allowServiceCapabilities.<get-allowServiceCapabilities>|<get-allowServiceCapabilities>(){}[0]
     final val withSourceLocation // com.apollographql.apollo.ast/ParserOptions.withSourceLocation|{}withSourceLocation[0]
@@ -1330,6 +1340,9 @@ final class com.apollographql.apollo.ast/ParserOptions { // com.apollographql.ap
         final var allowEmptyDocuments // com.apollographql.apollo.ast/ParserOptions.Builder.allowEmptyDocuments|{}allowEmptyDocuments[0]
             final fun <get-allowEmptyDocuments>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.Builder.allowEmptyDocuments.<get-allowEmptyDocuments>|<get-allowEmptyDocuments>(){}[0]
             final fun <set-allowEmptyDocuments>(kotlin/Boolean) // com.apollographql.apollo.ast/ParserOptions.Builder.allowEmptyDocuments.<set-allowEmptyDocuments>|<set-allowEmptyDocuments>(kotlin.Boolean){}[0]
+        final var allowFragmentArguments // com.apollographql.apollo.ast/ParserOptions.Builder.allowFragmentArguments|{}allowFragmentArguments[0]
+            final fun <get-allowFragmentArguments>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.Builder.allowFragmentArguments.<get-allowFragmentArguments>|<get-allowFragmentArguments>(){}[0]
+            final fun <set-allowFragmentArguments>(kotlin/Boolean) // com.apollographql.apollo.ast/ParserOptions.Builder.allowFragmentArguments.<set-allowFragmentArguments>|<set-allowFragmentArguments>(kotlin.Boolean){}[0]
         final var allowServiceCapabilities // com.apollographql.apollo.ast/ParserOptions.Builder.allowServiceCapabilities|{}allowServiceCapabilities[0]
             final fun <get-allowServiceCapabilities>(): kotlin/Boolean // com.apollographql.apollo.ast/ParserOptions.Builder.allowServiceCapabilities.<get-allowServiceCapabilities>|<get-allowServiceCapabilities>(){}[0]
             final fun <set-allowServiceCapabilities>(kotlin/Boolean) // com.apollographql.apollo.ast/ParserOptions.Builder.allowServiceCapabilities.<set-allowServiceCapabilities>|<set-allowServiceCapabilities>(kotlin.Boolean){}[0]
@@ -1339,6 +1352,7 @@ final class com.apollographql.apollo.ast/ParserOptions { // com.apollographql.ap
 
         final fun allowDirectivesOnDirectives(kotlin/Boolean): com.apollographql.apollo.ast/ParserOptions.Builder // com.apollographql.apollo.ast/ParserOptions.Builder.allowDirectivesOnDirectives|allowDirectivesOnDirectives(kotlin.Boolean){}[0]
         final fun allowEmptyDocuments(kotlin/Boolean): com.apollographql.apollo.ast/ParserOptions.Builder // com.apollographql.apollo.ast/ParserOptions.Builder.allowEmptyDocuments|allowEmptyDocuments(kotlin.Boolean){}[0]
+        final fun allowFragmentArguments(kotlin/Boolean): com.apollographql.apollo.ast/ParserOptions.Builder // com.apollographql.apollo.ast/ParserOptions.Builder.allowFragmentArguments|allowFragmentArguments(kotlin.Boolean){}[0]
         final fun allowServiceCapabilities(kotlin/Boolean): com.apollographql.apollo.ast/ParserOptions.Builder // com.apollographql.apollo.ast/ParserOptions.Builder.allowServiceCapabilities|allowServiceCapabilities(kotlin.Boolean){}[0]
         final fun build(): com.apollographql.apollo.ast/ParserOptions // com.apollographql.apollo.ast/ParserOptions.Builder.build|build(){}[0]
         final fun withSourceLocation(kotlin/Boolean): com.apollographql.apollo.ast/ParserOptions.Builder // com.apollographql.apollo.ast/ParserOptions.Builder.withSourceLocation|withSourceLocation(kotlin.Boolean){}[0]
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/Issue.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/Issue.kt
index 22ce805b580..5c933499524 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/Issue.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/Issue.kt
@@ -10,7 +10,7 @@ sealed interface Issue {
 }
 
 /**
- * An issue from the GraphQL spec
+ * An issue from the GraphQL spec, either a parsing error or a validation issue.
  */
 sealed interface GraphQLIssue : Issue
 
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
index 314497b25ad..5c75aa146e0 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
@@ -76,7 +76,8 @@ class ParserOptions private constructor(
     val allowEmptyDocuments: Boolean,
     val withSourceLocation: Boolean,
     val allowDirectivesOnDirectives: Boolean,
-    val allowServiceCapabilities: Boolean
+    val allowServiceCapabilities: Boolean,
+    val allowFragmentArguments: Boolean
 ) {
   class Builder {
     var allowEmptyDocuments = true
@@ -88,6 +89,9 @@ class ParserOptions private constructor(
     @ApolloExperimental
     var allowServiceCapabilities = false
 
+    @ApolloExperimental
+    var allowFragmentArguments = false
+
     fun allowEmptyDocuments(allowEmptyDocuments: Boolean) = apply {
       this.allowEmptyDocuments = allowEmptyDocuments
     }
@@ -106,12 +110,18 @@ class ParserOptions private constructor(
       this.allowDirectivesOnDirectives = allowDirectivesOnDirectives
     }
 
+    @ApolloExperimental
+    fun allowFragmentArguments(allowFragmentArguments: Boolean) = apply {
+      this.allowFragmentArguments = allowFragmentArguments
+    }
+
     fun build(): ParserOptions {
       return ParserOptions(
           allowEmptyDocuments = allowEmptyDocuments,
           withSourceLocation = withSourceLocation,
           allowDirectivesOnDirectives = allowDirectivesOnDirectives,
-          allowServiceCapabilities = allowServiceCapabilities
+          allowServiceCapabilities = allowServiceCapabilities,
+          allowFragmentArguments = allowFragmentArguments
       )
     }
   }
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
index 737f9cf9ed1..c3b0ddaae41 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
@@ -230,14 +230,33 @@ class GQLOperationDefinition(
   }
 }
 
-class GQLFragmentDefinition(
+class GQLFragmentDefinition @ApolloExperimental constructor(
     override val sourceLocation: SourceLocation? = null,
     override val name: String,
+    val variableDefinitions: List<GQLVariableDefinition>,
     override val directives: List<GQLDirective>,
     val typeCondition: GQLNamedType,
     val selections: List<GQLSelection>,
-    override val description: String?, // spec extension
+    override val description: String?,
 ) : GQLExecutableDefinition, GQLNamed, GQLDescribed, GQLHasDirectives {
+
+  constructor(
+      sourceLocation: SourceLocation? = null,
+      name: String,
+      directives: List<GQLDirective>,
+      typeCondition: GQLNamedType,
+      selections: List<GQLSelection>,
+      description: String?,
+  ) : this(
+      sourceLocation = sourceLocation,
+      name = name,
+      variableDefinitions = emptyList(),
+      directives = directives,
+      typeCondition = typeCondition,
+      selections = selections,
+      description = description
+  )
+
   @Suppress("DEPRECATION_ERROR")
   @Deprecated("Use selections directly", level = DeprecationLevel.ERROR)
   @ApolloDeprecatedSince(ApolloDeprecatedSince.Version.v4_0_0)
@@ -249,11 +268,15 @@ class GQLFragmentDefinition(
       )
     }
 
-  override val children = directives + selections + typeCondition
+  override val children = variableDefinitions + directives + selections + typeCondition
 
   override fun writeInternal(writer: SDLWriter) {
     with(writer) {
-      write("fragment $name on ${typeCondition.name}")
+      write("fragment $name")
+      if (variableDefinitions.isNotEmpty()) {
+        variableDefinitions.join(writer = writer, separator = ", ", prefix = "(", postfix = ")")
+      }
+      write(" on ${typeCondition.name}")
       if (directives.isNotEmpty()) {
         write(" ")
         directives.join(writer)
@@ -265,9 +288,11 @@ class GQLFragmentDefinition(
     }
   }
 
+  @ApolloExperimental
   fun copy(
       sourceLocation: SourceLocation? = this.sourceLocation,
       name: String = this.name,
+      variableDefinitions: List<GQLVariableDefinition> = this.variableDefinitions,
       directives: List<GQLDirective> = this.directives,
       typeCondition: GQLNamedType = this.typeCondition,
       selections: List<GQLSelection> = this.selections,
@@ -276,6 +301,26 @@ class GQLFragmentDefinition(
     return GQLFragmentDefinition(
         sourceLocation = sourceLocation,
         name = name,
+        variableDefinitions = variableDefinitions,
+        directives = directives,
+        typeCondition = typeCondition,
+        selections = selections,
+        description = description,
+    )
+  }
+
+  fun copy(
+      sourceLocation: SourceLocation? = this.sourceLocation,
+      name: String = this.name,
+      directives: List<GQLDirective> = this.directives,
+      typeCondition: GQLNamedType = this.typeCondition,
+      selections: List<GQLSelection> = this.selections,
+      description: String? = this.description,
+  ): GQLFragmentDefinition {
+    return copy(
+        sourceLocation = sourceLocation,
+        name = name,
+        variableDefinitions = variableDefinitions,
         directives = directives,
         typeCondition = typeCondition,
         selections = selections,
@@ -286,6 +331,7 @@ class GQLFragmentDefinition(
   override fun copyWithNewChildrenInternal(container: NodeContainer): GQLNode {
     return copy(
         directives = container.take(),
+        variableDefinitions = container.take(),
         typeCondition = container.take<GQLNamedType>().single(),
         selections = container.take(),
     )
@@ -1440,8 +1486,14 @@ class GQLInputValueDefinition(
 }
 
 /**
- * A variable definition is very similar to an InputValue definition except it doesn't
- * have a description
+ * A variable definition is very similar to a [GQLInputValueDefinition].
+ * They are different grammar rules because [GQLVariableDefinition] didn't support descriptions early on.
+ * Also input values have a `name` and variables have a `$name`.
+ *
+ * We could probably merge them.
+ *
+ * See https://github.com/graphql/graphql-spec/pull/1170 for the PR that adds description to the variable
+ * definitions
  */
 class GQLVariableDefinition(
     override val sourceLocation: SourceLocation? = null,
@@ -1873,17 +1925,33 @@ class GQLInlineFragment(
   }
 }
 
-class GQLFragmentSpread(
+class GQLFragmentSpread @ApolloExperimental constructor(
     override val sourceLocation: SourceLocation? = null,
     override val name: String,
+    @ApolloExperimental
+    val arguments: List<GQLArgument>,
     override val directives: List<GQLDirective>,
 ) : GQLSelection(), GQLNamed, GQLHasDirectives {
 
-  override val children = directives
+  constructor(
+      sourceLocation: SourceLocation? = null,
+      name: String,
+      directives: List<GQLDirective>,
+  ) : this(
+      sourceLocation = sourceLocation,
+      name = name,
+      arguments = emptyList(),
+      directives = directives
+  )
+
+  override val children: List<GQLNode> = arguments + directives
 
   override fun writeInternal(writer: SDLWriter) {
     with(writer) {
       write("...${name}")
+      if (arguments.isNotEmpty()) {
+        arguments.writeArguments(writer)
+      }
       if (directives.isNotEmpty()) {
         write(" ")
         directives.join(writer)
@@ -1892,19 +1960,38 @@ class GQLFragmentSpread(
     }
   }
 
+  @ApolloExperimental
   fun copy(
       sourceLocation: SourceLocation? = this.sourceLocation,
       name: String = this.name,
+      arguments: List<GQLArgument> = this.arguments,
       directives: List<GQLDirective> = this.directives,
-  ) = GQLFragmentSpread(
-      sourceLocation = sourceLocation,
-      name = name,
-      directives = directives,
-  )
+  ): GQLFragmentSpread {
+    return GQLFragmentSpread(
+        sourceLocation = sourceLocation,
+        name = name,
+        arguments = arguments,
+        directives = directives,
+    )
+  }
+
+  fun copy(
+      sourceLocation: SourceLocation? = this.sourceLocation,
+      name: String = this.name,
+      directives: List<GQLDirective> = this.directives,
+  ): GQLFragmentSpread {
+    return copy(
+        sourceLocation = sourceLocation,
+        name = name,
+        arguments = arguments,
+        directives = directives,
+    )
+  }
 
   override fun copyWithNewChildrenInternal(container: NodeContainer): GQLNode {
     return copy(
-        directives = container.take()
+        arguments = container.take(),
+        directives = container.take(),
     )
   }
 }
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
index fa8d131b9a5..14d52d05c69 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
@@ -1,5 +1,6 @@
 package com.apollographql.apollo.ast.internal
 
+import com.apollographql.apollo.annotations.ApolloExperimental
 import com.apollographql.apollo.annotations.ApolloInternal
 import com.apollographql.apollo.ast.AnonymousOperation
 import com.apollographql.apollo.ast.DeprecatedUsage
@@ -16,6 +17,7 @@ import com.apollographql.apollo.ast.GQLFloatValue
 import com.apollographql.apollo.ast.GQLFragmentDefinition
 import com.apollographql.apollo.ast.GQLFragmentSpread
 import com.apollographql.apollo.ast.GQLInlineFragment
+import com.apollographql.apollo.ast.GQLInputValueDefinition
 import com.apollographql.apollo.ast.GQLIntValue
 import com.apollographql.apollo.ast.GQLListType
 import com.apollographql.apollo.ast.GQLListValue
@@ -30,6 +32,7 @@ import com.apollographql.apollo.ast.GQLStringValue
 import com.apollographql.apollo.ast.GQLType
 import com.apollographql.apollo.ast.GQLTypeDefinition
 import com.apollographql.apollo.ast.GQLValue
+import com.apollographql.apollo.ast.GQLVariableDefinition
 import com.apollographql.apollo.ast.GQLVariableValue
 import com.apollographql.apollo.ast.Issue
 import com.apollographql.apollo.ast.OtherValidationIssue
@@ -41,7 +44,9 @@ import com.apollographql.apollo.ast.definitionFromScope
 import com.apollographql.apollo.ast.findCatch
 import com.apollographql.apollo.ast.findDeprecationReason
 import com.apollographql.apollo.ast.getArgumentValueOrDefault
+import com.apollographql.apollo.ast.internal.pretty
 import com.apollographql.apollo.ast.internal.validation.validateDeferLabels
+import com.apollographql.apollo.ast.isInputType
 import com.apollographql.apollo.ast.pretty
 import com.apollographql.apollo.ast.rawType
 import com.apollographql.apollo.ast.responseName
@@ -49,7 +54,7 @@ import com.apollographql.apollo.ast.rootTypeDefinition
 import com.apollographql.apollo.ast.sharesPossibleTypesWith
 
 
-@OptIn(ApolloInternal::class)
+@OptIn(ApolloInternal::class, ApolloExperimental::class)
 internal class ExecutableValidationScope(
     private val schema: Schema,
 ) : ValidationScope {
@@ -64,7 +69,11 @@ internal class ExecutableValidationScope(
    */
   override val issues = mutableListOf<Issue>()
   private val fragmentDefinitions = mutableMapOf<String, GQLFragmentDefinition>()
-  private val fragmentVariableUsages = mutableMapOf<String, List<VariableUsage>>()
+
+  /**
+   * Contains the direct variable usages in the given fragment definition that are not defined by the fragment itself.
+   */
+  private val fragmentOperationVariableUsages = mutableMapOf<String, List<VariableUsage>>()
   private val cyclicFragments = mutableSetOf<String>()
   private val usedFragments = mutableSetOf<String>()
   private val hasCatchByDefault = schema.directiveDefinitions.any { schema.originalDirectiveName(it.key) == Schema.CATCH_BY_DEFAULT }
@@ -113,7 +122,11 @@ internal class ExecutableValidationScope(
             val index = path.indexOf("__${name}")
             val nextPath = path + "__${fragment.name}"
             if (index != -1) {
-              issues.add(FragmentCycle("Fragment '$name' spreads itself, creating a cycle at '${nextPath.subList(index, nextPath.size).joinToString(".")}'", it.sourceLocation))
+              issues.add(FragmentCycle("Fragment '$name' spreads itself, creating a cycle at '${
+                nextPath.subList(index, nextPath.size).joinToString(".")
+              }'", it.sourceLocation
+              )
+              )
               cyclicFragments.add(name)
               return@forEach
             }
@@ -143,6 +156,7 @@ internal class ExecutableValidationScope(
     val fragments = document.definitions.filterIsInstance<GQLFragmentDefinition>()
     fragments.checkDuplicateFragments()
     fragments.forEach {
+      // Needs to happen before validating the operations to set `fragmentVariableUsages`
       it.validate()
     }
 
@@ -163,7 +177,7 @@ internal class ExecutableValidationScope(
 
     val fragmentVariables = fragments.associate {
       it.name to (setOf(it.name) + it.selections.collectFragmentSpreads()).fold(emptyList<VariableUsage>()) { acc, item ->
-        acc + fragmentVariableUsages.get(item).orEmpty()
+        acc + fragmentOperationVariableUsages.get(item).orEmpty()
       }
     }
     return ExecutableValidationResult(fragmentVariables, issues)
@@ -204,7 +218,8 @@ internal class ExecutableValidationScope(
     }
 
     if (typeDefinition !is GQLScalarTypeDefinition
-        && typeDefinition !is GQLEnumTypeDefinition) {
+        && typeDefinition !is GQLEnumTypeDefinition
+    ) {
       if (selections.isEmpty()) {
         registerIssue(
             message = "Field `$name` of type `${fieldDefinition.type.pretty()}` must have a selection of sub-fields",
@@ -342,6 +357,24 @@ internal class ExecutableValidationScope(
       return
     }
 
+    validateArguments(
+        arguments,
+        sourceLocation,
+        fragmentDefinition.variableDefinitions.map {
+          GQLInputValueDefinition(
+              sourceLocation = it.sourceLocation,
+              description = it.description,
+              name = it.name,
+              directives = it.directives,
+              type = it.type,
+              defaultValue = it.defaultValue
+          )
+        },
+        debug = "fragment `$name`"
+    ) {
+      variableUsages.add(it)
+    }
+
     validateDirectives(directives, this) {
       variableUsages.add(it)
     }
@@ -371,12 +404,20 @@ internal class ExecutableValidationScope(
       return
     }
 
-    validateCommon(this, selections, directives, rootTypeDefinition)
+    validateCommon(this, selections, directives, variableDefinitions, rootTypeDefinition)
+
     if (schema.errorAware) {
       validateCatch(selections.collectFieldsNoFragments())
     }
 
-    fragmentVariableUsages[name] = variableUsages.toList()
+    val ownVariables = variableDefinitions.map { it.name }.toSet()
+    val (ownVariableUsages, operationVariableUsages) = variableUsages.partition { it.variable.name in ownVariables }
+    validateVariableUsages(variableDefinitions, ownVariableUsages, context = "fragment `$name`")
+
+    /**
+     * We only track the variables that are not by this fragment.
+     */
+    fragmentOperationVariableUsages[name] = operationVariableUsages
   }
 
   /**
@@ -387,6 +428,7 @@ internal class ExecutableValidationScope(
       directiveContext: GQLNode,
       selections: List<GQLSelection>,
       directives: List<GQLDirective>,
+      variableDefinitions: List<GQLVariableDefinition>,
       rootTypeDefinition: GQLTypeDefinition,
   ) {
     variableUsages.clear()
@@ -394,8 +436,36 @@ internal class ExecutableValidationScope(
     selections.validate(rootTypeDefinition)
 
     validateDirectives(directives, directiveContext) {
+      /**
+       * ```graphql
+       * query GetFoo($arg: Int!) @myDirective(arg: $arg) {
+       *   foo
+       * }
+       * ```
+       */
       variableUsages.add(it)
     }
+
+    variableDefinitions.forEach { varDef ->
+      if (!varDef.type.isInputType(typeDefinitions)) {
+        registerIssue(
+            message = "Variable `${varDef.name}` of type `${varDef.type.pretty()}` is not an input type",
+            sourceLocation = varDef.sourceLocation
+        )
+      }
+      if (varDef.defaultValue != null) {
+        validateAndCoerceValue(
+            value = varDef.defaultValue,
+            expectedType = varDef.type,
+            hasLocationDefaultValue = false,
+            isOneOfInputField = false
+        ) {
+          issues.add(it.constContextError())
+        }
+      }
+
+      validateDirectivesInConstContext(varDef.directives, varDef)
+    }
   }
 
   private fun GQLOperationDefinition.validate() {
@@ -408,7 +478,7 @@ internal class ExecutableValidationScope(
       )
       return
     }
-    validateCommon(this, selections, directives, rootTypeDefinition)
+    validateCommon(this, selections, directives, variableDefinitions, rootTypeDefinition)
 
     if (schema.errorAware) {
       validateCatch(selections.collectFieldsNoFragments())
@@ -423,36 +493,34 @@ internal class ExecutableValidationScope(
       it.key !in cyclicFragments
     })
 
+    validateDirectives(directives, this) {
+      variableUsages.add(it)
+    }
     issues.addAll(validateDeferLabels(this, rootTypeDefinition.name, schema, fragmentDefinitions))
 
-    val allVariableUsages = selections.collectFragmentSpreads().flatMap { fragmentVariableUsages.get(it) ?: emptyList() } + variableUsages
-    (allVariableUsages).forEach {
-      validateVariable(this, it)
+    val allVariableUsages = selections.collectFragmentSpreads().flatMap { fragmentOperationVariableUsages.get(it) ?: emptyList() } + variableUsages
+    validateVariableUsages(variableDefinitions, allVariableUsages, context = this.pretty())
+  }
+
+  private fun validateVariableUsages(variableDefinitions: List<GQLVariableDefinition>, variableUsages: List<VariableUsage>, context: String) {
+    variableUsages.forEach {
+      validateVariableUsage(
+          variableUsage = it,
+          variableDefinitions = variableDefinitions,
+          context = context,
+      )
     }
-    val foundVariables = allVariableUsages.map { it.variable.name }.toSet()
+    val foundVariables = variableUsages.map { it.variable.name }.toSet()
     variableDefinitions.forEach {
       if (!foundVariables.contains(it.name)) {
         issues.add(UnusedVariable(
-            message = "Variable `${it.name}` is unused",
+            message = "Variable `${it.name}` is unused in $context",
             sourceLocation = it.sourceLocation
-        ))
-      }
-    }
-    validateDirectives(directives, this) {
-      variableUsages.add(it)
-    }
-    variableDefinitions.forEach {
-      if (it.defaultValue != null) {
-        validateAndCoerceValue(
-            value = it.defaultValue,
-            expectedType = it.type,
-            hasLocationDefaultValue = false,
-            isOneOfInputField = false
-        ) {
-          issues.add(it.constContextError())
-        }
+        )
+        )
       }
     }
+
   }
 
   private fun List<GQLSelection>.collectFragmentSpreads(): Set<String> {
@@ -601,7 +669,8 @@ internal class ExecutableValidationScope(
         issues.add(OtherValidationIssue(
             message = "Fragment ${it.name} is already defined",
             sourceLocation = it.sourceLocation,
-        ))
+        )
+        )
       }
     }
     return issues
@@ -615,7 +684,8 @@ internal class ExecutableValidationScope(
         issues.add(AnonymousOperation(
             message = "Apollo does not support anonymous operations",
             sourceLocation = it.sourceLocation,
-        ))
+        )
+        )
         return@forEach
       }
       val existing = filtered.putIfAbsentMpp(it.name, it)
@@ -623,7 +693,8 @@ internal class ExecutableValidationScope(
         issues.add(OtherValidationIssue(
             message = "Operation ${it.name} is already defined",
             sourceLocation = it.sourceLocation,
-        ))
+        )
+        )
       }
     }
     return issues
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/Parser.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/Parser.kt
index 4fd8c0d57fc..50903abe1db 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/Parser.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/Parser.kt
@@ -15,6 +15,7 @@ internal class Parser(
   private val allowEmptyDocuments = options.allowEmptyDocuments
   private val allowDirectivesOnDirectives = options.allowDirectivesOnDirectives
   private val allowServiceCapabilities = options.allowServiceCapabilities
+  private val allowFragmentArguments = options.allowFragmentArguments
 
   fun parseDocument(): GQLDocument {
     val start = token
@@ -198,11 +199,18 @@ internal class Parser(
     val on = expectOptionalKeyword("on")
     return if (on == null && peek<Token.Name>()) {
       val name = parseFragmentName()
+      val arguments: List<GQLArgument>
+      if (allowFragmentArguments) {
+        arguments = parseArguments(false)
+      } else {
+        arguments = emptyList()
+      }
       val directives = parseDirectives(const = false)
       GQLFragmentSpread(
           sourceLocation = sourceLocation(start),
           name = name,
-          directives = directives
+          arguments = arguments,
+          directives = directives,
       )
     } else {
       val typeCondition = if (on != null) parseNamedType() else null
@@ -865,6 +873,11 @@ internal class Parser(
     val description = parseDescription()
     expectKeyword("fragment")
     val name = parseFragmentName()
+    val variableDefinitions = if (allowFragmentArguments) {
+      parseVariableDefinitions()
+    } else {
+      emptyList()
+    }
     expectKeyword("on")
     val typeCondition = parseNamedType()
     val directives = parseDirectives(const = false)
@@ -875,7 +888,8 @@ internal class Parser(
         name = name,
         typeCondition = typeCondition,
         directives = directives,
-        selections = selections
+        selections = selections,
+        variableDefinitions = variableDefinitions
     )
   }
 
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ValidationCommon.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ValidationCommon.kt
index 16ae06b6ff5..ccc0a3bb3d4 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ValidationCommon.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ValidationCommon.kt
@@ -345,7 +345,7 @@ internal fun ValidationScope.validateArguments(
         // This will be caught later when validating individual arguments
         // registerIssue((message = "Cannot pass `null` for a required argument", sourceLocation = argumentValue.sourceLocation))
       } else if (argumentValue == null) {
-        registerIssue(message = "No value passed for required argument '${inputValueDefinition.name}'", sourceLocation = sourceLocation)
+        registerIssue(message = "No value passed for required argument `${inputValueDefinition.name}` on $debug", sourceLocation = sourceLocation)
       }
     }
   }
@@ -355,20 +355,24 @@ internal fun ValidationScope.validateArguments(
   }
 }
 
-internal fun ValidationScope.validateVariable(
-    operation: GQLOperationDefinition?,
-    variableUsage: VariableUsage,
-) {
-  if (operation == null) {
-    // if operation is null, it means we're currently validating a fragment outside the context of an operation
-    return
+internal fun GQLOperationDefinition.pretty(): String {
+  return if (name == null) {
+    "anonymous operation"
+  } else {
+    "operation `${name}`"
   }
+}
 
+internal fun ValidationScope.validateVariableUsage(
+    variableUsage: VariableUsage,
+    variableDefinitions: List<GQLVariableDefinition>,
+    context: String,
+) {
   val variable = variableUsage.variable
-  val variableDefinition = operation.variableDefinitions.firstOrNull { it.name == variable.name }
+  val variableDefinition = variableDefinitions.firstOrNull { it.name == variable.name }
   if (variableDefinition == null) {
     registerIssue(
-        message = "Variable `${variable.name}` is not defined by operation `${operation.name}`",
+        message = "Variable `${variable.name}` is not defined by $context",
         sourceLocation = variable.sourceLocation
     )
     return
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
index dc62b80e160..30dd5a85a8f 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
@@ -1,5 +1,6 @@
 package com.apollographql.apollo.ast.internal
 
+import com.apollographql.apollo.annotations.ApolloExperimental
 import com.apollographql.apollo.ast.*
 
 /**
@@ -8,7 +9,7 @@ import com.apollographql.apollo.ast.*
  * There is no caching per-fieldset because it hides some otherwise useful diagnostics.
  *
  * See `reports_each_conflict_once` for an example. The caching only works when reusing fragment
- * spreads but because the fragments may be spread at different paths, having the full path for
+ * spreads, but because the fragments may be spread at different paths, having the full path for
  * each issue can be useful.
  */
 internal fun IssuesScope.fieldsInSetCanMerge(
@@ -30,8 +31,7 @@ internal fun IssuesScope.fieldsInSetCanMerge(
   }
 
   val fieldMap = mutableMapOf<String, MutableSet<FieldAndType>>()
-  val visitedFragmentSpreads = mutableSetOf<String>()
-  collectFields(fieldMap, operation.selections, rootType, visitedFragmentSpreads, context)
+  collectFields(fieldMap, operation.selections, rootType, context)
 
   sameResponseShapeByName(fieldMap, emptyList(), context)
   sameForCommonParentsByName(fieldMap, emptyList(), context)
@@ -61,11 +61,11 @@ private data class ValidationContext(
     val fragments: Map<String, GQLFragmentDefinition>,
 )
 
+@OptIn(ApolloExperimental::class)
 private fun collectFields(
     fieldMap: MutableMap<String, MutableSet<FieldAndType>>,
     selections: List<GQLSelection>,
     parentType: GQLTypeDefinition,
-    visitedFragmentSpreads: MutableSet<String>,
     context: ValidationContext,
 ) {
   for (selection in selections) {
@@ -90,17 +90,22 @@ private fun collectFields(
         }
         // See ignores_unknown_types test
         if (fragmentType != null) {
-          collectFields(fieldMap, selection.selections, fragmentType, visitedFragmentSpreads, context)
+          collectFields(fieldMap, selection.selections, fragmentType, context)
         }
       }
 
       is GQLFragmentSpread -> {
         val fragment = context.fragments[selection.name]
-        if (fragment != null && fragment.name !in visitedFragmentSpreads) {
-          visitedFragmentSpreads.add(fragment.name)
+        if (fragment != null) {
+          // Use name + arguments as key so same fragment with different arguments is collected twice
           val fragmentType = context.schema.typeDefinitions[fragment.typeCondition.name]
           if (fragmentType != null) {
-            collectFields(fieldMap, fragment.selections, fragmentType, visitedFragmentSpreads, context)
+            val selections = if (selection.arguments.isNotEmpty() && fragment.variableDefinitions.isNotEmpty()) {
+              substituteFragmentVariables(fragment.selections, fragment.variableDefinitions, selection.arguments)
+            } else {
+              fragment.selections
+            }
+            collectFields(fieldMap, selections, fragmentType, context)
           }
         }
       }
@@ -129,12 +134,10 @@ private fun mergeSubSelections(sameNameFields: Set<FieldAndType>, context: Valid
   val fieldMap = mutableMapOf<String, MutableSet<FieldAndType>>()
   for (fieldAndType in sameNameFields) {
     if (fieldAndType.field.selections.isNotEmpty() && fieldAndType.type != null) {
-      val visitedFragmentSpreads = mutableSetOf<String>()
-
       val unwrappedType = fieldAndType.type.rawType()
       val typeDefinition = context.schema.typeDefinitions[unwrappedType.name]
       if (typeDefinition != null) {
-        collectFields(fieldMap, fieldAndType.field.selections, typeDefinition, visitedFragmentSpreads, context)
+        collectFields(fieldMap, fieldAndType.field.selections, typeDefinition, context)
       }
     }
   }
@@ -329,4 +332,69 @@ private data class FieldAndType(
 private fun buildMessage(path: List<String>, message: String): String {
   return "Field at path `${path.joinToString(".")}` conflicts with another field: " +
       "$message. Use different aliases on the fields to fetch both if this was intentional."
+}
+
+/**
+ * Substitutes fragment variable references in selections with actual argument values.
+ * This ensures field merging compares resolved values when a fragment is spread with arguments.
+ */
+@OptIn(ApolloExperimental::class)
+private fun substituteFragmentVariables(
+    selections: List<GQLSelection>,
+    variableDefinitions: List<GQLVariableDefinition>,
+    arguments: List<GQLArgument>,
+): List<GQLSelection> {
+  val argMap = mutableMapOf<String, GQLValue>()
+  for (varDef in variableDefinitions) {
+    val arg = arguments.firstOrNull { it.name == varDef.name }
+    if (arg != null) {
+      argMap[varDef.name] = arg.value
+    } else if (varDef.defaultValue != null) {
+      argMap[varDef.name] = varDef.defaultValue
+    }
+  }
+  if (argMap.isEmpty()) return selections
+  return selections.map { it.substituteVariables(argMap) }
+}
+
+@OptIn(ApolloExperimental::class)
+private fun GQLSelection.substituteVariables(argMap: Map<String, GQLValue>): GQLSelection {
+  return when (this) {
+    is GQLField -> GQLField(
+        sourceLocation = sourceLocation,
+        alias = alias,
+        name = name,
+        arguments = arguments.map { arg ->
+          GQLArgument(
+              sourceLocation = arg.sourceLocation,
+              name = arg.name,
+              value = arg.value.substituteVariables(argMap)
+          )
+        },
+        directives = directives,
+        selections = selections.map { it.substituteVariables(argMap) }
+    )
+
+    is GQLInlineFragment -> GQLInlineFragment(
+        sourceLocation = sourceLocation,
+        typeCondition = typeCondition,
+        directives = directives,
+        selections = selections.map { it.substituteVariables(argMap) }
+    )
+
+    is GQLFragmentSpread -> this
+  }
+}
+
+private fun GQLValue.substituteVariables(argMap: Map<String, GQLValue>): GQLValue {
+  return when (this) {
+    is GQLVariableValue -> argMap[name] ?: this
+    is GQLListValue -> GQLListValue(sourceLocation = sourceLocation, values = values.map { it.substituteVariables(argMap) })
+    is GQLObjectValue -> GQLObjectValue(
+        sourceLocation = sourceLocation,
+        fields = fields.map { GQLObjectField(sourceLocation = it.sourceLocation, name = it.name, value = it.value.substituteVariables(argMap)) }
+    )
+
+    else -> this
+  }
 }
\ No newline at end of file
diff --git a/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/ExecutableValidationTest.kt b/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/ExecutableValidationTest.kt
index 93d738130fc..e5086708f11 100644
--- a/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/ExecutableValidationTest.kt
+++ b/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/ExecutableValidationTest.kt
@@ -21,7 +21,8 @@ class ExecutableValidationTest {
   @Test
   fun testValidation(@TestParameter(valuesProvider = ParametersProvider::class) graphQLFile: File) {
     findSchemaAndCheck(graphQLFile) { schema ->
-      val parseResult = graphQLFile.source().buffer().parseAsGQLDocument(graphQLFile.name)
+      val parserOptions = graphQLFile.pragmas().toParserOptions()
+      val parseResult = graphQLFile.source().buffer().parseAsGQLDocument(graphQLFile.name, parserOptions)
       val issues = if (parseResult.issues.isNotEmpty()) {
         parseResult.issues
       } else {
diff --git a/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/fixtures.kt b/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/fixtures.kt
index 764959cff30..96ce4090a6c 100644
--- a/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/fixtures.kt
+++ b/libraries/apollo-ast/src/jvmTest/kotlin/com/apollographql/apollo/graphql/ast/test/fixtures.kt
@@ -73,18 +73,17 @@ enum class Pragma {
   // Parser
   allowDirectivesOnDirectives,
   allowServiceCapabilities,
-
   // Merger
   allowMergingFieldDefinitions,
-
   // Schema validation
   addBuiltinForeignSchemas,
   addKotlinLabsDefinitions,
   addBuiltinDefinitions,
   noAddBuiltinDefinitions,
-
-  //
+  // Executable validation
   allowDirectiveRedefinition,
+  // Parser and validation
+  allowFragmentArguments,
 }
 
 fun File.pragmas(): List<Pragma> =
@@ -99,6 +98,9 @@ fun List<Pragma>.toParserOptions(): ParserOptions {
         if (Pragma.allowDirectivesOnDirectives in this@toParserOptions) {
           allowDirectivesOnDirectives(true)
         }
+        if (Pragma.allowFragmentArguments in this@toParserOptions) {
+          allowFragmentArguments(true)
+        }
       }
       .build()
 }
diff --git a/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.expected b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.expected
new file mode 100644
index 00000000000..ced9532d2f9
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.expected
@@ -0,0 +1,2 @@
+ParsingError (2:9)
+Expected Name, found '('.
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.graphql b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.graphql
new file mode 100644
index 00000000000..57cceb0bfd3
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments-error.graphql
@@ -0,0 +1,7 @@
+{
+  ...foo(a: 42, b: $b)
+}
+
+fragment foo on Query($a: Int, $b: [String]) {
+  __typename
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.expected b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.expected
new file mode 100644
index 00000000000..a378465c553
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.expected
@@ -0,0 +1,8 @@
+
+query {
+  ...foo(a: 42, b: $b)
+}
+
+fragment foo($a: Int, $b: [String]) on Query {
+  __typename
+}
diff --git a/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.graphql b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.graphql
new file mode 100644
index 00000000000..765d20ebbec
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/parser/fragment-arguments.graphql
@@ -0,0 +1,9 @@
+# PRAGMA allowFragmentArguments
+
+{
+  ...foo(a: 42, b: $b)
+}
+
+fragment foo($a: Int, $b: [String]) on Query {
+  __typename
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/UnusedVariable.expected b/libraries/apollo-ast/test-fixtures/validation/executable/UnusedVariable.expected
index a4b55dbce15..7611db3511d 100644
--- a/libraries/apollo-ast/test-fixtures/validation/executable/UnusedVariable.expected
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/UnusedVariable.expected
@@ -1,2 +1,2 @@
 UnusedVariable (2:16)
-Variable `condition` is unused
\ No newline at end of file
+Variable `condition` is unused in operation `HeroName`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.graphql
new file mode 100644
index 00000000000..100cbdb3114
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/default_value.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean! = true) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.expected
new file mode 100644
index 00000000000..6d6e3e87042
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.expected
@@ -0,0 +1,11 @@
+OtherValidationIssue (4:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (12:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (18:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (12:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.graphql
new file mode 100644
index 00000000000..04e8a1f35e4
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/merge_error.graphql
@@ -0,0 +1,31 @@
+# PRAGMA allowFragmentArguments
+
+query GetFoo {
+  users(first: 20) {
+    totalCount
+  }
+  # invalid: different literals
+  ...queryDetails(first: 10)
+}
+
+fragment queryDetails($first: Int!) on Query {
+  users(first: $first) {
+    totalCount
+  }
+}
+
+query GetFoo2($first: Int!) {
+  users(first: $first) {
+    totalCount
+  }
+  # invalid: different variables
+  ...queryDetails(first: 10)
+}
+
+query GetFoo3($first: Int!) {
+  users(first: $first) {
+    totalCount
+  }
+  # valid
+  ...queryDetails(first: $first)
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.expected
new file mode 100644
index 00000000000..0eee718c8b2
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.expected
@@ -0,0 +1,2 @@
+OtherValidationIssue (10:9)
+No value passed for required argument `includeEmail` on fragment `UserFields`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.graphql
new file mode 100644
index 00000000000..61a55704150
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/missing_required_argument.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_with_different_aliases.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_with_different_aliases.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.graphql
new file mode 100644
index 00000000000..cea4daff9cb
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/operation_variable_passthrough.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser($showEmail: Boolean!) {
+    user(id: "1") {
+        ...UserFields(includeEmail: $showEmail)
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/schema.graphqls
new file mode 100644
index 00000000000..affa654dc67
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/schema.graphqls
@@ -0,0 +1,29 @@
+# PRAGMA allowFragmentArguments
+
+type Query {
+    user(id: ID!): User
+    users(first: Int, after: String): UserConnection
+    node(id: ID!): Node
+}
+
+type User implements Node {
+    id: ID!
+    name: String
+    age: Int
+    email: String
+    friends(first: Int, after: String): UserConnection
+}
+
+type UserConnection {
+    edges: [UserEdge]
+    totalCount: Int
+}
+
+type UserEdge {
+    node: User
+    cursor: String
+}
+
+interface Node {
+    id: ID!
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.expected
new file mode 100644
index 00000000000..ce88e6ffcd1
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.expected
@@ -0,0 +1,2 @@
+OtherValidationIssue (10:37)
+Value `"not_a_boolean"` cannot be used in position expecting `Boolean`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.graphql
new file mode 100644
index 00000000000..a38c2ab1ba1
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/type_mismatch.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields(includeEmail: "not_a_boolean")
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.expected
new file mode 100644
index 00000000000..9f4217bedcd
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.expected
@@ -0,0 +1,2 @@
+OtherValidationIssue (10:43)
+Unknown argument `unknownArg` on fragment `UserFields`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.graphql
new file mode 100644
index 00000000000..ebf6bf136ea
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unknown_argument.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields(includeEmail: true, unknownArg: "foo")
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.expected
new file mode 100644
index 00000000000..8b358a0c0e4
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.expected
@@ -0,0 +1,2 @@
+UnusedVariable (3:46)
+Variable `unused` is unused in fragment `UserFields`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.graphql
new file mode 100644
index 00000000000..f21b10928f2
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/unused_fragment_variable.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!, $unused: String) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields(includeEmail: true)
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_directives_with_different_aliases.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_directives_with_different_aliases.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.graphql
new file mode 100644
index 00000000000..685cc1fc84a
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/valid_usage.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($includeEmail: Boolean!) on User {
+    name
+    email @include(if: $includeEmail)
+}
+
+query GetUser {
+    user(id: "1") {
+        ...UserFields(includeEmail: true)
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_skip_include_directives_accepted.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_skip_include_directives_accepted.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.graphql
new file mode 100644
index 00000000000..e6ddd30de82
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/variable_scoping.graphql
@@ -0,0 +1,18 @@
+# PRAGMA allowFragmentArguments
+
+fragment UserFields($first: Int!) on User {
+    friends(first: $first) {
+        edges {
+            node {
+                name
+            }
+        }
+    }
+}
+
+query GetUser($first: Int!) {
+    user(id: "1") {
+        ...UserFields(first: $first)
+        name
+    }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/LICENSE b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/LICENSE
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/LICENSE
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/LICENSE
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/README.md b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/README.md
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/README.md
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/README.md
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/allows_different_order_of_args.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/allows_different_order_of_args.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/allows_different_order_of_args.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/allows_different_order_of_args.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/allows_different_order_of_args.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/allows_different_order_of_args.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/allows_different_order_of_args.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/allows_different_order_of_args.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/schema.graphqls
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema2/schema.graphqls
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/field_merging_order/schema.graphqls
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/allows_different_order_of_input_object_fields_in_arg_values.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/allows_different_order_of_input_object_fields_in_arg_values.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/allows_different_order_of_input_object_fields_in_arg_values.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/allows_different_order_of_input_object_fields_in_arg_values.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/allows_different_order_of_input_object_fields_in_arg_values.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/allows_different_order_of_input_object_fields_in_arg_values.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/allows_different_order_of_input_object_fields_in_arg_values.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/allows_different_order_of_input_object_fields_in_arg_values.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/schema.graphqls
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema3/schema.graphqls
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/input_field_order/schema.graphqls
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/schema.graphqls
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/schema.graphqls
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/schema.graphqls
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/works_for_field_names_that_are_js_keywords.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/works_for_field_names_that_are_js_keywords.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/works_for_field_names_that_are_js_keywords.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/works_for_field_names_that_are_js_keywords.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/works_for_field_names_that_are_js_keywords.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/works_for_field_names_that_are_js_keywords.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema5/works_for_field_names_that_are_js_keywords.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/keywords/works_for_field_names_that_are_js_keywords.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/schema.graphqls
new file mode 100644
index 00000000000..5527f01fdb0
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/schema.graphqls
@@ -0,0 +1,13 @@
+  type Query {
+    foo: String
+  }
+
+  directive @onQuery on QUERY
+  directive @onMutation on MUTATION
+  directive @onSubscription on SUBSCRIPTION
+  directive @onField on FIELD
+  directive @onFragmentDefinition on FRAGMENT_DEFINITION
+  directive @onFragmentSpread on FRAGMENT_SPREAD
+  directive @onInlineFragment on INLINE_FRAGMENT
+  directive @onVariableDefinition on VARIABLE_DEFINITION
+  directive @onFragmentVariableDefinition on VARIABLE_DEFINITION
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.expected
new file mode 100644
index 00000000000..e73e67aec21
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.expected
@@ -0,0 +1,29 @@
+OtherValidationIssue (9:7)
+Directive 'onQuery' cannot be applied on 'FIELD'
+------------
+OtherValidationIssue (8:44)
+Directive 'onQuery' cannot be applied on 'FRAGMENT_DEFINITION'
+------------
+OtherValidationIssue (8:25)
+Directive 'onField' cannot be applied on 'VARIABLE_DEFINITION'
+------------
+UnusedVariable (8:15)
+Variable `arg` is unused in fragment `Frag`
+------------
+AnonymousOperation (3:1)
+Apollo does not support anonymous operations
+------------
+OtherValidationIssue (4:22)
+Directive 'onQuery' cannot be applied on 'FRAGMENT_SPREAD'
+------------
+OtherValidationIssue (5:7)
+Directive 'onQuery' cannot be applied on 'FIELD'
+------------
+OtherValidationIssue (3:28)
+Directive 'onMutation' cannot be applied on 'QUERY'
+------------
+OtherValidationIssue (3:18)
+Directive 'onQuery' cannot be applied on 'VARIABLE_DEFINITION'
+------------
+OtherValidationIssue (3:28)
+Directive 'onMutation' cannot be applied on 'QUERY'
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.graphql
new file mode 100644
index 00000000000..31a85965684
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_misplaced_directives.graphql
@@ -0,0 +1,10 @@
+# PRAGMA allowFragmentArguments
+
+query ($var: Int @onQuery) @onMutation {
+  ...Frag(arg: $var) @onQuery
+  foo @onQuery
+}
+
+fragment Frag($arg: Int @onField) on Query @onQuery {
+  foo @onQuery
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.graphql
new file mode 100644
index 00000000000..b2170e856b9
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_no_directive.graphql
@@ -0,0 +1,8 @@
+query Foo {
+  foo
+  ...Frag
+}
+
+fragment Frag on Query {
+  foo
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.expected
new file mode 100644
index 00000000000..b1706a1018c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.expected
@@ -0,0 +1,2 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.graphql
new file mode 100644
index 00000000000..062535e50e3
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_standard_directives.graphql
@@ -0,0 +1,4 @@
+{
+  foo @skip(if: false)
+  foo @include(if: true)
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.expected
new file mode 100644
index 00000000000..a622bc69e31
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.expected
@@ -0,0 +1,5 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
+------------
+UnknownDirective (2:7)
+Unknown directive '@unknown'
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.graphql
new file mode 100644
index 00000000000..b84b33f5fd9
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/known_directive/with_unknown_directive.graphql
@@ -0,0 +1,3 @@
+{
+  foo @unknown(directive: "value")
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_args.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_args.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.graphql
new file mode 100644
index 00000000000..f0233f07832
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_or_undefined_variables.graphql	
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+query Foo($b: String) {
+  field {
+    ...FragA(a: $b)
+  }
+}
+fragment FragA($a: String) on Type {
+  field(a: $a) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_directives.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_variables.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_directives.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/defined_variables_used as_fragment_arguments_are_not_unused_variables.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.graphql
new file mode 100644
index 00000000000..444f4834400
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/fragment_defined_arguments_are_not_unused_or_undefined_variables.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+query Foo {
+  field {
+    ...FragA
+  }
+}
+fragment FragA($a: String) on Type {
+  field(a: $a) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.expected
new file mode 100644
index 00000000000..5ffe948dfb5
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.expected
@@ -0,0 +1,35 @@
+OtherValidationIssue (12:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (21:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (16:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (12:12)
+Variable `a` is not defined by operation `Foo`
+------------
+OtherValidationIssue (16:12)
+Variable `a` is not defined by operation `Foo`
+------------
+OtherValidationIssue (21:12)
+Variable `c` is not defined by operation `Foo`
+------------
+OtherValidationIssue (12:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (21:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (16:3)
+Field at path `field.field` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (12:19)
+Variable `b` is not defined by operation `Bar`
+------------
+OtherValidationIssue (16:19)
+Variable `b` is not defined by operation `Bar`
+------------
+OtherValidationIssue (21:12)
+Variable `c` is not defined by operation `Bar`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.graphql
new file mode 100644
index 00000000000..7268a421a7e
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_undefined_variables_produce_multiple_errors.graphql
@@ -0,0 +1,24 @@
+query Foo($b: String) {
+  field {
+    ...FragAB
+  }
+}
+query Bar($a: String) {
+  field {
+    ...FragAB
+  }
+}
+fragment FragAB on Type {
+  field(a: $a, b: $b) {
+    foo
+  }
+  ...FragC
+  field(a: $a, b: $b) {
+    foo
+  }
+}
+fragment FragC on Type {
+  field(c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.expected
new file mode 100644
index 00000000000..c2700cefdcd
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.expected
@@ -0,0 +1,5 @@
+OtherValidationIssue (7:12)
+Variable `a` is not defined by operation `Foo`
+------------
+OtherValidationIssue (17:12)
+Variable `c` is not defined by operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.graphql
new file mode 100644
index 00000000000..d943360de17
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_in_fragments_not_defined.graphql
@@ -0,0 +1,20 @@
+query Foo($b: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    ...FragB
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    ...FragC
+  }
+}
+fragment FragC on Type {
+  field(c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.expected
new file mode 100644
index 00000000000..6dce7a07100
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.expected
@@ -0,0 +1,5 @@
+OtherValidationIssue (2:12)
+Variable `a` is not defined by operation `Foo`
+------------
+OtherValidationIssue (2:26)
+Variable `c` is not defined by operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.graphql
new file mode 100644
index 00000000000..336738713d0
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_defined.graphql
@@ -0,0 +1,5 @@
+query Foo($b: String) {
+  field(a: $a, b: $b, c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.expected
new file mode 100644
index 00000000000..ea399ca9066
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.expected
@@ -0,0 +1,5 @@
+UnusedVariable (1:11)
+Variable `a` is unused in operation `Foo`
+------------
+UnusedVariable (1:35)
+Variable `c` is unused in operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.graphql
new file mode 100644
index 00000000000..4d52296a65f
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used.graphql
@@ -0,0 +1,5 @@
+query Foo($a: String, $b: String, $c: String) {
+  field(b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.expected
new file mode 100644
index 00000000000..ea399ca9066
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.expected
@@ -0,0 +1,5 @@
+UnusedVariable (1:11)
+Variable `a` is unused in operation `Foo`
+------------
+UnusedVariable (1:35)
+Variable `c` is unused in operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.graphql
new file mode 100644
index 00000000000..09e0df678b3
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/multiple_variables_not_used_in_fragments.graphql
@@ -0,0 +1,20 @@
+query Foo($a: String, $b: String, $c: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field {
+    ...FragB
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    ...FragC
+  }
+}
+fragment FragC on Type {
+  field {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.expected
new file mode 100644
index 00000000000..b1706a1018c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.expected
@@ -0,0 +1,2 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.graphql
new file mode 100644
index 00000000000..ec35ba4dff6
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/no_unused_variable.graphql
@@ -0,0 +1,5 @@
+query ($a: String, $b: String, $c: String) {
+  field(a: $a, b: $b, c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/schema.graphqls
new file mode 100644
index 00000000000..9ca5222e607
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/schema.graphqls
@@ -0,0 +1,8 @@
+type Query {
+  field(a: String, b: String, c: String): Type
+}
+
+type Type {
+  field(a: String, b: String, c: String): Type
+  foo: String
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.expected
new file mode 100644
index 00000000000..f7a2bde8091
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.expected
@@ -0,0 +1,5 @@
+OtherValidationIssue (12:19)
+Variable `b` is not defined by operation `Foo`
+------------
+OtherValidationIssue (12:19)
+Variable `b` is not defined by operation `Bar`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.graphql
new file mode 100644
index 00000000000..f1a7dd6a088
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/single_variable_in_fragment_not_defined_by_multiple_operations.graphql
@@ -0,0 +1,15 @@
+query Foo($a: String) {
+  field {
+    ...FragAB
+  }
+}
+query Bar($a: String) {
+  field {
+    ...FragAB
+  }
+}
+fragment FragAB on Type {
+  field(a: $a, b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.expected
new file mode 100644
index 00000000000..99b508932b9
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.expected
@@ -0,0 +1,2 @@
+UnusedVariable (8:16)
+Variable `a` is unused in fragment `FragA`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.graphql
new file mode 100644
index 00000000000..11c6a6b03f0
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/unused_fragment_variables_are_reported.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+query Foo {
+  field {
+    ...FragA(a: "value")
+  }
+}
+fragment FragA($a: String) on Type {
+  field {
+    foo
+  }
+}
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/unique_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/unique_fields.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.graphql
new file mode 100644
index 00000000000..11c9c705cec
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply.graphql
@@ -0,0 +1,9 @@
+query Foo($a: String, $b: String, $c: String) {
+  field(a: $a) {
+    field(b: $b) {
+      field(c: $c) {
+        foo
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_inline_fragments_without_type_condition.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_inline_fragments_without_type_condition.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.graphql
new file mode 100644
index 00000000000..2673eca1248
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_deeply_in_inline_fragments.graphql
@@ -0,0 +1,13 @@
+query Foo($a: String, $b: String, $c: String) {
+  field(a: $a) {
+    ... on Type {
+      field(b: $b) {
+        ... on Type {
+          field(c: $c) {
+            foo
+          }
+        }
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_non_conflicting_overlapping_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_in_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_non_conflicting_overlapping_types.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_in_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_in_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_in_fragments.graphql
new file mode 100644
index 00000000000..ea56411befd
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/uses_all_variables_in_fragments.graphql
@@ -0,0 +1,20 @@
+query Foo($a: String, $b: String, $c: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    ...FragB
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    ...FragC
+  }
+}
+fragment FragC on Type {
+  field(c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.expected
new file mode 100644
index 00000000000..ef249ab4242
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.expected
@@ -0,0 +1,2 @@
+OtherValidationIssue (17:12)
+Variable `c` is not defined by operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.graphql
new file mode 100644
index 00000000000..9e623bb17fa
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_operation.graphql
@@ -0,0 +1,20 @@
+query Foo($a: String, $b: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    ...FragB
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    ...FragC
+  }
+}
+fragment FragC on Type {
+  field(c: $c) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.expected
new file mode 100644
index 00000000000..070deb1ece2
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.expected
@@ -0,0 +1,5 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
+------------
+OtherValidationIssue (7:12)
+Variable `a` is not defined by anonymous operation
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.graphql
new file mode 100644
index 00000000000..34e192ad136
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_not_defined_by_unnamed_query.graphql
@@ -0,0 +1,10 @@
+{
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.expected
new file mode 100644
index 00000000000..4792c4d5933
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.expected
@@ -0,0 +1,11 @@
+OtherValidationIssue (12:12)
+Variable `a` is not defined by operation `Foo`
+------------
+UnusedVariable (1:11)
+Variable `b` is unused in operation `Foo`
+------------
+OtherValidationIssue (17:12)
+Variable `b` is not defined by operation `Bar`
+------------
+UnusedVariable (6:11)
+Variable `a` is unused in operation `Bar`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.graphql
new file mode 100644
index 00000000000..d471844b2bd
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_in_fragment_used_by_other_operation.graphql
@@ -0,0 +1,20 @@
+query Foo($b: String) {
+  field {
+    ...FragA
+  }
+}
+query Bar($a: String) {
+  field {
+    ...FragB
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    foo
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.expected
new file mode 100644
index 00000000000..363f744e4c8
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.expected
@@ -0,0 +1,2 @@
+OtherValidationIssue (2:30)
+Unknown argument `d` on field `field`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.graphql
new file mode 100644
index 00000000000..251c5a106f3
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined.graphql
@@ -0,0 +1,5 @@
+query Foo($a: String, $b: String, $c: String) {
+  field(a: $a, b: $b, c: $c, d: $d) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.expected
new file mode 100644
index 00000000000..44ca4a7f203
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.expected
@@ -0,0 +1,5 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
+------------
+OtherValidationIssue (2:12)
+Variable `a` is not defined by anonymous operation
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.graphql
new file mode 100644
index 00000000000..7c2e92af70c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_defined_by_anonymous_query.graphql
@@ -0,0 +1,5 @@
+{
+  field(a: $a) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.expected
new file mode 100644
index 00000000000..4d6e373c1a6
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.expected
@@ -0,0 +1,5 @@
+AnonymousOperation (1:1)
+Apollo does not support anonymous operations
+------------
+UnusedVariable (1:32)
+Variable `c` is unused in anonymous operation
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.graphql
new file mode 100644
index 00000000000..9da60d80721
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used.graphql
@@ -0,0 +1,5 @@
+query ($a: String, $b: String, $c: String) {
+  field(a: $a, b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.expected
new file mode 100644
index 00000000000..4792c4d5933
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.expected
@@ -0,0 +1,11 @@
+OtherValidationIssue (12:12)
+Variable `a` is not defined by operation `Foo`
+------------
+UnusedVariable (1:11)
+Variable `b` is unused in operation `Foo`
+------------
+OtherValidationIssue (17:12)
+Variable `b` is not defined by operation `Bar`
+------------
+UnusedVariable (6:11)
+Variable `a` is unused in operation `Bar`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.graphql
new file mode 100644
index 00000000000..d471844b2bd
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_fragment_used_by_other_operation.graphql
@@ -0,0 +1,20 @@
+query Foo($b: String) {
+  field {
+    ...FragA
+  }
+}
+query Bar($a: String) {
+  field {
+    ...FragB
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    foo
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.expected
new file mode 100644
index 00000000000..361d2800e85
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.expected
@@ -0,0 +1,8 @@
+OtherValidationIssue (7:12)
+Variable `a` is not defined by operation `Foo`
+------------
+UnusedVariable (1:11)
+Variable `b` is unused in operation `Foo`
+------------
+UnusedFragment (11:1)
+Fragment 'FragB' is not used
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.graphql
new file mode 100644
index 00000000000..a39746fa17a
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_by_unreferenced_fragment.graphql
@@ -0,0 +1,15 @@
+query Foo($b: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    foo
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.expected
new file mode 100644
index 00000000000..f3526598127
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.expected
@@ -0,0 +1,2 @@
+UnusedVariable (1:35)
+Variable `c` is unused in operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.graphql
new file mode 100644
index 00000000000..7f3390bf86a
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_not_used_in_fragments.graphql
@@ -0,0 +1,20 @@
+query Foo($a: String, $b: String, $c: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    ...FragB
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    ...FragC
+  }
+}
+fragment FragC on Type {
+  field {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compatible_return_shapes_on_different_return_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_fragment_in_multiple_operations.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compatible_return_shapes_on_different_return_types.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_fragment_in_multiple_operations.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_fragment_in_multiple_operations.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_fragment_in_multiple_operations.graphql
new file mode 100644
index 00000000000..8a059b6709c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_fragment_in_multiple_operations.graphql
@@ -0,0 +1,20 @@
+query Foo($a: String) {
+  field {
+    ...FragA
+  }
+}
+query Bar($b: String) {
+  field {
+    ...FragB
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    foo
+  }
+}
+fragment FragB on Type {
+  field(b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.expected
new file mode 100644
index 00000000000..78f221843a9
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.expected
@@ -0,0 +1,2 @@
+FragmentCycle (8:5)
+Fragment 'FragA' spreads itself, creating a cycle at '__FragA.field.__FragA'
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.graphql
new file mode 100644
index 00000000000..c9a36d8b5e3
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variable_used_by_recursive_fragment.graphql
@@ -0,0 +1,10 @@
+query Foo($a: String) {
+  field {
+    ...FragA
+  }
+}
+fragment FragA on Type {
+  field(a: $a) {
+    ...FragA
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.expected
new file mode 100644
index 00000000000..894268a694a
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.expected
@@ -0,0 +1,5 @@
+OtherValidationIssue (12:12)
+Variable `a` is not defined by operation `Foo`
+------------
+OtherValidationIssue (12:19)
+Variable `b` is not defined by operation `Bar`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.graphql
new file mode 100644
index 00000000000..8ebd3eaf9c4
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_in_fragment_not_defined_by_multiple_operations.graphql
@@ -0,0 +1,15 @@
+query Foo($b: String) {
+  field {
+    ...FragAB
+  }
+}
+query Bar($a: String) {
+  field {
+    ...FragAB
+  }
+}
+fragment FragAB on Type {
+  field(a: $a, b: $b) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.expected
new file mode 100644
index 00000000000..b61ba629392
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.expected
@@ -0,0 +1,5 @@
+UnusedVariable (8:16)
+Variable `a` is unused in fragment `FragA`
+------------
+OtherValidationIssue (12:12)
+Variable `a` is not defined by operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.graphql
new file mode 100644
index 00000000000..65d50e6e5c4
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_shadowed_by_parent_fragment_arguments_are_still_undefined_variables.graphql
@@ -0,0 +1,15 @@
+# PRAGMA allowFragmentArguments
+
+query Foo {
+  field {
+    ...FragA
+  }
+}
+fragment FragA($a: String) on Type {
+  ...FragB
+}
+fragment FragB on Type {
+  field(a: $a) {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.expected
new file mode 100644
index 00000000000..e6bfd61c763
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.expected
@@ -0,0 +1,5 @@
+UnusedVariable (8:16)
+Variable `a` is unused in fragment `FragA`
+------------
+OtherValidationIssue (5:17)
+Variable `a` is not defined by operation `Foo`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.graphql
new file mode 100644
index 00000000000..f1beb670f73
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/no_unused_or_undefined_variable/variables_used_as_fragment_arguments_may_be_undefined_variables.graphql
@@ -0,0 +1,12 @@
+# PRAGMA allowFragmentArguments
+
+query Foo {
+  field {
+    ...FragA(a: $a)
+  }
+}
+fragment FragA($a: String) on Type {
+  field {
+    foo
+  }
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/same_wrapped_scalar_return_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_inline_fragments_without_type_condition.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/same_wrapped_scalar_return_types.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_inline_fragments_without_type_condition.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_inline_fragments_without_type_condition.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_inline_fragments_without_type_condition.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_inline_fragments_without_type_condition.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_inline_fragments_without_type_condition.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_non_conflicting_overlapping_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_non_conflicting_overlapping_types.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_non_conflicting_overlapping_types.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_non_conflicting_overlapping_types.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/allows_non_conflicting_overlapping_types.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/allows_non_conflicting_overlapping_types.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compares_deep_types_including_list.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compares_deep_types_including_list.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compares_deep_types_including_list.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compares_deep_types_including_list.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compares_deep_types_including_list.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compares_deep_types_including_list.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compares_deep_types_including_list.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compares_deep_types_including_list.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compatible_return_shapes_on_different_return_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compatible_return_shapes_on_different_return_types.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compatible_return_shapes_on_different_return_types.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compatible_return_shapes_on_different_return_types.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/compatible_return_shapes_on_different_return_types.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/compatible_return_shapes_on_different_return_types.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/conflicting_return_types_which_potentially_overlap.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/conflicting_return_types_which_potentially_overlap.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/conflicting_return_types_which_potentially_overlap.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/conflicting_return_types_which_potentially_overlap.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/conflicting_return_types_which_potentially_overlap.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/conflicting_return_types_which_potentially_overlap.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/conflicting_return_types_which_potentially_overlap.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/conflicting_return_types_which_potentially_overlap.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_deep_return_types_despite_no_overlap.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_deep_return_types_despite_no_overlap.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_deep_return_types_despite_no_overlap.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_deep_return_types_despite_no_overlap.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_deep_return_types_despite_no_overlap.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_deep_return_types_despite_no_overlap.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_deep_return_types_despite_no_overlap.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_deep_return_types_despite_no_overlap.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_1.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_1.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_1.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_1.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_1.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_1.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_1.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_1.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_2.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_2.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_2.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_2.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_2.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_2.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_list_despite_no_overlap_2.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_list_despite_no_overlap_2.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_nullability_despite_no_overlap.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_nullability_despite_no_overlap.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_nullability_despite_no_overlap.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_nullability_despite_no_overlap.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_nullability_despite_no_overlap.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_nullability_despite_no_overlap.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_type_nullability_despite_no_overlap.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_type_nullability_despite_no_overlap.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_types_despite_no_overlap.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_types_despite_no_overlap.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_types_despite_no_overlap.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_types_despite_no_overlap.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_types_despite_no_overlap.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_types_despite_no_overlap.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_return_types_despite_no_overlap.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_return_types_despite_no_overlap.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_subfields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_subfields.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_subfields.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_subfields.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_subfields.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_subfields.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/disallows_differing_subfields.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/disallows_differing_subfields.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/ignores_unknown_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/ignores_unknown_types.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/ignores_unknown_types.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/ignores_unknown_types.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/ignores_unknown_types.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/ignores_unknown_types.graphql
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rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/ignores_unknown_types.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/ignores_unknown_types.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/reports_correctly_when_a_non_exclusive_follows_an_exclusive.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/reports_correctly_when_a_non_exclusive_follows_an_exclusive.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/reports_correctly_when_a_non_exclusive_follows_an_exclusive.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/reports_correctly_when_a_non_exclusive_follows_an_exclusive.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/reports_correctly_when_a_non_exclusive_follows_an_exclusive.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/reports_correctly_when_a_non_exclusive_follows_an_exclusive.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/reports_correctly_when_a_non_exclusive_follows_an_exclusive.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/reports_correctly_when_a_non_exclusive_follows_an_exclusive.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/same_wrapped_scalar_return_types.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/same_wrapped_scalar_return_types.expected
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index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/same_wrapped_scalar_return_types.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/same_wrapped_scalar_return_types.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/same_wrapped_scalar_return_types.graphql
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diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/schema.graphqls
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema4/schema.graphqls
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/same_response_shape/schema.graphqls
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/alias_masking_direct_field_access.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/alias_masking_direct_field_access.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/alias_masking_direct_field_access.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/alias_masking_direct_field_access.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/alias_masking_direct_field_access.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/alias_masking_direct_field_access.graphql
similarity index 100%
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rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/alias_masking_direct_field_access.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/allows_different_args_where_no_conflict_is_possible.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.expected
new file mode 100644
index 00000000000..d6151c8d959
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.expected
@@ -0,0 +1,5 @@
+AnonymousOperation (3:1)
+Apollo does not support anonymous operations
+------------
+OtherValidationIssue (5:19)
+Unknown argument `unknown` on fragment `withoutArg`
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.graphql
new file mode 100644
index 00000000000..e84dd9c5acc
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/arg_passed_to_fragment_without_arg_is_reported.graphql
@@ -0,0 +1,10 @@
+# PRAGMA allowFragmentArguments
+
+{
+  dog {
+    ...withoutArg(unknown: true)
+  }
+}
+fragment withoutArg on Dog {
+  doesKnowCommand
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_names.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_names.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_names.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_names.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_names.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_names.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_names.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_names.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_values.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_values.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_values.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_values.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_values.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_values.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/conflicting_arg_values.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/conflicting_arg_values.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict_with_multiple_issues.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict_with_multiple_issues.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict_with_multiple_issues.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict_with_multiple_issues.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict_with_multiple_issues.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict_with_multiple_issues.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/deep_conflict_with_multiple_issues.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/deep_conflict_with_multiple_issues.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_adds_an_argument.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_adds_an_argument.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_adds_an_argument.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_adds_an_argument.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_adds_an_argument.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_adds_an_argument.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_adds_an_argument.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_adds_an_argument.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_missing_an_argument.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_missing_an_argument.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_missing_an_argument.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_missing_an_argument.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_missing_an_argument.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_missing_an_argument.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_second_missing_an_argument.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_second_missing_an_argument.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_with_different_aliases.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_with_different_aliases.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_with_different_aliases.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_with_different_aliases.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_args_with_different_aliases.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_args_with_different_aliases.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_directives_with_different_aliases.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_directives_with_different_aliases.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_directives_with_different_aliases.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_directives_with_different_aliases.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_directives_with_different_aliases.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_directives_with_different_aliases.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_skip_include_directives_accepted.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_skip_include_directives_accepted.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/different_skip_include_directives_accepted.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_skip_include_directives_accepted.graphql
similarity index 100%
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rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/different_skip_include_directives_accepted.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_immediately_recursive_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragment_with_a_field_named_after_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.graphql
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rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_recursive_fragments_separated_by_fields.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.expected
similarity index 100%
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rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/does_not_infinite_loop_on_transitively_recursive_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/encounters_conflict_in_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/encounters_conflict_in_fragments.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/encounters_conflict_in_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/encounters_conflict_in_fragments.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.expected
new file mode 100644
index 00000000000..40be299b56f
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.expected
@@ -0,0 +1,8 @@
+AnonymousOperation (3:1)
+Apollo does not support anonymous operations
+------------
+OtherValidationIssue (8:3)
+Field at path `foo` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (8:3)
+Field at path `foo` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.graphql
new file mode 100644
index 00000000000..ed08641659c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/encounters_conflict_in_fragments_with_args.graphql
@@ -0,0 +1,9 @@
+# PRAGMA allowFragmentArguments
+
+{
+  ...WithArgs(x: 3)
+  ...WithArgs(x: 4)
+}
+fragment WithArgs($x: Int) on QueryRoot {
+  foo(x: $x)
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_case_even_with_immediately_recursive_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/finds_invalid_cases_even_with_field_named_after_fragment.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.expected
new file mode 100644
index 00000000000..ea58182f70c
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.expected
@@ -0,0 +1,2 @@
+AnonymousOperation (3:1)
+Apollo does not support anonymous operations
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.graphql
new file mode 100644
index 00000000000..10fac85faa2
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/fragment_args_are_known.graphql
@@ -0,0 +1,10 @@
+# PRAGMA allowFragmentArguments
+
+{
+  dog {
+    ...withArg(dogCommand: SIT)
+  }
+}
+fragment withArg($dogCommand: DogCommand) on Dog {
+  doesKnowCommand(dogCommand: $dogCommand)
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_args.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_args.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_args.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_args.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_args.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_args.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_directives.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_directives.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_directives.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_directives.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/identical_fields_with_identical_directives.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/identical_fields_with_identical_directives.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/ignores_unknown_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/ignores_unknown_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/ignores_unknown_fragments.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/ignores_unknown_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/ignores_unknown_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/ignores_unknown_fragments.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/ignores_unknown_fragments.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/ignores_unknown_fragments.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_after_nested_fragments.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_in_nested_fragments.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_deep_conflict_to_nearest_common_ancestor_in_fragments.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_each_conflict_once.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_each_conflict_once.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_each_conflict_once.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_each_conflict_once.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_each_conflict_once.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_each_conflict_once.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/reports_each_conflict_once.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/reports_each_conflict_once.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_allowed_on_non_overlapping_fields.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_with_different_field_targets.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_with_different_field_targets.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_with_different_field_targets.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_with_different_field_targets.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_with_different_field_targets.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_with_different_field_targets.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/same_aliases_with_different_field_targets.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/same_aliases_with_different_field_targets.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/schema.graphqls b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/schema.graphqls
similarity index 99%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/schema.graphqls
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/schema.graphqls
index 442a14f4375..909311ab74e 100644
--- a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/schema.graphqls
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/schema.graphqls
@@ -105,6 +105,7 @@ type QueryRoot {
   f1: Type
   f2: Type
   f3: Type
+  foo(x: Int): String
 }
 
 type Type {
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unique_fields.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unique_fields.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/unique_fields.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unique_fields.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/unique_fields.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unique_fields.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.expected
new file mode 100644
index 00000000000..43e29d3ed5f
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.expected
@@ -0,0 +1,8 @@
+OtherValidationIssue (6:19)
+Unknown argument `whoKnows` on field `doesKnowCommand`
+------------
+OtherValidationIssue (6:49)
+Unknown argument `unknown` on field `doesKnowCommand`
+------------
+AnonymousOperation (3:1)
+Apollo does not support anonymous operations
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.graphql
new file mode 100644
index 00000000000..17cbefcf9ab
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/unknown_args_amongst_known_args.graphql
@@ -0,0 +1,7 @@
+# PRAGMA allowFragmentArguments
+
+{ dog {...oneGoodArgOneInvalidArg } }
+
+fragment oneGoodArgOneInvalidArg on Dog {
+  doesKnowCommand(whoKnows: 1, dogCommand: SIT, unknown: true)
+}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/very_deep_conflict.expected b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/very_deep_conflict.expected
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/very_deep_conflict.expected
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/very_deep_conflict.expected
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/very_deep_conflict.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/very_deep_conflict.graphql
similarity index 100%
rename from libraries/apollo-ast/test-fixtures/validation/executable/fields_in_set_can_merge/graphql-js/schema1/very_deep_conflict.graphql
rename to libraries/apollo-ast/test-fixtures/validation/executable/graphql-js/schema1/very_deep_conflict.graphql
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/mandatory_argument/mandatory_argument.expected b/libraries/apollo-ast/test-fixtures/validation/executable/mandatory_argument/mandatory_argument.expected
index 0e4e1f63c51..2f64772383c 100644
--- a/libraries/apollo-ast/test-fixtures/validation/executable/mandatory_argument/mandatory_argument.expected
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/mandatory_argument/mandatory_argument.expected
@@ -1,2 +1,2 @@
 OtherValidationIssue (2:5)
-No value passed for required argument 'input'
\ No newline at end of file
+No value passed for required argument `input` on field `edit`
\ No newline at end of file
diff --git a/libraries/apollo-compiler/api/apollo-compiler.api b/libraries/apollo-compiler/api/apollo-compiler.api
index 4052b1b9188..998e9ed262d 100644
--- a/libraries/apollo-compiler/api/apollo-compiler.api
+++ b/libraries/apollo-compiler/api/apollo-compiler.api
@@ -286,8 +286,9 @@ public final class com/apollographql/apollo/compiler/InputFile {
 
 public final class com/apollographql/apollo/compiler/IrOptions {
 	public static final field Companion Lcom/apollographql/apollo/compiler/IrOptions$Companion;
-	public fun <init> (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;)V
+	public fun <init> (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/lang/Boolean;)V
 	public final fun getAddTypename ()Ljava/lang/String;
+	public final fun getAllowFragmentArguments ()Ljava/lang/Boolean;
 	public final fun getAlwaysGenerateTypesMatching ()Ljava/util/Set;
 	public final fun getCodegenModels ()Ljava/lang/String;
 	public final fun getDecapitalizeFields ()Ljava/lang/Boolean;
@@ -399,8 +400,8 @@ public final class com/apollographql/apollo/compiler/OptionsKt {
 	public static final field MODELS_RESPONSE_BASED Ljava/lang/String;
 	public static final fun buildCodegenOptions (Lcom/apollographql/apollo/compiler/TargetLanguage;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Lcom/apollographql/apollo/compiler/JavaNullable;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;)Lcom/apollographql/apollo/compiler/CodegenOptions;
 	public static synthetic fun buildCodegenOptions$default (Lcom/apollographql/apollo/compiler/TargetLanguage;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Lcom/apollographql/apollo/compiler/JavaNullable;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;ILjava/lang/Object;)Lcom/apollographql/apollo/compiler/CodegenOptions;
-	public static final fun buildIrOptions (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/util/Map;)Lcom/apollographql/apollo/compiler/IrOptions;
-	public static synthetic fun buildIrOptions$default (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/util/Map;ILjava/lang/Object;)Lcom/apollographql/apollo/compiler/IrOptions;
+	public static final fun buildIrOptions (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;)Lcom/apollographql/apollo/compiler/IrOptions;
+	public static synthetic fun buildIrOptions$default (Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;ILjava/lang/Object;)Lcom/apollographql/apollo/compiler/IrOptions;
 	public static final fun validate (Lcom/apollographql/apollo/compiler/CodegenOptions;)V
 }
 
diff --git a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ApolloCompiler.kt b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ApolloCompiler.kt
index 07f807a25d7..60b74992d8a 100644
--- a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ApolloCompiler.kt
+++ b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ApolloCompiler.kt
@@ -214,11 +214,11 @@ object ApolloCompiler {
   /**
    * Parses the given files. Throws if there are parsing errors
    */
-  private fun File.definitions(): List<GQLDefinition> {
+  private fun File.definitions(allowFragmentArguments: Boolean): List<GQLDefinition> {
     val definitions = mutableListOf<GQLDefinition>()
     val parseIssues = mutableListOf<Issue>()
 
-    val parseResult = parseAsGQLDocument(options = ParserOptions.Builder().build())
+    val parseResult = parseAsGQLDocument(options = ParserOptions.Builder().allowFragmentArguments(allowFragmentArguments).build())
     if (parseResult.issues.isNotEmpty()) {
       parseIssues.addAll(parseResult.issues)
     } else {
@@ -263,7 +263,7 @@ object ApolloCompiler {
      * See https://github.com/apollographql/apollo-kotlin/pull/5916
      */
     executableFiles.sortedBy { it.normalizedPath }.forEach { normalizedFile ->
-      val fileDefinitions = normalizedFile.file.definitions()
+      val fileDefinitions = normalizedFile.file.definitions(options.allowFragmentArguments ?: false)
 
       userDefinitions.addAll(fileDefinitions)
       fileDefinitions.forEach {
diff --git a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/Options.kt b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/Options.kt
index 497303e9fe6..dc833b63482 100644
--- a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/Options.kt
+++ b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/Options.kt
@@ -199,6 +199,8 @@ class IrOptions(
     val alwaysGenerateTypesMatching: Set<String>?,
 
     val codegenModels: String?,
+
+    val allowFragmentArguments: Boolean?
 )
 
 fun buildIrOptions(
@@ -210,6 +212,7 @@ fun buildIrOptions(
     alwaysGenerateTypesMatching: Set<String>? = null,
     codegenModels: String? = null,
     issueSeverity: Map<String, IssueSeverity>? = null,
+    allowFragmentArguments: Boolean? = null
 ): IrOptions = IrOptions(
     decapitalizeFields = decapitalizeFields,
     flattenModels = flattenModels,
@@ -218,7 +221,8 @@ fun buildIrOptions(
     generateOptionalOperationVariables = generateOptionalOperationVariables,
     alwaysGenerateTypesMatching = alwaysGenerateTypesMatching,
     codegenModels = codegenModels,
-    issueSeverities = issueSeverity
+    issueSeverities = issueSeverity,
+    allowFragmentArguments = allowFragmentArguments
 )
 
 interface CommonCodegenOpt {
diff --git a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ir/IrOperationsBuilder.kt b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ir/IrOperationsBuilder.kt
index 5a14a0653ce..859b8dc1bad 100644
--- a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ir/IrOperationsBuilder.kt
+++ b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/ir/IrOperationsBuilder.kt
@@ -300,7 +300,7 @@ internal class IrOperationsBuilder(
         description = description,
         filePath = fragmentNameToNormalizedPath[name] ?: "",
         typeCondition = typeDefinition.name,
-        variables = inferredVariables.map { it.toIr() },
+        variables = inferredVariables.map { it.toIr() } + variableDefinitions.map { it.toIr() },
         selectionSets = SelectionSetsBuilder(schema, allFragmentDefinitions).build(selections, typeCondition.name),
         interfaceModelGroup = interfaceModelGroup,
         dataProperty = dataProperty,
diff --git a/libraries/apollo-execution/api/apollo-execution.api b/libraries/apollo-execution/api/apollo-execution.api
index 824cd8ccf5a..3dbc44d82ce 100644
--- a/libraries/apollo-execution/api/apollo-execution.api
+++ b/libraries/apollo-execution/api/apollo-execution.api
@@ -33,6 +33,7 @@ public final class com/apollographql/apollo/execution/ExecutableSchema$Builder {
 	public final fun build ()Lcom/apollographql/apollo/execution/ExecutableSchema;
 	public final fun mutationRoot (Lcom/apollographql/apollo/execution/RootResolver;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
 	public final fun onError (Lcom/apollographql/apollo/execution/OnError;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
+	public final fun parserOptions (Lcom/apollographql/apollo/ast/ParserOptions;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
 	public final fun persistedDocumentCache (Lcom/apollographql/apollo/execution/PersistedDocumentCache;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
 	public final fun queryRoot (Lcom/apollographql/apollo/execution/RootResolver;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
 	public final fun resolver (Lcom/apollographql/apollo/execution/Resolver;)Lcom/apollographql/apollo/execution/ExecutableSchema$Builder;
diff --git a/libraries/apollo-execution/api/apollo-execution.klib.api b/libraries/apollo-execution/api/apollo-execution.klib.api
index 9235b4a52db..cd84e921298 100644
--- a/libraries/apollo-execution/api/apollo-execution.klib.api
+++ b/libraries/apollo-execution/api/apollo-execution.klib.api
@@ -79,6 +79,7 @@ final class com.apollographql.apollo.execution/ExecutableSchema { // com.apollog
         final fun build(): com.apollographql.apollo.execution/ExecutableSchema // com.apollographql.apollo.execution/ExecutableSchema.Builder.build|build(){}[0]
         final fun mutationRoot(com.apollographql.apollo.execution/RootResolver): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.mutationRoot|mutationRoot(com.apollographql.apollo.execution.RootResolver){}[0]
         final fun onError(com.apollographql.apollo.execution/OnError): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.onError|onError(com.apollographql.apollo.execution.OnError){}[0]
+        final fun parserOptions(com.apollographql.apollo.ast/ParserOptions): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.parserOptions|parserOptions(com.apollographql.apollo.ast.ParserOptions){}[0]
         final fun persistedDocumentCache(com.apollographql.apollo.execution/PersistedDocumentCache?): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.persistedDocumentCache|persistedDocumentCache(com.apollographql.apollo.execution.PersistedDocumentCache?){}[0]
         final fun queryRoot(com.apollographql.apollo.execution/RootResolver): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.queryRoot|queryRoot(com.apollographql.apollo.execution.RootResolver){}[0]
         final fun resolver(com.apollographql.apollo.execution/Resolver): com.apollographql.apollo.execution/ExecutableSchema.Builder // com.apollographql.apollo.execution/ExecutableSchema.Builder.resolver|resolver(com.apollographql.apollo.execution.Resolver){}[0]
diff --git a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/ExecutableSchema.kt b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/ExecutableSchema.kt
index 574145c4e5f..55f17fa1ce6 100644
--- a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/ExecutableSchema.kt
+++ b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/ExecutableSchema.kt
@@ -29,6 +29,7 @@ class ExecutableSchema internal constructor(
     private val instrumentations: List<Instrumentation>,
     private val persistedDocumentCache: PersistedDocumentCache?,
     private val onError: OnError,
+    private val parserOptions: ParserOptions
 ) {
   private val introspectionResolver: Resolver = introspectionResolver(schema)
 
@@ -36,7 +37,7 @@ class ExecutableSchema internal constructor(
       request: GraphQLRequest,
       executionContext: ExecutionContext = ExecutionContext.Empty,
   ): GraphQLResponse {
-    return prepareRequest(schema, coercings, persistedDocumentCache, request).fold(
+    return prepareRequest(schema, coercings, persistedDocumentCache, parserOptions, request).fold(
         ifLeft = {
           GraphQLResponse.Builder().errors(it).build()
         },
@@ -50,7 +51,7 @@ class ExecutableSchema internal constructor(
       request: GraphQLRequest,
       executionContext: ExecutionContext = ExecutionContext.Empty,
   ): Flow<SubscriptionEvent> {
-    return prepareRequest(schema, coercings, persistedDocumentCache, request).fold(
+    return prepareRequest(schema, coercings, persistedDocumentCache, parserOptions, request).fold(
         ifLeft = {
           flowOf(SubscriptionResponse(GraphQLResponse.Builder().errors(it).build()))
         },
@@ -90,6 +91,7 @@ class ExecutableSchema internal constructor(
     private val instrumentations = mutableListOf<Instrumentation>()
     private var persistedDocumentCache: PersistedDocumentCache? = null
     private var onError: OnError = OnError.PROPAGATE
+    private var parserOptions: ParserOptions = ParserOptions.Default
 
     fun schema(schema: GQLDocument): Builder = apply {
       this.schema = schema
@@ -138,6 +140,13 @@ class ExecutableSchema internal constructor(
       this.onError = onError
     }
 
+    /**
+     * Configures the parsing options for this executable schema.
+     */
+    fun parserOptions(parserOptions: ParserOptions): Builder = apply {
+      this.parserOptions = parserOptions
+    }
+
     fun build(): ExecutableSchema {
       check(schema != null) {
         "A schema is required to build an ExecutableSchema"
@@ -164,7 +173,8 @@ class ExecutableSchema internal constructor(
           typeResolver ?: ThrowingTypeResolver,
           instrumentations,
           persistedDocumentCache,
-          onError
+          onError,
+          parserOptions
       )
     }
   }
diff --git a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/OperationContext.kt b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/OperationContext.kt
index 7bac0ec0054..aebfdba1f10 100644
--- a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/OperationContext.kt
+++ b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/OperationContext.kt
@@ -163,31 +163,41 @@ internal class OperationContext(
   private fun resolveFieldEventStream(
       subscriptionType: GQLObjectTypeDefinition,
       rootValue: ResolverValue,
-      fields: List<GQLField>,
-      argumentValues: Map<String, InternalValue>,
+      collectedResult: CollectedResult,
       responseName: String,
   ): Flow<FieldEvent> {
     return flow {
-      val resolveInfo = ResolveInfo(
-          parentObject = rootValue,
-          executionContext = executionContext,
-          fields = fields,
-          schema = schema,
-          arguments = argumentValues,
-          parentType = subscriptionType.name,
-          path = emptyList()
-      )
+      val value = when (collectedResult) {
+        is CollectedError -> {
+          Error.Builder(collectedResult.message)
+              .build()
+        }
+        is CollectedField -> {
+          val resolveInfo = ResolveInfo(
+              parentObject = rootValue,
+              executionContext = executionContext,
+              fields = collectedResult.fields,
+              schema = schema,
+              arguments = collectedResult.coercedArguments,
+              parentType = subscriptionType.name,
+              path = emptyList()
+          )
+          resolveFieldValue(resolveInfo)
+        }
+      }
 
-      emit(resolveFieldValue(resolveInfo))
+      emit(value)
     }.flatMapConcat {
-      if (it !is Flow<*>) {
+      if (it is Error) {
+        flowOf(FieldEventError(it.message))
+      } else if (it !is Flow<*>) {
         flowOf(FieldEventError("Subscription resolvers must return a Flow<> (got '$it')"))
       } else {
         it.map { objectValue ->
           FieldEventItem(
               parentType = subscriptionType.name,
               objectValue = objectValue,
-              fields = fields,
+              collectedResult = collectedResult,
               responseName = responseName
           )
         }
@@ -199,7 +209,7 @@ internal class OperationContext(
   private class FieldEventItem(
       val parentType: String,
       val objectValue: InternalValue,
-      val fields: List<GQLField>,
+      val collectedResult: CollectedResult,
       val responseName: String,
   ) : FieldEvent
 
@@ -225,15 +235,12 @@ internal class OperationContext(
     check(groupedFieldsSet.size == 1) {
       return flowOf(FieldEventError("Subscriptions must have a single root field"))
     }
-    val fields = groupedFieldsSet.entries.single().value
-    val field = fields.first()
-    val argumentValues = coerceArgumentValues(schema, typeDefinition.name, field, coercings, variableValues)
+    val collectedResult = groupedFieldsSet.entries.single().value
     return resolveFieldEventStream(
         subscriptionType = typeDefinition,
         rootValue = rootValue,
-        fields = fields,
-        argumentValues = argumentValues,
-        responseName = fields.first().responseName()
+        collectedResult = collectedResult,
+        responseName = collectedResult.first.responseName()
     )
   }
 
@@ -256,8 +263,8 @@ internal class OperationContext(
         coroutineScope {
           val fieldData = completeValue(
               scope = this,
-              fieldType = event.fields.first().definitionFromScope(schema, event.parentType)!!.type,
-              fields = event.fields,
+              fieldType = event.collectedResult.first.definitionFromScope(schema, event.parentType)!!.type,
+              fields = (event.collectedResult as? CollectedField)?.fields.orEmpty(),
               result = event.objectValue,
               path = listOf(event.responseName)
           )
@@ -275,66 +282,69 @@ internal class OperationContext(
    * @param objectType the parent type of the field. Always a concrete object type.
    * @param objectValue the parent object as returned from a resolver.
    * @param fieldType the field type as in the schema field definition.
-   * @param fields the merged fields
-   * @param variableValues the coerced variable values.
+   * @param collectedResult the merged fields
    */
   private fun executeField(
       scope: CoroutineScope,
       objectType: GQLObjectTypeDefinition,
       objectValue: ResolverValue,
       fieldType: GQLType,
-      fields: List<GQLField>,
-      variableValues: Map<String, InternalValue>,
+      collectedResult: CollectedResult,
       path: List<Any>,
   ): Deferred<ExternalValue> {
-    val field = fields.first()
-    val argumentValues = coerceArgumentValues(schema, objectType.name, field, coercings, variableValues)
-
     return scope.async(start = CoroutineStart.UNDISPATCHED) {
-      val resolveInfo = ResolveInfo(
-          parentObject = objectValue,
-          executionContext = executionContext,
-          fields = fields,
-          schema = schema,
-          arguments = argumentValues,
-          parentType = objectType.name,
-          path = path,
-      )
+      when (collectedResult) {
+        is CollectedError -> Error.Builder(collectedResult.message)
+            .path(path)
+            .build()
+
+        is CollectedField -> {
+          val resolveInfo = ResolveInfo(
+              parentObject = objectValue,
+              executionContext = executionContext,
+              fields = collectedResult.fields,
+              schema = schema,
+              arguments = collectedResult.coercedArguments,
+              parentType = objectType.name,
+              path = path,
+          )
+
+          val fieldCallbacks = mutableListOf<FieldCallback>()
+          var instrumentationError: Error? = null
+          instrumentations.map {
+            try {
+              val callback = it.onField(resolveInfo)
+              if (callback != null) {
+                fieldCallbacks.add(callback)
+              }
+            } catch (e: Exception) {
+              if (e is CancellationException) {
+                throw e
+              }
+              instrumentationError = Error.Builder("Cannot instrument '${path.lastOrNull()}': ${e.message}")
+                  .path(path)
+                  .build()
+            }
+          }
 
-      val fieldCallbacks = mutableListOf<FieldCallback>()
-      var instrumentationError: Error? = null
-      instrumentations.map {
-        try {
-          val callback = it.onField(resolveInfo)
-          if (callback != null) {
-            fieldCallbacks.add(callback)
+          val completedValue = if (instrumentationError == null) {
+            val resolvedValue = resolveFieldValue(resolveInfo)
+            completeValue(
+                scope = scope,
+                fieldType = fieldType,
+                fields = collectedResult.fields,
+                result = resolvedValue,
+                path = path
+            )
+          } else {
+            instrumentationError
           }
-        } catch (e: Exception) {
-          if (e is CancellationException) {
-            throw e
+          fieldCallbacks.forEach {
+            it.onFieldCompleted(completedValue)
           }
-          instrumentationError = Error.Builder("Cannot instrument '${path.lastOrNull()}': ${e.message}")
-              .path(path)
-              .build()
+          completedValue
         }
       }
-
-      val completedValue = if (instrumentationError == null) {
-        val resolvedValue = resolveFieldValue(resolveInfo)
-        completeValue(
-            scope = scope,
-            fieldType = fieldType,
-            fields = fields,
-            result = resolvedValue,
-            path = path
-        )
-      } else {
-        instrumentationError
-      }
-      fieldCallbacks.forEach {
-        it.onFieldCompleted(completedValue)
-      }
-      completedValue
     }
   }
 
@@ -502,7 +512,7 @@ internal class OperationContext(
 
   private suspend fun executeGroupedFieldSet(
       scope: CoroutineScope,
-      groupedFieldSet: Map<String, List<GQLField>>,
+      groupedFieldSet: Map<String, CollectedResult>,
       typeDefinition: GQLObjectTypeDefinition,
       objectValue: ResolverValue,
       variableValues: Map<String, InternalValue>,
@@ -511,12 +521,12 @@ internal class OperationContext(
   ): ExternalValue {
     val typename = typeDefinition.name
     val entries = groupedFieldSet.entries.map { entry ->
-      val field = entry.value.first()
+      val field = entry.value.first
       val fieldDefinition = field.definitionFromScope(schema, typename)!!
       val fieldPath = path + field.responseName()
 
       val deferred =
-        executeField(scope, typeDefinition, objectValue, fieldDefinition.type, entry.value, variableValues, fieldPath)
+        executeField(scope, typeDefinition, objectValue, fieldDefinition.type, entry.value, fieldPath)
       if (serial) {
         deferred.await()
       }
@@ -573,22 +583,13 @@ internal class OperationContext(
     return false
   }
 
-  private fun <K, V> MutableMap<K, V>.update(key: K, update: (prev: V?) -> V) {
-    val newValue = if (this.containsKey(key)) {
-      update(this.get(key))
-    } else {
-      update(null)
-    }
-    put(key, newValue)
-  }
-
   private fun collectFields(
       objectType: String,
       selections: List<GQLSelection>,
       coercedVariables: Map<String, InternalValue>,
-  ): Map<String, List<GQLField>> {
-    val groupedFields = mutableMapOf<String, List<GQLField>>()
-    collectFields(objectType, selections, coercedVariables, mutableSetOf(), groupedFields)
+  ): Map<String, CollectedResult> {
+    val groupedFields = mutableMapOf<String, CollectedResult>()
+    collectFields(objectType, selections, coercedVariables, emptyMap(), mutableSetOf(), groupedFields)
     return groupedFields
   }
 
@@ -596,8 +597,9 @@ internal class OperationContext(
       objectType: String,
       selections: List<GQLSelection>,
       coercedVariables: Map<String, InternalValue>,
+      fragmentCoercedVariables: Map<String, InternalValue>,
       visitedFragments: MutableSet<String>,
-      groupedFields: MutableMap<String, List<GQLField>>,
+      groupedFields: MutableMap<String, CollectedResult>,
   ) {
     selections.forEach { selection ->
       if (selection.directives.shouldSkip(coercedVariables)) {
@@ -605,8 +607,21 @@ internal class OperationContext(
       }
       when (selection) {
         is GQLField -> {
-          groupedFields.update(selection.responseName()) {
-            (it.orEmpty()).plus(selection)
+          val responseName = selection.responseName()
+          val collectedField = groupedFields.get(responseName)
+          if (collectedField == null) {
+            val arguments = try {
+              // Fragment variables take precedence here
+              coerceArgumentValues(schema, objectType, selection, coercings, coercedVariables + fragmentCoercedVariables)
+            } catch (e: Exception) {
+              groupedFields.put(responseName, CollectedError(selection, e.message ?: "Error"))
+              return@forEach
+            }
+            groupedFields.put(responseName,
+                CollectedField(selection, arguments)
+            )
+          } else if (collectedField is CollectedField) {
+            collectedField.fields.add(selection)
           }
         }
 
@@ -619,14 +634,15 @@ internal class OperationContext(
           val fragmentDefinition = fragments.get(selection.name)!!
 
           if (schema.possibleTypes(fragmentDefinition.typeCondition.name).contains(objectType)) {
-            collectFields(objectType, fragmentDefinition.selections, coercedVariables, visitedFragments, groupedFields)
+            val fragmentCoercedVariables = coerceArgumentValues(schema, fragmentDefinition.variableDefinitions, selection.arguments, coercings, coercedVariables)
+            collectFields(objectType, fragmentDefinition.selections, coercedVariables, fragmentCoercedVariables, visitedFragments, groupedFields)
           }
         }
 
         is GQLInlineFragment -> {
           val typeCondition = selection.typeCondition?.name
           if (typeCondition == null || schema.possibleTypes(typeCondition).contains(objectType)) {
-            collectFields(objectType, selection.selections, coercedVariables, visitedFragments, groupedFields)
+            collectFields(objectType, selection.selections, coercedVariables, fragmentCoercedVariables, visitedFragments, groupedFields)
           }
         }
       }
@@ -641,3 +657,19 @@ private val GQLSelection.directives: List<GQLDirective>
     is GQLInlineFragment -> directives
   }
 
+internal class CollectedField(
+    override val first: GQLField,
+    val coercedArguments: Map<String, InternalValue>,
+) : CollectedResult {
+  val fields = mutableListOf<GQLField>()
+
+  init {
+    fields.add(first)
+  }
+}
+
+internal sealed interface CollectedResult {
+  val first: GQLField
+}
+
+internal class CollectedError(override val first: GQLField, val message: String) : CollectedResult
\ No newline at end of file
diff --git a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/coerceArgumentValues.kt b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/coerceArgumentValues.kt
index a09e2664614..837109417ba 100644
--- a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/coerceArgumentValues.kt
+++ b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/coerceArgumentValues.kt
@@ -1,9 +1,11 @@
 package com.apollographql.apollo.execution.internal
 
+import com.apollographql.apollo.ast.GQLArgument
 import com.apollographql.apollo.ast.GQLEnumTypeDefinition
 import com.apollographql.apollo.ast.GQLEnumValue
 import com.apollographql.apollo.ast.GQLField
 import com.apollographql.apollo.ast.GQLInputObjectTypeDefinition
+import com.apollographql.apollo.ast.GQLInputValueDefinition
 import com.apollographql.apollo.ast.GQLInterfaceTypeDefinition
 import com.apollographql.apollo.ast.GQLListType
 import com.apollographql.apollo.ast.GQLListValue
@@ -16,6 +18,7 @@ import com.apollographql.apollo.ast.GQLScalarTypeDefinition
 import com.apollographql.apollo.ast.GQLType
 import com.apollographql.apollo.ast.GQLUnionTypeDefinition
 import com.apollographql.apollo.ast.GQLValue
+import com.apollographql.apollo.ast.GQLVariableDefinition
 import com.apollographql.apollo.ast.GQLVariableValue
 import com.apollographql.apollo.ast.Schema
 import com.apollographql.apollo.ast.definitionFromScope
@@ -24,15 +27,45 @@ import com.apollographql.apollo.execution.InternalValue
 import com.apollographql.apollo.execution.scalarCoercingParseLiteral
 
 internal fun coerceArgumentValues(
-  schema: Schema,
-  typename: String,
-  field: GQLField,
-  coercings: Map<String, Coercing<*>>,
-  coercedVariables: Map<String, InternalValue>,
+    schema: Schema,
+    typename: String,
+    field: GQLField,
+    coercings: Map<String, Coercing<*>>,
+    coercedVariables: Map<String, InternalValue>,
 ): Map<String, InternalValue> {
-  val coercedValues = mutableMapOf<String, InternalValue>()
-  val argumentValues = field.arguments.associate { it.name to it.value }
   val argumentDefinitions = field.definitionFromScope(schema, typename)!!.arguments
+  return coerceArgumentValues(schema, coercings, argumentDefinitions, field.arguments, coercedVariables)
+}
+
+internal fun coerceArgumentValues(
+    schema: Schema,
+    variableDefinitions: List<GQLVariableDefinition>,
+    arguments: List<GQLArgument>,
+    coercings: Map<String, Coercing<*>>,
+    coercedVariables: Map<String, InternalValue>,
+): Map<String, InternalValue> {
+
+  return coerceArgumentValues(schema, coercings, variableDefinitions.map {
+    GQLInputValueDefinition(
+        sourceLocation = it.sourceLocation,
+        description = it.description,
+        name = it.name,
+        directives = it.directives,
+        type = it.type,
+        defaultValue = it.defaultValue
+    )
+  }, arguments, coercedVariables)
+}
+
+internal fun coerceArgumentValues(
+    schema: Schema,
+    coercings: Map<String, Coercing<*>>,
+    argumentDefinitions: List<GQLInputValueDefinition>,
+    arguments: List<GQLArgument>,
+    coercedVariables: Map<String, InternalValue>,
+): Map<String, InternalValue> {
+  val coercedValues = mutableMapOf<String, InternalValue>()
+  val argumentValues = arguments.associate { it.name to it.value }
 
   argumentDefinitions.forEach { argumentDefinition ->
     val argumentName = argumentDefinition.name
@@ -86,7 +119,13 @@ internal fun coerceArgumentValues(
  *
  * @throws IllegalStateException if [value] cannot be coerced.
  */
-internal fun coerceInputLiteralToInternal(schema: Schema, value: GQLValue, type: GQLType, coercings: Map<String, Coercing<*>>, coercedVariables: Map<String, InternalValue>?): InternalValue {
+internal fun coerceInputLiteralToInternal(
+    schema: Schema,
+    value: GQLValue,
+    type: GQLType,
+    coercings: Map<String, Coercing<*>>,
+    coercedVariables: Map<String, InternalValue>?,
+): InternalValue {
   if (value is GQLNullValue) {
     check(type !is GQLNonNullType) {
       "'null' found in non-null position"
@@ -166,7 +205,7 @@ internal fun coerceInputLiteralToInternal(schema: Schema, value: GQLValue, type:
         is GQLInterfaceTypeDefinition,
         is GQLObjectTypeDefinition,
         is GQLUnionTypeDefinition,
-        -> {
+          -> {
           error("Output type '${definition.name}' cannot be used in input position")
         }
 
@@ -178,7 +217,11 @@ internal fun coerceInputLiteralToInternal(schema: Schema, value: GQLValue, type:
   }
 }
 
-internal fun coerceEnumLiteralToInternal(value: GQLValue, coercings: Map<String, Coercing<*>>, definition: GQLEnumTypeDefinition): InternalValue {
+internal fun coerceEnumLiteralToInternal(
+    value: GQLValue,
+    coercings: Map<String, Coercing<*>>,
+    definition: GQLEnumTypeDefinition,
+): InternalValue {
   check(value is GQLEnumValue) {
     error("Don't know how to coerce '$value' to a '${definition.name}' enum value")
   }
@@ -196,7 +239,13 @@ internal fun coerceEnumLiteralToInternal(value: GQLValue, coercings: Map<String,
   }
 }
 
-private fun coerceInputObject(schema: Schema, definition: GQLInputObjectTypeDefinition, literalValue: GQLValue, coercings: Map<String, Coercing<*>>, coercedVariables: Map<String, InternalValue>?): InternalValue {
+private fun coerceInputObject(
+    schema: Schema,
+    definition: GQLInputObjectTypeDefinition,
+    literalValue: GQLValue,
+    coercings: Map<String, Coercing<*>>,
+    coercedVariables: Map<String, InternalValue>?,
+): InternalValue {
   if (literalValue !is GQLObjectValue) {
     error("Don't know how to coerce '$literalValue' to a '${definition.name}' input object")
   }
diff --git a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/prepare.kt b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/prepare.kt
index 99c988ce8fc..e2218a822fe 100644
--- a/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/prepare.kt
+++ b/libraries/apollo-execution/src/commonMain/kotlin/com/apollographql/apollo/execution/internal/prepare.kt
@@ -27,8 +27,8 @@ internal class PreparedRequest(
  * Parses and validates a document. When using persisted documents, the result of this function may be
  * cached for future reuse.
  */
-internal fun validateDocument(schema: Schema, document: String): Either<List<Issue>, GQLDocument> {
-  val parseResult = document.parseAsGQLDocument()
+internal fun validateDocument(schema: Schema, document: String, parserOptions: ParserOptions): Either<List<Issue>, GQLDocument> {
+  val parseResult = document.parseAsGQLDocument(parserOptions)
   var issues = parseResult.issues.filterIsInstance<GraphQLIssue>()
   if (issues.isNotEmpty()) {
     return issues.left()
@@ -98,6 +98,7 @@ internal fun Raise<String>.prepareRequest(
 internal fun Raise<String>.getPersistedDocument(
     schema: Schema,
     persistedDocumentCache: PersistedDocumentCache?,
+    parserOptions: ParserOptions,
     request: GraphQLRequest,
 ): PersistedDocument {
   val persistedQuery = request.extensions.get("persistedQuery")
@@ -125,7 +126,7 @@ internal fun Raise<String>.getPersistedDocument(
         raise("PersistedQueryNotFound")
       }
 
-      persistedDocument = validateDocument(schema, request.document).toPersistedDocument()
+      persistedDocument = validateDocument(schema, request.document, parserOptions).toPersistedDocument()
 
       /**
        * Note this code trusts the client for the id. Given that APQs are not a security
@@ -137,7 +138,7 @@ internal fun Raise<String>.getPersistedDocument(
     if (request.document == null) {
       raise("no GraphQL document found")
     }
-    persistedDocument = validateDocument(schema, request.document).toPersistedDocument()
+    persistedDocument = validateDocument(schema, request.document, parserOptions).toPersistedDocument()
   }
 
   return persistedDocument
@@ -156,12 +157,13 @@ internal fun Raise<List<Error>>.prepareRequest(
     schema: Schema,
     coercings: Map<String, Coercing<*>>,
     persistedDocumentCache: PersistedDocumentCache?,
+    parserOptions: ParserOptions,
     request: GraphQLRequest,
 ): PreparedRequest {
   val persistedDocument = withError({
     singleGraphQLError(it)
   }) {
-    getPersistedDocument(schema, persistedDocumentCache, request)
+    getPersistedDocument(schema, persistedDocumentCache, parserOptions, request)
   }
 
   if (persistedDocument is ErrorPersistedDocument) {
@@ -181,7 +183,8 @@ internal fun prepareRequest(
     schema: Schema,
     coercings: Map<String, Coercing<*>>,
     persistedDocumentCache: PersistedDocumentCache?,
+    parserOptions: ParserOptions,
     request: GraphQLRequest,
 ): Either<List<Error>, PreparedRequest> = either {
-  prepareRequest(schema, coercings, persistedDocumentCache, request)
+  prepareRequest(schema, coercings, persistedDocumentCache, parserOptions, request)
 }
\ No newline at end of file
diff --git a/libraries/apollo-execution/src/concurrentTest/kotlin/test/ExecutionTest.kt b/libraries/apollo-execution/src/concurrentTest/kotlin/test/ExecutionTest.kt
index 3829f901d91..cf2fb861ab3 100644
--- a/libraries/apollo-execution/src/concurrentTest/kotlin/test/ExecutionTest.kt
+++ b/libraries/apollo-execution/src/concurrentTest/kotlin/test/ExecutionTest.kt
@@ -2,7 +2,9 @@
 
 package test
 
+import com.apollographql.apollo.annotations.ApolloExperimental
 import com.apollographql.apollo.api.ExecutionContext
+import com.apollographql.apollo.ast.ParserOptions
 import com.apollographql.apollo.execution.ExecutableSchema
 import com.apollographql.apollo.execution.GraphQLRequest
 import com.apollographql.apollo.execution.OnError
@@ -22,6 +24,7 @@ fun String.toGraphQLRequest(): GraphQLRequest {
       .build()
 }
 
+@OptIn(ApolloExperimental::class)
 class ExecutionTest {
 
   @Test
@@ -67,12 +70,12 @@ class ExecutionTest {
     val response = ExecutableSchema.Builder()
         .schema(schema)
         .resolver { resolveInfo ->
-          resolveInfo.getArgument<Int>("first").getOrNull()?.toString(16)
+          resolveInfo.getArgument<Int>("first").getOrNull()?.toString()
         }
         .build()
         .execute(document.toGraphQLRequest(), ExecutionContext.Empty)
 
-    assertEquals(mapOf("foo" to "2a"), response.data)
+    assertEquals(mapOf("foo" to "42"), response.data)
     assertEquals(null, response.errors)
   }
 
@@ -216,4 +219,129 @@ class ExecutionTest {
           assertEquals(listOf("foo"), errors.orEmpty().single().path)
         }
   }
+
+  @Test
+  fun fragmentArgument() = runBlocking {
+    val schema = """
+            type Query {
+                foo(first: Int): String!
+            }
+        """.trimIndent()
+
+    val document = """
+            {
+                ...queryDetails(first: 42)
+            }
+            
+            fragment queryDetails(${'$'}first: Int) on Query {
+                foo(first: ${'$'}first)
+            }
+        """.trimIndent()
+
+    val response = ExecutableSchema.Builder()
+        .schema(schema)
+        .parserOptions(ParserOptions.Builder().allowFragmentArguments(true).build())
+        .resolver { resolveInfo ->
+          resolveInfo.getArgument<Int>("first").getOrNull()?.toString()
+        }
+        .build()
+        .execute(document.toGraphQLRequest(), ExecutionContext.Empty)
+
+    assertEquals(mapOf("foo" to "42"), response.data)
+    assertEquals(null, response.errors)
+  }
+
+  @Test
+  fun fragmentArgumentfromOperationVariable() = runBlocking {
+    val schema = """
+            type Query {
+                foo(first: Int): String!
+            }
+        """.trimIndent()
+
+    val document = """
+            query GetFoo(${'$'}first: Int!) {
+                ...queryDetails(first: ${'$'}first)
+            }
+            
+            fragment queryDetails(${'$'}first: Int) on Query {
+                foo(first: ${'$'}first)
+            }
+        """.trimIndent()
+
+    val response = ExecutableSchema.Builder()
+        .schema(schema)
+        .parserOptions(ParserOptions.Builder().allowFragmentArguments(true).build())
+        .resolver { resolveInfo ->
+          resolveInfo.getArgument<Int>("first").getOrNull()?.toString()
+        }
+        .build()
+        .execute(GraphQLRequest.Builder().document(document).variables(mapOf("first" to 42)).build(), ExecutionContext.Empty)
+
+    assertEquals(mapOf("foo" to "42"), response.data)
+    assertEquals(null, response.errors)
+  }
+
+  @Test
+  fun fragmentVariableTakePrecedenceOverOperationVariable() = runBlocking {
+    val schema = """
+            type Query {
+                foo(first: Int): String!
+            }
+        """.trimIndent()
+
+    val document = """
+            query GetFoo(${'$'}first: Int!) {
+                a: foo(first: ${'$'}first)
+                ...queryDetails(first: 42)
+            }
+            
+            fragment queryDetails(${'$'}first: Int) on Query {
+                foo(first: ${'$'}first)
+            }
+        """.trimIndent()
+
+    val response = ExecutableSchema.Builder()
+        .schema(schema)
+        .parserOptions(ParserOptions.Builder().allowFragmentArguments(true).build())
+        .resolver { resolveInfo ->
+          resolveInfo.getArgument<Int>("first").getOrNull()?.toString()
+        }
+        .build()
+        .execute(GraphQLRequest.Builder().document(document).variables(mapOf("first" to 43)).build(), ExecutionContext.Empty)
+
+    assertEquals(mapOf("a" to "43", "foo" to "42"), response.data)
+    assertEquals(null, response.errors)
+  }
+
+  @Test
+  fun variableReferencingOperationVariable() = runBlocking {
+    val schema = """
+            type Query {
+                foo(first: Int): String!
+            }
+        """.trimIndent()
+
+    val document = """
+            query GetFoo(${'$'}first: Int!) {
+                ...queryDetails
+            }
+            
+            fragment queryDetails on Query {
+                foo(first: ${'$'}first)
+            }
+        """.trimIndent()
+
+    val response = ExecutableSchema.Builder()
+        .schema(schema)
+        .parserOptions(ParserOptions.Builder().allowFragmentArguments(true).build())
+        .resolver { resolveInfo ->
+          resolveInfo.getArgument<Int>("first").getOrNull()?.toString()
+        }
+        .build()
+        .execute(GraphQLRequest.Builder().document(document).variables(mapOf("first" to 42)).build(), ExecutionContext.Empty)
+
+    assertEquals(mapOf("foo" to "42"), response.data)
+    assertEquals(null, response.errors)
+  }
 }
\ No newline at end of file
diff --git a/libraries/apollo-gradle-plugin-tasks/api/apollo-gradle-plugin-tasks.api b/libraries/apollo-gradle-plugin-tasks/api/apollo-gradle-plugin-tasks.api
index 26325ce379b..41254284612 100644
--- a/libraries/apollo-gradle-plugin-tasks/api/apollo-gradle-plugin-tasks.api
+++ b/libraries/apollo-gradle-plugin-tasks/api/apollo-gradle-plugin-tasks.api
@@ -61,11 +61,11 @@ public final class com/apollographql/apollo/gradle/task/ApolloGenerateIrOperatio
 public final class com/apollographql/apollo/gradle/task/ApolloGenerateOptionsEntryPoint {
 	public static final field Companion Lcom/apollographql/apollo/gradle/task/ApolloGenerateOptionsEntryPoint$Companion;
 	public fun <init> ()V
-	public static final fun run (Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/List;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;ZLjava/lang/String;ZZLjava/io/File;Ljava/io/File;Ljava/io/File;Ljava/io/File;)V
+	public static final fun run (Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/List;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;ZLjava/lang/String;ZZLjava/io/File;Ljava/io/File;Ljava/io/File;Ljava/io/File;)V
 }
 
 public final class com/apollographql/apollo/gradle/task/ApolloGenerateOptionsEntryPoint$Companion {
-	public final fun run (Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/List;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;ZLjava/lang/String;ZZLjava/io/File;Ljava/io/File;Ljava/io/File;Ljava/io/File;)V
+	public final fun run (Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/Map;Ljava/util/Map;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/Set;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/String;Ljava/util/Map;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/lang/Boolean;Ljava/util/List;Ljava/util/List;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/Boolean;Ljava/lang/String;Ljava/util/List;ZLjava/lang/String;ZZLjava/io/File;Ljava/io/File;Ljava/io/File;Ljava/io/File;)V
 }
 
 public final class com/apollographql/apollo/gradle/task/ApolloGenerateOptionsKt {
diff --git a/libraries/apollo-gradle-plugin-tasks/src/main/kotlin/com/apollographql/apollo/gradle/task/apolloGenerateOptions.kt b/libraries/apollo-gradle-plugin-tasks/src/main/kotlin/com/apollographql/apollo/gradle/task/apolloGenerateOptions.kt
index 06c3100ec0f..d079c78b09b 100644
--- a/libraries/apollo-gradle-plugin-tasks/src/main/kotlin/com/apollographql/apollo/gradle/task/apolloGenerateOptions.kt
+++ b/libraries/apollo-gradle-plugin-tasks/src/main/kotlin/com/apollographql/apollo/gradle/task/apolloGenerateOptions.kt
@@ -45,6 +45,7 @@ internal fun apolloGenerateOptions(
     generatedSchemaName: String?,
     operationManifestFormat: String?,
     severities: Map<String, String>?,
+    allowFragmentArguments: Boolean?,
     // JavaCodegenOptions
     generatePrimitiveTypes: Boolean?,
     nullableFieldStyle: String?,
@@ -110,6 +111,7 @@ internal fun apolloGenerateOptions(
       generateOptionalOperationVariables = generateOptionalOperationVariables,
       alwaysGenerateTypesMatching = alwaysGenerateTypesMatching,
       issueSeverities = severities?.convert(),
+      allowFragmentArguments = allowFragmentArguments
   ).writeTo(irOptionsFile)
 
   CodegenOptions(
diff --git a/libraries/apollo-gradle-plugin/api/apollo-gradle-plugin.api b/libraries/apollo-gradle-plugin/api/apollo-gradle-plugin.api
index aab3a652bb0..73b8d3c9787 100644
--- a/libraries/apollo-gradle-plugin/api/apollo-gradle-plugin.api
+++ b/libraries/apollo-gradle-plugin/api/apollo-gradle-plugin.api
@@ -139,6 +139,7 @@ public abstract interface class com/apollographql/apollo/gradle/api/Service {
 	public abstract fun dependsOn (Ljava/lang/Object;Z)V
 	public abstract fun getAddJvmOverloads ()Lorg/gradle/api/provider/Property;
 	public abstract fun getAddTypename ()Lorg/gradle/api/provider/Property;
+	public abstract fun getAllowFragmentArguments ()Lorg/gradle/api/provider/Property;
 	public abstract fun getAlwaysGenerateTypesMatching ()Lorg/gradle/api/provider/SetProperty;
 	public abstract fun getClassesForEnumsMatching ()Lorg/gradle/api/provider/ListProperty;
 	public abstract fun getCodegenModels ()Lorg/gradle/api/provider/Property;
@@ -244,6 +245,6 @@ public abstract interface class com/apollographql/apollo/gradle/api/Service$Outg
 }
 
 public final class com/apollographql/apollo/gradle/task/ApolloGenerateOptionsTaskKt {
-	public static synthetic fun registerApolloGenerateOptionsTask$default (Lorg/gradle/api/Project;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/gradle/api/file/FileCollection;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/file/FileCollection;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;IILjava/lang/Object;)Lorg/gradle/api/tasks/TaskProvider;
+	public static synthetic fun registerApolloGenerateOptionsTask$default (Lorg/gradle/api/Project;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/gradle/api/file/FileCollection;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/file/FileCollection;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;Lorg/gradle/api/provider/Provider;IILjava/lang/Object;)Lorg/gradle/api/tasks/TaskProvider;
 }
 
diff --git a/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/api/Service.kt b/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/api/Service.kt
index 0e29b0adc1f..0f354e5bc38 100644
--- a/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/api/Service.kt
+++ b/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/api/Service.kt
@@ -689,6 +689,13 @@ interface Service {
    */
   val decapitalizeFields: Property<Boolean>
 
+  /**
+   * Whether to allow fragment spread with arguments.
+   * Default: false
+   */
+  @ApolloExperimental
+  val allowFragmentArguments: Property<Boolean>
+
   /**
    * Configures [Introspection] to download an introspection Json schema
    */
diff --git a/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/internal/DefaultApolloExtension.kt b/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/internal/DefaultApolloExtension.kt
index f35789bc435..2f0efa220f5 100644
--- a/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/internal/DefaultApolloExtension.kt
+++ b/libraries/apollo-gradle-plugin/src/main/kotlin/com/apollographql/apollo/gradle/internal/DefaultApolloExtension.kt
@@ -475,6 +475,7 @@ abstract class DefaultApolloExtension(
         failOnWarnings = service.failOnWarnings,
         generateOptionalOperationVariables = service.generateOptionalOperationVariables,
         alwaysGenerateTypesMatching = service.alwaysGenerateTypesMatching,
+        allowFragmentArguments = service.allowFragmentArguments,
 
         /**
          * CommonCodegenOptions
diff --git a/tests/fragment-arguments/build.gradle.kts b/tests/fragment-arguments/build.gradle.kts
new file mode 100644
index 00000000000..6a0f6125052
--- /dev/null
+++ b/tests/fragment-arguments/build.gradle.kts
@@ -0,0 +1,24 @@
+@file:OptIn(ApolloExperimental::class)
+
+import com.apollographql.apollo.annotations.ApolloExperimental
+
+plugins {
+  id("org.jetbrains.kotlin.jvm")
+  id("com.apollographql.apollo")
+}
+
+apolloTest()
+
+dependencies {
+  implementation(libs.apollo.api)
+  testImplementation(libs.junit)
+  testImplementation(libs.apollo.execution)
+  testImplementation(libs.okhttp)
+}
+
+apollo {
+  service("service") {
+    packageName.set("fragment.arguments")
+    allowFragmentArguments.set(true)
+  }
+}
diff --git a/tests/fragment-arguments/src/main/graphql/operations.graphql b/tests/fragment-arguments/src/main/graphql/operations.graphql
new file mode 100644
index 00000000000..817d5e578f3
--- /dev/null
+++ b/tests/fragment-arguments/src/main/graphql/operations.graphql
@@ -0,0 +1,7 @@
+query GetFoo {
+  ...queryDetails(arg: 10)
+}
+
+fragment queryDetails($arg: Int!) on Query {
+  foo(arg: $arg)
+}
\ No newline at end of file
diff --git a/tests/fragment-arguments/src/main/graphql/schema.graphqls b/tests/fragment-arguments/src/main/graphql/schema.graphqls
new file mode 100644
index 00000000000..a0d06f2ff2e
--- /dev/null
+++ b/tests/fragment-arguments/src/main/graphql/schema.graphqls
@@ -0,0 +1,3 @@
+type Query {
+  foo(arg: Int!): Int!
+}
\ No newline at end of file
diff --git a/tests/fragment-arguments/src/test/kotlin/test/FragmentArgumentsTest.kt b/tests/fragment-arguments/src/test/kotlin/test/FragmentArgumentsTest.kt
new file mode 100644
index 00000000000..3c136c01d33
--- /dev/null
+++ b/tests/fragment-arguments/src/test/kotlin/test/FragmentArgumentsTest.kt
@@ -0,0 +1,39 @@
+package test
+
+import com.apollographql.apollo.api.json.MapJsonReader
+import com.apollographql.apollo.api.parseData
+import com.apollographql.apollo.api.parseResponse
+import com.apollographql.apollo.ast.ParserOptions
+import com.apollographql.apollo.ast.toGQLDocument
+import com.apollographql.apollo.execution.ExecutableSchema
+import com.apollographql.apollo.execution.GraphQLRequest
+import java.io.File
+import kotlin.test.Test
+import fragment.arguments.GetFooQuery
+import kotlinx.coroutines.runBlocking
+import kotlin.test.assertEquals
+
+class FragmentArguementsTest {
+  @Test
+  fun fragmentArgumentsEndToEnd() {
+    val parserOptions = ParserOptions.Builder().allowFragmentArguments(true).build()
+    val executableSchema = ExecutableSchema.Builder()
+        .schema(File("src/main/graphql/schema.graphqls").toGQLDocument())
+        .parserOptions(parserOptions)
+        .resolver {
+          42
+        }
+        .build()
+
+    val query = GetFooQuery()
+
+    val result = runBlocking {
+      executableSchema.execute(GraphQLRequest.Builder().document(query.document()).build())
+    }
+
+    val reader = MapJsonReader(result.data)
+    val data = query.parseData(reader)
+
+    assertEquals(42, data?.queryDetails?.foo)
+  }
+}
diff --git a/tests/settings.gradle.kts b/tests/settings.gradle.kts
index ff99af3862b..4642da4d911 100644
--- a/tests/settings.gradle.kts
+++ b/tests/settings.gradle.kts
@@ -29,6 +29,7 @@ listOf(
     "enums",
     "escaping",
     "filesystem-sensitivity",
+    "fragment-arguments",
     "generated-methods",
     "gzip",
     "http-cache",

From 32e079e15bc0ba5b6b141b3fff0a64a683a5f917 Mon Sep 17 00:00:00 2001
From: Martin Bonnin <martin@mbonnin.net>
Date: Tue, 24 Feb 2026 14:12:22 +0100
Subject: [PATCH 2/4] Add missing experimental flag, format

---
 .../commonMain/kotlin/com/apollographql/apollo/ast/api.kt   | 1 +
 .../commonMain/kotlin/com/apollographql/apollo/ast/gql.kt   | 1 +
 .../apollo/ast/internal/ExecutableValidationScope.kt        | 6 +-----
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
index 5c75aa146e0..9a1c2be9753 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/api.kt
@@ -77,6 +77,7 @@ class ParserOptions private constructor(
     val withSourceLocation: Boolean,
     val allowDirectivesOnDirectives: Boolean,
     val allowServiceCapabilities: Boolean,
+    @ApolloExperimental
     val allowFragmentArguments: Boolean
 ) {
   class Builder {
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
index c3b0ddaae41..9142eb433a8 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gql.kt
@@ -233,6 +233,7 @@ class GQLOperationDefinition(
 class GQLFragmentDefinition @ApolloExperimental constructor(
     override val sourceLocation: SourceLocation? = null,
     override val name: String,
+    @ApolloExperimental
     val variableDefinitions: List<GQLVariableDefinition>,
     override val directives: List<GQLDirective>,
     val typeCondition: GQLNamedType,
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
index 14d52d05c69..7b91d7925f9 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
@@ -122,11 +122,7 @@ internal class ExecutableValidationScope(
             val index = path.indexOf("__${name}")
             val nextPath = path + "__${fragment.name}"
             if (index != -1) {
-              issues.add(FragmentCycle("Fragment '$name' spreads itself, creating a cycle at '${
-                nextPath.subList(index, nextPath.size).joinToString(".")
-              }'", it.sourceLocation
-              )
-              )
+              issues.add(FragmentCycle("Fragment '$name' spreads itself, creating a cycle at '${nextPath.subList(index, nextPath.size).joinToString(".")}'", it.sourceLocation))
               cyclicFragments.add(name)
               return@forEach
             }

From 8328e27763fe3acac22ee1f37ad58481318d5835 Mon Sep 17 00:00:00 2001
From: Martin Bonnin <martin@mbonnin.net>
Date: Tue, 24 Feb 2026 15:12:07 +0100
Subject: [PATCH 3/4] Update
 libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt

Co-authored-by: Benoit 'BoD' Lubek <BoD@JRAF.org>
---
 .../apollo/ast/internal/ExecutableValidationScope.kt            | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
index 7b91d7925f9..a6114882b32 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExecutableValidationScope.kt
@@ -411,7 +411,7 @@ internal class ExecutableValidationScope(
     validateVariableUsages(variableDefinitions, ownVariableUsages, context = "fragment `$name`")
 
     /**
-     * We only track the variables that are not by this fragment.
+     * We only track the variables that are not defined by this fragment.
      */
     fragmentOperationVariableUsages[name] = operationVariableUsages
   }

From 8c74b4d2ec22491065c62bcdfb91106e9c25e8c4 Mon Sep 17 00:00:00 2001
From: Martin Bonnin <martin@mbonnin.net>
Date: Tue, 24 Feb 2026 17:19:15 +0100
Subject: [PATCH 4/4] fix validation of nested fragments

---
 .../apollo/ast/internal/ExtensionsMerger.kt   |   2 +-
 .../apollo/ast/internal/fields_merging.kt     | 112 ++++++++----------
 .../nested_merge_error.expected               |   5 +
 .../nested_merge_error.graphql                |  27 +++++
 4 files changed, 82 insertions(+), 64 deletions(-)
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.expected
 create mode 100644 libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.graphql

diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExtensionsMerger.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExtensionsMerger.kt
index 021079e63f4..3ab2e3b8283 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExtensionsMerger.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/ExtensionsMerger.kt
@@ -530,7 +530,7 @@ internal fun areEqual(a: GQLValue?, b: GQLValue?): Boolean {
       if (b !is GQLObjectValue) {
         false
       } else {
-        // TODO: Can object literal have duplicate fields?
+        // TODO: Can object literals have duplicate fields?
         if (a.fields.size != b.fields.size) {
           false
         } else {
diff --git a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
index 30dd5a85a8f..6664e223b34 100644
--- a/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
+++ b/libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/internal/fields_merging.kt
@@ -59,7 +59,47 @@ private fun IssuesScope.addDifferentShapeIssue(path: List<String>, message: Stri
 private data class ValidationContext(
     val schema: Schema,
     val fragments: Map<String, GQLFragmentDefinition>,
-)
+) {
+  val variableValuesInScope = mutableListOf<Map<String, GQLValue>>()
+
+  fun pushFragment(arguments: List<GQLArgument>, variableDefinitions: List<GQLVariableDefinition>) {
+    val newValues = mutableMapOf<String, GQLValue>()
+    variableDefinitions.forEach { variableDefinition ->
+      val argument = arguments.firstOrNull { it.name == variableDefinition.name }
+      if (argument == null) {
+        if (variableDefinition.defaultValue != null) {
+          newValues.put(variableDefinition.name, variableDefinition.defaultValue)
+        }
+      } else {
+        newValues.put(variableDefinition.name, substituteVariables(argument.value))
+      }
+    }
+    variableValuesInScope.add(variableValuesInScope.lastOrNull().orEmpty() + newValues)
+  }
+
+  fun substituteVariables(value: GQLValue): GQLValue {
+    return when (value) {
+      is GQLBooleanValue -> value
+      is GQLEnumValue -> value
+      is GQLFloatValue -> value
+      is GQLIntValue -> value
+      is GQLListValue -> value.copy(values = value.values.map { substituteVariables(it) })
+      is GQLNullValue -> value
+      is GQLObjectValue -> value.copy(fields = value.fields.map { it.copy(value = substituteVariables(it.value)) })
+      is GQLStringValue -> value
+      is GQLVariableValue -> variableValue(value.name)
+    }
+  }
+
+  fun popFragment() {
+    variableValuesInScope.removeLast()
+  }
+
+  fun variableValue(variableName: String): GQLValue {
+    // the variableName may not exist in the operation, which validation should catch
+    return variableValuesInScope.lastOrNull()?.get(variableName) ?: GQLVariableValue(null, variableName)
+  }
+}
 
 @OptIn(ApolloExperimental::class)
 private fun collectFields(
@@ -97,15 +137,12 @@ private fun collectFields(
       is GQLFragmentSpread -> {
         val fragment = context.fragments[selection.name]
         if (fragment != null) {
-          // Use name + arguments as key so same fragment with different arguments is collected twice
           val fragmentType = context.schema.typeDefinitions[fragment.typeCondition.name]
           if (fragmentType != null) {
-            val selections = if (selection.arguments.isNotEmpty() && fragment.variableDefinitions.isNotEmpty()) {
-              substituteFragmentVariables(fragment.selections, fragment.variableDefinitions, selection.arguments)
-            } else {
-              fragment.selections
-            }
+            context.pushFragment(selection.arguments, fragment.variableDefinitions)
+            val selections = fragment.selections.map { it.substituteVariables(context) }
             collectFields(fieldMap, selections, fragmentType, context)
+            context.popFragment()
           }
         }
       }
@@ -334,67 +371,16 @@ private fun buildMessage(path: List<String>, message: String): String {
       "$message. Use different aliases on the fields to fetch both if this was intentional."
 }
 
-/**
- * Substitutes fragment variable references in selections with actual argument values.
- * This ensures field merging compares resolved values when a fragment is spread with arguments.
- */
 @OptIn(ApolloExperimental::class)
-private fun substituteFragmentVariables(
-    selections: List<GQLSelection>,
-    variableDefinitions: List<GQLVariableDefinition>,
-    arguments: List<GQLArgument>,
-): List<GQLSelection> {
-  val argMap = mutableMapOf<String, GQLValue>()
-  for (varDef in variableDefinitions) {
-    val arg = arguments.firstOrNull { it.name == varDef.name }
-    if (arg != null) {
-      argMap[varDef.name] = arg.value
-    } else if (varDef.defaultValue != null) {
-      argMap[varDef.name] = varDef.defaultValue
-    }
-  }
-  if (argMap.isEmpty()) return selections
-  return selections.map { it.substituteVariables(argMap) }
-}
-
-@OptIn(ApolloExperimental::class)
-private fun GQLSelection.substituteVariables(argMap: Map<String, GQLValue>): GQLSelection {
+private fun GQLSelection.substituteVariables(context: ValidationContext): GQLSelection {
   return when (this) {
-    is GQLField -> GQLField(
-        sourceLocation = sourceLocation,
-        alias = alias,
-        name = name,
+    is GQLField -> copy(
         arguments = arguments.map { arg ->
-          GQLArgument(
-              sourceLocation = arg.sourceLocation,
-              name = arg.name,
-              value = arg.value.substituteVariables(argMap)
-          )
-        },
-        directives = directives,
-        selections = selections.map { it.substituteVariables(argMap) }
-    )
-
-    is GQLInlineFragment -> GQLInlineFragment(
-        sourceLocation = sourceLocation,
-        typeCondition = typeCondition,
-        directives = directives,
-        selections = selections.map { it.substituteVariables(argMap) }
+          arg.copy(value = context.substituteVariables(arg.value))
+        }
     )
 
+    is GQLInlineFragment -> this
     is GQLFragmentSpread -> this
   }
 }
-
-private fun GQLValue.substituteVariables(argMap: Map<String, GQLValue>): GQLValue {
-  return when (this) {
-    is GQLVariableValue -> argMap[name] ?: this
-    is GQLListValue -> GQLListValue(sourceLocation = sourceLocation, values = values.map { it.substituteVariables(argMap) })
-    is GQLObjectValue -> GQLObjectValue(
-        sourceLocation = sourceLocation,
-        fields = fields.map { GQLObjectField(sourceLocation = it.sourceLocation, name = it.name, value = it.value.substituteVariables(argMap)) }
-    )
-
-    else -> this
-  }
-}
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.expected b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.expected
new file mode 100644
index 00000000000..b09ca218710
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.expected
@@ -0,0 +1,5 @@
+OtherValidationIssue (14:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
+------------
+OtherValidationIssue (8:3)
+Field at path `users` conflicts with another field: they have different arguments. Use different aliases on the fields to fetch both if this was intentional.
\ No newline at end of file
diff --git a/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.graphql b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.graphql
new file mode 100644
index 00000000000..6ec7f4c96df
--- /dev/null
+++ b/libraries/apollo-ast/test-fixtures/validation/executable/fragment_arguments/nested_merge_error.graphql
@@ -0,0 +1,27 @@
+# PRAGMA allowFragmentArguments
+
+fragment queryDetails0($first: Int!) on Query {
+  ...queryDetails1(first: $first)
+}
+
+fragment queryDetails1($first: Int!) on Query {
+  users(first: $first) {
+    totalCount
+  }
+}
+
+query GetFoo($first: Int!, $second: Int!) {
+  users(first: $first) {
+    totalCount
+  }
+  # invalid: different variables
+  ...queryDetails0(first: $second)
+}
+
+query GetFoo1($first: Int!) {
+  users(first: $first) {
+    totalCount
+  }
+  # valid
+  ...queryDetails0(first: $first)
+}