feat(slang): integer literal narrowing

[hedgar2017]

Consumes slang's new literal-typing accessors to narrow integer literal emission, replaces the digit-count width heuristic, and unifies constant emission through a single builder entry point.

What's new

• Uses decimal.value(), hex.value(), literal_type.kind() — no more reaching into slang's evaluator or ir_node fields.
• Single Builder::emit_constant(&BigInt, Type) for all integer constants — dispatches to sol.address_cast, arith.constant, or sol.constant by target type.
• Deletes the text-based decimal/hex emitters, the boolean-specific helper, and the digit-count width heuristic.
• Supports rational decimals that reduce to integers (1.5 ether, 0.5 gwei), scientific notation (1e18, 2.5e10), and signed negatives via slang's prefix-expression fold.

Depends on NomicFoundation/slang#1722.

Newly passing tests

• tests/solidity/simple/constant_expressions/literal_types.sol — digit separators, underscored hex, address literal, ether/days units, zero, negative int8 literals, boolean keywords.
• tests/solidity/simple/constant_expressions/rational_literals.sol — 0.5 minutes, 0.5 gwei, 0.25 ether, 0.5 ether, 1.5 ether, 1e3, 1.5e3, 1e18.
• Six pre-existing tests recovered from the signed-negative path: loop/range_bound/{i8,i16,i32_lower,i64_lower}.sol::main, operator/arithmetic/exponentiation_i128_const.sol::{ordinar_positive,to_max}.

Known regression

• constant_expressions/bitwise.sol::test regresses from PASS to FAIL. Slang's binder does not fold binary expressions of literal operands, so the narrowed leaf widths (1 : ui8, 100 : ui8) cause 1 << 100 and similar constant subexpressions to overflow at 8-bit width. The previous code masked this by mapping every LiteralKind to ui256. Tracked by a TODO in resolve_expression_type; proper fix is constant-expression folding either upstream in slang's binder (matching solc's RationalNumberType::binaryOperatorResult) or locally in solx-slang.

[Copilot]

Pull request overview

This PR refactors Solidity literal lowering to route integer literal evaluation through Slang’s CompileConstantEvaluator and Slang literal width metadata, replacing local heuristics and per-format emitters. It also expands literal support to cover unit-multiplied rational decimals that fold to integers.

Changes:

• Add a unified Builder::emit_constant(&BigInt, Type) (plus emit_bool) and update call sites to use it for integer/address/bool constants.
• Switch decimal/hex literal lowering to Slang’s constant evaluator and resolve literal MLIR types via Slang’s literal-kind width metadata.
• Add new Solidity test cases covering literal typing edge cases and rational unit literals; update Slang dependency rev and lockfile accordingly.

Reviewed changes

Copilot reviewed 11 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
solx-mlir/src/context/builder/mod.rs	Introduces emit_constant(BigInt, Type) and emit_bool, consolidating constant emission and handling address/bool specially.
solx-slang/src/ast/contract/function/expression/mod.rs	Uses Slang constant evaluator for decimal/hex literals and emits constants via the new builder API.
solx-slang/src/ast/contract/function/expression/call/type_conversion.rs	Maps Slang literal kinds to narrower MLIR integer widths (including address/zero).
solx-slang/src/ast/contract/function/statement/control_flow.rs	Replaces boolean constant emission with emit_bool.
solx-slang/src/ast/contract/function/expression/logical.rs	Replaces boolean constant emission with emit_bool.
solx-slang/src/ast/contract/function/expression/arithmetic.rs	Adjusts call sites for updated constant helpers and minor unwrap_or cleanup.
solx-slang/src/ast/contract/function/statement/mod.rs	Minor unwrap_or cleanup for return-type fallback.
tests/solidity/simple/literal_types.sol	New test coverage for literal typing (separators, hex underscores, address literal, units, negatives, booleans).
tests/solidity/simple/rational_literals.sol	New test coverage for rational decimal literals with units that fold to integers.
solx-slang/Cargo.toml	Adds num workspace dep and bumps slang_solidity git rev.
solx-mlir/Cargo.toml	Adds num workspace dep.
Cargo.lock	Updates lockfile for the new Slang rev and transitive dependency changes.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 12 changed files in this pull request and generated no new comments.

[abinavpp]

thank you! not sure if we already have a lit test for this.

[hedgar2017]

@abinavpp thanks, lemme check and see if I can add a couple just in case!

[hedgar2017]

@abinavpp added one for literals, thanks!