refactor(slang): use StringExpression::value() from Slang

Replace the local concatenate_string_literals method with the upstream
StringExpression::value() added to Slang. Bump slang_solidity rev to
dd83dd2 which includes the new method.

Author: hedgar2017

Cargo.lock

@@ -16,7 +16,7 @@ semver.workspace = true
 # `__private_testing_utils` is required by `__private_backend_api` internals
 # (binder/types access in node_extensions). Both are unstable Slang APIs.
 # TODO: pin to a release tag instead of branch = "main"
-slang_solidity = { git = "https://github.com/NomicFoundation/slang.git", rev = "a01bc76b742173941cea1aff0b3b68a9006b38b8", features = ["__private_backend_api", "__private_testing_utils"] }
+slang_solidity = { git = "https://github.com/NomicFoundation/slang.git", rev = "dd83dd286dea844ce88a7a2748e16d94c65a0d22", features = ["__private_backend_api", "__private_testing_utils"] }
 melior = { git = "https://github.com/NomicFoundation/melior", rev = "62a909e2ff67fcc19f7f42dc4fb70c3e03376bd2", features = ["ods-dialects", "helpers"] }
 
 solx-codegen-evm = { path = "../solx-codegen-evm" }

solx-slang/Cargo.toml

@@ -103,10 +103,10 @@ impl<'emitter, 'state, 'context, 'block> CallEmitter<'emitter, 'state, 'context,
             let condition = args.next().expect("length checked above");
             let message_arg = args.next();
             let message = match &message_arg {
-                Some(Expression::StringExpression(string_expression)) => Some(
-                    self.expression_emitter
-                        .concatenate_string_literals(string_expression),
-                ),
+                Some(Expression::StringExpression(string_expression)) => {
+                    let bytes = string_expression.value();
+                    Some(String::from_utf8(bytes).expect("require message is valid UTF-8"))
+                }
                 Some(_) => anyhow::bail!("require message must be a string literal"),
                 None => None,
             };

solx-slang/src/ast/contract/function/expression/call/mod.rs

@@ -21,7 +21,6 @@ use melior::ir::r#type::IntegerType;
 use slang_solidity::backend::SemanticAnalysis;
 use slang_solidity::backend::ir::ast::Definition;
 use slang_solidity::backend::ir::ast::Expression;
-use slang_solidity::backend::ir::ast::StringExpression;
 use slang_solidity::cst::NodeId;
 
 use solx_mlir::CmpPredicate;
@@ -140,8 +139,9 @@ impl<'state, 'context, 'block> ExpressionEmitter<'state, 'context, 'block> {
                 Ok((Some(value), block))
             }
             Expression::StringExpression(string_expression) => {
-                let text = self.concatenate_string_literals(string_expression);
-                let value = self.state.builder.emit_sol_string_lit(&text, &block);
+                let bytes = string_expression.value();
+                let text = std::str::from_utf8(&bytes).expect("string literal is valid UTF-8");
+                let value = self.state.builder.emit_sol_string_lit(text, &block);
                 Ok((Some(value), block))
             }
             Expression::Identifier(identifier) => {
@@ -392,30 +392,4 @@ impl<'state, 'context, 'block> ExpressionEmitter<'state, 'context, 'block> {
             bits.div_ceil(solx_utils::BIT_LENGTH_BYTE as u32) * solx_utils::BIT_LENGTH_BYTE as u32;
         rounded.min(solx_utils::BIT_LENGTH_FIELD as u32)
     }
-
-    /// Concatenates string terminals from a `StringExpression::Strings` into a
-    /// single string, stripping the surrounding double quotes from each terminal.
-    ///
-    /// # Panics
-    ///
-    /// Panics if the expression is a hex or unicode string literal (not yet
-    /// supported), or if a terminal is not properly quoted.
-    pub(super) fn concatenate_string_literals(
-        &self,
-        string_expression: &StringExpression,
-    ) -> String {
-        let StringExpression::Strings(terminals) = string_expression else {
-            panic!("hex and unicode string literals are not yet supported");
-        };
-        let mut result = String::new();
-        for terminal in terminals {
-            let raw = terminal.text.as_str();
-            let content = raw
-                .strip_prefix('"')
-                .and_then(|stripped| stripped.strip_suffix('"'))
-                .expect("string terminal must be quoted");
-            result.push_str(content);
-        }
-        result
-    }
 }