fix(parser): Check comma in JSX expr lazily

[leaysgur]

Part of #9705, fixes #10578.

Continuing to treat the following code as an error:

// conformance/jsx/jsxParsingError1.tsx
<div className={class1, class2}/>

also enables the following code to be parsed:

// conformance/jsx/jsxReactTestSuite.tsx
<Comp {...(z = { a: "1" }, z)} />

by deferring the check to the semantic checker.

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[coderabbitai]

Walkthrough

The changes relocate the diagnostic enforcement for disallowing the comma operator within JSX expressions from the parser to the semantic checker. Specifically, the function responsible for generating the relevant diagnostic, jsx_expressions_may_not_use_the_comma_operator, was removed from the parser’s diagnostics module and reimplemented within the semantic checker’s TypeScript diagnostics. Correspondingly, the parser’s JSX assignment expression parsing logic was simplified to remove explicit checks for sequence expressions using the comma operator. Instead, the semantic checker now performs this validation by checking for sequence expressions within JSX expression containers and reporting the error with the appropriate diagnostic. No changes were made to public interfaces, except for the removal and addition of the diagnostic function in their respective modules.

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Reviewing files that changed from the base of the PR and between 0105253 and bd0f1eb.

⛔ Files ignored due to path filters (1)

• tasks/coverage/snapshots/estree_typescript.snap is excluded by !**/*.snap

📒 Files selected for processing (3)

• crates/oxc_parser/src/diagnostics.rs (0 hunks)
• crates/oxc_parser/src/jsx/mod.rs (1 hunks)
• crates/oxc_semantic/src/checker/typescript.rs (2 hunks)

💤 Files with no reviewable changes (1)

• crates/oxc_parser/src/diagnostics.rs

🧰 Additional context used

🧬 Code Graph Analysis (1)

crates/oxc_semantic/src/checker/typescript.rs (2)

npm/oxc-types/types.d.ts (3)

• Span (1514-1517)
• JSXExpression (923-923)
• SequenceExpression (318-321)

crates/oxc_parser/src/diagnostics.rs (1)

• ts_error (9-15)

⏰ Context from checks skipped due to timeout of 90000ms (14)

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🔇 Additional comments (3)

crates/oxc_parser/src/jsx/mod.rs (1)

301-305: Simplified JSX expression parsing by removing direct comma operator validation.

The code now defers checking for disallowed comma operators to the semantic checker rather than handling it during parsing. This simplification aligns with the PR objective of making comma expression checks lazy, which enables parsing of previously problematic code like <Comp {...(z = { a: "1" }, z)} /> while still treating them as semantic errors later.

crates/oxc_semantic/src/checker/typescript.rs (2)

548-552: Good implementation of the diagnostic function for comma operators in JSX.

The new diagnostic function correctly implements the TypeScript error TS18007 with appropriate error message and help text.

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564-566: Correctly implements semantic validation for comma operators in JSX expressions.

This change completes the move of comma operator validation from the parser to the semantic checker. The code now checks if a JSX expression container contains a sequence expression (comma operator) and reports the appropriate error. This implementation enables the parser to parse but semantically reject expressions like <div className={class1, class2}/>.

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[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #10739 will not alter performance

_{Comparing fix/lazy-comma-check-jsx-expr (bd0f1eb) with main (0105253)}

Summary

✅ 36 untouched benchmarks