jquery / jquery/esprima

Parses invalid yield in for-in statement

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Dominant language
TypeScript
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Description

When a yield (@mikesherov ) appears within the Initializer of an AssignmentElement outside of a generator function body, it behaves as an IdentifierReference. (For..in statement)

Steps to reproduce
esprima.parse('for ([ x = yield ] in [[]]) ;')
Expected output

Should throw

Actual output

Parses invalid AST

Contributor guide

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the esprima.parse reproduction shown in the issue and trace how the parser handles yield inside the for-in initializer. Confirm that the invalid input throws instead of producing an AST, and use the reproduction to verify the completed behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
45/100

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