microsoft / microsoft/TypeScript

numeric literal types disrespect arithmetics

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Description

declare var a : -1 | 0 | 1;
a = -a; // <-- problem

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 by reproducing the minimal example in the issue and tracing how the TypeScript type checker handles numeric literal types and unary arithmetic. No file or test is named; done should include a decided and tested behavior for assigning the negated value to the declared literal union.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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