Port "Check if switch statements are exhaustive when their expressions is generic with a literal type constraint" #1071
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…s is generic with a literal type constraint"
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Pull Request Overview
This PR ports the “exhaustive switch” behavior for generic literal type constraints, addressing #986.
- Adds a new test case (exhaustiveSwitchStatementsGeneric1.ts) to validate exhaustive switch statements on generic types.
- Updates baseline reference files (.types and .symbols) to reflect the changes.
- Adjusts the flow checker in internal/checker/flow.go to use getBaseConstraintOrType for improved type handling.
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| testdata/tests/cases/compiler/exhaustiveSwitchStatementsGeneric1.ts | Introduces a test case demonstrating exhaustive switch on generic literal type constraints. |
| testdata/baselines/reference/compiler/exhaustiveSwitchStatementsGeneric1.types | Updates type baseline output for the new test. |
| testdata/baselines/reference/compiler/exhaustiveSwitchStatementsGeneric1.symbols | Updates symbol baseline output for the new test. |
| internal/checker/flow.go | Modifies type retrieval to use getBaseConstraintOrType for proper enforcement of exhaustiveness. |
jakebailey
approved these changes
Jun 5, 2025
auto-merge was automatically disabled
June 5, 2025 23:16
Pull request was closed
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ports microsoft/TypeScript#60644
fixes #986