Port "Check if switch statements are exhaustive when their expressions is generic with a literal type constraint"#1071
Merged
jakebailey merged 1 commit intomicrosoft:mainfrom Jun 5, 2025
Conversation
…s is generic with a literal type constraint"
Contributor
There was a problem hiding this comment.
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
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
ports microsoft/TypeScript#60644
fixes #986