Fixed an issue with reverse mapped types inference when single type variable is left after inferring from matching types #55941
Conversation
This file contains 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
…ariable is left after inferring from matching types
Andarist
commented
Oct 2, 2023
src/compiler/checker.ts
Outdated
| @@ -25078,7 +25078,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker { | |||
| target = getIntersectionType(targets); | |||
| } | |||
| } | |||
| else if (target.flags & (TypeFlags.IndexedAccess | TypeFlags.Substitution)) { | |||
| if (target.flags & (TypeFlags.IndexedAccess | TypeFlags.Substitution)) { | |||
There was a problem hiding this comment.
preceding logic (such as the one responsible for inferring from matching types in unions here) could "reduce" the target in various ways - potentially to leaving indexed access or substitution in the target (when the target doesn't start as such). For that reason, we always need to getActualTypeVariable here as it should be called on the "reduced" target and not based on the pre-reduction flags (which sort of happened when this condition was used as just a fallback branch)
weswigham
approved these changes
Nov 1, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
No description provided.