Improve constraints for non-homomorphic mapped types #29121
Merged
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This PR improves our logic for reasoning over constraints for non-homomorphic mapped types (such as
Pick<T, K>
andRecord<K, T>
). Previously we would only produce non-empty constraints for non-homomorphic mapped types with generic key types in very limited scenarios. Now we do much better. For example, all of the following were previously errors, but now none of them are:Fixes #28821.