Three fixes to SAM type handling #21596
Merged
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Outdated suggestions cannot be applied.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.
The first two fixes concern characterization of SAM types. One condition of a SAM type is that it can be instantiated with an empty argument list. This was implemented incorrectly. First, we missed the case where the SAM type is a trait with a parent class that takes arguments. In this case the SAM type cannot be instantiated with an empty argument list. Second, we missed the case where the SAM type constructor has a single vararg parameter. In this case the SAM type can be instantiated with an empty argument list.
The second case was also translated incorrectly which led to illegal bytecodes.
Fixes #15855