Restrict captureWildcards to only be used if needed #16799
Merged
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
dwijnand
added
the
backport:nominated
|
seems really elegant! |
odersky
requested changes
Feb 3, 2023
Rather than blindly using the newly wildcard-captured type, check that it's compatible with the proto/formal type. That way values that have wildcard types can be passed, uncast, to extension methods that don't require the capture. For instance in specs2, a value of type `Class[? <: Foo]` needn't become `Class[?1.CAP]` just so it can be applied to `def theValue[T](t: => T)`. For the zio-http case, despite knowing that JFuture is morally covariant, we don't have any way to knowing that - so we must be safe and error.
dwijnand
force-pushed
the
let-wildtypes-run-free
branch
from
1c0e383
to
11854bb
Compare
odersky
approved these changes
Feb 4, 2023
Kordyjan
added
backport:accepted
dwijnand
removed
the
backport:accepted
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Outdated suggestions cannot be applied.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.
Rather than blindly using the newly wildcard-captured type, check that
it's compatible with the proto/formal type. That way values that have
wildcard types can be passed, uncast, to extension methods that don't
require the capture.
For instance in specs2, a value of type
Class[? <: Foo]needn't becomeClass[?1.CAP]just so it can be applied todef theValue[T](t: => T).For the zio-http case, despite knowing that JFuture is morally
covariant, we don't have any way to knowing that - so we must be safe
and error.