Update Sema cast checks for subclass existentials... and more! #8876
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
|
@swift-ci Please smoke test |
|
@swift-ci smoke test Linux |
Normally there is very little the type checker can conclude about casts between existentials, because new conformances can be added retroactively. However if the existentials are class-constrained, we can rule out certain casts as always failing by looking at superclass bounds.
…asses We would misreport a cast from G<T> to G<Int> or vice versa as always failing, because we were checking for an exact subtype relationship instead of archetype binding. Fixes <https://bugs.swift.org/browse/SR-3609>.
... if the value is 'nil'! Fixes <https://bugs.swift.org/browse/SR-3505>.
slavapestov
force-pushed
the
subclass-existentials-sema-casts
branch
from
b72bde4
to
191afb0
Compare
|
@swift-ci smoke test Linux |
|
@swift-ci smoke test |
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Outdated suggestions cannot be applied.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.
Fixes https://bugs.swift.org/browse/SR-3609, https://bugs.swift.org/browse/SR-3505, rdar://problem/22298598.