GSB: Fix maybeResolveEquivalenceClass() with member type of superclass-constrained type [5.3] #31923
Conversation
This file contains hidden or 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
… when resolving equivalence classes
…s-constrained type Name lookup might find an associated type whose protocol is not in our conforms-to list, if we have a superclass constraint and the superclass conforms to the associated type's protocol. We used to return an unresolved type in this case, which would result in the constraint getting delayed forever and dropped. While playing wack-a-mole with regressing crashers, I had to do some refactoring to get all the tests to pass. Unfortuanately these refactorings don't lend themselves well to being peeled off into their own commits: - maybeAddSameTypeRequirementForNestedType() was almost identical to concretizeNestedTypeFromConcreteParent(), except for superclasses instead of concrete same-type constraints. I merged them together. - We used to drop same-type constraints where the subject type was an ErrorType, because maybeResolveEquivalenceClass() would return an unresolved type in this case. This violated some invariants around nested types of ArchetypeTypes, because now it was possible for a nested type of a concrete type to be non-concrete, if the type witness in the conformance was missing due to an error. Fix this by removing the ErrorType hack, and adjusting a couple of other places to handle ErrorTypes in order to avoid regressing with invalid code. Fixes <rdar://problem/45216921>, <https://bugs.swift.org/browse/SR-8945>, <https://bugs.swift.org/browse/SR-12744>.
tkremenek
approved these changes
Jun 17, 2020
|
@swift-ci test and merge |
AnthonyLatsis
added
swift 5.3
🍒 release cherry pick
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.
Name lookup might find an associated type whose protocol is not in our
conforms-to list, if we have a superclass constraint and the superclass
conforms to the associated type's protocol.
We used to return an unresolved type in this case, which would result in
the constraint getting delayed forever and dropped.
While playing wack-a-mole with regressing crashers, I had to do some
refactoring to get all the tests to pass. Unfortuanately these refactorings
don't lend themselves well to being peeled off into their own commits:
maybeAddSameTypeRequirementForNestedType() was almost identical to
concretizeNestedTypeFromConcreteParent(), except for superclasses
instead of concrete same-type constraints. I merged them together.
We used to drop same-type constraints where the subject type was an
ErrorType, because maybeResolveEquivalenceClass() would return an
unresolved type in this case.
This violated some invariants around nested types of ArchetypeTypes,
because now it was possible for a nested type of a concrete type to
be non-concrete, if the type witness in the conformance was missing
due to an error.
Fix this by removing the ErrorType hack, and adjusting a couple of
other places to handle ErrorTypes in order to avoid regressing with
invalid code.
Fixes rdar://problem/45216921, https://bugs.swift.org/browse/SR-8945,
https://bugs.swift.org/browse/SR-12744.