AST: Refine name lookup rule for protocol extension 'where' clauses #72364
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
slavapestov
requested review from
AnthonyLatsis,
hborla and
xedin
as code owners
|
@swift-ci Please smoke test |
|
@swift-ci Please test source compatibility |
We have two "levels" of name lookup, and the more primitive level is used by name lookup itself to avoid certain cycles. For example, extension binding, resolution of inheritance clauses, etc. One interesting case is that a protocol extension can impose additional requiremnts on `Self`, and members of the right-hand side type are visible to unqualified lookup. The right-hand side of a `Self` requirement in this case is always a protocol type or class type canonically, but it might be written to refer to a protocol type alias. Before some changes for noncopyable generics, the primitive name lookup mechanism, implemented in directReferencesForTypeRepr() and such, would check if the TypeRepr had already been resolved by resolveType(). If so, it would immediately return the decl. This masked an issue, where the right-hand side of a `Self` requirement was resolved in the parent DeclContext. A more subtle rule is needed; for a protocol extension, we must resolve the right-hand side in the protocol, but disregard the protocol extension's `Self` requirements, because doing so would recursively trigger the same lookup again. Fixes rdar://problem/124498054.
slavapestov
force-pushed
the
fix-rdar124498054
branch
from
625f204 to
e46a0c5
Compare
|
@swift-ci Please 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Outdated suggestions cannot be applied.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.
We have two "levels" of name lookup, and the more primitive level is
used by name lookup itself to avoid certain cycles. For example,
extension binding, resolution of inheritance clauses, etc.
One interesting case is that a protocol extension can impose additional
requiremnts on
Self, and members of the right-hand side type arevisible to unqualified lookup.
The right-hand side of a
Selfrequirement in this case is always aprotocol type or class type canonically, but it might be written to
refer to a protocol type alias.
Before some changes for noncopyable generics, the primitive name
lookup mechanism, implemented in directReferencesForTypeRepr() and
such, would check if the TypeRepr had already been resolved by
resolveType(). If so, it would immediately return the decl.
This masked an issue, where the right-hand side of a
Selfrequirementwas resolved in the parent DeclContext. A more subtle rule is needed;
for a protocol extension, we must resolve the right-hand side in the
protocol, but disregard the protocol extension's
Selfrequirements,because doing so would recursively trigger the same lookup again.
Fixes rdar://problem/124498054.