Add a Recursion Breaker to Opaque Type Substitution #40971
Merged
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
|
@swift-ci smoke test |
CodaFi
force-pushed
the
hitting-the-stacks
branch
from
10cfe59 to
33168de
Compare
|
@swift-ci smoke test |
|
Docker's busted @swift-ci smoke test Linux platform |
The current check in MiscDiagnostics can only handle local 2-cycles as in:
func foo() -> some P { return bar() }
func bar() -> some P { return foo() }
Larger cycles, such as the 3-cycle present in the validation test in this patch cannot be detected without resolving all substitutions up front. Therefore, we take the tact that we can at least prevent the compiler from crashing. At runtime, instead, type resolution will blow out the stack.
The check here is simple: Plumb through a set of opaque type decls that the resolution machinery has already seen, and if we encounter a recursive opaque type substitution bail with the original opaque type.
rdar://87121502
CodaFi
force-pushed
the
hitting-the-stacks
branch
from
33168de to
ad94cbd
Compare
|
@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Outdated suggestions cannot be applied.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.
The current check in MiscDiagnostics can only handle local 2-cycles as in:
func foo() -> some P { return bar() }
func bar() -> some P { return foo() }
Larger cycles, such as the 3-cycle present in the validation test in this patch cannot be detected without resolving all substitutions up front. Therefore, we take the tact that we can at least prevent the compiler from crashing. At runtime, instead, type resolution will blow out the stack.
The check here is simple: Plumb through a set of opaque type decls that the resolution machinery has already seen, and if we encounter a recursive opaque type substitution bail with the original opaque type.
rdar://87121502