Skip to content

Sema: Members with availability in unavailable containers should be unavailable #58680

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
May 5, 2022

Conversation

tshortli
Copy link
Contributor

@tshortli tshortli commented May 5, 2022

When computing potential unavailability of a decl, first check whether the decl is explicitly unavailable and the context is also unavailable. If those conditions are met, treat the decl as if it were always available since unavailable code is allowed to reference unavailable decls.

Previously, TypeChecker::checkDeclarationAvailability() would behave this way for most explicitly unavailable decls by accident. An explicitly unavailable decl has no introduction version, and the existing logic therefore would fail to find a lower bound on the availability of the decl. The edge case that exposed the fragility of this logic was an unavailable extension containing a member with its own explicit availability. The unavailability of the extension ought to trump the availability of the member, but the existing logic couldn't detect that.

The compiler also ought to diagnose the conflicting availability annotations but I'd like to address that separately.

Resolves rdar://92551870

…whether the decl is explicitly unavailable and the context is also unavailable. If those conditions are met, treat the decl as if it were always available since unavailable code is allowed to reference unavailable decls.

Previously, `TypeChecker::checkDeclarationAvailability()` would behave this way for most explicitly unavailable decls by _accident_. An explicitly unavailable decl has no introduction version, and the existing logic therefore would fail to find a lower bound on the availability of the decl. The edge case that exposed the fragility of this logic was an unavailable extension containing a member with it's own explicit availability. The unavailability of the extension ought to trump the availability of the member, but the existing logic couldn't detect that.

The compiler also ought to diagnose the conflicting availability annotations but I'd like to address that separately.

Resolves rdar://92551870
@tshortli tshortli force-pushed the unavailable-wins branch from cb17aa9 to c78090b Compare May 5, 2022 14:22
@tshortli
Copy link
Contributor Author

tshortli commented May 5, 2022

@swift-ci please smoke test

@tshortli tshortli marked this pull request as ready for review May 5, 2022 14:23
@tshortli tshortli requested review from xymus and xedin May 5, 2022 14:31
@tshortli
Copy link
Contributor Author

tshortli commented May 5, 2022

This fixes the issue that caused #58466 to be reverted and adds a regression test for it.

@tshortli tshortli merged commit 94a4d84 into swiftlang:main May 5, 2022
@tshortli tshortli deleted the unavailable-wins branch May 8, 2022 16:30
tshortli added a commit that referenced this pull request Jun 1, 2022
… min` (#59176)

Cherry-pick and squash of the following PRs to release/5.7:

#42585
#58417
#58654
#58680
#58707
#58870
#58963
#59040
#59065

* Sema: Fix `isExported()` for extension decls in order to correct availability diagnostics when `-target-min-inlining-version min` is specified.

Resolves rdar://91382040

* Sema: Avoid diagnosing potential unavailability of type components (extension nominal type, superclass, etc.) on declarations that are explicitly unavailable.

Resolves rdar://92179327

* Sema: Downgrade diagnostics about potential unavailability of the extended type in an extension declaration when the following conditions are met:

1. The extension is missing explicit availability.
2. The required availability is before the deployment target.

Resolves rdar://92621567

* NFC: Expand `-target-min-inlining-versiong` tests to cover a number of corner cases:

- unavailable declarations and unavailable containers
- SPI declarations and spi containers
- property initializer expressions
- property wrappers

* Sema: When computing potential unavailability of a decl, first check whether the decl is explicitly unavailable and the context is also unavailable. If those conditions are met, treat the decl as if it were always available since unavailable code is allowed to reference unavailable decls.

Resolves rdar://92551870

* Sema: Use the deployment target when checking availability for SPI and unavailable API declarations with `-target-min-inlining-version min` specified. There's not much benefit to more accurate enforcement of availability in these decls since API clients can't use them and there's a lot of existing code that would be needlessly diagnosed without these exceptions.

Resolves rdar://92716633

* Sema: Teach the compiler to refine `VarDecl` initializer expressions using the deployment target when the init would not be exposed to module clients. Without this, the initializers of public properties in API modules could be misdiagnosed as potentially unavailable to clients of the module, even though the expression will only ever execute on the deployment target or higher.

Resolves rdar://92713589

* Tests: Update `attr_inlinable_available.swift` to require macOS and remove the OS versions for other platforms from availability attributes.

* Tests: Add test cases for potential unavailability in class inheritance when  is specified.

* Sema: Reword diagnostics about potentially unavailable decls to improve clarity for authors of API libraries. When decls are diagnosed as potentially unavailable on an OS earlier than the deployment target, the message will now indicate that the issue would be faced by clients of the module.

Resolves rdar://93466875

* Sema: Use the availability of the extended nominal as a floor for the availability of extensions. The primary motivation for this change is to reduce unnecessary availability diagnostics for API library authors. Many API libraries contain existing extension decls that lack declared availability where the extension introduces additional members to the extended type in the same release that the extended type was declared. Others contain extensions where the extension itself does not have declared availability but each of the members do. In both cases, the code is safe as written so the extra diagnostics would be a nuisance.

Resolves rdar://93630782

* Sema: Downgrade diagnostics about inheritance from a less available type when `-target-min-inlining-version min` is specified.

As a concession to source compatibility for API libraries, downgrade diagnostics about inheritance from a less available type when the following conditions are met:
1. The inherited type is only potentially unavailable before the deployment target.
2. The inheriting type is `@usableFromInline`.

Resolves rdar://92747826
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants