When in "existing" Swift code that is Swift 5.x and has not adopted
concurrency, allow mismatches in function types that only involve
ABI-neutral concurrency changes (e.g., adding `@Sendable` or removing
a global actor) by downgrading the diagnostic to a warning. This
improves the story for incremental adoption of concurrency in an
existing code base.
As part of this, generalize the facility for downgrading an error to a
warning when performing diagnostics in the constraint solver, using the
new diagnostic behavior limits rather than duplicating diagnostics.
Diagnostics cannot assume that solution would always be applied
to the constraint system, so all of the elements affected by the
mismatch have to be determined by the fix.
Resolves: rdar://85021348
Not all of the pre-check errors could be diagnosed by re-running
`PreCheckExpression` e.g. key path expressions are mutated to
a particular form after an error has been produced.
To make the behavior consistent, let's allow pre-check to emit
diagnostics and unify pre-check and constraint generation fixes.
Resolves: rdar://77466241
One can convert from a function value without a global actor to a
similar function type that does have a global actor, but one cannot
remove or change a global actor on a function type.
Is the same argument is out-of-order in multiple solutions, let's
diagnose it as if there was no ambiguity.
Resolves: SR-14093
Resolves: rdar://73600328
If multiple solutions have exactly a fix for exactly the same invalid member
reference in key path, let's diagnose that as if there is no ambiguity there.
It's possible that different overload choices could have the same
conformance requirement, so diagnostics should be able to emit an
error in situations where multiple solutions point to the missing
conformance at the same location (both in AST and requirement list).
Resolves: rdar://74447308
* [Sema] Implementing is runtime check always true diagnostic as a fix
* [AST] Implement getWithoutThrows on function type
* [CSSimplify] Detect that checked cast types conversion is always true and record warning fix
* [test] Some additional test cases for SR-13789
* [Sema] Fixing typo on fix name
* [Sema] Move and adjust the ConditionalCast diagnostics to the fix format
* [Sema] Remove some checked cast diagnostics from check constraints and move to fix
* [Sema] Renaming checked cast coercible types fix
* [Sema] Some adjustments and rewrite on the logic for downcast record fix
* [Sema] Move logic of runtime function type to AllowUnsupportedRuntimeCheckedCast::attempt
* [Sema] Abstract checked cast fix logic to static function and minor adjustments
* [Sema] Renamings from review
Introduce `@concurrent` attribute on function types, including:
* Parsing as a type attribute
* (De-/re-/)mangling for concurrent function types
* Implicit conversion from @concurrent to non-@concurrent
- (De-)serialization for concurrent function types
- AST printing and dumping support
