defining module, and diagnose redundant Sendable conformances.
We still allow re-stating inherited unchecked Sendable conformances in
subclasses because inherited Sendable conformances are surprising when
they opt out of static checking. Otherwise, warning on redundant Sendable
conformances nudges programmers toward cleaning up unnecessary retroactive
Sendable conformances over time as libraries incrementally add the
conformances directly.
The check for actor methods in `isSemanticallyFinal` was accidentally
kicking in for class members, which avoided `Sendable` checking on
classes nested in actors.
This means that:
1. In test cases where minimal is the default (swift 5 without
-warn-concurrency), I added RUN lines for targeted, complete, and complete +
sns.
2. In test cases where complete is the default (swift 6, -warn-concurrency,
specified complete with -strict-concurrency), I added a send non-sendable run
line.
In each of these cases, I added additional expected-* lines as appropriate so
the tests can compile in each mode successfully.
Don't set allowMissing to true when checking conformance of a superclass requirement
to a protocol, since this prevents us from being able to express something like
'T : C, T : Sendable' to mean 'T can be any subclass of C which is also Sendable'.
Fixes rdar://problem/91530343.
A recent change to `Sendable` conformance handling resulted in subclasses of global-actor-confined classes being rejected if they explicitly declared a conformance to `Sendable`.
This behavior is technically correct because actor-isolated types are implicitly `Sendable`, but the source compatibility regression was not desirable. We are also considering requiring subclasses to explicitly repeat their superclass's `Sendable` conformance, so it makes sense to allow these redundant conformances in the general case to ease that potential transition.
Fixes rdar://88700507.
When a non-isolated requirement is witnessed by an actor-isolated
witness, we are crossing into the actor. Ensure that we perform
Sendable checking across the actor boundary here.
Fixes the rest of rdar://80424675.
