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.
The blocking nature of these APIs means that the closures passed to
them do not actually escape the concurrency domain of the caller.
Remove the implicit `@Sendable`.
When referencing a function that contains parameters with the hidden
`@_unsafeSendable` or `@_unsafeMainActor` attributes, adjust the
function type to make the types of those parameters `@Sendable` or
`@MainActor`, respectively, based on both the context the expression:
* `@Sendable` will be applied when we are in a context with strict
concurrency checking.
* `@MainActor` will be applied when we are in a context with strict
concurrency checking *or* the function is being directly applied so
that an argument is provided in the immediate expression.
The second part of the rule of `@MainActor` reflects the fact that
making the parameter `@MainActor` doesn't break existing code (because
there is a conversion to add a global actor to a function value), but
it does enable such code to synchronously use a `@MainActor`-qualified
API.
The main effect of this change is that, in a strict concurrency
context, the type of referencing an unapplied function involving
`@_unsafeSendable` or `@_unsafeMainActor` in a strict context will
make those parameters `@Sendable` or `@MainActor`, which ensures that
these constraints properly work with non-closure arguments. The former
solution only applied to closure literals, which left some holes in
Sendable checking.
Fixes rdar://77753021.
Introduce the notion of "unsafe" @Sendable parameters, indicated by the
hidden @_unsafeSendable parameter attribute. Closure arguments to such
parameters are treated as @Sendable within code that has already
adopted concurrency, but are otherwise enert, allowing them to be
applied to existing concurrency-related APIs to smooth the transition
path to concurrency.
Additionally, introduce the notion of an "unsafe" @MainActor closure,
for cases where we have determined that the closure will execute on
the main actor but it (also) isn't part of the type system.
Pattern-match uses of the Dispatch library's DispatchQueue to infer
both kinds of "unsafe" as appropriate, especially (e.g.) matching the pattern
DispatchQueue.main.async { ... }
to treat the closure as unsafe @Sendable and @MainActor, allowing such
existing code to better integrate with concurrency.
Implements rdar://75988966.
