A protocol conformance can be ill-formed due to isolation mismatches
between witnesses and requirements, or with associated conformances.
Previously, such failures would be emitted as a number of separate
errors (downgraded to warnings in Swift 5), one for each witness and
potentially an extra for associated conformances. The rest was a
potential flood of diagnostics that was hard to sort through.
Collect all of the isolation-related problems for a given conformance
together and produce a single error (downgraded to a warning when
appropriate) that describes the overall issue. That error will have up
to three notes suggesting specific courses of action:
* Isolating the conformance (when the experimental feature is enabled)
* Marking the witnesses as 'nonisolated' where needed
*
The diagnostic also has notes to point out the witnesses/associated
conformances that have isolation problems. There is a new educational
note that also describes these options.
We give the same treatment to missing 'distributed' on witnesses to a
distributed protocol.
When diagnosing an isolation mismatch between a requirement and witness,
we would produce notes on the requirement itself suggesting the addition of
`async`. This is almost never what you want to do, and is often so far
away from the actual conforming type as to be useless. Remove this note,
and the non-function fallback that just points at the requirement, because
they are unhelpful.
This is staging for a rework of the way we deal with conformance-level
actor isolation problems.
Find all the usages of `--enable-experimental-feature` or
`--enable-upcoming-feature` in the tests and replace some of the
`REQUIRES: asserts` to use `REQUIRES: swift-feature-Foo` instead, which
should correctly apply to depending on the asserts/noasserts mode of the
toolchain for each feature.
Remove some comments that talked about enabling asserts since they don't
apply anymore (but I might had miss some).
All this was done with an automated script, so some formatting weirdness
might happen, but I hope I fixed most of those.
There might be some tests that were `REQUIRES: asserts` that might run
in `noasserts` toolchains now. This will normally be because their
feature went from experimental to upcoming/base and the tests were not
updated.
Instead, use the `%target-swift-5.1-abi-triple` substitution to compile the tests
for deployment to the minimum OS versions required for use of _Concurrency APIs.
`@GlobalActor(unsafe)` and `@preconcurrency @GlobalActor` mean the same
thing, but there were two different representations in the actor isolation
checker. Standardize on the preconcurrency representation.
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.
Reimplement the final client of ActorIsolationRestriction, conformance
isolation checking, to base it on the new "actor reference" logic.
Centralize the diagnostics emission so we have a single place where we
emit the primary diagnostic (which is heavily customized based on
actor isolation/distributed/etc.) and any relevant notes to make
adjustments to the witness and/or requirement, e.g., adding
'distributed', 'async', 'throws', etc. Improve the diagnostics
slightly by providing Fix-Its when suggesting that we add "async"
and/or "throws".
With the last client of ActorIsolationRestriction gone, remove it
entirely.
When determining whether to warn, error, or be silent about
concurrency-related issues detected between a protocol requirement and
its witness, decide based on the context of the conformance rather
than based on the context of the witness. Fixes rdar://88205585.
Determine whether a particular missing Sendable diagnostic should be
emitted as a warning or error, or even ignored entirely, based on the
emerging rules from the proposal for incremental adoption of Sendable
checking.
Extend the diagnostics for `Sendable` conformances to always diagnose
missing `Sendable` conformances for nominal types that are within the
same module. The intuition here is that if the type is in the same
module, it can be updated and evaluated at the same time as code
requiring the `Sendable` conformance is introduced.
Another part of rdar://78269348.
Attempting to conform an actor to a global actor isolated protocol
creates a clash in isolation when members are accessed so, let's
detect and diagnose that.
Resolves: rdar://75849035
Check actor isolation of calls to functions with global-actor-qualified
type. This closes a pre-existing loophole where a value of
global-actor-qualified function type could be called from any context.
Paired with this, references to global-actor-qualified function
declarations will get global-actor-qualified function type whenever
they are referenced within an experience, i.e., whenever we form a
value of that type. Such references can occur anywhere (one does not
need to be on the actor), and carrying the global actor along with the
function type ensures that they can only be called from the right
actor. For example:
@MainActor func onlyOnMainActor() { ... }
func callIt(_ fn: @MainActor () -> Void) {
fn() // error: not on the main actor, so cannot synchronously call
// this wasn't previously diagnosed
}
func passIt() {
callIt(onlyOnMainActor) // okay to pass the function
// used to be an error
}
While here, fix up some broken substitution logic for
global-actor-qualified function types and "override" actor isolation.
Propagate "unsafe" global actors in the same manner as "safe" global
actors. This propagates global actors much further (especially from
classes and protocols), allowing more code to implicitly be known to be
running on the given global actor.
Fixes rdar://75548170.
