Added Hashable conformance to Async(Throwing)Stream.Continuation

[nickolas-pohilets]

See the pitch.

[ktoso]

I think we'll need to take this through evolution; the type is not frozen and in general any public api changes need to be evolved.

[nickolas-pohilets]

Evolution PR - swiftlang/swift-evolution#2700

[ktoso]

This was accepted through evolution

[ktoso]

@swift-ci please smoke test

[ktoso]

Why that, isn't the hash function enough?

[nickolas-pohilets]

Apparently no. If omitted it gets synthesised as expected, but then test complains that it does not have availability annotations. I'm not sure if this is expected or a bug in code gen of the Hashable conformance.

[ktoso]

Is this expected @lorentey ?

[lorentey]

This definitely is a bug! Conformances with availability are a relatively recent development, and evidently we have not yet tried to combine them with synthesized requirements. The expected behavior is that the synthesized requirement would match the availability of the conformance itself.

It feels like this might be a good candidate for a starter task in compiler development.

(The hashValue as implemented matches the synthesized one; when the compiler issue is resolved, then it can simply be deleted to have it be replaced with the implicit default.)

[lorentey]

Oh hang on -- can you tell me what test is failing?

The compiler itself seems fine with it; this compiles with no diagnostic:

@available(macOS 11, *)
public struct Foo {
  public var value: Int
}
@available(macOS 12, *)
extension Foo: Hashable {
  @available(macOS 12, *)
  public func hash(into hasher: inout Hasher) {
    hasher.combine(value)
  }
}

The generated .swiftinterface indeed doesn't set availability directly on the synthesized members (== and hashValue), but they still inherit that from the extension's own context:

import Swift
import _Concurrency
import _StringProcessing
import _SwiftConcurrencyShims
@available(macOS 11, *)
public struct Foo {
  public var value: Swift.Int
}
@available(macOS 12, *)
extension foo.Foo : Swift.Hashable {
  @available(macOS 12, *)
  public func hash(into hasher: inout Swift.Hasher)
  public static func == (a: foo.Foo, b: foo.Foo) -> Swift.Bool
  public var hashValue: Swift.Int {
    get
  }
}

This sounds like it might actually be due to an overzealous test that attempts to analyze the interface. (If my diagnosis is correct, then the choice is between seeing if the test can be adjusted, or changing the compiler to generate the extra @available attributes anyway.)

[nickolas-pohilets]

The failing test was test/api-digester/stability-concurrency-abi.test

[ktoso]

I see, that makes sense.

[ktoso]

@swift-ci please smoke test

[ktoso]

lldb-api :: functionalities/fork/concurrent_vfork/TestConcurrentVFork.py

[ktoso]

@swift-ci please smoke test Linux

[ktoso]

@swift-ci please smoke test Linux

[ktoso]

Unrelated failure

/home/build-user/swift-testing/Sources/Testing/ExitTests/ExitTest.swift:125:32: error: cannot find 'CapturedValue' in scope
123 |   /// child processes.
124 |   @_spi(Experimental) @_spi(ForToolsIntegrationOnly)
125 |   public var capturedValues = [CapturedValue]()
    |                                `- error: cannot find 'CapturedValue' in scope
126 | 
127 |   /// Make a copy of this instance.