Remove the mention of ~Sendable from the concurrency chapter.

[hborla]

This syntax does not exist yet, and if you write ~Sendable, you'll get a compiler error that a conformance to Sendable cannot be suppressed. It's a good idea but it is neither pitched nor implemented.

[heckj]

Is it correct to describe using the availability annotation as an unavailable conformance? If there's not a ~Sendable, then I might suggest using a phrasing like:

"mark the Sendable conformance as unavailable."

[hborla]

I've always used the term "unavailable conformance" for this. What I don't like about "mark the Sendable conformance as unavailable" is that it doesn't tell you that you need to actually add the conformance and then mark it as unavailable. I personally prefer the existing wording. Curious what @amartini51 thinks.

[amartini51]

I prefer the term "unavailable conformance", which I think is more descriptive. The extension adds conformance to the Sendable protocol, and the @available attribute marks the conformance as unavailable.

For comparison/precedent, the Protocols chapter describes the same syntax in its example as:

Another way to suppress implicit conformance is with an extension that you mark as unavailable:

And it uses the wording "suppress an implicit conformance" for the ~Protocol syntax.

[amartini51]

Thanks for catching & fixing this issue, Holly!

[amartini51]

I prefer the term "unavailable conformance", which I think is more descriptive. The extension adds conformance to the Sendable protocol, and the @available attribute marks the conformance as unavailable.

For comparison/precedent, the Protocols chapter describes the same syntax in its example as:

Another way to suppress implicit conformance is with an extension that you mark as unavailable:

And it uses the wording "suppress an implicit conformance" for the ~Protocol syntax.

[amartini51]

We might want to keep some form of cross-reference here, since the Protocols chapter contrasts the ~Protocol syntax with this syntax. Added in 9056504 as a starting point:

You can also use an unavailable conformance
to suppress implicit conformance to a protocol,
as discussed in <doc:Protocols#Implicit-Conformance-to-a-Protocol>.

[amartini51]

Please excuse the force-push. I added the cross reference back in the wrong spot, which caused a merge conflict. Putting it in the right spot instead is cleaner that handling the conflict, and produces a better diff for review here.