associated type syntax mismatch between PR 731 and the design docs

[jsiek]

In PR 731 (https://github.com/carbon-language/carbon-lang/blob/trunk/proposals/p0731.md#syntax-for-associated-constants) it says that the syntax for specifying an associated type for an impl is to use let. As in the following example:

class DynamicArray(T:! Type) {
  ...
  impl as Stack {
    let ElementType:! Type = T;
    ...
  }
}

However, in the design documents (https://github.com/carbon-language/carbon-lang/blob/trunk/docs/design/generics/details.md#associated-types), there's this example that is using a where clause to specify an associated type:

  impl as StackAssociatedType where .ElementType = T { ... }

Which one of these is correct?

[jonmeow]

Just to note, that example is from #1013 "Generics: Set associated constants using where constraints" -- the let example is more likely outdated here.

[jonmeow]

I don't see "let ElementType:! Type = T;" in the current design. I think the design is correct here, and reflects the proposal evolution.

[jsiek]

Ok, then the link to outdated rationale should be removed.

[chandlerc]

Yeah, the design here changed in #1013 to use where clauses rather than the syntax in PR 731. @josh11b to maybe help track down any lingering bits of the design that need updating to reflect this.

[jsiek]

On further thought, I'm concerned about this change to using where clauses to satisfy associated type requirements. I've posted a note explaining why on the #generics channel.

[josh11b]

#731 is out of date, superseded by #1013 . Is there text in the design doc that I missed updating that I should fix, other than the text in https://github.com/carbon-language/carbon-lang/blob/trunk/proposals/p0731.md ?

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