std.traits.ParameterIdentifierTuple problem

[Carl Sturtivant]

On Sunday, 31 March 2024 at 11:35:39 UTC, Nick Treleaven wrote:
> If a function type does include identifiers, then would two 
> function types with the same argument types but different 
> identifiers compare equal using `is`?

Yes. That is the idea. Define `is` to work this way.

> Yes, it's not possible to instantiate a function type.

But with extern it seems the semantics is fine as a function is 
not being instantiated. It is merely associating a name with a 
type: in what sense is this instantiation in any reasonable way?