Unexpected unsatisfied trait bound

[benluelo]

I tried this code:

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=761c1cce2cdf196f23ef8eab2a59bf6d

There seems to be an issue when resolving a blanket impl through the GAT when an associated type of the T is used - the above code is as far as I could minimize it while keeping the error message the same.

Interesting to note is this line in the error:

help: the trait Unsatisfied<()> is implemented for GenericStruct<T>

Which is true(!) but the error states that:

the trait Unsatisfied<<GenericStruct<<Counterparty as HasAssoc>::Assoc> as Proto>::Proto> is not implemented for GenericStruct<<Counterparty as HasAssoc>::Assoc>

Which leads me to believe this is similar to #41756 or #24066? But I'm not sure honestly.

EDIT: I refactored the original (non-minimized) code to not use GATS and encountered this: #89910; perhaps the original issue is related?

[fmease]

(fixed by next solver: fail → pass)

[benluelo]

Another example, not sure if it's just a smaller example than the one I posted previously but it's also fixed by trait-solver=next: godbolt