Auto traits are not handled for generic closures

[matthewjasper]

The following test fails with both solvers (returning ambiguous).

program {
      #[auto]
      trait Send { }

      closure with_ty<T>(self,) { T }
}

goal {
    forall<T> { if (T: Send) { with_ty<T>: Send } }
} yields {
    "Unique"
}

The empty substs here seem suspicious.

chalk/chalk-solve/src/clauses.rs

Line 167 in e0c94db

.closure_upvars(*closure_id, &Substitution::empty(interner));

[pierwill]

I'm interested in learning more about chalk, so I'll @rustbot claim.

[shamatar]

Can I mark it somehow for review and resolution via rustbot?

[pierwill]

@rustbot release-assignment

[shamatar]

@rustbot claim I suppose

[rustbot]

Error: Parsing assign command in comment failed: ...'tbot claim' | error: expected end of command at >| ' I suppose'...

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