- On compiler-error's suggestion of moving this lower down the stack, along the path of `report_mismatched_types()`, which is used by `rustc_hir_analysis` and `rustc_hir_typeck`. - update ui tests, add test - add suggestions for references to fn pointers - modify `TypeErrCtxt::same_type_modulo_infer` to take `T: relate::Relate` instead of `Ty`