Rollup merge of #106973 - oli-obk:tait_ice_closure_in_impl_header, r=lcnr

Rollup merge of #106973 - oli-obk:tait_ice_closure_in_impl_header, r=lcnr

Don't treat closures from other crates as local

fixes #104817

r? `@lcnr`

Specialization can prefer an impl for an opaque type over a blanket impls that also matches. If the blanket impl only applies if an auto-trait applies, we look at the hidden type of the opaque type to see if that implements the auto trait. The hidden type can be a closure or generator, and thus we will end up seeing these types in coherence and have to handle them properly.