Auto merge of #86249 - FabianWolff:issue-86238, r=varkor
Report an error if resolution of closure call functions failed
This pull request fixes #86238. The current implementation seems to assume that resolution of closure call functions (I'm not sure what the proper term is; I mean `call` of `Fn` etc.) can never fail:
https://github.com/rust-lang/rust/blob/
60f1a2fc4b535ead9c85ce085fdce49b1b097531/compiler/rustc_typeck/src/check/callee.rs#L590-L595
But actually, it can, if the `fn`/`fn_mut`/`fn_once` lang items are not defined, or don't have an associated `call`/`call_mut`/`call_once` function, leading to the ICE described in #86238. I have therefore turned the `span_bug!()` into an error message, which prevents the ICE.