Rollup merge of #138256 - compiler-errors:anon-const-ty, r=BoxyUwU

Do not feed anon const a type that references generics that it does not have

Fixes #137865

See the comment I left in the code. We could alternatively give these anon consts the generics from the parent, but that would be moving in a GCE-esque direction that we may not want. Open to tweaks here.

r? BoxyUwU

Author: matthiaskrgr