eb0f3ed59c
Make subtyping explicit in MIR This adds new mir-opt that pushes new `ProjectionElem` called `ProjectionElem::Subtype(T)` to `Rvalue` of a subtyped assignment so we can unsoundness issues like https://github.com/rust-lang/rust/issues/107205 Addresses https://github.com/rust-lang/rust/issues/112651 r? `@lcnr`