24a7a010d1
This commit refactors the `UserTypeAnnotation` type to be referred to by an index within `UserTypeProjection`. `UserTypeAnnotation` is instead kept in an `IndexVec` within the `Mir` struct. Further, instead of `UserTypeAnnotation` containing canonicalized types, it now contains normal types and the entire `UserTypeAnnotation` is canonicalized. To support this, the type was moved from the `rustc::mir` module to `rustc::ty` module.