error[E0271]: type mismatch resolving ` as SuperTrait>::A == B` --> $DIR/enforce-supertrait-projection.rs:9:17 | LL | fn transmute(x: A) -> B { | - - expected type parameter | | | found type parameter LL | foo::>(x) | ^^^^^^^^^^^^^^^^^^^^^^^ expected type parameter `B`, found type parameter `A` | = note: expected type parameter `B` found type parameter `A` = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters note: required by a bound in `foo` --> $DIR/enforce-supertrait-projection.rs:15:8 | LL | fn foo(x: T::A) -> B | --- required by a bound in this LL | where LL | T: Trait, | ^^^^^^^^^^^^ required by this bound in `foo` error: aborting due to previous error For more information about this error, try `rustc --explain E0271`.