error[E0277]: the trait bound `::AssocA: TransmuteFrom<(), Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not satisfied --> $DIR/assoc-bound.rs:16:19 | LL | type AssocB = T::AssocA; | ^^^^^^^^^ unsatisfied trait bound | = help: the trait `TransmuteFrom<(), Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `::AssocA` note: required by a bound in `B::AssocB` --> $DIR/assoc-bound.rs:9:18 | LL | type AssocB: std::mem::TransmuteFrom<()>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `B::AssocB` help: consider further restricting the associated type | LL | T: A, ::AssocA: TransmuteFrom<(), Assume { alignment: false, lifetimes: false, safety: false, validity: false }> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error[E0277]: `()` cannot be safely transmuted into `<&i32 as A>::AssocA` --> $DIR/assoc-bound.rs:24:19 | LL | type AssocB = <&'static i32 as A>::AssocA; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ `<&i32 as A>::AssocA` has an unknown layout | note: required by a bound in `B::AssocB` --> $DIR/assoc-bound.rs:9:18 | LL | type AssocB: std::mem::TransmuteFrom<()>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `B::AssocB` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0277`.