#![crate_type = "lib"] #![feature(transmutability)] trait A { type AssocA; } trait B { type AssocB: std::mem::TransmuteFrom<()>; } impl B for (T, u8) where T: A, { type AssocB = T::AssocA; //~ERROR: the trait bound `::AssocA: TransmuteFrom<(), Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not satisfied [E0277] } impl B for (T, u16) where for<'a> &'a i32: A, { type AssocB = <&'static i32 as A>::AssocA; //~ERROR: `()` cannot be safely transmuted into `<&i32 as A>::AssocA` }