struct MyType; struct MyType1(T); trait Bar { type Out; } impl MyType { //~^ ERROR the type parameter `T` is not constrained } impl MyType1 { // OK, T is used in `Foo`. } impl MyType1 { //~^ ERROR the type parameter `U` is not constrained } impl MyType1 where T: Bar { // OK, T is used in `Foo`. } fn main() { }