1 #![feature(trait_alias)] // Enabled to reduce stderr output, but can be triggered even if disabled.
6 trait Alias<T> = where T: Trait;
8 impl<T> WithType for T {
9 type Ctx = dyn Alias<T>;
10 //~^ ERROR the size for values of type `(dyn Trait + 'static)` cannot be known at compilation time