#![feature(const_trait_impl)] trait ConstDefaultFn: Sized { fn b(self); #[default_method_body_is_const] fn a(self) { self.b(); } } struct NonConstImpl; struct ConstImpl; impl ConstDefaultFn for NonConstImpl { fn b(self) {} } impl const ConstDefaultFn for ConstImpl { fn b(self) {} } const fn test() { NonConstImpl.a(); //~^ ERROR the trait bound //~| ERROR cannot call non-const fn ConstImpl.a(); } fn main() {}