// Tests that specializing trait impls must be at least as const as the default impl. #![feature(const_trait_impl)] #![feature(min_specialization)] #[const_trait] trait Value { fn value() -> u32; } impl const Value for T { default fn value() -> u32 { 0 } } struct FortyTwo; impl Value for FortyTwo { //~ ERROR cannot specialize on const impl with non-const impl fn value() -> u32 { println!("You can't do that (constly)"); 42 } } fn main() {}