// Test if the on_unimplemented message override works #![feature(rustc_attrs)] struct Foo(T); struct Bar(T); #[rustc_on_unimplemented = "trait message"] trait Index { type Output: ?Sized; fn index(&self, index: Idx) -> &Self::Output; } #[rustc_on_unimplemented = "on impl for Foo"] impl Index> for [i32] { type Output = i32; fn index(&self, _index: Foo) -> &i32 { loop {} } } #[rustc_on_unimplemented = "on impl for Bar"] impl Index> for [i32] { type Output = i32; fn index(&self, _index: Bar) -> &i32 { loop {} } } fn main() { Index::index(&[] as &[i32], 2u32); //~^ ERROR E0277 //~| ERROR E0277 Index::index(&[] as &[i32], Foo(2u32)); //~^ ERROR E0277 //~| ERROR E0277 Index::index(&[] as &[i32], Bar(2u32)); //~^ ERROR E0277 //~| ERROR E0277 }