#![feature(lang_items)] trait Foo { #[lang = "dummy_lang_item_1"] //~ ERROR definition fn foo() {} #[lang = "dummy_lang_item_2"] //~ ERROR definition fn bar(); #[lang = "dummy_lang_item_3"] //~ ERROR definition type MyType; } struct Bar; impl Bar { #[lang = "dummy_lang_item_4"] //~ ERROR definition fn test() {} } fn main() {}