#![allow(unused_variables)] #![deny(dead_code)] #![feature(rustc_attrs, start)] struct Foo; trait Bar { fn bar1(&self); fn bar2(&self) { self.bar1(); } } impl Bar for Foo { fn bar1(&self) { live_fn(); } } fn live_fn() {} fn dead_fn() {} //~ ERROR: function `dead_fn` is never used #[rustc_main] fn dead_fn2() {} //~ ERROR: function `dead_fn2` is never used fn used_fn() {} #[start] fn start(_: isize, _: *const *const u8) -> isize { used_fn(); let foo = Foo; foo.bar2(); 0 } // this is not main fn main() { //~ ERROR: function `main` is never used dead_fn(); dead_fn2(); }