src/test/ui/gated-bad-feature.rs

#![feature(foo_bar_baz, foo(bar), foo = "baz", foo)]
//~^ ERROR malformed `feature`
//~| ERROR malformed `feature`

#![feature] //~ ERROR malformed `feature` attribute
#![feature = "foo"] //~ ERROR malformed `feature` attribute

#![feature(test_removed_feature)] //~ ERROR: feature has been removed

fn main() {}