src/test/ui/unused/unused-result.rs

   1 #![allow(dead_code)]
   2 #![deny(unused_results, unused_must_use)]
   3 //~^ NOTE: the lint level is defined here
   4 //~| NOTE: the lint level is defined here
   5
   6 #[must_use]
   7 enum MustUse { Test }
   8
   9 #[must_use = "some message"]
  10 enum MustUseMsg { Test2 }
  11
  12 fn foo<T>() -> T { panic!() }
  13
  14 fn bar() -> isize { return foo::<isize>(); }
  15 fn baz() -> MustUse { return foo::<MustUse>(); }
  16 fn qux() -> MustUseMsg { return foo::<MustUseMsg>(); }
  17
  18 #[allow(unused_results)]
  19 fn test() {
  20     foo::<isize>();
  21     foo::<MustUse>(); //~ ERROR: unused `MustUse` that must be used
  22     foo::<MustUseMsg>(); //~ ERROR: unused `MustUseMsg` that must be used
  23     //~^ NOTE: some message
  24 }
  25
  26 #[allow(unused_results, unused_must_use)]
  27 fn test2() {
  28     foo::<isize>();
  29     foo::<MustUse>();
  30     foo::<MustUseMsg>();
  31 }
  32
  33 fn main() {
  34     foo::<isize>(); //~ ERROR: unused result
  35     foo::<MustUse>(); //~ ERROR: unused `MustUse` that must be used
  36     foo::<MustUseMsg>(); //~ ERROR: unused `MustUseMsg` that must be used
  37     //~^ NOTE: some message
  38
  39     let _ = foo::<isize>();
  40     let _ = foo::<MustUse>();
  41     let _ = foo::<MustUseMsg>();
  42 }