tests/ui/lint/unused/must-use-ops.rs

   1 // Issue #50124 - Test warning for unused operator expressions
   2
   3 // check-pass
   4
   5 #![warn(unused_must_use)]
   6 #![feature(never_type)]
   7
   8 fn deref_never(x: &!) {
   9     // Don't lint for uninhabited typess
  10     *x;
  11 }
  12
  13 fn main() {
  14     let val = 1;
  15     let val_pointer = &val;
  16
  17     // Comparison Operators
  18     val == 1; //~ WARNING unused comparison
  19     val < 1; //~ WARNING unused comparison
  20     val <= 1; //~ WARNING unused comparison
  21     val != 1; //~ WARNING unused comparison
  22     val >= 1; //~ WARNING unused comparison
  23     val > 1; //~ WARNING unused comparison
  24
  25     // Arithmetic Operators
  26     val + 2; //~ WARNING unused arithmetic operation
  27     val - 2; //~ WARNING unused arithmetic operation
  28     val / 2; //~ WARNING unused arithmetic operation
  29     val * 2; //~ WARNING unused arithmetic operation
  30     val % 2; //~ WARNING unused arithmetic operation
  31
  32     // Logical Operators
  33     true && true; //~ WARNING unused logical operation
  34     false || true; //~ WARNING unused logical operation
  35
  36     // Bitwise Operators
  37     5 ^ val; //~ WARNING unused bitwise operation
  38     5 & val; //~ WARNING unused bitwise operation
  39     5 | val; //~ WARNING unused bitwise operation
  40     5 << val; //~ WARNING unused bitwise operation
  41     5 >> val; //~ WARNING unused bitwise operation
  42
  43     // Unary Operators
  44     !val; //~ WARNING unused unary operation
  45     -val; //~ WARNING unused unary operation
  46     *val_pointer; //~ WARNING unused unary operation
  47
  48     if false {
  49         deref_never(&panic!());
  50     }
  51 }