tests/ui/consts/promotion.rs

   1 // revisions: noopt opt opt_with_overflow_checks
   2 //[noopt]compile-flags: -C opt-level=0
   3 //[opt]compile-flags: -O
   4 //[opt_with_overflow_checks]compile-flags: -C overflow-checks=on -O
   5
   6 // build-pass
   7
   8 const fn assert_static<T>(_: &'static T) {}
   9
  10 #[allow(unconditional_panic)]
  11 const fn fail() -> i32 {
  12     1/0
  13 }
  14 const C: i32 = {
  15     // Promoted that fails to evaluate in dead code -- this must work
  16     // (for backwards compatibility reasons).
  17     if false {
  18         assert_static(&fail());
  19     }
  20     42
  21 };
  22
  23 fn main() {
  24     assert_static(&["a", "b", "c"]);
  25     assert_static(&["d", "e", "f"]);
  26     assert_eq!(C, 42);
  27
  28     // make sure that these do not cause trouble despite overflowing
  29     assert_static(&(0-1));
  30     assert_static(&-i32::MIN);
  31
  32     // div-by-non-0 is okay
  33     assert_static(&(1/1));
  34     assert_static(&(1%1));
  35
  36     // in-bounds array access is okay
  37     assert_static(&([1,2,3][0] + 1));
  38     assert_static(&[[1,2][1]]);
  39
  40     // Top-level projections are not part of the promoted, so no error here.
  41     if false {
  42         #[allow(unconditional_panic)]
  43         assert_static(&[1,2,3][4]);
  44     }
  45 }