src/test/ui/consts/unstable-const-fn-in-libcore.rs

   1 // This is a non-regression test for const-qualification of unstable items in libcore
   2 // as explained in issue #67053.
   3 // const-qualification could miss some `const fn`s if they were unstable and the feature
   4 // gate was not enabled in libcore.
   5
   6 #![stable(feature = "core", since = "1.6.0")]
   7 #![feature(const_if_match)]
   8 #![feature(rustc_const_unstable)]
   9 #![feature(staged_api)]
  10
  11 enum Opt<T> {
  12     Some(T),
  13     None,
  14 }
  15
  16 impl<T> Opt<T> {
  17     #[rustc_const_unstable(feature = "foo", issue = "0")]
  18     #[stable(feature = "rust1", since = "1.0.0")]
  19     const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
  20     //~^ ERROR destructors cannot be evaluated at compile-time
  21     //~| ERROR destructors cannot be evaluated at compile-time
  22         match self {
  23             Opt::Some(t) => t,
  24             Opt::None => f(), //~ ERROR E0015
  25         }
  26     }
  27 }
  28
  29 fn main() {}