src/test/ui/const-generics/issues/issue-71381.rs

   1 // revisions: full min
   2 #![cfg_attr(full, feature(const_generics))]
   3 #![cfg_attr(full, allow(incomplete_features))]
   4 #![cfg_attr(min, feature(min_const_generics))]
   5
   6 struct Test(*const usize);
   7
   8 type PassArg = ();
   9
  10 unsafe extern "C" fn pass(args: PassArg) {
  11     println!("Hello, world!");
  12 }
  13
  14 impl Test {
  15     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "C" fn(Args)>(&self) {
  16         //~^ ERROR: using function pointers as const generic parameters is forbidden
  17         //~| ERROR: the type of const parameters must not depend on other generic parameters
  18         self.0 = Self::trampiline::<Args, IDX, FN> as _
  19     }
  20
  21     unsafe extern "C" fn trampiline<
  22         Args: Sized,
  23         const IDX: usize,
  24         const FN: unsafe extern "C" fn(Args),
  25         //~^ ERROR: using function pointers as const generic parameters is forbidden
  26         //~| ERROR: the type of const parameters must not depend on other generic parameters
  27     >(
  28         args: Args,
  29     ) {
  30         FN(args)
  31     }
  32 }
  33
  34 fn main() {
  35     let x = Test();
  36     x.call_me::<PassArg, 30, pass>()
  37 }