src/test/ui/mir/mir_calls_to_shims.rs

   1 // run-pass
   2 // ignore-wasm32-bare compiled with panic=abort by default
   3
   4 #![feature(fn_traits)]
   5 #![feature(never_type)]
   6
   7 use std::panic;
   8
   9 fn foo(x: u32, y: u32) -> u32 { x/y }
  10 fn foo_diverges() -> ! { panic!() }
  11
  12 fn test_fn_ptr<T>(mut t: T)
  13     where T: Fn(u32, u32) -> u32,
  14 {
  15     let as_fn = <T as Fn<(u32, u32)>>::call;
  16     assert_eq!(as_fn(&t, (9, 3)), 3);
  17     let as_fn_mut = <T as FnMut<(u32, u32)>>::call_mut;
  18     assert_eq!(as_fn_mut(&mut t, (18, 3)), 6);
  19     let as_fn_once = <T as FnOnce<(u32, u32)>>::call_once;
  20     assert_eq!(as_fn_once(t, (24, 3)), 8);
  21 }
  22
  23 fn assert_panics<F>(f: F) where F: FnOnce() {
  24     let f = panic::AssertUnwindSafe(f);
  25     let result = panic::catch_unwind(move || {
  26         f.0()
  27     });
  28     if let Ok(..) = result {
  29         panic!("diverging function returned");
  30     }
  31 }
  32
  33 fn test_fn_ptr_panic<T>(mut t: T)
  34     where T: Fn() -> !
  35 {
  36     let as_fn = <T as Fn<()>>::call;
  37     assert_panics(|| as_fn(&t, ()));
  38     let as_fn_mut = <T as FnMut<()>>::call_mut;
  39     assert_panics(|| as_fn_mut(&mut t, ()));
  40     let as_fn_once = <T as FnOnce<()>>::call_once;
  41     assert_panics(|| as_fn_once(t, ()));
  42 }
  43
  44 fn main() {
  45     test_fn_ptr(foo);
  46     test_fn_ptr(foo as fn(u32, u32) -> u32);
  47     test_fn_ptr_panic(foo_diverges);
  48     test_fn_ptr_panic(foo_diverges as fn() -> !);
  49 }