tests/ui/unboxed-closures/unboxed-closure-sugar-equiv.rs

   1 // Test that the unboxed closure sugar can be used with an arbitrary
   2 // struct type and that it is equivalent to the same syntax using
   3 // angle brackets. This test covers only simple types and in
   4 // particular doesn't test bound regions.
   5
   6 #![feature(unboxed_closures)]
   7 #![allow(dead_code)]
   8
   9 trait Foo<T> {
  10     type Output;
  11     fn dummy(&self, t: T, u: Self::Output);
  12 }
  13
  14 trait Eq<X: ?Sized> { }
  15 impl<X: ?Sized> Eq<X> for X { }
  16 fn eq<A: ?Sized,B: ?Sized +Eq<A>>() { }
  17
  18 fn test<'a,'b>() {
  19     // No errors expected:
  20     eq::< dyn Foo<(),Output=()>,                       dyn Foo()                         >();
  21     eq::< dyn Foo<(isize,),Output=()>,                 dyn Foo(isize)                      >();
  22     eq::< dyn Foo<(isize,usize),Output=()>,            dyn Foo(isize,usize)                 >();
  23     eq::< dyn Foo<(isize,usize),Output=usize>,         dyn Foo(isize,usize) -> usize         >();
  24     eq::< dyn Foo<(&'a isize,&'b usize),Output=usize>, dyn Foo(&'a isize,&'b usize) -> usize >();
  25
  26     // Test that anonymous regions in `()` form are equivalent
  27     // to fresh bound regions, and that we can intermingle
  28     // named and anonymous as we choose:
  29     eq::< dyn for<'x,'y> Foo<(&'x isize,&'y usize),Output=usize>,
  30           dyn for<'x,'y> Foo(&'x isize,&'y usize) -> usize            >();
  31     eq::< dyn for<'x,'y> Foo<(&'x isize,&'y usize),Output=usize>,
  32           dyn for<'x> Foo(&'x isize,&usize) -> usize                  >();
  33     eq::< dyn for<'x,'y> Foo<(&'x isize,&'y usize),Output=usize>,
  34           dyn for<'y> Foo(&isize,&'y usize) -> usize                  >();
  35     eq::< dyn for<'x,'y> Foo<(&'x isize,&'y usize),Output=usize>,
  36           dyn Foo(&isize,&usize) -> usize                             >();
  37
  38     // lifetime elision
  39     eq::< dyn for<'x> Foo<(&'x isize,), Output=&'x isize>,
  40           dyn Foo(&isize) -> &isize                                   >();
  41
  42     // Errors expected:
  43     eq::< dyn Foo<(),Output=()>,
  44           dyn Foo(char)                                               >();
  45     //~^ ERROR E0277
  46 }
  47
  48 fn main() { }