src/test/ui/traits/pointee-deduction.rs

   1 // run-pass
   2
   3 #![feature(ptr_metadata)]
   4
   5 use std::alloc::Layout;
   6 use std::ptr::Pointee;
   7
   8 trait Foo {
   9     type Bar;
  10 }
  11
  12 impl Foo for () {
  13     type Bar = ();
  14 }
  15
  16 struct Wrapper1<T: Foo>(#[allow(unused_tuple_struct_fields)] <T as Foo>::Bar);
  17 struct Wrapper2<T: Foo>(#[allow(unused_tuple_struct_fields)] <Wrapper1<T> as Pointee>::Metadata);
  18
  19 fn main() {
  20     let _: Wrapper2<()> = Wrapper2(());
  21     let _ = Layout::new::<Wrapper2<()>>();
  22 }