1 files changed, 71 insertions, 0 deletions
diff --git a/src/test/ui/mir/mir_coercions.rs b/src/test/ui/mir/mir_coercions.rs
new file mode 100644
index 000000000..f3dcc6b85
--- /dev/null
+++ b/src/test/ui/mir/mir_coercions.rs
@@ -0,0 +1,71 @@
+// run-pass
+#![feature(coerce_unsized, unsize)]
+
+use std::ops::CoerceUnsized;
+use std::marker::Unsize;
+
+fn identity_coercion(x: &(dyn Fn(u32)->u32 + Send)) -> &dyn Fn(u32)->u32 {
+    x
+}
+fn fn_coercions(f: &fn(u32) -> u32) ->
+    (unsafe fn(u32) -> u32,
+     &(dyn Fn(u32) -> u32+Send))
+{
+    (*f, f)
+}
+
+fn simple_array_coercion(x: &[u8; 3]) -> &[u8] { x }
+
+fn square(a: u32) -> u32 { a * a }
+
+#[derive(PartialEq,Eq)]
+struct PtrWrapper<'a, T: 'a+?Sized>(u32, u32, (), &'a T);
+impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
+    CoerceUnsized<PtrWrapper<'a, U>> for PtrWrapper<'a, T> {}
+
+struct TrivPtrWrapper<'a, T: 'a+?Sized>(&'a T);
+impl<'a, T: ?Sized+Unsize<U>, U: ?Sized>
+    CoerceUnsized<TrivPtrWrapper<'a, U>> for TrivPtrWrapper<'a, T> {}
+
+fn coerce_ptr_wrapper(p: PtrWrapper<[u8; 3]>) -> PtrWrapper<[u8]> {
+    p
+}
+
+fn coerce_triv_ptr_wrapper(p: TrivPtrWrapper<[u8; 3]>) -> TrivPtrWrapper<[u8]> {
+    p
+}
+
+fn coerce_fat_ptr_wrapper(p: PtrWrapper<dyn Fn(u32) -> u32+Send>)
+                          -> PtrWrapper<dyn Fn(u32) -> u32> {
+    p
+}
+
+fn coerce_ptr_wrapper_poly<'a, T, Trait: ?Sized>(p: PtrWrapper<'a, T>)
+                                                 -> PtrWrapper<'a, Trait>
+    where PtrWrapper<'a, T>: CoerceUnsized<PtrWrapper<'a, Trait>>
+{
+    p
+}
+
+fn main() {
+    let a = [0,1,2];
+    let square_local : fn(u32) -> u32 = square;
+    let (f,g) = fn_coercions(&square_local);
+    assert_eq!(f as usize, square as usize);
+    assert_eq!(g(4), 16);
+    assert_eq!(identity_coercion(g)(5), 25);
+
+    assert_eq!(simple_array_coercion(&a), &a);
+    let w = coerce_ptr_wrapper(PtrWrapper(2,3,(),&a));
+    assert!(w == PtrWrapper(2,3,(),&a) as PtrWrapper<[u8]>);
+
+    let w = coerce_triv_ptr_wrapper(TrivPtrWrapper(&a));
+    assert_eq!(&w.0, &a);
+
+    let z = coerce_fat_ptr_wrapper(PtrWrapper(2,3,(),&square_local));
+    assert_eq!((z.3)(6), 36);
+
+    let z: PtrWrapper<dyn Fn(u32) -> u32> =
+        coerce_ptr_wrapper_poly(PtrWrapper(2,3,(),&square_local));
+    assert_eq!((z.3)(6), 36);
+}