1 files changed, 102 insertions, 0 deletions
diff --git a/src/test/ui/dynamically-sized-types/dst-trait-tuple.rs b/src/test/ui/dynamically-sized-types/dst-trait-tuple.rs
new file mode 100644
index 000000000..c1e45215a
--- /dev/null
+++ b/src/test/ui/dynamically-sized-types/dst-trait-tuple.rs
@@ -0,0 +1,102 @@
+// run-pass
+#![allow(type_alias_bounds)]
+
+#![allow(unused_features)]
+#![feature(unsized_tuple_coercion)]
+
+type Fat<T: ?Sized> = (isize, &'static str, T);
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+struct Bar;
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+struct Bar1 {
+    f: isize
+}
+
+trait ToBar {
+    fn to_bar(&self) -> Bar;
+    fn to_val(&self) -> isize;
+}
+
+impl ToBar for Bar {
+    fn to_bar(&self) -> Bar {
+        *self
+    }
+    fn to_val(&self) -> isize {
+        0
+    }
+}
+impl ToBar for Bar1 {
+    fn to_bar(&self) -> Bar {
+        Bar
+    }
+    fn to_val(&self) -> isize {
+        self.f
+    }
+}
+
+// x is a fat pointer
+fn foo(x: &Fat<dyn ToBar>) {
+    assert_eq!(x.0, 5);
+    assert_eq!(x.1, "some str");
+    assert_eq!(x.2.to_bar(), Bar);
+    assert_eq!(x.2.to_val(), 42);
+
+    let y = &x.2;
+    assert_eq!(y.to_bar(), Bar);
+    assert_eq!(y.to_val(), 42);
+}
+
+fn bar(x: &dyn ToBar) {
+    assert_eq!(x.to_bar(), Bar);
+    assert_eq!(x.to_val(), 42);
+}
+
+fn baz(x: &Fat<Fat<dyn ToBar>>) {
+    assert_eq!(x.0, 5);
+    assert_eq!(x.1, "some str");
+    assert_eq!((x.2).0, 8);
+    assert_eq!((x.2).1, "deep str");
+    assert_eq!((x.2).2.to_bar(), Bar);
+    assert_eq!((x.2).2.to_val(), 42);
+
+    let y = &(x.2).2;
+    assert_eq!(y.to_bar(), Bar);
+    assert_eq!(y.to_val(), 42);
+
+}
+
+pub fn main() {
+    let f1 = (5, "some str", Bar1 {f :42});
+    foo(&f1);
+    let f2 = &f1;
+    foo(f2);
+    let f3: &Fat<dyn ToBar> = f2;
+    foo(f3);
+    let f4: &Fat<dyn ToBar> = &f1;
+    foo(f4);
+    let f5: &Fat<dyn ToBar> = &(5, "some str", Bar1 {f :42});
+    foo(f5);
+
+    // Zero size object.
+    let f6: &Fat<dyn ToBar> = &(5, "some str", Bar);
+    assert_eq!(f6.2.to_bar(), Bar);
+
+    // &*
+    //
+    let f7: Box<dyn ToBar> = Box::new(Bar1 {f :42});
+    bar(&*f7);
+
+    // Deep nesting
+    let f1 = (5, "some str", (8, "deep str", Bar1 {f :42}));
+    baz(&f1);
+    let f2 = &f1;
+    baz(f2);
+    let f3: &Fat<Fat<dyn ToBar>> = f2;
+    baz(f3);
+    let f4: &Fat<Fat<dyn ToBar>> = &f1;
+    baz(f4);
+    let f5: &Fat<Fat<dyn ToBar>> = &(5, "some str", (8, "deep str", Bar1 {f :42}));
+    baz(f5);
+}