1 files changed, 47 insertions, 0 deletions
diff --git a/src/test/ui/associated-types/defaults-in-other-trait-items.rs b/src/test/ui/associated-types/defaults-in-other-trait-items.rs
new file mode 100644
index 000000000..505751969
--- /dev/null
+++ b/src/test/ui/associated-types/defaults-in-other-trait-items.rs
@@ -0,0 +1,47 @@
+#![feature(associated_type_defaults)]
+
+// Associated type defaults may not be assumed inside the trait defining them.
+// ie. they only resolve to `<Self as Tr>::A`, not the actual type `()`
+trait Tr {
+    type A = (); //~ NOTE associated type defaults can't be assumed inside the trait defining them
+
+    fn f(p: Self::A) {
+        let () = p;
+        //~^ ERROR mismatched types
+        //~| NOTE expected associated type, found `()`
+        //~| NOTE expected associated type `<Self as Tr>::A`
+        //~| NOTE this expression has type `<Self as Tr>::A`
+    }
+}
+
+// An impl that doesn't override the type *can* assume the default.
+impl Tr for () {
+    fn f(p: Self::A) {
+        let () = p;
+    }
+}
+
+impl Tr for u8 {
+    type A = ();
+
+    fn f(p: Self::A) {
+        let () = p;
+    }
+}
+
+trait AssocConst {
+    type Ty = u8; //~ NOTE associated type defaults can't be assumed inside the trait defining them
+
+    // Assoc. consts also cannot assume that default types hold
+    const C: Self::Ty = 0u8;
+    //~^ ERROR mismatched types
+    //~| NOTE expected associated type, found `u8`
+    //~| NOTE expected associated type `<Self as AssocConst>::Ty`
+}
+
+// An impl can, however
+impl AssocConst for () {
+    const C: Self::Ty = 0u8;
+}
+
+fn main() {}