1 files changed, 31 insertions, 0 deletions
diff --git a/src/test/ui/associated-types/associated-types-incomplete-object.rs b/src/test/ui/associated-types/associated-types-incomplete-object.rs
new file mode 100644
index 000000000..4627dfd2b
--- /dev/null
+++ b/src/test/ui/associated-types/associated-types-incomplete-object.rs
@@ -0,0 +1,31 @@
+// Check that the user gets an error if they omit a binding from an
+// object type.
+
+pub trait Foo {
+    type A;
+    type B;
+    fn boo(&self) -> <Self as Foo>::A;
+}
+
+struct Bar;
+
+impl Foo for isize {
+    type A = usize;
+    type B = char;
+    fn boo(&self) -> usize {
+        42
+    }
+}
+
+pub fn main() {
+    let a = &42isize as &dyn Foo<A=usize, B=char>;
+
+    let b = &42isize as &dyn Foo<A=usize>;
+    //~^ ERROR the value of the associated type `B` (from trait `Foo`) must be specified
+
+    let c = &42isize as &dyn Foo<B=char>;
+    //~^ ERROR the value of the associated type `A` (from trait `Foo`) must be specified
+
+    let d = &42isize as &dyn Foo;
+    //~^ ERROR the value of the associated types `A` (from trait `Foo`), `B` (from trait
+}