1 files changed, 77 insertions, 0 deletions
diff --git a/src/test/ui/specialization/specialization-no-default.rs b/src/test/ui/specialization/specialization-no-default.rs
new file mode 100644
index 000000000..ae739b235
--- /dev/null
+++ b/src/test/ui/specialization/specialization-no-default.rs
@@ -0,0 +1,77 @@
+#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
+
+// Check a number of scenarios in which one impl tries to override another,
+// without correctly using `default`.
+
+// Test 1: one layer of specialization, multiple methods, missing `default`
+
+trait Foo {
+    fn foo(&self);
+    fn bar(&self);
+}
+
+impl<T> Foo for T {
+    fn foo(&self) {}
+    fn bar(&self) {}
+}
+
+impl Foo for u8 {}
+impl Foo for u16 {
+    fn foo(&self) {} //~ ERROR E0520
+}
+impl Foo for u32 {
+    fn bar(&self) {} //~ ERROR E0520
+}
+
+// Test 2: one layer of specialization, missing `default` on associated type
+
+trait Bar {
+    type T;
+}
+
+impl<T> Bar for T {
+    type T = u8;
+}
+
+impl Bar for u8 {
+    type T = (); //~ ERROR E0520
+}
+
+// Test 3a: multiple layers of specialization, missing interior `default`
+
+trait Baz {
+    fn baz(&self);
+}
+
+impl<T> Baz for T {
+    default fn baz(&self) {}
+}
+
+impl<T: Clone> Baz for T {
+    fn baz(&self) {}
+}
+
+impl Baz for i32 {
+    fn baz(&self) {} //~ ERROR E0520
+}
+
+// Test 3b: multiple layers of specialization, missing interior `default`,
+// redundant `default` in bottom layer.
+
+trait Redundant {
+    fn redundant(&self);
+}
+
+impl<T> Redundant for T {
+    default fn redundant(&self) {}
+}
+
+impl<T: Clone> Redundant for T {
+    fn redundant(&self) {}
+}
+
+impl Redundant for i32 {
+    default fn redundant(&self) {} //~ ERROR E0520
+}
+
+fn main() {}