1 files changed, 34 insertions, 0 deletions
diff --git a/src/test/ui/generic-associated-types/type-param-defaults.rs b/src/test/ui/generic-associated-types/type-param-defaults.rs
new file mode 100644
index 000000000..f034076b0
--- /dev/null
+++ b/src/test/ui/generic-associated-types/type-param-defaults.rs
@@ -0,0 +1,34 @@
+// Check that we disallow GAT param defaults, even with `invalid_type_param_default` allowed
+
+#![allow(invalid_type_param_default)]
+
+trait Trait {
+    type Assoc<T = u32>;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for () {
+    type Assoc<T = u32> = u64;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for u32 {
+    type Assoc<T = u32> = T;
+    //~^ defaults for type parameters are only allowed
+}
+
+trait Other {}
+impl Other for u32 {}
+
+fn foo<T>()
+where
+    T: Trait<Assoc = u32>,
+    T::Assoc: Other {
+    }
+
+fn main() {
+    // errors
+    foo::<()>();
+    // works
+    foo::<u32>();
+}