1 files changed, 14 insertions, 0 deletions
diff --git a/tests/ui/generic-const-items/parameter-defaults.rs b/tests/ui/generic-const-items/parameter-defaults.rs
new file mode 100644
index 000000000..a6f82c249
--- /dev/null
+++ b/tests/ui/generic-const-items/parameter-defaults.rs
@@ -0,0 +1,14 @@
+#![feature(generic_const_items)]
+#![allow(incomplete_features)]
+
+// Check that we emit a *hard* error (not just a lint warning or error for example) for generic
+// parameter defaults on free const items since we are not limited by backward compatibility.
+#![allow(invalid_type_param_default)] // Should have no effect here.
+
+// FIXME(default_type_parameter_fallback): Consider reallowing them once they work properly.
+
+const NONE<T = ()>: Option<T> = None::<T>; //~ ERROR defaults for type parameters are only allowed
+
+fn main() {
+    let _ = NONE;
+}