Using an optional type as generic parameter was not properly caught #2799

test/test_suite/generic/generic_param_opt.c3

@@ -0,0 +1,8 @@
+import std;
+
+alias Aa = List{Path?}; // #error: The generic type can never be an optional, please use only non-optional types
+
+fn int main()
+{
+	return 0;
+}