Call user defined type operator by member function

test/libsolidity/syntaxTests/operators/custom/call_operator_by_member_function.sol

@@ -0,0 +1,15 @@
+type Int is int16;
+
+using {add as +} for Int;
+
+function add(Int, Int) returns (Int) {
+    return Int.wrap(0);
+}
+
+function f() {
+    Int a;
+    a.add(a);
+}
+
+// ----
+// TypeError 9582: (143-148): Member "add" not found or not visible after argument-dependent lookup in Int.