Test for binding user type operator to error

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

@@ -0,0 +1,12 @@
+type Int is int16;
+
+using {f as +} for IntError;
+
+error IntError();
+
+function f(Int _a, Int _b) pure returns (Int) {
+    return Int.wrap(0);
+}
+
+// ----
+// TypeError 5172: (39-47): Name has to refer to a user-defined value type, struct, enum or contract.