Updates after code review

test/libsolidity/syntaxTests/using/function_bound_to_operator_in_contract_scope_as_global.sol

@@ -0,0 +1,16 @@
+type Int is int16;
+
+function add(Int, Int) pure returns (Int) {
+    return Int.wrap(0);
+}
+
+contract C {
+    using {add as +} for Int global;
+
+    function test() pure public {
+        Int.wrap(0) + Int.wrap(0);
+    }
+}
+
+// ----
+// SyntaxError 3367: (108-140): "global" can only be used at file level.

test/libsolidity/syntaxTests/using/two_functions_bound_to_the_same_binary_operator_as_global_and_non_global.sol

@@ -0,0 +1,20 @@
+==== Source: s1.sol ====
+type Int is int;
+
+using {add as +} for Int global;
+using {another_add as +} for Int;
+
+function add(Int, Int) pure returns (Int) {
+    return Int.wrap(0);
+}
+
+function another_add(Int, Int) pure returns (Int) {
+    return Int.wrap(0);
+}
+
+function test() pure returns (Int) {
+    return Int.wrap(1) + Int.wrap(2);
+}
+
+// ----
+// TypeError 2271: (s1.sol:284-309): Binary operator + not compatible with types Int and Int. Multiple user-defined functions provided for this operator.

test/libsolidity/syntaxTests/using/two_functions_bound_to_the_same_unary_operator_as_global_and_non_global.sol

@@ -0,0 +1,15 @@
+type Int is int;
+
+using {unsub as -} for Int global;
+using {another_unsub as -} for Int;
+
+function unsub(Int) pure returns (Int) {}
+
+function another_unsub(Int) pure returns (Int) {}
+
+function test() pure returns (Int) {
+    return -Int.wrap(2);
+}
+
+// ----
+// TypeError 4907: (232-244): Built-in unary operator - cannot be applied to type Int. Multiple user-defined functions provided for this operator.

test/libsolidity/syntaxTests/using/user_type_operator_defined_as_global.sol

@@ -1,15 +1,23 @@
 ==== Source: s1.sol ====
 type Int is int;
 using {add as +} for Int global;
+using {sub as -} for Int;
 
 function add(Int, Int) pure returns (Int) {
     return Int.wrap(3);
 }
 
+function sub(Int, Int) pure returns (Int) {
+    return Int.wrap(4);
+}
+
 ==== Source: s2.sol ====
 import "s1.sol";
 contract C {
     function f() pure public {
         Int.wrap(0) + Int.wrap(0);
+        Int.wrap(0) - Int.wrap(0);
     }
 }
+// ----
+// TypeError 2271: (s2.sol:104-129): Binary operator - not compatible with types Int and Int. No matching user-defined operator found.