feat(es/minifier): Drop useless assignments (#3528)

testing:
 - Allow skipping diff using an environment variable `DIFF`.

swc_ecma_minifier:
 - `pure`: Drop useless assignemnts.

.github/workflows/cargo.yml

@@ -17,6 +17,7 @@ env:
   CARGO_INCREMENTAL: 0
   RUST_LOG: "debug"
   SWC_CACHE_TEST: 1
+  DIFF: 0
 
 jobs:
   check-license:

crates/swc/tests/tsc-references/assignFromBooleanInterface_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignFromBooleanInterface_es5.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignFromNumberInterface_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignFromNumberInterface_es5.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignFromStringInterface_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignFromStringInterface_es5.2.minified.js

@@ -1,2 +0,0 @@
-var a;
-a = a;

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures2_es2015.2.minified.js

@@ -1,16 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = {
-    f: ()=>1
-}, a = {
-    f: (x)=>1
-}, a = {
-    f: function(x) {
-        return "";
-    }
-}, a = ()=>1
-, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = (x)=>1
-, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures2_es5.2.minified.js

@@ -1,22 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = {
-    f: function() {
-        return 1;
-    }
-}, a = {
-    f: function(x) {
-        return 1;
-    }
-}, a = {
-    f: function(x) {
-        return "";
-    }
-}, a = function() {
-    return 1;
-}, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = function(x) {
-    return 1;
-}, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures3_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18;
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b7 = b7, b8 = b8, b9 = b9, b10 = b10, b11 = b11, b12 = b12, b13 = b13, b14 = b14, b15 = b15, b16 = b16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures3_es5.2.minified.js

@@ -44,7 +44,7 @@ function _createSuper(Derived1) {
         })(self);
     };
 }
-var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18, Base = function() {
+var Base = function() {
     "use strict";
     _classCallCheck(this, Base);
 }, Derived = function(Base1) {
@@ -72,4 +72,3 @@ var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b
     }
     return OtherDerived;
 }(Base);
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b7 = b7, b8 = b8, b9 = b9, b10 = b10, b11 = b11, b12 = b12, b13 = b13, b14 = b14, b15 = b15, b16 = b16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures4_es2015.2.minified.js

@@ -1,8 +1,7 @@
 var Errors;
 !function(Errors) {
-    var b2, b7, b8, b10, b11, b12, b15, b15a, b16, b17, b21, b3;
     let WithNonGenericSignaturesInBaseType;
-    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), b2 = b2, b7 = b7, b8 = b8, b10 = b10, b11 = b11, b12 = b12, b15 = b15, b15a = b15a, b16 = b16, b17 = b17;
+    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {});
     let WithGenericSignaturesInBaseType;
-    WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {}), b21 = b21, b3 = b3;
+    WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {});
 }(Errors || (Errors = {}));

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures4_es5.2.minified.js

@@ -46,7 +46,7 @@ function _createSuper(Derived) {
     };
 }
 !function(Errors) {
-    var WithNonGenericSignaturesInBaseType, WithGenericSignaturesInBaseType, b2, b7, b8, b10, b11, b12, b15, b15a, b16, b17, b21, b3, Base1 = function() {
+    var WithNonGenericSignaturesInBaseType, WithGenericSignaturesInBaseType, Base1 = function() {
         "use strict";
         _classCallCheck(this, Base1);
     }, Derived = function(Base) {
@@ -74,5 +74,5 @@ function _createSuper(Derived) {
         }
         return OtherDerived;
     }(Base1);
-    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), b2 = b2, b7 = b7, b8 = b8, b10 = b10, b11 = b11, b12 = b12, b15 = b15, b15a = b15a, b16 = b16, b17 = b17, WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {}), b21 = b21, b3 = b3;
+    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {});
 }(Errors || (Errors = {}));

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures5_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2, b3, b4, b5, b6, b11, b15, b17, b18;
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b11 = b11, b15 = b15, b15 = void 0, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures5_es5.2.minified.js

@@ -44,7 +44,7 @@ function _createSuper(Derived1) {
         })(self);
     };
 }
-var a16, b, b2, b3, b4, b5, b6, b11, b15, b17, b18, Base = function() {
+var Base = function() {
     "use strict";
     _classCallCheck(this, Base);
 }, Derived = function(Base1) {
@@ -72,4 +72,3 @@ var a16, b, b2, b3, b4, b5, b6, b11, b15, b17, b18, Base = function() {
     }
     return OtherDerived;
 }(Base);
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b11 = b11, b15 = b15, b15 = a16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures_es2015.2.minified.js

@@ -1,9 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = (x)=>1
-, a = ()=>1
-, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = (x)=>1
-, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithCallSignatures_es5.2.minified.js

@@ -1,12 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = function(x) {
-    return 1;
-}, a = function() {
-    return 1;
-}, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = function(x) {
-    return 1;
-}, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures2_es2015.2.minified.js

@@ -1,8 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = ()=>1
-, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = (x)=>1
-, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures2_es5.2.minified.js

@@ -1,10 +0,0 @@
-var a, s2, a3;
-a = a, a = void 0, a = void 0, a = function() {
-    return 1;
-}, a = function(x) {
-    return "";
-}, a = s2, a = a3, a = function(x) {
-    return 1;
-}, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures3_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18;
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b7 = b7, b8 = b8, b9 = b9, b10 = b10, b11 = b11, b12 = b12, b13 = b13, b14 = b14, b15 = b15, b16 = b16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures3_es5.2.minified.js

@@ -44,7 +44,7 @@ function _createSuper(Derived1) {
         })(self);
     };
 }
-var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18, Base = function() {
+var Base = function() {
     "use strict";
     _classCallCheck(this, Base);
 }, Derived = function(Base1) {
@@ -72,4 +72,3 @@ var b, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b
     }
     return OtherDerived;
 }(Base);
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b7 = b7, b8 = b8, b9 = b9, b10 = b10, b11 = b11, b12 = b12, b13 = b13, b14 = b14, b15 = b15, b16 = b16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures4_es2015.2.minified.js

@@ -1,8 +1,7 @@
 var Errors;
 !function(Errors) {
-    var b2, b7, b8, b10, b11, b12, b15, b15a, b16, b17, b21, b3;
     let WithNonGenericSignaturesInBaseType;
-    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), b2 = b2, b7 = b7, b8 = b8, b10 = b10, b11 = b11, b12 = b12, b15 = b15, b15a = b15a, b16 = b16, b17 = b17;
+    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {});
     let WithGenericSignaturesInBaseType;
-    WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {}), b21 = b21, b3 = b3;
+    WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {});
 }(Errors || (Errors = {}));

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures4_es5.2.minified.js

@@ -46,7 +46,7 @@ function _createSuper(Derived) {
     };
 }
 !function(Errors) {
-    var WithNonGenericSignaturesInBaseType, WithGenericSignaturesInBaseType, b2, b7, b8, b10, b11, b12, b15, b15a, b16, b17, b21, b3, Base1 = function() {
+    var WithNonGenericSignaturesInBaseType, WithGenericSignaturesInBaseType, Base1 = function() {
         "use strict";
         _classCallCheck(this, Base1);
     }, Derived = function(Base) {
@@ -74,5 +74,5 @@ function _createSuper(Derived) {
         }
         return OtherDerived;
     }(Base1);
-    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), b2 = b2, b7 = b7, b8 = b8, b10 = b10, b11 = b11, b12 = b12, b15 = b15, b15a = b15a, b16 = b16, b17 = b17, WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {}), b21 = b21, b3 = b3;
+    WithNonGenericSignaturesInBaseType || (WithNonGenericSignaturesInBaseType = {}), WithGenericSignaturesInBaseType || (WithGenericSignaturesInBaseType = {});
 }(Errors || (Errors = {}));

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures5_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2, b3, b4, b5, b6, b11, b15, b17, b18;
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b11 = b11, b15 = b15, b15 = void 0, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures5_es5.2.minified.js

@@ -44,7 +44,7 @@ function _createSuper(Derived1) {
         })(self);
     };
 }
-var a16, b, b2, b3, b4, b5, b6, b11, b15, b17, b18, Base = function() {
+var Base = function() {
     "use strict";
     _classCallCheck(this, Base);
 }, Derived = function(Base1) {
@@ -72,4 +72,3 @@ var a16, b, b2, b3, b4, b5, b6, b11, b15, b17, b18, Base = function() {
     }
     return OtherDerived;
 }(Base);
-b = b, b2 = b2, b3 = b3, b4 = b4, b5 = b5, b6 = b6, b11 = b11, b15 = b15, b15 = a16, b17 = b17, b18 = b18;

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures_es2015.2.minified.js

@@ -1,5 +0,0 @@
-var a;
-a = a, a = void 0, a = void 0, a = void 0, a = void 0, a = (x)=>1
-, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithConstructSignatures_es5.2.minified.js

@@ -1,6 +0,0 @@
-var a;
-a = a, a = void 0, a = void 0, a = void 0, a = void 0, a = function(x) {
-    return 1;
-}, a = function(x) {
-    return "";
-};

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures2_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b;
-b = b;

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures2_es5.2.minified.js

@@ -1,2 +0,0 @@
-var b;
-b = b;

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures4_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var y;
-y = y;

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures4_es5.2.minified.js

@@ -1,2 +0,0 @@
-var y;
-y = y;

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var g;
-g = g; // ok

crates/swc/tests/tsc-references/assignmentCompatWithGenericCallSignatures_es5.2.minified.js

@@ -1,2 +0,0 @@
-var g;
-g = g; // ok

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer2_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2;
-b = b, b2 = b2;

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer2_es5.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2;
-b = b, b2 = b2;

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer3_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2;
-b = b, b2 = b2;

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer3_es5.2.minified.js

@@ -11,12 +11,10 @@ function _setPrototypeOf(o, p) {
         return o.__proto__ = p, o;
     }, _setPrototypeOf(o, p);
 }
-var b, b2, Generics, A = function() {
+var Generics, A = function() {
     "use strict";
     _classCallCheck(this, A);
-};
+}, B2 = function(A1) {
-b = b;
-var B2 = function(A1) {
     "use strict";
     !function(subClass, superClass) {
         if ("function" != typeof superClass && null !== superClass) throw new TypeError("Super expression must either be null or a function");
@@ -53,9 +51,9 @@ var B2 = function(A1) {
     }
     return B2;
 }(A);
-b2 = b2, (function(Generics) {
+!function(Generics) {
     var A2 = function() {
         "use strict";
         _classCallCheck(this, A2);
     };
-})(Generics || (Generics = {}));
+}(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b, b2;
-b = b, b2 = b2;

crates/swc/tests/tsc-references/assignmentCompatWithNumericIndexer_es5.2.minified.js

@@ -11,11 +11,11 @@ function _setPrototypeOf(o, p) {
         return o.__proto__ = p, o;
     }, _setPrototypeOf(o, p);
 }
-var b, b2, Generics, A = function() {
+var Generics, A = function() {
     "use strict";
     _classCallCheck(this, A);
 };
-b = b, b2 = b2, (function(Generics) {
+!function(Generics) {
     var A1 = function() {
         "use strict";
         _classCallCheck(this, A1);
@@ -56,4 +56,4 @@ b = b, b2 = b2, (function(Generics) {
         }
         return B;
     }(A1);
-})(Generics || (Generics = {}));
+}(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers2_es2015.2.minified.js

@@ -1,4 +0,0 @@
-var t, t2, b, b2 = {
-    foo: ""
-};
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers2_es5.2.minified.js

@@ -1,13 +1,10 @@
 function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
-var t, t2, b, S = function() {
+var S = function() {
     "use strict";
     _classCallCheck(this, S);
 }, T = function() {
     "use strict";
     _classCallCheck(this, T);
-}, b2 = {
-    foo: ""
 };
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers3_es2015.2.minified.js

@@ -1,4 +0,0 @@
-var t, t2, b, b2 = {
-    foo: ""
-};
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers3_es5.2.minified.js

@@ -1,13 +1,10 @@
 function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
-var t, t2, b, S = function() {
+var S = function() {
     "use strict";
     _classCallCheck(this, S);
 }, T = function() {
     "use strict";
     _classCallCheck(this, T);
-}, b2 = {
-    foo: ""
 };
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers4_es2015.2.minified.js

@@ -2,22 +2,12 @@ var OnlyDerived, WithBase;
 !function(OnlyDerived) {
     class Base {
     }
-    var t, t2, b, a2 = {
+    new class extends Base {
-        foo: new class extends Base {
+    }(), new class extends Base {
-        }()
+    }();
-    }, b2 = {
-        foo: new class extends Base {
-        }()
-    };
-    t2 = t2, b = b, b2 = b2, t = t;
 }(OnlyDerived || (OnlyDerived = {})), (function(WithBase) {
     class Base {
     }
-    var t, t2, b, a2 = {
+    new Base(), new class extends Base {
-        foo: new Base()
+    }();
-    }, b2 = {
-        foo: new class extends Base {
-        }()
-    };
-    t2 = t2, b = b, b2 = b2, t = t;
 })(WithBase || (WithBase = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers4_es5.2.minified.js

@@ -46,7 +46,7 @@ function _createSuper(Derived) {
     };
 }
 !function(OnlyDerived) {
-    var t, t2, b, Base1 = function() {
+    var Base1 = function() {
         "use strict";
         _classCallCheck(this, Base1);
     }, Derived = function(Base) {
@@ -71,14 +71,10 @@ function _createSuper(Derived) {
     }, T = function() {
         "use strict";
         _classCallCheck(this, T);
-    }, a2 = {
-        foo: new Derived()
-    }, b2 = {
-        foo: new Derived2()
     };
-    t2 = t2, b = b, b2 = b2, t = t;
+    new Derived(), new Derived2();
 }(OnlyDerived || (OnlyDerived = {})), (function(WithBase) {
-    var t, t2, b, Base2 = function() {
+    var Base2 = function() {
         "use strict";
         _classCallCheck(this, Base2);
     }, Derived = function(Base) {
@@ -103,10 +99,6 @@ function _createSuper(Derived) {
     }, T = function() {
         "use strict";
         _classCallCheck(this, T);
-    }, a2 = {
-        foo: new Base2()
-    }, b2 = {
-        foo: new Derived2()
     };
-    t2 = t2, b = b, b2 = b2, t = t;
+    new Base2(), new Derived2();
 })(WithBase || (WithBase = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers5_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i;
-i = i; // error

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers5_es5.2.minified.js

@@ -1,7 +1,6 @@
-var i, C = function() {
+var C = function() {
     "use strict";
     !function(instance, Constructor) {
         if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
     }(this, C);
 };
-i = i; // error

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersAccessibility_es2015.2.minified.js

@@ -1,8 +1,8 @@
 var TargetIsPublic;
 !function(TargetIsPublic) {
     var a, b, i, d, e;
-    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = e = d;
+    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = d;
 }(TargetIsPublic || (TargetIsPublic = {})), (function(TargetIsPublic) {
     var a, b, i, d, e;
-    a = b, a = i, a = d, b = a = e, b = i, b = d, b = b = e, i = a, i = b, i = d, i = i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = e = d;
+    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = d;
 })(TargetIsPublic || (TargetIsPublic = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersAccessibility_es5.2.minified.js

@@ -13,7 +13,7 @@ function _classCallCheck(instance, Constructor) {
         "use strict";
         _classCallCheck(this, E);
     };
-    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = e = d;
+    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = d;
 }(TargetIsPublic || (TargetIsPublic = {})), (function(TargetIsPublic) {
     var a, b, i, d, e, Base = function() {
         "use strict";
@@ -25,5 +25,5 @@ function _classCallCheck(instance, Constructor) {
         "use strict";
         _classCallCheck(this, E);
     };
-    a = b, a = i, a = d, b = a = e, b = i, b = d, b = b = e, i = a, i = b, i = d, i = i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = e = d;
+    a = b, a = i, a = d, b = a = e, b = i, b = d, b = e, i = a, i = b, i = d, i = e, d = a, d = b, d = i, d = e, e = a, e = b, e = i, e = d;
 })(TargetIsPublic || (TargetIsPublic = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersNumericNames_es2015.2.minified.js

@@ -1,4 +0,0 @@
-var t, t2, b, b2 = {
-    1: ""
-};
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersNumericNames_es5.2.minified.js

@@ -1,13 +1,10 @@
 function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
-var t, t2, b, S = function() {
+var S = function() {
     "use strict";
     _classCallCheck(this, S);
 }, T = function() {
     "use strict";
     _classCallCheck(this, T);
-}, b2 = {
-    1: ""
 };
-t2 = t2, b = b, b2 = b2, t = t;

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersStringNumericNames_es2015.2.minified.js

@@ -1,12 +0,0 @@
-var JustStrings, NumbersAndStrings;
-!function(JustStrings) {
-    var t, t2, b, b2 = {
-        "1": ""
-    };
-    t2 = t2, b = b, b2 = b2, t = t;
-}(JustStrings || (JustStrings = {})), (function(NumbersAndStrings) {
-    var t, t2, b, b2 = {
-        1: ""
-    };
-    t2 = t2, b = b, b2 = b2, t = t;
-})(NumbersAndStrings || (NumbersAndStrings = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembersStringNumericNames_es5.2.minified.js

@@ -3,25 +3,19 @@ function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
 !function(JustStrings) {
-    var t, t2, b, S = function() {
+    var S = function() {
         "use strict";
         _classCallCheck(this, S);
     }, T = function() {
         "use strict";
         _classCallCheck(this, T);
-    }, b2 = {
-        "1": ""
     };
-    t2 = t2, b = b, b2 = b2, t = t;
 }(JustStrings || (JustStrings = {})), (function(NumbersAndStrings) {
-    var t, t2, b, S = function() {
+    var S = function() {
         "use strict";
         _classCallCheck(this, S);
     }, T = function() {
         "use strict";
         _classCallCheck(this, T);
-    }, b2 = {
-        1: ""
     };
-    t2 = t2, b = b, b2 = b2, t = t;
 })(NumbersAndStrings || (NumbersAndStrings = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers_es2015.2.minified.js

@@ -1,14 +1,9 @@
-var SimpleTypes, ObjectTypes;
+var ObjectTypes;
-!function(SimpleTypes) {
+!function(ObjectTypes) {
-    var t, t2, b, b2 = {
-        foo: ""
-    };
-    t2 = t2, b = b, b2 = b2, t = t;
-}(SimpleTypes || (SimpleTypes = {})), (function(ObjectTypes) {
     var t, t2, b, a2 = {
         foo: a2
     }, b2 = {
         foo: b2
     };
-    t = t, t2 = t2, b = b, b2 = a2 = b2, a2 = b, a2 = t2, a2 = t;
+    b2 = a2 = b2, a2 = b, a2 = t2, a2 = t;
-})(ObjectTypes || (ObjectTypes = {}));
+}(ObjectTypes || (ObjectTypes = {}));

crates/swc/tests/tsc-references/assignmentCompatWithObjectMembers_es5.2.minified.js

@@ -3,16 +3,13 @@ function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
 !function(SimpleTypes) {
-    var t, t2, b, S = function() {
+    var S = function() {
         "use strict";
         _classCallCheck(this, S);
     }, T = function() {
         "use strict";
         _classCallCheck(this, T);
-    }, b2 = {
-        foo: ""
     };
-    t2 = t2, b = b, b2 = b2, t = t;
 }(SimpleTypes || (SimpleTypes = {})), (function(ObjectTypes) {
     var t, t2, b, S = function() {
         "use strict";
@@ -25,5 +22,5 @@ function _classCallCheck(instance, Constructor) {
     }, b2 = {
         foo: b2
     };
-    t = t, t2 = t2, b = b, b2 = a2 = b2, a2 = b, a2 = t2, a2 = t;
+    b2 = a2 = b2, a2 = b, a2 = t2, a2 = t;
 })(ObjectTypes || (ObjectTypes = {}));

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer2_es2015.2.minified.js

@@ -1,5 +0,0 @@
-var b, b2, Generics;
-b = b, b2 = b2, (function(Generics) {
-    var b1, b21;
-    b1 = b1, b21 = b21;
-})(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer2_es5.2.minified.js

@@ -1,5 +0,0 @@
-var b, b2, Generics;
-b = b, b2 = b2, (function(Generics) {
-    var b1, b21;
-    b1 = b1, b21 = b21;
-})(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer3_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b1;
-b1 = b1;

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer3_es5.2.minified.js

@@ -1,9 +1,9 @@
-var b1, Generics;
+var Generics;
-b1 = b1, (function(Generics) {
+!function(Generics) {
     var A = function() {
         "use strict";
         !function(instance, Constructor) {
             if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
         }(this, A);
     };
-})(Generics || (Generics = {}));
+}(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer_es2015.2.minified.js

@@ -1,5 +0,0 @@
-var b, b2, Generics;
-b = b, b2 = b2, (function(Generics) {
-    var b1, b21;
-    b1 = b1, b21 = b21;
-})(Generics || (Generics = {}));

crates/swc/tests/tsc-references/assignmentCompatWithStringIndexer_es5.2.minified.js

@@ -44,12 +44,12 @@ function _createSuper(Derived) {
         })(self);
     };
 }
-var b, b2, Generics, A = function() {
+var Generics, A = function() {
     "use strict";
     _classCallCheck(this, A);
 };
-b = b, b2 = b2, (function(Generics) {
+!function(Generics) {
-    var b1, b21, A1 = function() {
+    var A1 = function() {
         "use strict";
         _classCallCheck(this, A1);
     }, B = function(A2) {
@@ -60,9 +60,7 @@ b = b, b2 = b2, (function(Generics) {
             return _classCallCheck(this, B), _super.apply(this, arguments);
         }
         return B;
-    }(A1);
+    }(A1), B2 = function(A3) {
-    b1 = b1;
-    var B2 = function(A3) {
         "use strict";
         _inherits(B2, A3);
         var _super = _createSuper(B2);
@@ -71,5 +69,4 @@ b = b, b2 = b2, (function(Generics) {
         }
         return B2;
     }(A1);
-    b21 = b21;
+}(Generics || (Generics = {}));
-})(Generics || (Generics = {}));

crates/swc/tests/tsc-references/asyncMethodWithSuperConflict_es6_es5.2.minified.js

@@ -58,7 +58,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/asyncMethodWithSuper_es2017_es5.2.minified.js

@@ -58,7 +58,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/asyncMethodWithSuper_es5_es5.2.minified.js

@@ -58,7 +58,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/asyncMethodWithSuper_es6_es5.2.minified.js

@@ -112,7 +112,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/boolInsteadOfBoolean_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var x;
-x = x;

crates/swc/tests/tsc-references/boolInsteadOfBoolean_es5.2.minified.js

@@ -1,2 +0,0 @@
-var x;
-x = x;

crates/swc/tests/tsc-references/classWithOnlyPublicMembersEquivalentToInterface2_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i;
-i = i;

crates/swc/tests/tsc-references/classWithOnlyPublicMembersEquivalentToInterface2_es5.2.minified.js

@@ -1,10 +1,10 @@
 function _defineProperties(target, props) {
-    for(var i1 = 0; i1 < props.length; i1++){
+    for(var i = 0; i < props.length; i++){
-        var descriptor = props[i1];
+        var descriptor = props[i];
         descriptor.enumerable = descriptor.enumerable || !1, descriptor.configurable = !0, "value" in descriptor && (descriptor.writable = !0), Object.defineProperty(target, descriptor.key, descriptor);
     }
 }
-var i, C = function() {
+var C = function() {
     "use strict";
     var Constructor, protoProps, staticProps;
     function C() {
@@ -28,4 +28,3 @@ var i, C = function() {
         }
     ], _defineProperties(Constructor.prototype, protoProps), staticProps && _defineProperties(Constructor, staticProps), C;
 }();
-i = i;

crates/swc/tests/tsc-references/classWithOnlyPublicMembersEquivalentToInterface_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i;
-i = i;

crates/swc/tests/tsc-references/classWithOnlyPublicMembersEquivalentToInterface_es5.2.minified.js

@@ -1,10 +1,10 @@
 function _defineProperties(target, props) {
-    for(var i1 = 0; i1 < props.length; i1++){
+    for(var i = 0; i < props.length; i++){
-        var descriptor = props[i1];
+        var descriptor = props[i];
         descriptor.enumerable = descriptor.enumerable || !1, descriptor.configurable = !0, "value" in descriptor && (descriptor.writable = !0), Object.defineProperty(target, descriptor.key, descriptor);
     }
 }
-var i, C = function() {
+var C = function() {
     "use strict";
     var Constructor, protoProps, staticProps;
     function C() {
@@ -28,4 +28,3 @@ var i, C = function() {
         }
     ], _defineProperties(Constructor.prototype, protoProps), staticProps && _defineProperties(Constructor, staticProps), C;
 }();
-i = i;

crates/swc/tests/tsc-references/contextualTypeWithTuple_es2015.2.minified.js

@@ -1,15 +1,4 @@
-var numStrBoolTuple = [
-    5,
-    "foo",
-    !0
-];
 class C {
 }
-new C(), new C();
+new C(), new C(), new C(), new class {
-var unionTuple2 = [
+}();
-    new C(),
-    "foo",
-    new class {
-    }()
-];
-numStrBoolTuple = numStrBoolTuple, unionTuple2 = unionTuple2;

crates/swc/tests/tsc-references/contextualTypeWithTuple_es5.2.minified.js

@@ -1,25 +1,11 @@
 function _classCallCheck(instance, Constructor) {
     if (!(instance instanceof Constructor)) throw new TypeError("Cannot call a class as a function");
 }
-var numStrBoolTuple = [
+var C = function() {
-    5,
-    "foo",
-    !0
-], C = function() {
     "use strict";
     _classCallCheck(this, C);
 }, D = function() {
     "use strict";
     _classCallCheck(this, D);
-}, unionTuple = [
+};
-    new C(),
+new C(), new C(), new C(), new D();
-    "foo"
-], unionTuple1 = [
-    new C(),
-    "foo"
-], unionTuple2 = [
-    new C(),
-    "foo",
-    new D()
-];
-numStrBoolTuple = numStrBoolTuple, unionTuple2 = unionTuple2;

crates/swc/tests/tsc-references/enumAssignability_es2015.2.minified.js

@@ -1,7 +1,6 @@
-!function(E) {
+var E, F;
+(function(E) {
     E[E.A = 0] = "A";
-}(E || (E = {})), (function(F) {
+})(E || (E = {})), (function(F) {
     F[F.B = 0] = "B";
-})(F || (F = {}));
+})(F || (F = {})), E.A, F.B;
-var E, F, e = E.A, f = F.B;
-f = f, f = 1;

crates/swc/tests/tsc-references/enumAssignability_es5.2.minified.js

@@ -1,10 +1,9 @@
-!function(E) {
+var E, F, Others;
+(function(E) {
     E[E.A = 0] = "A";
-}(E || (E = {})), (function(F) {
+})(E || (E = {})), (function(F) {
     F[F.B = 0] = "B";
-})(F || (F = {}));
+})(F || (F = {})), E.A, F.B, (function(Others) {
-var E, F, Others, e = E.A, f = F.B;
-f = f, f = 1, (function(Others) {
     var C = function() {
         "use strict";
         !function(instance, Constructor) {

crates/swc/tests/tsc-references/errorSuperPropertyAccess_es5.2.minified.js

@@ -48,7 +48,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/genericTypeAliases_es2015.2.minified.js

@@ -1,2 +1,2 @@
-var y, p;
+var p;
-y = y, p.a = 1, p.b = 2, p.tag = "test";
+p.a = 1, p.b = 2, p.tag = "test";

crates/swc/tests/tsc-references/genericTypeAliases_es5.2.minified.js

@@ -1,2 +1,2 @@
-var y, p;
+var p;
-y = y, p.a = 1, p.b = 2, p.tag = "test";
+p.a = 1, p.b = 2, p.tag = "test";

crates/swc/tests/tsc-references/interfaceExtendingClass_es2015.2.minified.js

@@ -1,2 +1,2 @@
 var i;
-i.x, i.y(), i.Z, i = i;
+i.x, i.y(), i.Z;

crates/swc/tests/tsc-references/interfaceExtendingClass_es5.2.minified.js

@@ -25,4 +25,4 @@ var i, Foo = function() {
         }
     ], _defineProperties((Constructor = Foo).prototype, protoProps), staticProps && _defineProperties(Constructor, staticProps), Foo;
 }();
-i.x, i.y(), i.Z, i = i;
+i.x, i.y(), i.Z;

crates/swc/tests/tsc-references/isomorphicMappedTypeInference_es2015.2.minified.js

@@ -1,3 +1,6 @@
+function getProps(obj, list) {
+    return {};
+}
 applySpec({
     sum: (a)=>3
     ,
@@ -10,15 +13,7 @@ applySpec({
             baz: (x)=>!0
         }
     }
-});
+}), f20({
-let o = {
-    a: 5,
-    b: 7
-};
-function getProps(obj, list) {
-    return {};
-}
-o = o, f20({
     foo: 42,
     bar: "hello"
 }), f21({

crates/swc/tests/tsc-references/nonPrimitiveUnionIntersection_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var b = "";
-b = b;

crates/swc/tests/tsc-references/nonPrimitiveUnionIntersection_es5.2.minified.js

@@ -1,2 +0,0 @@
-var b = "";
-b = b;

crates/swc/tests/tsc-references/numberAssignableToEnum_es2015.2.minified.js

@@ -1,4 +1,4 @@
-var E, n;
+var E;
 !function(E) {
     E[E.A = 0] = "A";
-}(E || (E = {})), n = n;
+}(E || (E = {}));

crates/swc/tests/tsc-references/numberAssignableToEnum_es5.2.minified.js

@@ -1,4 +1,4 @@
-var E, n;
+var E;
 !function(E) {
     E[E.A = 0] = "A";
-}(E || (E = {})), n = n;
+}(E || (E = {}));

crates/swc/tests/tsc-references/objectTypeHidingMembersOfObjectAssignmentCompat2_es2015.2.minified.js

@@ -1,5 +0,0 @@
-i = i, c = c;
-var i, c, a = {
-    toString: ()=>{}
-};
-a = a;

crates/swc/tests/tsc-references/objectTypeHidingMembersOfObjectAssignmentCompat2_es5.2.minified.js

@@ -1,11 +1,10 @@
 function _defineProperties(target, props) {
-    for(var i1 = 0; i1 < props.length; i1++){
+    for(var i = 0; i < props.length; i++){
-        var descriptor = props[i1];
+        var descriptor = props[i];
         descriptor.enumerable = descriptor.enumerable || !1, descriptor.configurable = !0, "value" in descriptor && (descriptor.writable = !0), Object.defineProperty(target, descriptor.key, descriptor);
     }
 }
-i = i;
+var C = function() {
-var i, c, C = function() {
     "use strict";
     var Constructor, protoProps, staticProps;
     function C() {
@@ -22,8 +21,3 @@ var i, c, C = function() {
         }
     ], _defineProperties((Constructor = C).prototype, protoProps), staticProps && _defineProperties(Constructor, staticProps), C;
 }();
-c = c;
-var a = {
-    toString: function() {}
-};
-a = a; // ok

crates/swc/tests/tsc-references/objectTypeHidingMembersOfObjectAssignmentCompat_es2015.2.minified.js

@@ -1,5 +0,0 @@
-i = i, c = c;
-var i, c, a = {
-    toString: ()=>{}
-};
-a = a;

crates/swc/tests/tsc-references/objectTypeHidingMembersOfObjectAssignmentCompat_es5.2.minified.js

@@ -1,11 +1,10 @@
 function _defineProperties(target, props) {
-    for(var i1 = 0; i1 < props.length; i1++){
+    for(var i = 0; i < props.length; i++){
-        var descriptor = props[i1];
+        var descriptor = props[i];
         descriptor.enumerable = descriptor.enumerable || !1, descriptor.configurable = !0, "value" in descriptor && (descriptor.writable = !0), Object.defineProperty(target, descriptor.key, descriptor);
     }
 }
-i = i;
+var C = function() {
-var i, c, C = function() {
     "use strict";
     var Constructor, protoProps, staticProps;
     function C() {
@@ -20,8 +19,3 @@ var i, c, C = function() {
         }
     ], _defineProperties((Constructor = C).prototype, protoProps), staticProps && _defineProperties(Constructor, staticProps), C;
 }();
-c = c;
-var a = {
-    toString: function() {}
-};
-a = a; // ok

crates/swc/tests/tsc-references/objectTypeWithCallSignatureHidingMembersOfFunctionAssignmentCompat_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/objectTypeWithCallSignatureHidingMembersOfFunctionAssignmentCompat_es5.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/objectTypeWithConstructSignatureHidingMembersOfFunctionAssignmentCompat_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/objectTypeWithConstructSignatureHidingMembersOfFunctionAssignmentCompat_es5.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/parserArrowFunctionExpression4_es5.2.minified.js

@@ -1 +0,0 @@
-a = a;

crates/swc/tests/tsc-references/parserAutomaticSemicolonInsertion1_es2015.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/parserAutomaticSemicolonInsertion1_es5.2.minified.js

@@ -1,2 +0,0 @@
-var i, a;
-i = i, a = a;

crates/swc/tests/tsc-references/parserSuperExpression4_es5.2.minified.js

@@ -25,7 +25,7 @@ function set(target, property, value, receiver) {
         if (desc = Object.getOwnPropertyDescriptor(receiver, property)) {
             if (!desc.writable) return !1;
             desc.value = value, Object.defineProperty(receiver, property, desc);
-        } else obj = receiver, value = value, (key = property) in obj ? Object.defineProperty(obj, key, {
+        } else obj = receiver, (key = property) in obj ? Object.defineProperty(obj, key, {
             value: value,
             enumerable: !0,
             configurable: !0,

crates/swc/tests/tsc-references/stringLiteralTypesOverloadAssignability01_es2015.2.minified.js

@@ -1,4 +0,0 @@
-let b = function(x) {
-    return 0;
-};
-b = b;

crates/swc/tests/tsc-references/stringLiteralTypesOverloadAssignability01_es5.2.minified.js

@@ -1,4 +0,0 @@
-var b = function(x) {
-    return 0;
-};
-b = b;

crates/swc/tests/tsc-references/stringLiteralTypesOverloadAssignability02_es2015.2.minified.js

@@ -1,4 +0,0 @@
-let b = function(x) {
-    return 0;
-};
-b = b;