fix: arrow-fn transformation when 'arguments' is defined as var

packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/arguments/input.js

@@ -43,3 +43,47 @@ function six(obj) {
   return fn();
 }
 six();
+
+var seven = () => {
+    var arguments = 1;
+    return arguments;
+};
+seven();
+
+var eight = () => {
+    var arguments = 1;
+    return () => arguments;
+};
+eight();
+
+function nine() {
+    var arguments = 1;
+    var foo = () => {
+      return arguments;
+    };
+}
+nine();
+
+var arguments = 1;
+function ten() {
+  var foo = () => {
+    return arguments;
+  };
+}
+ten();
+
+var eleven = () => {
+  var arguments = 2;
+  return function () {
+    return () => arguments;
+  }
+};
+eleven()(1,2,3)();
+
+var twelve = () => {
+  var arguments = 2;
+  return class {
+    m() { return () => arguments; }
+  }
+};
+twelve();

packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/arguments/output.js

@@ -1,8 +1,10 @@
+var _arguments4 = arguments;
+
 function one() {
-  var _arguments = arguments;
+  var _arguments2 = arguments;
 
   var inner = function () {
-    return _arguments;
+    return _arguments2;
   };
 
   return [].slice.call(inner());
@@ -11,17 +13,13 @@ function one() {
 one(1, 2);
 
 function two() {
-  var _arguments2 = arguments;
-
   var inner = function () {
-    return _arguments2;
+    return _arguments;
   };
 
   var another = function () {
-    var _arguments3 = arguments;
-
     var inner2 = function () {
-      return _arguments3;
+      return _arguments;
     };
   };
 
@@ -31,10 +29,8 @@ function two() {
 two(1, 2);
 
 function three() {
-  var _arguments4 = arguments;
-
   var fn = function () {
-    return _arguments4[0] + "bar";
+    return _arguments[0] + "bar";
   };
 
   return fn();
@@ -43,10 +39,8 @@ function three() {
 three("foo");
 
 function four() {
-  var _arguments5 = arguments;
-
   var fn = function () {
-    return _arguments5[0].foo + "bar";
+    return _arguments[0].foo + "bar";
   };
 
   return fn();
@@ -71,7 +65,7 @@ five({
 function six(obj) {
   var fn = function () {
     var fn2 = function () {
-      return arguments[0];
+      return _arguments[0];
     };
 
     return fn2("foobar");
@@ -81,3 +75,66 @@ function six(obj) {
 }
 
 six();
+
+var seven = function () {
+  var arguments = 1;
+  return arguments;
+};
+
+seven();
+
+var eight = function () {
+  var _arguments3 = 1;
+  return function () {
+    return _arguments4;
+  };
+};
+
+eight();
+
+function nine() {
+  var _arguments6 = arguments;
+  var _arguments5 = 1;
+
+  var foo = function () {
+    return _arguments6;
+  };
+}
+
+nine();
+var _arguments = 1;
+
+function ten() {
+  var foo = function () {
+    return _arguments;
+  };
+}
+
+ten();
+
+var eleven = function () {
+  var _arguments7 = 2;
+  return function () {
+    var _arguments8 = arguments;
+    return function () {
+      return _arguments8;
+    };
+  };
+};
+
+eleven()(1, 2, 3)();
+
+var twelve = function () {
+  var _arguments9 = 2;
+  return class {
+    m() {
+      var _arguments10 = arguments;
+      return function () {
+        return _arguments10;
+      };
+    }
+
+  };
+};
+
+twelve();

packages/babel-traverse/src/path/conversion.ts

@@ -236,10 +236,20 @@ function hoistFunctionEnvironment(
     );
 
     argumentsPaths.forEach(argumentsChild => {
-      const argsRef = t.identifier(argumentsBinding);
-      argsRef.loc = argumentsChild.node.loc;
-
-      argumentsChild.replaceWith(argsRef);
+      let currentScope = argumentsChild.scope;
+      do {
+        if (
+          !currentScope.hasOwnBinding("arguments") &&
+          !(
+            currentScope.path.isFunction() &&
+            !currentScope.path.isArrowFunctionExpression()
+          )
+        ) {
+          const argsRef = t.identifier(argumentsBinding);
+          argsRef.loc = argumentsChild.node.loc;
+          argumentsChild.replaceWith(argsRef);
+        }
+      } while ((currentScope = currentScope.parent));
     });
   }
 
@@ -586,9 +596,17 @@ function getScopeInformation(fnPath) {
       if (child.get("object").isSuper()) superProps.push(child);
     },
     ReferencedIdentifier(child) {
-      if (child.node.name !== "arguments") return;
-
-      argumentsPaths.push(child);
+      let curr = child.scope;
+      do {
+        if (curr.hasOwnBinding("arguments")) return;
+        if (curr.path.isFunction() && !curr.path.isArrowFunctionExpression()) {
+          break;
+        }
+        if (child.node.name !== "arguments") return;
+
+        curr.rename("arguments");
+        argumentsPaths.push(child);
+      } while ((curr = curr.parent));
     },
     MetaProperty(child) {
       if (!child.get("meta").isIdentifier({ name: "new" })) return;