Don't resolve shadowed arguments variables from functions (#14036)

The-x-Theorist · web-flow · commit add64e870bef · 2021-12-13T18:29:10.000+01:00
diff --git a/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/arguments-global-var/output.js b/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/arguments-global-var/output.js
@@ -1,7 +1,7 @@
 var _arguments2 = 1;
 
 function fn() {
-  var _arguments = _arguments2;
+  var _arguments = arguments;
 
   var foo = function () {
     return _arguments;
diff --git a/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/exec.js b/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/exec.js
@@ -0,0 +1,11 @@
+var arguments = [1, 2, 3];
+var arr = () => arguments[0];
+
+expect(arr()).toStrictEqual(1)
+
+function foo(n) {
+var f = () => arguments[0] + n; // foo's implicit arguments binding. arguments[0] is n
+return f();
+}
+ 
+expect(foo(3)).toStrictEqual(6)
diff --git a/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/input.js b/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/input.js
@@ -0,0 +1,10 @@
+var arguments = [1, 2, 3];
+var arr = (n) => arguments[0];
+
+arr(4); // 1
+
+function foo(n) {
+var f = () => arguments[0] + n; // foo's implicit arguments binding. arguments[0] is n
+return f();
+}
+ 
diff --git a/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/options.json b/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "script",
+  "plugins": ["transform-arrow-functions"]
+}
diff --git a/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/output.js b/packages/babel-plugin-transform-arrow-functions/test/fixtures/arrow-functions/implicit-var-arguments/output.js
@@ -0,0 +1,18 @@
+var _arguments = [1, 2, 3];
+
+var arr = function (n) {
+  return _arguments[0];
+};
+
+arr(4); // 1
+
+function foo(n) {
+  var _arguments2 = arguments;
+
+  var f = function () {
+    return _arguments2[0] + n;
+  }; // foo's implicit arguments binding. arguments[0] is n
+
+
+  return f();
+}
diff --git a/packages/babel-traverse/src/scope/index.ts b/packages/babel-traverse/src/scope/index.ts
@@ -1138,6 +1138,13 @@ export default class Scope {
         } else {
           return binding;
         }
+      } else if (
+        !binding &&
+        name === "arguments" &&
+        scope.path.isFunction() &&
+        !scope.path.isArrowFunctionExpression()
+      ) {
+        break;
       }
       previousPath = scope.path;
     } while ((scope = scope.parent));

-Original file line number
+Diff line change
@@ @@ -0,0 +1,4 @@ @@
 +{
 +  "sourceType": "script",
 +  "plugins": ["transform-arrow-functions"]
 +}
Original file line number	Diff line number	Diff line change
`@@ -1138,6 +1138,13 @@ export default class Scope {`
`1138`	`1138`	`} else {`
`1139`	`1139`	`return binding;`
`1140`	`1140`	`}`
	`1141`	`+ } else if (`
	`1142`	`+ !binding &&`
	`1143`	`+ name === "arguments" &&`
	`1144`	`+ scope.path.isFunction() &&`
	`1145`	`+ !scope.path.isArrowFunctionExpression()`
	`1146`	`+ ) {`
	`1147`	`+ break;`
`1141`	`1148`	`}`
`1142`	`1149`	`previousPath = scope.path;`
`1143`	`1150`	`} while ((scope = scope.parent));`