Merge pull request webpack#6968 from webpack/fix/harmony_this

sokra · web-flow · commit dd03262e0a4f · 2018-04-09T08:03:09.000+02:00
Fix 'this' replacement for harmony modules
diff --git a/lib/Parser.js b/lib/Parser.js
@@ -1060,9 +1060,10 @@ class Parser extends Tapable {
 	}
 
 	walkFunctionDeclaration(statement) {
+		const wasTopLevel = this.scope.topLevelScope;
+		this.scope.topLevelScope = false;
 		for (const param of statement.params) this.walkPattern(param);
 		this.inScope(statement.params, () => {
-			this.scope.topLevelScope = false;
 			if (statement.body.type === "BlockStatement") {
 				this.detectStrictMode(statement.body.body);
 				this.prewalkStatement(statement.body);
@@ -1071,6 +1072,7 @@ class Parser extends Tapable {
 				this.walkExpression(statement.body);
 			}
 		});
+		this.scope.topLevelScope = wasTopLevel;
 	}
 
 	prewalkImportDeclaration(statement) {
@@ -1465,9 +1467,10 @@ class Parser extends Tapable {
 	}
 
 	walkFunctionExpression(expression) {
+		const wasTopLevel = this.scope.topLevelScope;
+		this.scope.topLevelScope = false;
 		for (const param of expression.params) this.walkPattern(param);
 		this.inScope(expression.params, () => {
-			this.scope.topLevelScope = false;
 			if (expression.body.type === "BlockStatement") {
 				this.detectStrictMode(expression.body.body);
 				this.prewalkStatement(expression.body);
@@ -1476,6 +1479,7 @@ class Parser extends Tapable {
 				this.walkExpression(expression.body);
 			}
 		});
+		this.scope.topLevelScope = wasTopLevel;
 	}
 
 	walkArrowFunctionExpression(expression) {
@@ -1621,10 +1625,10 @@ class Parser extends Tapable {
 				}
 				this.walkExpression(argOrThis);
 			};
+			const wasTopLevel = this.scope.topLevelScope;
+			this.scope.topLevelScope = false;
 			const params = functionExpression.params;
-			const renameThis = currentThis
-				? renameArgOrThis.call(this, currentThis)
-				: null;
+			const renameThis = currentThis ? renameArgOrThis(currentThis) : null;
 			const args = options.map(renameArgOrThis);
 			this.inScope(params.filter((identifier, idx) => !args[idx]), () => {
 				if (renameThis) {
@@ -1641,6 +1645,7 @@ class Parser extends Tapable {
 					this.walkStatement(functionExpression.body);
 				} else this.walkExpression(functionExpression.body);
 			});
+			this.scope.topLevelScope = wasTopLevel;
 		};
 		if (
 			expression.callee.type === "MemberExpression" &&
@@ -1652,8 +1657,7 @@ class Parser extends Tapable {
 			expression.arguments.length > 0
 		) {
 			// (function(…) { }.call/bind(?, …))
-			walkIIFE.call(
-				this,
+			walkIIFE(
 				expression.callee.object,
 				expression.arguments.slice(1),
 				expression.arguments[0]
@@ -1663,7 +1667,7 @@ class Parser extends Tapable {
 			expression.arguments
 		) {
 			// (function(…) { }(…))
-			walkIIFE.call(this, expression.callee, expression.arguments);
+			walkIIFE(expression.callee, expression.arguments, null);
 		} else if (expression.callee.type === "Import") {
 			result = this.hooks.importCall.call(expression);
 			if (result === true) return;
diff --git a/test/configCases/parsing/harmony-this/abc.js b/test/configCases/parsing/harmony-this/abc.js
@@ -1,15 +1,12 @@
 function returnThis() {
-	if(typeof this === "undefined") return "undefined";
+	if (typeof this === "undefined") return "undefined";
 	return this;
 }
 
 var a = returnThis;
 var b = returnThis;
 
-export {
-	a,
-	b
-}
+export { a, b };
 
 export const that = this;
 export const returnThisArrow = () => this;
@@ -29,10 +26,38 @@ export class C {
 
 export const extendThisClass = () => {
 	return class extends this.Buffer {};
-}
+};
 
 export function D() {
 	this.prop = () => "ok";
 }
 
+// See https://github.com/webpack/webpack/issues/6379
+export const E = {
+	x: "bar",
+	foo(x = this.x) {
+		return x;
+	}
+};
+
+// See https://github.com/webpack/webpack/issues/6967
+export const F = function() {
+	return this;
+}.call("ok");
+
+export function f1(x = this.x) {
+	return x;
+}
+
+export const f2 = function(x = this.x) {
+	return x;
+};
+
+export const f3 = (x = this) => x;
+
+export function G(x) {
+	this.x = x;
+	this.getX = (y = this.x) => y;
+}
+
 export default returnThis;
diff --git a/test/configCases/parsing/harmony-this/index.js b/test/configCases/parsing/harmony-this/index.js
@@ -1,6 +1,8 @@
 "use strict";
 
-import d, {a, b as B, C as _C, D as _D, extendThisClass, returnThisArrow, returnThisMember, that} from "./abc";
+import should from "should";
+import {extendThisClass, returnThisArrow, returnThisMember, that} from "./abc";
+import d, {a, b as B, C as _C, D as _D, E, F, f1, f2, f3, G} from "./abc";
 
 import * as abc from "./abc";
 
@@ -24,6 +26,13 @@ it("should not break classes and functions", function() {
 	(new _C).foo().should.be.eql("bar");
 	(new _C).bar().should.be.eql("bar");
 	(new _D).prop().should.be.eql("ok");
+	E.foo().should.be.eql("bar");
+	F.should.be.eql("ok");
+	f1.call({x: "f1"}).should.be.eql("f1");
+	f2.call({x: "f2"}).should.be.eql("f2");
+	should(f3.call("f3")).be.eql(undefined);
+	should(f3()).be.eql(undefined);
+	(new G("ok")).getX().should.be.eql("ok");
 });
 
 function x() { throw new Error("should not be executed"); }
