Merge pull request #132 from esperantojs/gh-119

Prevent function arguments shadowing imports

Author: Rich-Harris

src/standalone/getModule.js

@@ -19,7 +19,7 @@ export default function getStandaloneModule ( options ) {
 			sourceType: 'module',
 			onComment ( block, text, start, end ) {
 				// sourceMappingURL comments should be removed
-				if ( !block && /^# sourceMappingURL=/.test( text ) ) {
+				if ( !block && SOURCEMAPPINGURL_REGEX.test( text ) ) {
 					toRemove.push({ start, end });
 				}
 			}
@@ -73,7 +73,7 @@ function determineImportNames ( imports, userFn, usedNames ) {
 
 			if ( hasOwnProp.call( usedNames, name ) ) {
 				// TODO write a test for this
-				throw new Error( 'Naming collision: module ' + moduleId + ' cannot be called ' + name );
+				throw new Error( `Naming collision: module ${moduleId} cannot be called ${name}` );
 			}
 		}
 

src/utils/ast/annotate.js

@@ -5,6 +5,7 @@
 */
 
 import walk from './walk';
+import { getName } from '../mappers';
 
 var Scope = function ( options ) {
 	options = options || {};
@@ -69,9 +70,13 @@ export default function annotateAst ( ast ) {
 						}
 					}
 
+					let names = node.params.map( getName );
+
+					names.forEach( name => declared[ name ] = true );
+
 					scope = node._scope = new Scope({
 						parent: scope,
-						params: node.params.map( x => x.name ) // TODO rest params?
+						params: names // TODO rest params?
 					});
 
 					break;

test/samples/clashingFunctionArguments/_config.js

@@ -0,0 +1,4 @@
+module.exports = {
+	description: 'prevents function arguments from shadowing imports',
+	strict: true
+};

test/samples/clashingFunctionArguments/source.js

@@ -0,0 +1,5 @@
+import { foo } from 'x/y/z';
+
+export function bar ( z ) {
+	return foo( z );
+}

test/strictMode/output/amd/clashingFunctionArguments.js

@@ -0,0 +1,11 @@
+define(['exports', 'x/y/z'], function (exports, y__z) {
+
+	'use strict';
+
+	exports.bar = bar;
+
+	function bar ( z ) {
+		return y__z.foo( z );
+	}
+
+});

test/strictMode/output/cjs/clashingFunctionArguments.js

@@ -0,0 +1,9 @@
+'use strict';
+
+exports.bar = bar;
+
+var y__z = require('x/y/z');
+
+function bar ( z ) {
+	return y__z.foo( z );
+}

test/strictMode/output/umd/clashingFunctionArguments.js

@@ -0,0 +1,13 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('x/y/z')) :
+	typeof define === 'function' && define.amd ? define(['exports', 'x/y/z'], factory) :
+	factory((global.myModule = {}), global.y__z)
+}(this, function (exports, y__z) { 'use strict';
+
+	exports.bar = bar;
+
+	function bar ( z ) {
+		return y__z.foo( z );
+	}
+
+}));