handle assignment patterns

src/Statement.js

@@ -3,6 +3,11 @@ import getLocation from './utils/getLocation';
 import walk from './ast/walk';
 import Scope from './ast/Scope';
 
+const blockDeclarations = {
+	'const': true,
+	'let': true
+};
+
 function isIife ( node, parent ) {
 	return parent && parent.type === 'CallExpression' && node === parent.callee;
 }
@@ -73,7 +78,7 @@ export default class Statement {
 
 				switch ( node.type ) {
 					case 'FunctionDeclaration':
-						scope.addDeclaration( node.id.name, node, false );
+						scope.addDeclaration( node, false, false );
 
 					case 'BlockStatement':
 						if ( parent && /Function/.test( parent.type ) ) {
@@ -86,7 +91,7 @@ export default class Statement {
 							// named function expressions - the name is considered
 							// part of the function's scope
 							if ( parent.type === 'FunctionExpression' && parent.id ) {
-								newScope.addDeclaration( parent.id.name, parent, false );
+								newScope.addDeclaration( parent, false, false );
 							}
 						} else {
 							newScope = new Scope({
@@ -108,12 +113,13 @@ export default class Statement {
 
 					case 'VariableDeclaration':
 						node.declarations.forEach( declarator => {
-							scope.addDeclaration( declarator.id.name, node, true );
+							const isBlockDeclaration = node.type === 'VariableDeclaration' && blockDeclarations[ node.kind ];
+							scope.addDeclaration( declarator, isBlockDeclaration, true );
 						});
 						break;
 
 					case 'ClassDeclaration':
-						scope.addDeclaration( node.id.name, node, false );
+						scope.addDeclaration( node, false, false );
 						break;
 				}
 

src/ast/Scope.js

@@ -1,10 +1,38 @@
 import { blank } from '../utils/object';
 
-const blockDeclarations = {
-	'const': true,
-	'let': true
+const extractors = {
+	Identifier ( names, param ) {
+		names.push( param.name );
+	},
+
+	ObjectPattern ( names, param ) {
+		param.properties.forEach( prop => {
+			extractors[ prop.key.type ]( names, prop.key );
+		});
+	},
+
+	ArrayPattern ( names, param ) {
+		param.elements.forEach( element => {
+			if ( element ) extractors[ element.type ]( names, element );
+		});
+	},
+
+	RestElement ( names, param ) {
+		extractors[ param.argument.type ]( names, param.argument );
+	},
+
+	AssignmentPattern ( names, param ) {
+		return extractors[ param.left.type ]( names, param.left );
+	}
 };
 
+function extractNames ( param ) {
+	let names = [];
+
+	extractors[ param.type ]( names, param );
+	return names;
+}
+
 export default class Scope {
 	constructor ( options ) {
 		options = options || {};
@@ -18,26 +46,29 @@ export default class Scope {
 
 		if ( options.params ) {
 			options.params.forEach( param => {
-				this.declarations[ param.name ] = param;
+				extractNames( param ).forEach( name => {
+					this.declarations[ name ] = true;
+				});
 			});
 		}
 	}
 
-	addDeclaration ( name, declaration, isVar ) {
-		const isBlockDeclaration = declaration.type === 'VariableDeclaration' && blockDeclarations[ declaration.kind ];
-
+	addDeclaration ( declaration, isBlockDeclaration, isVar ) {
 		if ( !isBlockDeclaration && this.isBlockScope ) {
-			// it's a `var` or function declaration, and this
+			// it's a `var` or function node, and this
 			// is a block scope, so we need to go up
-			this.parent.addDeclaration( name, declaration, isVar );
+			this.parent.addDeclaration( declaration, isBlockDeclaration, isVar );
 		} else {
-			this.declarations[ name ] = declaration;
-			if ( isVar ) this.varDeclarations.push( name );
+			extractNames( declaration.id ).forEach( name => {
+				this.declarations[ name ] = true;
+				if ( isVar ) this.varDeclarations.push( name );
+			});
 		}
 	}
 
 	contains ( name ) {
-		return !!this.getDeclaration( name );
+		return this.declarations[ name ] ||
+		       ( this.parent ? this.parent.contains( name ) : false );
 	}
 
 	findDefiningScope ( name ) {
@@ -51,9 +82,4 @@ export default class Scope {
 
 		return null;
 	}
-
-	getDeclaration ( name ) {
-		return this.declarations[ name ] ||
-		       this.parent && this.parent.getDeclaration( name );
-	}
 }

test/function/assignment-patterns/_config.js

@@ -0,0 +1,4 @@
+module.exports = {
+	description: 'allows reassigments to default parameters that shadow imports',
+	babel: true
+};

test/function/assignment-patterns/main.js

@@ -0,0 +1,21 @@
+import { bar, baz, x, items, p, q, r, s } from './other';
+
+function foo ( bar = 1, { baz } = { baz: 2 }, [[[,x = 3] = []] = []] = [], ...items ) {
+	bar += 1;
+	baz += 1;
+	x += 1;
+
+	let { p, q } = { p: 4, q: 5 };
+	let [ r, s ] = [ 6, 7 ];
+
+	p++;
+	q += 1;
+	r = 7;
+	s = 6;
+
+	return bar + baz + x + items.length + p + q + r + s;
+}
+
+assert.equal( foo(), 33 );
+assert.equal( foo( 2 ), 34 );
+assert.equal( foo( 2, { baz: 3 }, [[[99,10]]], 'a', 'b', 'c' ), 45 );

test/function/assignment-patterns/other.js

@@ -0,0 +1,8 @@
+export const bar = 'bar';
+export const baz = 'baz';
+export const x = 'x';
+export const items = 'items';
+export const p = 'p';
+export const q = 'q';
+export const r = 'r';
+export const s = 's';