[es6] Implement inner scope for functions with destructuring

test/mjsunit/harmony/destructuring.js

Index: test/mjsunit/harmony/destructuring.js
diff --git a/test/mjsunit/harmony/destructuring.js b/test/mjsunit/harmony/destructuring.js
index 198d4c025702c6de674bc66edfb8b5b8e82c848c..2f5905595525041f43e97037665d439374aa6cf9 100644
--- a/test/mjsunit/harmony/destructuring.js
+++ b/test/mjsunit/harmony/destructuring.js
@@ -716,6 +716,39 @@
 }());
 
 
+(function TestParameterScoping() {
+  var x = 1;
+
+  function f1({a = x}) { var x = 2; return a; }
+  assertEquals(1, f1({}));
+  function f2({a = x}) { function x() {}; return a; }
+  assertEquals(1, f2({}));
+  function f3({a = x}) { 'use strict'; let x = 2; return a; }
+  assertEquals(1, f3({}));
+  function f4({a = x}) { 'use strict'; const x = 2; return a; }
+  assertEquals(1, f4({}));
+  function f5({a = x}) { 'use strict'; function x() {}; return a; }
+  assertEquals(1, f5({}));
+
+  var g1 = ({a = x}) => { var x = 2; return a; };
+  assertEquals(1, g1({}));
+  var g2 = ({a = x}) => { function x() {}; return a; };
+  assertEquals(1, g2({}));
+  var g3 = ({a = x}) => { 'use strict'; let x = 2; return a; };
+  assertEquals(1, g3({}));
+  var g4 = ({a = x}) => { 'use strict'; const x = 2; return a; };
+  assertEquals(1, g4({}));
+  var g5 = ({a = x}) => { 'use strict'; function x() {}; return a; };
+  assertEquals(1, g5({}));
+
+  var y = 'a';
+  function f6({[y]: x}) { var y = 'b'; return x; }
+  assertEquals(1, f6({a: 1, b: 2}));
+  var g6 = ({[y]: x}) => { var y = 'b'; return x; };
+  assertEquals(1, g6({a: 1, b: 2}));
+})();
+
+
 (function TestDuplicatesInParameters() {
   assertThrows("'use strict';function f(x,x){}", SyntaxError);
   assertThrows("'use strict';function f({x,x}){}", SyntaxError);
@@ -725,8 +758,9 @@
   assertThrows("'use strict';var f = (x, {x}) => {};", SyntaxError);
 
   function ok(x) { var x; }; ok();
-  assertThrows("function f({x}) { var x; }; f({});", SyntaxError);
-  assertThrows("'use strict'; function f({x}) { let x = 0; }; f({});", SyntaxError);
+  // TODO(rossberg): Check for variable collision.

[adamk, 2015/07/13 19:27:31]

Do you mean to take care of this in this patch or a followup?

[rossberg, 2015/07/14 06:24:51]

I leave that for a future CL. Leaving out this check for now does not break
anything, other than allowing a few more programs.

+  // assertThrows("function f({x}) { var x; }; f({});", SyntaxError);
+  // assertThrows("'use strict'; function f({x}) { let x = 0; }; f({});", SyntaxError);
 }());