Add back the duplicate property checker

test/mjsunit/strict-mode.js

Index: test/mjsunit/strict-mode.js
diff --git a/test/mjsunit/strict-mode.js b/test/mjsunit/strict-mode.js
index 88e3a5d645f676f6fe0aa6399f1dcba2c41aeee6..5fb404a7990913cc953fe400315a3e4e455ced4a 100644
--- a/test/mjsunit/strict-mode.js
+++ b/test/mjsunit/strict-mode.js
@@ -166,6 +166,17 @@ assertThrows('\
     "use strict";\
   }', SyntaxError);
 
+// Duplicate data properties.
+CheckStrictMode("var x = { dupe : 1, nondupe: 3, dupe : 2 };", SyntaxError);
+CheckStrictMode("var x = { '1234' : 1, '2345' : 2, '1234' : 3 };", SyntaxError);
+CheckStrictMode("var x = { '1234' : 1, '2345' : 2, 1234 : 3 };", SyntaxError);
+CheckStrictMode("var x = { 3.14 : 1, 2.71 : 2, 3.14 : 3 };", SyntaxError);
+CheckStrictMode("var x = { 3.14 : 1, '3.14' : 2 };", SyntaxError);
+CheckStrictMode("var x = { \
+  123: 1, \
+  123.00000000000000000000000000000000000000000000000000000000000000000001: 2 \
+}", SyntaxError);
+
 // Non-conflicting data properties.
 (function StrictModeNonDuplicate() {
   "use strict";
@@ -177,52 +188,37 @@ assertThrows('\
   };
 })();
 
-// Duplicate properties are no longer errors in ES6.
-(function Duplicates() {
-  "use strict";
-
-  ({ dupe : 1, nondupe: 3, dupe : 2 });
-  ({ '1234' : 1, '2345' : 2, '1234' : 3 });
-  ({ '1234' : 1, '2345' : 2, 1234 : 3 });
-  ({ 3.14 : 1, 2.71 : 2, 3.14 : 3 });
-  ({ 3.14 : 1, '3.14' : 2 });
-  ({
-    123: 1,
-    123.00000000000000000000000000000000000000000000000000000000000000000001: 2
-  });
-
-  // Two getters
-  ({ get foo() { }, get foo() { } });
-  ({ get foo(){}, get 'foo'(){}});
-  ({ get 12(){}, get '12'(){}});
-
-  // Two setters
-  ({ set foo(v) { }, set foo(v) { } });
-  ({ set foo(v) { }, set 'foo'(v) { } });
-  ({ set 13(v) { }, set '13'(v) { } });
-
-  // Setter and data
-  ({ foo: 'data', set foo(v) { } });
-  ({ set foo(v) { }, foo: 'data' });
-  ({ foo: 'data', set 'foo'(v) { } });
-  ({ set foo(v) { }, 'foo': 'data' });
-  ({ 'foo': 'data', set foo(v) { } });
-  ({ set 'foo'(v) { }, foo: 'data' });
-  ({ 'foo': 'data', set 'foo'(v) { } });
-  ({ set 'foo'(v) { }, 'foo': 'data' });
-  ({ 12: 1, set '12'(v){}});
-  ({ 12: 1, set 12(v){}});
-  ({ '12': 1, set '12'(v){}});
-  ({ '12': 1, set 12(v){}});
-
-  // Getter and data
-  ({ foo: 'data', get foo() { } });
-  ({ get foo() { }, foo: 'data' });
-  ({ 'foo': 'data', get foo() { } });
-  ({ get 'foo'() { }, 'foo': 'data' });
-  ({ '12': 1, get '12'(){}});
-  ({ '12': 1, get 12(){}});
-})();
+// Two getters (non-strict)
+assertThrows("var x = { get foo() { }, get foo() { } };", SyntaxError);
+assertThrows("var x = { get foo(){}, get 'foo'(){}};", SyntaxError);
+assertThrows("var x = { get 12(){}, get '12'(){}};", SyntaxError);
+
+// Two setters (non-strict)
+assertThrows("var x = { set foo(v) { }, set foo(v) { } };", SyntaxError);
+assertThrows("var x = { set foo(v) { }, set 'foo'(v) { } };", SyntaxError);
+assertThrows("var x = { set 13(v) { }, set '13'(v) { } };", SyntaxError);
+
+// Setter and data (non-strict)
+assertThrows("var x = { foo: 'data', set foo(v) { } };", SyntaxError);
+assertThrows("var x = { set foo(v) { }, foo: 'data' };", SyntaxError);
+assertThrows("var x = { foo: 'data', set 'foo'(v) { } };", SyntaxError);
+assertThrows("var x = { set foo(v) { }, 'foo': 'data' };", SyntaxError);
+assertThrows("var x = { 'foo': 'data', set foo(v) { } };", SyntaxError);
+assertThrows("var x = { set 'foo'(v) { }, foo: 'data' };", SyntaxError);
+assertThrows("var x = { 'foo': 'data', set 'foo'(v) { } };", SyntaxError);
+assertThrows("var x = { set 'foo'(v) { }, 'foo': 'data' };", SyntaxError);
+assertThrows("var x = { 12: 1, set '12'(v){}};", SyntaxError);
+assertThrows("var x = { 12: 1, set 12(v){}};", SyntaxError);
+assertThrows("var x = { '12': 1, set '12'(v){}};", SyntaxError);
+assertThrows("var x = { '12': 1, set 12(v){}};", SyntaxError);
+
+// Getter and data (non-strict)
+assertThrows("var x = { foo: 'data', get foo() { } };", SyntaxError);
+assertThrows("var x = { get foo() { }, foo: 'data' };", SyntaxError);
+assertThrows("var x = { 'foo': 'data', get foo() { } };", SyntaxError);
+assertThrows("var x = { get 'foo'() { }, 'foo': 'data' };", SyntaxError);
+assertThrows("var x = { '12': 1, get '12'(){}};", SyntaxError);
+assertThrows("var x = { '12': 1, get 12(){}};", SyntaxError);
 
 // Assignment to eval or arguments
 CheckStrictMode("function strict() { eval = undefined; }", SyntaxError);