harmony-scoping: make assignment to 'const' a late error.

test/mjsunit/harmony/block-const-assign.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 17 matching lines @@
 // Flags: --harmony-scoping
 
 // Test that we throw early syntax errors in harmony mode
 // when using an immutable binding in an assigment or with
 // prefix/postfix decrement/increment operators.
 
 "use strict";
 
 // Function local const.
 function constDecl0(use) {
-  return "(function() { const constvar = 1; " + use + "; });";
+  return "(function() { const constvar = 1; " + use + "; })();";
 }
 
 
 function constDecl1(use) {
-  return "(function() { " + use + "; const constvar = 1; });";
+  return "(function() { " + use + "; const constvar = 1; })();";
 }
 
 
 // Function local const, assign from eval.
 function constDecl2(use) {
-  use = "eval('(function() { " + use + " })')";
+  use = "eval('(function() { " + use + " })')()";
   return "(function() { const constvar = 1; " + use + "; })();";
 }
 
 
 function constDecl3(use) {
-  use = "eval('(function() { " + use + " })')";
+  use = "eval('(function() { " + use + " })')()";
   return "(function() { " + use + "; const constvar = 1; })();";
 }
 
 
 // Block local const.
 function constDecl4(use) {
-  return "(function() { { const constvar = 1; " + use + "; } });";
+  return "(function() { { const constvar = 1; " + use + "; } })();";
 }
 
 
 function constDecl5(use) {
-  return "(function() { { " + use + "; const constvar = 1; } });";
+  return "(function() { { " + use + "; const constvar = 1; } })();";
 }
 
 
 // Block local const, assign from eval.
 function constDecl6(use) {
-  use = "eval('(function() {" + use + "})')";
+  use = "eval('(function() {" + use + "})')()";
   return "(function() { { const constvar = 1; " + use + "; } })();";
 }
 
 
 function constDecl7(use) {
-  use = "eval('(function() {" + use + "})')";
+  use = "eval('(function() {" + use + "})')()";
   return "(function() { { " + use + "; const constvar = 1; } })();";
 }
 
 
 // Function expression name.
 function constDecl8(use) {
-  return "(function constvar() { " + use + "; });";
+  return "(function constvar() { " + use + "; })();";
 }
 
 
 // Function expression name, assign from eval.
 function constDecl9(use) {
-  use = "eval('(function(){" + use + "})')";
+  use = "eval('(function(){" + use + "})')()";
   return "(function constvar() { " + use + "; })();";
 }
 
 let decls = [ constDecl0,
               constDecl1,
               constDecl2,
               constDecl3,
               constDecl4,
               constDecl5,
               constDecl6,
               constDecl7,
               constDecl8,
               constDecl9
               ];
+let declsForTDZ = new Set([constDecl1, constDecl3, constDecl5, constDecl7]);
 let uses = [ 'constvar = 1;',
              'constvar += 1;',
              '++constvar;',
              'constvar++;'
              ];
 
 function Test(d,u) {
   'use strict';
   try {
     print(d(u));
     eval(d(u));
   } catch (e) {
-    assertInstanceof(e, SyntaxError);
+    if (declsForTDZ.has(d) && u !== uses[0]) {
+      // In these cases, read of a const variable occurs
+      // before a write to it, so TDZ kicks in before const check.
+      assertInstanceof(e, ReferenceError);
+      return;
+    }
+    assertInstanceof(e, TypeError);
     assertTrue(e.toString().indexOf("Assignment to constant variable") >= 0);
     return;
   }
   assertUnreachable();
 }
 
 for (var d = 0; d < decls.length; ++d) {
   for (var u = 0; u < uses.length; ++u) {
     Test(decls[d], uses[u]);
   }
 }