[es6] Handle conflicts for sloppy let

test/mjsunit/harmony/block-conflicts-sloppy.js

Index: test/mjsunit/harmony/block-conflicts-sloppy.js
diff --git a/test/mjsunit/es6/block-conflicts.js b/test/mjsunit/harmony/block-conflicts-sloppy.js
similarity index 84%
copy from test/mjsunit/es6/block-conflicts.js
copy to test/mjsunit/harmony/block-conflicts-sloppy.js
index fdd581dd70b0e7b1d840054f527d6dcc940f24c7..70b2017b117a3ba1b3e7b3315d8920eb03532bad 100644
--- a/test/mjsunit/es6/block-conflicts.js
+++ b/test/mjsunit/harmony/block-conflicts-sloppy.js
@@ -4,7 +4,7 @@
 
 // Test for conflicting variable bindings.
 
-"use strict";
+// Flags: --no-legacy-const --harmony-sloppy
 
 function CheckException(e) {
   var string = e.toString();
@@ -44,8 +44,10 @@ function TestAll(expected,s,opt_e) {
   var e = "";
   var msg = s;
   if (opt_e) { e = opt_e; msg += opt_e; }
-  assertEquals(expected === 'LocalConflict' ? 'NoConflict' : expected,
-      TestGlobal(s,e), "global:'" + msg + "'");
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // assertEquals(expected === 'LocalConflict' ? 'NoConflict' : expected,
+  //     TestGlobal(s,e), "global:'" + msg + "'");
   assertEquals(expected === 'LocalConflict' ? 'NoConflict' : expected,
       TestFunction(s,e), "function:'" + msg + "'");
   assertEquals(expected === 'LocalConflict' ? 'Conflict' : expected,
@@ -55,17 +57,22 @@ function TestAll(expected,s,opt_e) {
 
 function TestConflict(s) {
   TestAll('Conflict', s);
-  TestAll('Conflict', 'eval("' + s + '");');
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // TestAll('Conflict', 'eval("' + s + '");');

[Dan Ehrenberg, 2015/07/08 23:42:13]

I don't see why these tests wouldn't make sense. Wouldn't there be a conflict in
the new eval-driven block scope, even in sloppy mode?

[arv (Not doing code reviews), 2015/07/09 14:30:53]

See the bug.

  eval('let x; var x;')

is more similar to

  eval('{ let x; var x; }')

we are not creating the lexical block correctly for sloppy evals so these tests
are not passing or the tests are not correct for sloppy mode.

[rossberg, 2015/07/10 12:13:17]

I suppose

let x; eval('var x');

is an error in sloppy mode, but not in strict mode. That's a fairly unfortunate
semantic deviation, actually. But why does this difference only pop up in the
global scope tests?

These tests should probably be changed to use Realm.eval in TestGlobal, so that
we test the actual global scope, and there should be a separate TestEval
(similarly for strict mode). Can you add a TODO for that?

[arv (Not doing code reviews), 2015/07/10 13:00:48]

The other tests wrap the string in a function or a block so the implicit lexical
scope is not relevant.
I'll add a todo (and/or add a comment to the bug)

 }
 
 function TestNoConflict(s) {
   TestAll('NoConflict', s, "'NoConflict'");
-  TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
 }
 
 function TestLocalConflict(s) {
   TestAll('LocalConflict', s, "'NoConflict'");
-  TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
+  // TODO(littledan): https://code.google.com/p/v8/issues/detail?id=4288
+  // It is also not clear whether these tests makes sense in sloppy mode.
+  // TestAll('NoConflict', 'eval("' + s + '");', "'NoConflict'");
 }
 
 var letbinds = [ "let x;",