harmony-scoping: better error messages for let declarations in sloppy mode.

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index 2f42eadc84fba4774f810db86765090a8e7351cb..a36bd92763270a4b839b43d5e5a9ead34f645b7b 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -4432,3 +4432,28 @@ TEST(ScanUnterminatedTemplateLiterals) {
   RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
                     arraysize(always_flags));
 }
+
+
+TEST(LexicalScopingSloppyMode) {
+  const char* context_data[][2] = {
+      {"", ""},
+      {"function f() {", "}"},
+      {"{", "}"},
+      {NULL, NULL}};
+  const char* bad_data[] = {
+    "let x = 1;",
+    "for(let x = 1;;){}",
+    "for(let x of []){}",
+    "for(let x in []){}",
+    NULL};
+  static const ParserFlag always_flags[] = {kAllowHarmonyScoping};
+  RunParserSyncTest(context_data, bad_data, kError, NULL, 0, always_flags,
+                    arraysize(always_flags));
+
+  const char* good_data[] = {
+    "let = 1;",
+    "for(let = 1;;){}",
+    NULL};
+  RunParserSyncTest(context_data, good_data, kSuccess, NULL, 0, always_flags,
+                    arraysize(always_flags));
+}