[es6] emit error when for-in loop declarations are initialized in strict mode

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 8ed20ee2121cfec8d313b042ac5ea878e66be628..2d0f1e59b2f386c8db37ffe62d4a2da70a5d5ece 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -2218,8 +2218,8 @@ Block* Parser::ParseVariableStatement(VariableDeclarationContext var_context,
   //   VariableDeclarations ';'
 
   const AstRawString* ignore;
-  Block* result =
-      ParseVariableDeclarations(var_context, NULL, names, &ignore, CHECK_OK);
+  Block* result = ParseVariableDeclarations(var_context, NULL, names, &ignore,

[arv (Not doing code reviews), 2015/03/25 09:17:43]

NULL -> nullptr

[caitp (gmail), 2015/03/25 11:22:42]

Acknowledged.

+                                            nullptr, CHECK_OK);
   ExpectSemicolon(CHECK_OK);
   return result;
 }
@@ -2233,9 +2233,8 @@ Block* Parser::ParseVariableStatement(VariableDeclarationContext var_context,
 Block* Parser::ParseVariableDeclarations(
     VariableDeclarationContext var_context,
     VariableDeclarationProperties* decl_props,
-    ZoneList<const AstRawString*>* names,
-    const AstRawString** out,
-    bool* ok) {
+    ZoneList<const AstRawString*>* names, const AstRawString** out,
+    Scanner::Location* first_initializer_loc, bool* ok) {
   // VariableDeclarations ::
   //   ('var' | 'const' | 'let') (Identifier ('=' AssignmentExpression)?)+[',']
   //
@@ -2249,7 +2248,6 @@ Block* Parser::ParseVariableDeclarations(
   // TODO(ES6):
   // ConstBinding ::
   //   BindingPattern '=' AssignmentExpression
-
   int pos = peek_position();
   VariableMode mode = VAR;
   // True if the binding needs initialization. 'let' and 'const' declared
@@ -2308,12 +2306,14 @@ Block* Parser::ParseVariableDeclarations(
   int nvars = 0;  // the number of variables declared
   const AstRawString* name = NULL;
   bool is_for_iteration_variable;
+  bool initializer_recorded = false;
   do {
     if (fni_ != NULL) fni_->Enter();
 
     // Parse variable name.
     if (nvars > 0) Consume(Token::COMMA);
     name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    Scanner::Location variable_loc = scanner()->location();
     if (fni_ != NULL) fni_->PushVariableName(name);
 
     // Declare variable.
@@ -2388,6 +2388,13 @@ Block* Parser::ParseVariableDeclarations(
       Expect(Token::ASSIGN, CHECK_OK);
       pos = position();
       value = ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
+      variable_loc.end_pos = scanner()->location().end_pos;
+
+      if (first_initializer_loc && !initializer_recorded) {

[arv (Not doing code reviews), 2015/03/25 09:17:43]

Can you use IsValid here instead of adding the boolean?

[caitp (gmail), 2015/03/25 11:22:42]

Acknowledged.

+        *first_initializer_loc = variable_loc;
+        initializer_recorded = true;
+      }
+
       // Don't infer if it is "a = function(){...}();"-like expression.
       if (fni_ != NULL &&
           value->AsCall() == NULL &&
@@ -3364,16 +3371,28 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
         (peek() == Token::CONST && is_sloppy(language_mode()))) {
       const AstRawString* name = NULL;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
+      Scanner::Location first_initializer_loc = Scanner::Location::invalid();
       Block* variable_statement =
           ParseVariableDeclarations(kForStatement, &decl_props, NULL, &name,
-                                    CHECK_OK);
-      bool accept_OF = decl_props == kHasNoInitializers;
+                                    &first_initializer_loc, CHECK_OK);
+      bool accept_OF = true;
       ForEachStatement::VisitMode mode;
       int each_beg_pos = scanner()->location().beg_pos;
       int each_end_pos = scanner()->location().end_pos;
 
       if (name != NULL && CheckInOrOf(accept_OF, &mode, ok)) {
         if (!*ok) return nullptr;
+        if (first_initializer_loc.IsValid() &&
+            (is_strict(language_mode()) || mode == ForEachStatement::ITERATE)) {
+          if (mode == ForEachStatement::ITERATE) {
+            ReportMessageAt(first_initializer_loc, "for_of_loop_initializer");
+          } else {
+            ReportMessageAt(first_initializer_loc,
+                            "strict_for_in_loop_initializer");
+          }
+          *ok = false;
+          return nullptr;
+        }
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
@@ -3403,9 +3422,9 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
       is_const = peek() == Token::CONST;
       const AstRawString* name = NULL;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
-      Block* variable_statement =
-          ParseVariableDeclarations(kForStatement, &decl_props,
-                                    &lexical_bindings, &name, CHECK_OK);
+      Block* variable_statement = ParseVariableDeclarations(
+          kForStatement, &decl_props, &lexical_bindings, &name, nullptr,
+          CHECK_OK);
       bool accept_IN = name != NULL && decl_props != kHasInitializers;
       bool accept_OF = decl_props == kHasNoInitializers;
       ForEachStatement::VisitMode mode;