[parser] Disallow Expression in for..of statements

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index 0048b8da698b718cc01671f52ab659b905427c2e..f57e424af2e05f3a4610b16e476010129e44dc84 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -3676,7 +3676,14 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
-        Expression* enumerable = ParseExpression(true, CHECK_OK);
+        Expression* enumerable;
+        if (mode == ForEachStatement::ITERATE) {
+          ExpressionClassifier classifier;
+          enumerable = ParseAssignmentExpression(true, &classifier, CHECK_OK);
+          ParserTraits::RewriteNonPattern(enumerable, &classifier, CHECK_OK);

[adamk, 2016/01/20 00:35:57]

I think the calling convention here is to assign it back to the original (as I
said, this is brand new to me):

enumerable = RewriteNonPattern(...)

[mike3, 2016/01/20 17:55:40]

Acknowledged.

+        } else {
+          enumerable = ParseExpression(true, CHECK_OK);
+        }
 
         Expect(Token::RPAREN, CHECK_OK);
 
@@ -3791,7 +3798,15 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
-        Expression* enumerable = ParseExpression(true, CHECK_OK);
+        Expression* enumerable;
+        if (mode == ForEachStatement::ITERATE) {
+          ExpressionClassifier classifier;
+          enumerable = ParseAssignmentExpression(true, &classifier, CHECK_OK);
+          ParserTraits::RewriteNonPattern(enumerable, &classifier, CHECK_OK);

[adamk, 2016/01/20 00:35:57]

Same note here.

[mike3, 2016/01/20 17:55:40]

Acknowledged.

+        } else {
+          enumerable = ParseExpression(true, CHECK_OK);
+        }
+
         Expect(Token::RPAREN, CHECK_OK);
 
         // Make a block around the statement in case a lexical binding