[parsing] Fix maybe-assigned flag in some cases.

src/parsing/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 1891 matching lines @@
                                          kNoSourcePosition),
           scope());
       auto block = factory()->NewBlock(nullptr, 2, false, kNoSourcePosition);
       block->statements()->Add(
           factory()->NewExpressionStatement(assign_each, kNoSourcePosition),
           zone());
       block->statements()->Add(body, zone());
       body = block;
       each = factory()->NewVariableProxy(temp);
     }
+    MarkExpressionAsAssigned(each);
     stmt->AsForInStatement()->Initialize(each, subject, body);
   }
   return stmt;
 }
 
 // Special case for legacy for
 //
 //    for (var x = initializer in enumerable) body
 //
 // An initialization block of the form
@@ skipping 129 matching lines @@
                                             int next_result_pos) {
   // Create the auxiliary expressions needed for iterating over the iterable,
   // and initialize the given ForOfStatement with them.
   // If finalize is true, also instrument the loop with code that performs the
   // proper ES6 iterator finalization.  In that case, the result is not
   // immediately a ForOfStatement.
 
   const int nopos = kNoSourcePosition;
   auto avfactory = ast_value_factory();
 
-  Variable* iterator = NewTemporary(ast_value_factory()->dot_iterator_string());
-  Variable* result = NewTemporary(ast_value_factory()->dot_result_string());
+  Variable* iterator = NewTemporary(avfactory->dot_iterator_string());
+  Variable* result = NewTemporary(avfactory->dot_result_string());
   Variable* completion = NewTemporary(avfactory->empty_string());
 
   // iterator = GetIterator(iterable)
   Expression* assign_iterator;
   {
     assign_iterator = factory()->NewAssignment(
         Token::ASSIGN, factory()->NewVariableProxy(iterator),
         factory()->NewGetIterator(iterable, iterable->position()),
         iterable->position());
   }
@@ skipping 3369 matching lines @@
 
   return final_loop;
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8