[ast] Never declare non-lexical variables as kNeedsInitialization.

src/ast/variables.h

 // Copyright 2011 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.
 
 #ifndef V8_AST_VARIABLES_H_
 #define V8_AST_VARIABLES_H_
 
 #include "src/ast/ast-value-factory.h"
 #include "src/zone.h"
 
@@ skipping 55 matching lines @@
   bool IsUnallocatedOrGlobalSlot() const {
     return IsUnallocated() || IsGlobalSlot();
   }
   bool IsLookupSlot() const { return location_ == VariableLocation::LOOKUP; }
   bool IsGlobalObjectProperty() const;
   bool IsStaticGlobalObjectProperty() const;
 
   bool is_dynamic() const { return IsDynamicVariableMode(mode_); }
   bool is_const_mode() const { return IsImmutableVariableMode(mode_); }
   bool binding_needs_init() const {
+    DCHECK(initialization_flag_ != kNeedsInitialization ||
+           IsLexicalVariableMode(mode_));
     return initialization_flag_ == kNeedsInitialization;
   }
 
   bool is_function() const { return kind_ == FUNCTION; }
   bool is_this() const { return kind_ == THIS; }
   bool is_arguments() const { return kind_ == ARGUMENTS; }
 
   // For script scopes, the "this" binding is provided by a ScriptContext added
   // to the global's ScriptContextTable.  This binding might not statically
   // resolve to a Variable::THIS binding, instead being DYNAMIC_LOCAL.  However
@@ skipping 75 matching lines @@
   // Usage info.
   bool force_context_allocation_;  // set by variable resolver
   bool is_used_;
   InitializationFlag initialization_flag_;
   MaybeAssignedFlag maybe_assigned_;
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_VARIABLES_H_