Fix #23871: identical on consts should be always const

runtime/vm/ast.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/ast.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object_store.h"
 #include "vm/resolver.h"
@@ skipping 211 matching lines @@
     case Token::kGT:
     case Token::kLTE:
     case Token::kGTE:
       if ((left_val->IsNumber() || left_val->IsNull()) &&
           (right_val->IsNumber() || right_val->IsNull())) {
         return &Bool::False();
       }
       return NULL;
     case Token::kEQ:
     case Token::kNE:
-    case Token::kEQ_STRICT:
-    case Token::kNE_STRICT:
       // The comparison is a compile time const if both operands are either a
       // number, string, or boolean value (but not necessarily the same type).
       if ((left_val->IsNumber() ||
           left_val->IsString() ||
           left_val->IsBool() ||
           left_val->IsNull()) &&
           (right_val->IsNumber() ||
           right_val->IsString() ||
           right_val->IsBool() ||
           right_val->IsNull())) {
         return &Bool::False();
       }
       return NULL;
+    case Token::kEQ_STRICT:
+    case Token::kNE_STRICT:
+      // identical(a, b) is a compile time const if both operands are
+      // compile time constants, regardless of their type.
+      return &Bool::True();
     default:
       return NULL;
   }
   return NULL;
 }
 
 
 
 bool BinaryOpNode::IsKindValid() const {
   switch (kind_) {
@@ skipping 492 matching lines @@
   if (result.IsError() || result.IsNull()) {
     // TODO(turnidge): We could get better error messages by returning
     // the Error object directly to the parser.  This will involve
     // replumbing all of the EvalConstExpr methods.
     return NULL;
   }
   return &Instance::ZoneHandle(Instance::Cast(result).raw());
 }
 
 }  // namespace dart