Remove assertion in compile-time constant map literals

runtime/vm/parser.cc

 // Copyright (c) 2012, 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/parser.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/bigint_operations.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
@@ skipping 9269 matching lines @@
 
 
 static void AddKeyValuePair(GrowableArray<AstNode*>* pairs,
                             bool is_const,
                             AstNode* key,
                             AstNode* value) {
   if (is_const) {
     ASSERT(key->IsLiteralNode());
     const Instance& new_key = key->AsLiteralNode()->literal();
     for (int i = 0; i < pairs->length(); i += 2) {
-      const Instance& key_i =
-          (*pairs)[i]->AsLiteralNode()->literal();
-      ASSERT(key_i.IsString());
-      if (new_key.Equals(key_i)) {
+      const Instance& key_i = (*pairs)[i]->AsLiteralNode()->literal();
+      // The keys of a compile time constant map are compile time
+      // constants, i.e. canonicalized values. Thus, we can compare
+      // raw pointers to check for equality.
+      if (new_key.raw() == key_i.raw()) {
         // Duplicate key found. The new value replaces the previously
         // defined value.
         (*pairs)[i + 1] = value;
         return;
       }
     }
   }
   pairs->Add(key);
   pairs->Add(value);
 }
@@ skipping 1059 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart