- Make use of the fact that idents and literals are symbols.

runtime/vm/scanner.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/scanner.h"
 
 #include "platform/assert.h"
 #include "vm/dart.h"
 #include "vm/flags.h"
 #include "vm/object.h"
@@ skipping 351 matching lines @@
         ErrorMsg("missing exponent digits");
         return;
       }
       while (IsDecimalDigit(c0_)) {
         ReadChar();
       }
     }
   }
   if (current_token_.kind != Token::kILLEGAL) {
     intptr_t len = lookahead_pos_ - token_start_;
-    current_token_.literal =
-        &String::ZoneHandle(
-            String::SubString(source_, token_start_, len, Heap::kOld));
+    String& str = String::ZoneHandle(
+        String::SubString(source_, token_start_, len, Heap::kOld));
+    str = Symbols::New(str);
+    current_token_.literal = &str;
   }
 }
 
 
 void Scanner::SkipLine() {
   while (c0_ != '\n' && c0_ != '\0') {
     ReadChar();
   }
 }
 
@@ skipping 554 matching lines @@
   for (int i = 0; i < Token::numKeywords; i++) {
     Token::Kind token = static_cast<Token::Kind>(Token::kFirstKeyword + i);
     keywords_[i].kind = token;
     keywords_[i].keyword_chars = Token::Str(token);
     keywords_[i].keyword_len = strlen(Token::Str(token));
     keywords_[i].keyword_symbol = &Symbols::Keyword(token);
   }
 }
 
 }  // namespace dart