Make "as" a built-in identifier aka pseudo keyword

runtime/vm/token.h

 // 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.
 
 #ifndef VM_TOKEN_H_
 #define VM_TOKEN_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 90 matching lines @@
   /* Please update IsRelationalOperator() if you make  */                      \
   /* any changes to this block.                        */                      \
   TOK(kLT, "<", 10, kNoAttribute)                                              \
   TOK(kGT, ">", 10, kNoAttribute)                                              \
   TOK(kLTE, "<=", 10, kNoAttribute)                                            \
   TOK(kGTE, ">=", 10, kNoAttribute)                                            \
                                                                                \
   /* Internal token for !(expr is Type) negative type test operator */         \
   TOK(kISNOT, "", 10, kNoAttribute)                                            \
                                                                                \
-  /* Internal token for (expr as Type) type cast operator */                   \
-  TOK(kAS, "", 10, kNoAttribute)                                               \
-                                                                               \
   TOK(kINDEX, "[]", 0, kNoAttribute)                                           \
   TOK(kASSIGN_INDEX, "[]=", 0, kNoAttribute)                                   \
   TOK(kNEGATE, "unary-", 0, kNoAttribute)                                      \
                                                                                \
   TOK(kIDENT, "", 0, kNoAttribute)                                             \
   TOK(kSTRING, "", 0, kNoAttribute)                                            \
   TOK(kINTEGER, "", 0, kNoAttribute)                                           \
   TOK(kDOUBLE, "", 0, kNoAttribute)                                            \
                                                                                \
   TOK(kINTERPOL_VAR, "$", 0, kNoAttribute)                                     \
   TOK(kINTERPOL_START, "${", 0, kNoAttribute)                                  \
   TOK(kINTERPOL_END, "}", 0, kNoAttribute)                                     \
                                                                                \
   TOK(kAT, "@", 0, kNoAttribute)                                               \
                                                                                \
   TOK(kWHITESP, "", 0, kNoAttribute)                                           \
   TOK(kERROR, "", 0, kNoAttribute)                                             \
   TOK(kILLEGAL, "", 0, kNoAttribute)                                           \
                                                                                \
   /* Support for Dart scripts. */                                              \
   TOK(kSCRIPTTAG, "#!", 0, kNoAttribute)                                       \
 
 // List of keywords. The list must be alphabetically ordered. The
 // keyword recognition code depends on the ordering.
 // If you add a keyword at the beginning or end of this list, make sure
 // to update kFirstKeyword and kLastKeyword below.
 #define DART_KEYWORD_LIST(KW)                                                  \
   KW(kABSTRACT, "abstract", 0, kPseudoKeyword) /* == kFirstKeyword */          \
-  KW(kASSERT, "assert", 0, kKeyword)                                           \
+  KW(kAS, "as", 10, kPseudoKeyword)                                            \
+  KW(kASSERT, "assert", 10, kKeyword)                                          \
   KW(kBREAK, "break", 0, kKeyword)                                             \
   KW(kCASE, "case", 0, kKeyword)                                               \
   KW(kCATCH, "catch", 0, kKeyword)                                             \
   KW(kCLASS, "class", 0, kKeyword)                                             \
   KW(kCONST, "const", 0, kKeyword)                                             \
   KW(kCONTINUE, "continue", 0, kKeyword)                                       \
   KW(kDEFAULT, "default", 0, kKeyword)                                         \
   KW(kDO, "do", 0, kKeyword)                                                   \
   KW(kELSE, "else", 0, kKeyword)                                               \
   KW(kEXPORT, "export", 0, kPseudoKeyword)                                     \
@@ skipping 158 matching lines @@
   static const char* name_[];
   static const char* tok_str_[];
   static const uint8_t precedence_[];
   static const Attribute attributes_[];
 };
 
 
 }  // namespace dart
 
 #endif  // VM_TOKEN_H_