Library prefix should be an identifier

vm/parser.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/parser.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/compiler_stats.h"
@@ skipping 3144 matching lines @@
       if ((CurrentToken() != Token::kIDENT) ||
           !kPrefix.Equals(*CurrentLiteral())) {
         ErrorMsg("prefix: expected");
       }
       ConsumeToken();
       ExpectToken(Token::kCOLON);
       if (CurrentToken() != Token::kSTRING) {
         ErrorMsg("prefix expected");
       }
       prefix = CurrentLiteral()->raw();
+      // TODO(asiva): Need to also check that prefix is not a reserved keyword.
+      if (!Scanner::IsIdent(prefix)) {
+        ErrorMsg("prefix should be an identifier");
+      }
       ConsumeToken();
     }
     ExpectToken(Token::kRPAREN);
     ExpectToken(Token::kSEMICOLON);
     Dart_Handle handle = CallLibraryTagHandler(kCanonicalizeUrl,
                                                import_pos,
                                                url);
     const String& canon_url = String::CheckedHandle(Api::UnwrapHandle(handle));
     // Lookup the library URL.
     Library& library = Library::Handle(Library::LookupLibrary(canon_url));
@@ skipping 4254 matching lines @@
 }
 
 
 void Parser::SkipNestedExpr() {
   const bool saved_mode = SetAllowFunctionLiterals(true);
   SkipExpr();
   SetAllowFunctionLiterals(saved_mode);
 }
 
 }  // namespace dart