Add parsing for type aliases

src/parsing/preparser.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 175 matching lines @@
     case Token::CONST:
       if (allow_const()) {
         return ParseVariableStatement(kStatementListItem, ok);
       }
       break;
     case Token::LET:
       if (IsNextLetKeyword()) {
         return ParseVariableStatement(kStatementListItem, ok);
       }
       break;
+    case Token::IDENTIFIER: {
+      if (!scope_->typed()) break;
+      int pos = peek_position();
+      if (CheckContextualKeyword(CStrVector("type"))) {
+        return ParseTypeAliasDeclaration(pos, ok);
+      }
+      break;
+    }
+    // TODO(nikolaos): interface
+    // TODO(nikolaos): ambient
     default:
       break;
   }
   return ParseStatement(ok);
 }
 
 
 void PreParser::ParseStatementList(int end_token, bool* ok,
                                    Scanner::BookmarkScope* bookmark) {
   // SourceElements ::
@@ skipping 988 matching lines @@
     Expect(Token::RBRACE, CHECK_OK);
     return PreParserExpression::Default();
   }
 }
 
 #undef CHECK_OK
 
 
 }  // namespace internal
 }  // namespace v8