Implement handling of arrow functions in the parser

src/scanner.cc

Index: src/scanner.cc
diff --git a/src/scanner.cc b/src/scanner.cc
index 2e039ca40353ee695e28b465ebdf3e7006aee5a8..05e24cacb7f435e49f9820ff203b7b204fd30be4 100644
--- a/src/scanner.cc
+++ b/src/scanner.cc
@@ -209,6 +209,7 @@ Token::Value Scanner::Next() {
   current_ = next_;
   has_line_terminator_before_next_ = false;
   has_multiline_comment_before_next_ = false;
+  param_list_finder_.Update(current_.token, current_.location.beg_pos);
   if (static_cast<unsigned>(c0_) <= 0x7f) {
     Token::Value token = static_cast<Token::Value>(one_char_tokens[c0_]);
     if (token != Token::ILLEGAL) {
@@ -394,10 +395,12 @@ void Scanner::Scan() {
         break;
 
       case '=':
-        // = == ===
+        // = == === =>
         Advance();
         if (c0_ == '=') {
           token = Select('=', Token::EQ_STRICT, Token::EQ);
+        } else if (c0_ == '>') {
+          token = Select(Token::ARROW);
         } else {
           token = Token::ASSIGN;
         }