ripper: fix `#tok` on some error events [Bug 17345]

sorting alias target by event arity, and setup suitable `Elem` for error.

1 files changed, 9 insertions, 4 deletions

diff --git a/ext/ripper/lib/ripper/lexer.rb b/ext/ripper/lib/ripper/lexer.rb
index 6a9a9cb39a..cff38c617d 100644
--- a/ext/ripper/lib/ripper/lexer.rb
+++ b/ext/ripper/lib/ripper/lexer.rb
@@ -190,13 +190,18 @@ class Ripper
       e
     end
 
-    def on_error(mesg, tok = token())
-      @errors.push Elem.new([lineno(), column()], __callee__, tok, state(), mesg)
+    def on_error1(mesg)
+      @errors.push Elem.new([lineno(), column()], __callee__, token(), state(), mesg)
+    end
+
+    def on_error2(mesg, elem)
+      @errors.push Elem.new(elem.pos, __callee__, elem.tok, elem.state, mesg)
     end
     PARSER_EVENTS.grep(/_error\z/) do |e|
-      alias_method "on_#{e}", :on_error
+      arity = PARSER_EVENT_TABLE.fetch(e)
+      alias_method "on_#{e}", "on_error#{arity}"
     end
-    alias compile_error on_error
+    alias compile_error on_error1
 
     (SCANNER_EVENTS.map {|event|:"on_#{event}"} - private_instance_methods(false)).each do |event|
       alias_method event, :_push_token