Hide internal IDs

* parse.y (internal_id): number the ID serial for internal use by
  counting down from the neary maximum value, not to accidentally
  match permanent IDs.

[Bug #15768]

1 files changed, 5 insertions, 0 deletions

diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb
index beffaa8ce0..4e20534dfa 100644
--- a/test/ruby/test_method.rb
+++ b/test/ruby/test_method.rb
@@ -615,6 +615,11 @@ class TestMethod < Test::Unit::TestCase
     assert_equal([[:req, :a], [:opt, :b], [:rest, :c], [:req, :d], [:keyrest, :o]], self.class.instance_method(:pmk7).parameters)
   end
 
+  def test_hidden_parameters
+    instance_eval("def m((_)"+",(_)"*256+");end")
+    assert_empty(method(:m).parameters.map{|_,n|n}.compact)
+  end
+
   def test_public_method_with_zsuper_method
     c = Class.new
     c.class_eval do