Issue #1648 has been updated by Rick DeNatale. -1 I believe that the current behavior is correct. The requirement on the argument is that it respond to :coerce, not that it be a kind of Numeric. The current exception is fine. The patch precludes ducktyping the argument. I can't see a spec in rubyspecs which uses a nil argument to Rational#div where is this failing spec. If it's there I'd argue that it shouldn't be. ---------------------------------------- http://redmine.ruby-lang.org/issues/show/1648 ---------------------------------------- http://redmine.ruby-lang.org