IO.open with three arguments where third argument is bogus reports an arity problem instead of type problem
I am reporting this against 2.0.rc2 but it also applies to mri 1.9.3. If I run the following one-liner:
mri20 -e 'f = File.open("tmp"); IO.open(f.fileno, "r", :heh)'
I get the error:
-e:1:in `initialize': wrong number of arguments (3 for 1..2) (ArgumentError)
This seems wrong because if I change the third argument to an options hash it works fine. So having an arity of 3 is not a problem for open. It is that :heh is not a hash. I think this should generate a TypeError.