Recent changes in Range#step behavior

Hi,

Since after MRI 1.8.6 patchlevel 111, there were some changes in
Range#step, and I'm not sure they are intentional or not, so I'd like
to clarify.

Here's an example:
ruby -v -e '(1.0..5.0).step(1.5) { |x| p x }'

With MRI 1.8.6 patchlevel 111, the output is:
ruby 1.8.6 (2007-09-24 patchlevel 111) [i686-linux]
1.0
2.5
4.0

With recent 1.8 branch:
1.0
2.0
3.0
4.0
5.0

With trunk (1.9):
ruby 1.9.0 (2008-03-11 revision 0) [i686-linux]
1.0
2.0
3.0
4.0
5.0

As you see, now Range#step first converts the argument to integer, and
then adds it during every iteration.
(Btw, this whole behaviour of using the argument not as a step, but as
an increment, is completely unspecified in the docs).

For floats, the new behavior leads to loss of precision, since step is
always integer (or converted to one).

So, the question is: is the current trunk behavior is regression or intentional?

Thanks,
  --Vladimir