Some problems in Ruby 1.8.7

[toupeira]

The following work as expected in Ruby 1.9:

printf '%d' % lazy { 23 }            # -> '23'
puts lazy { [] }.respond_to? :to_ary # -> 'true'

But in Ruby 1.8.7 they seem to act on the Lazy object itself:

printf '%d' % lazy { 23 }
# TypeError: can't convert Lazy into Integer
#   from (irb):3:in `%'
#   from (irb):3

puts lazy { [] }.respond_to? :to_ary # -> 'false'

Not sure if it's possible to fix this in 1.8.7, I just thought I'd report this and ask if you know any workarounds?