Ruby

• numeric.c (int_to_f): raise NotImplementedError when a receiver
  class is unknown.

• test/-ext-/integer/test_my_integer.rb (test_my_integer_to_f): modify
  a test for the above change.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e