class.c: ensure_includable * class.c (ensure_includable): extract checks to include and prepend. class.c: prohibit refinement module * class.c (ensure_includable): cannot include refinement module, or the type and the class do not match. [ruby-core:79632] [Bug #13236]
merge revision(s) 58082,58083: [Backport #13236]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@58519 b2dd03c8-39d4-4d8f-98ff-823fe69b080e