merge revision(s) 63417: [Backport #14756]
error.c: check redefined backtrace result * error.c (rb_get_backtrace): check the result of `backtrace` even if the method is redefined. [ruby-core:87013] [Bug #14756]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@64430 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 63417: [Backport #14756]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@64430 b2dd03c8-39d4-4d8f-98ff-823fe69b080e