Issue #4650 has been updated by Nobuyoshi Nakada. It's spec. Cited from doc/re.rdoc: *Note*: A regexp can't use named backreferences and numbered backreferences simultaneously. ---------------------------------------- Bug #4650: sub/gsub with named group captures discards numbered group captures http://redmine.ruby-lang.org/issues/4650 Author: NoƩ Rubinstein Status: Open Priority: Normal Assignee: Category: core Target version: ruby -v: ruby 1.9.2p180 (2011-02-18 revision 30909) [i686-linux] puts "ab".sub(/(?<g>.)(.)/, "0=\\0 1=\\1 2=\\2 g=\\k<g>") # outputs "0=ab 1= 2= g=a" Expected: "0=ab 1=b 2= g=a" (or maybe "0=ab 1= 2=b g=a"? Though I think it's the former) -- http://redmine.ruby-lang.org