unable to view available ri doc for gem inside vim (no problem on command line with ri)

[pan]

The ri doc is available on command line, for example, ri submit_tag or other methods of rails work perfectly on command line but it is not found inside vim(8.0.1175), if typing \r in the launched autocomplete window, it says "User defined completion (^U^N^P) Pattern not found" after hitting the enter key.

For other methods of from ruby, like popen, or class IO, etc. it works without any issue.

Any hint what might be wrong?

[wikimatze]

Actually no, I haven't looked into this plugin recently, I'll have to investigate it.