My previous change that "set @A=NULL" doesn't change charset
  fixed 'Bug #6321' as well. Prove with a new test that
  FIELD(<uservariable content NULL>, ...) now works fine too.


mysql-test/t/user_var.test:
  My previous change that "set @A=NULL" doesn't change charset
  fixed 'Bug #6321' as well. Prove with a new test that
  FIELD(<uservariable content NULL>, ...) now works fine too.
mysql-test/r/user_var.result:
  My previous change that "set @A=NULL" doesn't change charset
  fixed 'Bug #6321' as well. Prove with a new test that
  FIELD(<uservariable content NULL>, ...) now works fine too.