More informative error message when the tactic tries to generate a new goal with metavariables in it.
More informative error message when the tactic tries to generate a new
goal with metavariables in it.


git-svn-id: a49b465eaba45b67e2e1e4e0b2c256a71f59fecb@6233 85f007b7-540e-0410-9357-904b9bb8a0f7

SamB/coq