fact: Definition Mby' {A} (t: tactic) : M A := e <- evar A; l <- t (Goal Typeₛ e); l' <- T.filter_goals l; match l' with mnil => ret e | _ => failwith "couldn't solve" end.
imports: Mtac2(Base Datatypes List MTele MTeleMatch MTeleMatchDef MFixDef Sorts tactics.Tactics) Strings.String