fact: Definition match_eta2 {T} {x : T} (E : x = x) : (idpath = match E in (_ = y) return (x = y) with | idpath => idpath end) -> idpath = E := fun H => match_eta1 E (H ^)%path.
imports: Basics.Overture Basics.Tactics Basics.PathGroupoids Basics.Contractible Basics.Equivalences Types.Prod Types.Forall Tactics.BinderApply