{motive : Mathlib.Tactic.Push.Head → Sort u} →
  ((c : Lean.Name) → motive (Mathlib.Tactic.Push.Head.const c)) →
    motive Mathlib.Tactic.Push.Head.lambda →
      motive Mathlib.Tactic.Push.Head.forall → (t : Mathlib.Tactic.Push.Head) → motive t