{motive : Mathlib.Tactic.BicategoryLike.StructuralAtom → Sort u} →
  (t : Mathlib.Tactic.BicategoryLike.StructuralAtom) →
    t.ctorIdx = 1 →
      ((e : Lean.Expr) →
          (f : Mathlib.Tactic.BicategoryLike.Mor₁) →
            motive (Mathlib.Tactic.BicategoryLike.StructuralAtom.leftUnitor e f)) →
        motive t