{motive : Mathlib.Meta.FunProp.LambdaTheoremArgs → Sort u} →
  (ctorIdx : ℕ) →
    (t : Mathlib.Meta.FunProp.LambdaTheoremArgs) →
      ctorIdx = t.ctorIdx → Mathlib.Meta.FunProp.LambdaTheoremArgs.ctorElimType ctorIdx → motive t