(motive : Mathlib.Meta.FunProp.MaybeFunctionData → Sort u_1) →
  (fData? : Mathlib.Meta.FunProp.MaybeFunctionData) →
    ((fData : Mathlib.Meta.FunProp.FunctionData) → motive (Mathlib.Meta.FunProp.MaybeFunctionData.data fData)) →
      ((x : Mathlib.Meta.FunProp.MaybeFunctionData) → motive x) → motive fData?