∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {E : Type u_2} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {F : Type u_3} [inst_3 : NormedAddCommGroup F] [inst_4 : NormedSpace 𝕜 F] {p : E × F}
  {L : Filter (E × F)}, HasFDerivAtFilter Prod.fst (ContinuousLinearMap.fst 𝕜 E F) p L