∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α] [inst_2 : DecidableEq α] (a : α) (x : G),
  MulAction.instDecidablePredMemSubgroupStabilizerOfDecidableEq a x = inferInstanceAs (Decidable (x • a = a))