(motive : Lean.Compiler.LCNF.Arg Lean.Compiler.LCNF.Purity.pure → Sort u_1) →
  (x : Lean.Compiler.LCNF.Arg Lean.Compiler.LCNF.Purity.pure) →
    ((argFVarId : Lean.FVarId) → motive (Lean.Compiler.LCNF.Arg.fvar argFVarId)) →
      ((x : Lean.Compiler.LCNF.Arg Lean.Compiler.LCNF.Purity.pure) → motive x) → motive x