(pu : Lean.Compiler.LCNF.Purity) →
  (motive : Option (Lean.Compiler.LCNF.FunDecl pu) → Sort u_1) →
    (x : Option (Lean.Compiler.LCNF.FunDecl pu)) →
      ((decl : Lean.Compiler.LCNF.FunDecl pu) → motive (some decl)) →
        ((x : Option (Lean.Compiler.LCNF.FunDecl pu)) → motive x) → motive x