module T::Private::Methods

def self.finalize_proc(decl)
  decl.finalized = true
  if decl.mode != Modes.standard
    raise "Procs cannot have override/abstract modifiers"
  end
  if decl.mod != PROC_TYPE
    raise "You are passing a DeclBuilder as a type. Did you accidentally use `self` inside a `sig` block?"
  end
  if decl.returns == ARG_NOT_PROVIDED
    raise "Procs must specify a return type"
  end
  if decl.on_failure != ARG_NOT_PROVIDED
    raise "Procs cannot use .on_failure"
  end
  if decl.params == ARG_NOT_PROVIDED
    decl.params = {}
  end
  T::Types::Proc.new(decl.params, decl.returns)
end