#!/usr/bin/env perl use warnings; use strict; use Foo; use feature 'signatures'; foo(9,10); sub foo($x,$y) { print $x+$y,"\n"; } #### #!perl package Foo; use warnings; use strict; sub import { warnings->unimport('experimental::signatures') if $] >= 5.020; } 1; #### #!perl package Foo; use warnings; use strict; use parent 'Exporter'; sub import { warnings->unimport('experimental::signatures') if $] >= 5.020; __PACKAGE__->export_to_level(1, @_); } 1;