use strict;
use warnings;

# selfcontained simulation of feature pragma
  package my_feature;
  use Carp;
  sub import {
    my $pkg = (caller)[0];
    if ( grep {$_ eq "try"} @_ ) {
      for my $func (qw/try catch finally/) {
        carp "Warning: ${pkg}::$func() will be shadowed by feature 'try'"
          if exists &{"${pkg}::$func"};
      }
    }
  }
  1;

  BEGIN {  $INC{"my_feature.pm"} = "DEMO from " . __FILE__ }
# end simulation

package Foo;
use Try::Tiny;
use my_feature "try";                 

##</code><code>##

perl /home/lanx/perl/pm/check_stash_sub.pl
Warning: Foo::try() will be shadowed by feature 'try' at /home/lanx/perl/pm/check_stash_sub.pl line 23.
Warning: Foo::catch() will be shadowed by feature 'try' at /home/lanx/perl/pm/check_stash_sub.pl line 23.
Warning: Foo::finally() will be shadowed by feature 'try' at /home/lanx/perl/pm/check_stash_sub.pl line 23.