Check implicit loading of features with use VERSION.

__END__
# Standard feature bundle
use feature ":5.10";
say "Hello", "world";
EXPECT
Helloworld
########
# VERSION requirement, dotted notation
use 5.9.5;
say "Hello", "world";
EXPECT
Helloworld
########
# VERSION requirement, v-dotted notation
use v5.9.5;
say "Hello", "world";
EXPECT
Helloworld
########
# VERSION requirement, decimal notation
use 5.009005;
say "Helloworld";
EXPECT
Helloworld
########
# VERSION requirement, doesn't load anything with require
require 5.9.5;
print "<".$INC{"feature.pm"}.">\n";
EXPECT
<>
########
# VERSION requirement in eval {}
eval {
    use 5.9.5;
    say "Hello", "world";
}
EXPECT
Helloworld
########
# VERSION requirement in eval ""
eval q{
    use 5.9.5;
    say "Hello", "world";
}
EXPECT
Helloworld
########
# VERSION requirement in BEGIN
BEGIN {
    use 5.9.5;
    say "Hello", "world";
}
EXPECT
Helloworld
########
# no implicit features with 'no'
eval "no " . ($]+1); print $@;
EXPECT
########
# lower version after higher version
sub evalbytes { print "evalbytes sub\n" }
sub say { print "say sub\n" }
use 5.015;
evalbytes "say 'yes'";
use 5.014;
evalbytes;
use 5;
say "no"
EXPECT
Downgrading a use VERSION declaration to below v5.11 is deprecated, and will become fatal in Perl 5.40 at - line 8.
yes
evalbytes sub
say sub
########
# Implicit unicode_string feature
use v5.14;
my $sharp_s = chr utf8::unicode_to_native(0xdf);
print 'ss' =~ /$sharp_s/i ? "ok\n" : "nok\n";
use v5.8.8;
print 'ss' =~ /$sharp_s/i ? "ok\n" : "nok\n";
EXPECT
Downgrading a use VERSION declaration to below v5.11 is deprecated, and will become fatal in Perl 5.40 at - line 5.
ok
nok
########
# Implicit unicode_eval feature
use v5.15;
require '../../t/charset_tools.pl';
my $long_s = byte_utf8a_to_utf8n("\xc5\xbf");
print eval "use utf8; q|$long_s|" eq $long_s ? "ok\n" : "nok\n";
use v5.8.8;
print eval "use utf8; q|$long_s|" eq "\x{17f}" ? "ok\n" : "nok\n";
EXPECT
Downgrading a use VERSION declaration to below v5.11 is deprecated, and will become fatal in Perl 5.40 at - line 6.
ok
ok