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
yes
evalbytes sub
say sub
########
# No $[ under 5.15
# SKIP ? not defined DynaLoader::boot_DynaLoader
use v5.14;
no warnings 'deprecated';
$[ = 1;
print qw[a b c][2], "\n";
use v5.15;
print qw[a b c][2], "\n";
EXPECT
b
c
########
# $[ under < 5.10
# SKIP ? not defined DynaLoader::boot_DynaLoader
use feature 'say'; # make sure it is loaded and modifies %^H; we are test-
use v5.8.8;        # ing to make sure it does not disable $[
no warnings 'deprecated';
$[ = 1;
print qw[a b c][2], "\n";
EXPECT
b
########
# $[ under < 5.10 after use v5.15
# SKIP ? not defined DynaLoader::boot_DynaLoader
use v5.15;
use v5.8.8;
no warnings 'deprecated';
$[ = 1;
print qw[a b c][2], "\n";
EXPECT
b
########
# Implicit unicode_string feature
use v5.14;
print 'ss' =~ /\xdf/i ? "ok\n" : "nok\n";
use v5.8.8;
print 'ss' =~ /\xdf/i ? "ok\n" : "nok\n";
EXPECT
ok
nok
########
# Implicit unicode_eval feature
use v5.15;
print eval "use utf8; q|\xc5\xbf|" eq "\xc5\xbf" ? "ok\n" : "nok\n";
use v5.8.8;
print eval "use utf8; q|\xc5\xbf|" eq "\x{17f}" ? "ok\n" : "nok\n";
EXPECT
ok
ok