Not surprising, $/="\n" assignment is always true

Ack!

5.12 is not a module (maybe you wants features)

I didn't know that. From the use docs:

use VERSION also enables all features available in the requested version as defined by the feature pragma,

In any case, like the op I'm wondering where the name 'say' is stored? It is not in main's symbol table:

use strict;
use warnings;
use 5.012;

our $x;

use Data::Dumper;
say Dumper($main::{x});     #%main:: is the name of the symbol table
say Dumper($main::{say});
say Dumper($main::{print});


--output:--
$VAR1 = *::x;   #typeglob for 'x', in package ::(shorthand for main::)

$VAR1 = undef;

$VAR1 = undef;
[download]

So it appears that the name 'say' might be in the same place as the name 'print', i.e. not in the main:: symbol table. But then why doesn't 'use subs' succeed in redefining say()? Then again, I can't redefine print() with 'use subs' either:

use strict;
use warnings;
use 5.012;

use subs qw( print );

sub print {
    printf "%s %s\n", shift, 'world';
}

print 'hello';

--output:--
hello
[download]

I am able to redefine the chdir() builtin:

use strict;
use warnings;
use 5.012;

use Data::Dumper;
say Dumper($main::{chdir});

--output:--
$VAR1 = undef;
[download]

use strict;
use warnings;
use 5.012;

use subs qw( chdir );

sub chdir {
    printf "%s %s\n", shift, 'world';
}

chdir 'hello';

--output:--
hello world
[download]

It appears that some builtins are more builtin than others.