At 340460, I was replying and used the construct $self->{_$_}. I didn't quote it because hashkeys autoquote. Yet. Fletch correctly pointed out that $self->{_$_} deparses to $self->{$_->_}. Not only that, but it actually executes! 
perl -e '$self->{a$_};print keys %$self, $/;'
--------
Can't call method "a" on an undefined value at -e line 1.

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Going further, I get the following: 

package Foo;

sub new { my $c = shift; bless \$c, $c }
sub bar { 'bar' }

package main;

$foo = Foo->new;
$x{bar$foo} = 1;
print "$_ => $x{$_}\n" for keys %x;

--------

bar => 1

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Further testing shows that $x{bar $foo} and $x{$foo->bar} also work.

Now, I knew that $x{bar()} works, because that's how you get constants in there. But, method calls?

------
We are the carpenters and bricklayers of the Information Age.

Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

In reply to Hashkey stringification ... sometimes. by dragonchild

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