I had tested with the following. Note the lack of warning 

>perl -wle"$r=[]; print eval { %$r || 1 }

[download]

Turns out we're both wrong. eval returns an empty list. 

>perl -wle"$r=[]; print scalar(() = eval { %$r || 1 });
0

[download]

An empty list is interpreted as undef in scalar context.

In reply to Re^5: Blessing interior hashes by ikegami
in thread Blessing interior hashes by throop

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