That very question just came up on p5p, the Perl developers' mailing list. It turns out that some rvalue operations autovivify and some don't. Spoke Nicolas Clark, the pumpking:

So why are indexing and defined special?
Are they the only exceptions to the exception?

No answer was obtained.

Source: Perl RT 63810

In reply to Re^3: Why nothing from 'strict' or 'warnings' with deref'd undef value? by ikegami
in thread Why nothing from 'strict' or 'warnings' with deref'd undef value? by jeremym

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