perl589delta claims "A new entry has been added to the MAGIC vtable - svt_local. This is used when copying magic to the new value during local, allowing certain problems with localising shared variables to be resolved."

I thought it might relate to this issue, but I don't seem to.

>c:\progs\perl588\bin\perl 722505.pl
pre
STORE undef
post
STORE undef

pre
STORE undef
STORE [a]
post
STORE undef

>c:\progs\perl589\bin\perl 722505.pl
pre
STORE undef
post
STORE undef

pre
STORE undef        <-- Still there
STORE [a]
post
STORE undef
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The code is in Re^2: Setting signal handlers considered unsafe? (local assigns undef)