Comment (by Roland Haas):

I do not see these warnings on my workstation with Perl v5.30.3 but do see them on BW with Perl v5.10.0.

The code in question is:

print $sep . scalar(split(" ", $parameter_database{"\U$thorn $block\E variables"})) . " $block";

and the warning goes away if I change it to:

my @vars = split(/ /, $parameter_database{"\U$thorn $block\E variables"});
print $sep . scalar(@vars) . " $block";

The code has been like this since 1999 so this must be triggered now by something else, most likely by the $parameters_database hash now actually containing a value while having been empty (due to a typo) before.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2466/new-perl-warnings-use-of-implicit-split-to