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I'd like to get rid of "use UNIVERSAL;"

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Ævar Arnfjörð Bjarmason
September 26, 2016 20:32
I'd like to get rid of "use UNIVERSAL;"
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In 5.12 rjbs deprecated "use UNIVERSAL qw(can isa ...)" with a
warning, in v5.22 Dagfinn made this a fatal error.

I've just pushed a smoke-me branch to remote UNIVERSAL::import from
that package, and make its (no)?import a fatal error via a hack to

The motivation here is that someone doing "use UNIVERSAL;" in some
module shouldn't make $pkg->can("import") true for any value of $pkg
in your program.

But technically this does break backwards compatibility without a
deprecation cycle. Because "use UNIVERSAL;" isn't an error today, and
some code on the CPAN redundantly uses that.

So what do you think we should do about that? Should we wait until
around 2020 until $pkg->can("import") won't be true at a distance by
going through the full warn/error cycle for this, or just try to push
this to blead and see if it's a big deal? The fix to broken code is
trivial, just remove the "use" line for UNIVERSAL, or if you feel you
must have it import it with a () argument.

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