my $s = do {
  # don't care about warnings.
  local *STDERR;
  open STDERR, '>', File::Spec->devnull();
  code_that_warns_deep_in_core_perl(); # and I can't figure out why
};

##</code><code>##

Use of uninitialized value in lc at /usr/lib/perl5/5.8.7/utf8_heavy.pl
 line 123.

##</code><code>##

if (my $base = ($utf8::Canonical{$canonical} || $utf8::Canonical{ lc $utf8::PropertyAlias{$canonical} })) {