It only matches everything until you've matched anything. (Think that's cryptic?)

for (qw( a b403 c<<>_# d84930 e89293->><{}W )) {
  print if //;
}

"foo" =~ /foo/;

for (qw( a b403 c<<>_# d84930 e89293->><{}W )) {
  print if //;
}
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japhy -- Perl and Regex Hacker