See for example the limitations in L<Switch>, which uses source filters,
and thus is does not work inside a string eval, the presence of
regexes with embedded newlines that are specified with raw C</.../>
-delimiters and don't have a modifier C</x> are indistinguishable from
+delimiters and don't have a modifier C<//x> are indistinguishable from
code chunks beginning with the division operator C</>. As a workaround
-you must use C<m/.../> or C<m?...?> for such patterns. See
+you must use C<m/.../> or C<m?...?> for such patterns. Also, the presence of
+regexes specified with raw C<?...?> delimiters may cause mysterious
+errors. The workaround is to use C<m?...?> instead. See
L<http://search.cpan.org/perldoc?Switch#LIMITATIONS>
Currently the content of the C<__DATA__> block is not filtered.