Well, there is a bug in CPerl mode. It is a bit evasive and not that easy to trigger. choroba has filed a bug report and there's a patch which you should be able to use at least in Emacs 27.1. It also contains a test case with a sequence of commands which triggers the bug in Emacs 26.1 to Emacs 28.

I am well aware of the deprecation of cperl-under-as-char and provided it only as a possible workaround. By the way: There be dragons. Superword mode treats all symbol characters as word characters, and in CPerl mode the colon : is also a symbol character.

In general, the fontification of CPerl mode should not depend on the setting of this variable nor on the setting of superword mode, and in most (but not all, as we see here) cases the underscore is explicitly included when parsing Perl identifiers.

In reply to Re^7: IDE for Perl programming? ( *cperl-mode* bug) by haj
in thread IDE for Perl programming? by rsFalse

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