The PPI documentation says:

"However, there are going to be limits to this process. Because PPI cannot adapt to changing grammars, any code written using source filters should not be assumed to be parsable"

So, what are the specific modules that cause problems with PPI? (and, by extension, Perl::Tidy and Perl::Critic, and other static analysis tools that depend on PPI)

• Filter::Util::Call — The vast majority of source filters use this module to help get the job done. If you see this module in the "dependencies" column on MetaCPAN, it's a good sign that module uses source filters.
• Test::Base <111 reverse deps>