#536 CB freezes when original generated preprocessor file and original file have same extension

[Jannick]

Settings > Compiler > tab 'Other settings' > btn 'Advanced options ...' > tab 'Commands:
Using in the generated files window '$file_ext' freezes CB upon loading a project where this compiler rule is relevant.

I suspect that CB then jumps into an infinite loop which would be the simplest case of circular dependencies amongst the preprocessors (in terms of file extensions).