Hi,I'm working with regex, and I isolated an unexpected behaviour.If I paste attached code code in scratch buffer and evaluate it, emacs hangs (cpu stays at 100% until I kill emacs)Im running emacs for windows x64, in particular this package: https://sourceforge.net/projects/emacsbinw64/files/release/emacs-w64-25.3-O2-with-modules.7z/download The variable case-fold-search is set to t. Can you help me? Thank you very much, Michele Pes