https://issues.dlang.org/show_bug.cgi?id=23464
Issue ID: 23464 Summary: Pathological compilation slowdown when mixin in large switches Product: D Version: D2 Hardware: x86 OS: Windows Status: NEW Severity: enhancement Priority: P1 Component: dmd Assignee: nob...@puremagic.com Reporter: deadal...@gmail.com Unfortunately, because this bug require to mix in a large switch, I'm not able to share a small sample code. You can find an example able to trigger the problem here: https://github.com/snazzy-d/sdc/tree/compiletime The compilation time is dominated by the mixin in lexHtmlEntity in lexstring.d With this function, compiling the json lexer takes 45s on my system. Without it, it takes 0.3s . There seems to be something non linear somewhere, because similar switches are mixed in in other places, but the one in lexHtmlEntity is definitively the biggest one. --