Detected by clang:

src\jdk.accessibility\windows\native\libwindowsaccessbridge\WinAccessBridge.cpp(2776,47): warning: multi-character character constant [-Wmultichar]
            if (pkg->rTextItemsInfo.letter != '/0') {
                                              ^
'/0' is equivalent to L'\u2f30', https://charbase.com/2f30-unicode-kangxi-radical-oneself