Package: libc++-21-dev Version: 1:21.1.8-3 Package libc++-21-dev contains two libc++.modules.json files:
$ dpkg -S libc++.modules.json libc++-21-dev: /usr/lib/llvm-21/lib/libc++.modules.json libc++-21-dev: /usr/lib/x86_64-linux-gnu/libc++.modules.json While the first one looks good, the second contains incorrect paths: $ cat /usr/lib/x86_64-linux-gnu/libc++.modules.json [...] "source-path": "../share/libc++/v1/std.cppm", [...] $ ls /usr/lib/x86_64-linux-gnu/../share/libc++/v1/std.cppm ls: cannot access '/usr/lib/x86_64-linux-gnu/../share/libc++/v1/std.cppm': No such file or directory Naturally, Clang chooses to print the path to the broken file: $ clang++-21 -print-file-name=libc++.modules.json /lib/x86_64-linux-gnu/libc++.modules.json Feels like either Clang needs to be fixed to report the other file (and the broken file probably removed) or the broken file needs to be fixed. BTW, this bug can be worked around with the following symlink: # mkdir /usr/lib/share # ln -s /usr/lib/llvm-21/share/libc++ /usr/lib/share/
