Hi, I have the same problem with ccls which has stopped finding C++ headers.
the quick fix is to install libstdc++-14-dev. The problem seems to be a dependency error: Debian testing's `clang`depends on `clang-16`which depends on `libstdc++-13-dev`. but the program `clang-16`only depends on `libstdc++-14-dev`at runtime (see the section "#include <...> search starts here:"): ``` ~$ clang-16 -E -v -xc++ /dev/null Debian clang version 16.0.6 (19) Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/bin Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/13 Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/14 Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/14 Candidate multilib: .;@m64 Selected multilib: .;@m64 Found HIP installation: /usr, version 5.2.21153 (in-process) "/usr/lib/llvm-16/bin/clang" -cc1 -triple x86_64-pc-linux-gnu -E -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name null -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -v -fcoverage-compilation-dir=/home/rem -resource-dir /usr/lib/llvm-16/lib/clang/16 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/x86_64-linux-gnu/c++/14 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/backward -internal-isystem /usr/lib/llvm-16/lib/clang/16/include -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir=/home/rem -ferror-limit 19 -fgnuc-version=4.2.1 -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o - -x c++ /dev/null clang -cc1 version 16.0.6 based upon LLVM 16.0.6 default target x86_64-pc-linux-gnu ignoring nonexistent directory "/usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include" ignoring nonexistent directory "/include" #include "..." search starts here: #include <...> search starts here: /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14 /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/x86_64-linux-gnu/c++/14 /usr/bin/../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/backward /usr/lib/llvm-16/lib/clang/16/include /usr/local/include /usr/include/x86_64-linux-gnu /usr/include End of search list. # 1 "/dev/null" # 1 "<built-in>" 1 # 1 "<built-in>" 3 # 437 "<built-in>" 3 # 1 "<command line>" 1 # 1 "<built-in>" 2 # 1 "/dev/null" 2 ``` As the actual `gcc`package depends on `gcc-13`, `clang-16`(as the default clang version) should too. my 2¢ Rémi
