Cannot compile latest master with clang 6 or 7 #23273

This is a known issue:-

https://stackoverflow.com/questions/49639808/fatal-error-charconv-file-not-found-in-clang-6-0-with-std-c17

This became an issue when charconv was added to master - so the build documentation will need updating to cater for the new dependency on a newer version of clang (or GCC).

Potential fix:-

apt install build-essential xz-utils curl
curl -SL https://releases.llvm.org/7.0.1/clang%2bllvm-7.0.1-x86_64-linux-gnu-ubuntu-18.04.tar.xz | tar -xJC .
sudo cp -r clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-18.04/ /usr/local/clang-7.0.1
export LD_LIBRARY_PATH=/usr/local/clang-7.0.1/lib:$LD_LIBRARY_PATH
export PATH=/usr/local/clang-7.0.1/bin:$PATH
sudo ldconfig

(still editing this)

This became an issue when charconv was added to master - so the build documentation will need updating to cater for the new dependency on a newer version of clang (or GCC).

Isn't the documentation already updated? https://github.com/bitcoin/bitcoin/blob/master/doc/dependencies.md:

@hebasto up until less than 1 month ago, the build-window instructions said to use Ubuntu 18.04 for WSL - this has older versions of clang and libc++ than the latest dependencies says are required.

This became an issue when charconv was added to master - so the build documentation will need updating to cater for the new dependency on a newer version of clang (or GCC).

As mentioned, the documentation is already up to date. In fact it was up to date before the charconv change you mention was merged into master.

Ubuntu 18.04 for WSL - this has older versions of clang and libc++ than the latest dependencies says are required.

Ubuntu 18.04 has a Clang-7 package that works perfectly fine to compile master. We currently use it in our CI: https://github.com/bitcoin/bitcoin/blob/71a85fbd09b5a450edc53a8ba4131f32e7136ca7/ci/test/00_setup_env_native_nowallet.sh#L11.