Arch Linux

Description:
gcc compiler error while using precompiled header and -Wmismatched-tags flag

Additional info:

$ /usr/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/usr/bin/g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --with-isl --with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit --enable-cet=auto --enable-checking=release --enable-clocale=gnu --enable-default-pie --enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object --enable-install-libiberty --enable-linker-build-id --enable-lto --enable-multilib --enable-plugin --enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch --disable-libunwind-exceptions --disable-werror gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (GCC)

# pacman -F /usr/bin/g++
usr/bin/g++ is owned by core/gcc 10.2.0-6

Steps to reproduce:
$ cat pch.h
#include <string>

$ cat main.cpp
#include <fstream>
#include "pch.h"
int main () {}

$ /usr/bin/g++ -Wmismatched-tags -c pch.h -o pch.h.gch

$ /usr/bin/g++ -Wmismatched-tags -include pch.h main.cpp
main.cpp:3:14: internal compiler error: in diag_mismatched_tags, at cp/parser.c:31360
3 | int main () {}
| ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.