https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78702
--- Comment #3 from AK <hiraditya at msn dot com> --- llvm-project/install/bin/clang++ -std=gnu++14 -D_GLIBCXX_SHARED -fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi -fdiagnostics-show-location=once -ffunction-sections -fdata-sections -frandom-seed=cxx11-shim_facets.lo -c ../../../src/c++11/cxx11-shim_facets.cc -fPIC -DPIC -D_GLIBCXX_SHARED -o cxx11-shim_facets.o (+ some include flags from Makefile) ../../../src/c++11/cxx11-shim_facets.cc:230:60: error: '__shim' is a private member of 'std::locale::facet' struct numpunct_shim : std::numpunct<_CharT>, facet::__shim ^ ~/s/work/gcc/libstdc++-v3/build/include/bits/locale_classes.h:464:11: note: declared private here class __shim; clang version 4.0.0 Target: x86_64-unknown-linux-gnu