https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104691
Bug ID: 104691
Summary: SFINAE does not disable static_assert
Product: gcc
Version: og10 (devel/omp/gcc-10)
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: github at quantconsulting dot com
Target Milestone: ---
Created attachment 52516
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52516&action=edit
File generated by -save-temps
Description: "Substitution failure is not an error" (SFINAE) correctly disables
a second instantiation of a templated function and compilation continues to
completion -- unless the implementation to be disabled by SFINAE contains a
failing static_assert, in which case compilation reports the static_assert
failure as an error and halts.
Expected behavior:
Even when the failing static_assert is present, compilation should continue to
completion because there is substitution failure -- which is *earlier* in that
function instantiation, no less -- and thus the static_assert failure should be
ignored.
gcc -v:
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/10/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
10.3.0-1ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-10/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-10
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-10-S4I5Pr/gcc-10-10.3.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-10-S4I5Pr/gcc-10-10.3.0/debian/tmp-gcn/usr,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
--with-build-config=bootstrap-lto-lean --enable-link-mutex
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.3.0 (Ubuntu 10.3.0-1ubuntu1~20.04)
Command line that triggers the bug:
g++ -save-temps -o test3 test3.cc
Error message:
test3.cc: In function ‘std::enable_if_t<std::is_class<typename
TContainer::allocator_type>::value, TContainer> MakeFilled(const typename
std::remove_reference<decltype (* TContainer{}.begin())>::type&)’:
test3.cc:23:17: error: static assertion failed: Substitution failure so this
should never be checked!
23 | static_assert(false, "Substitution failure so this should never be
checked!");
| ^~~~~
