type_traits assertion fails when compiling in Debug mode with gcc 10 on aarch64

[hlitz]

Describe the bug Compilation fails with: [ 33%] Building CXX object hphp/runtime/CMakeFiles/hphp_runtime_static.dir/base/unit-cache.cpp.o In file included from /usr/include/c++/10/bits/move.h:57, from /usr/include/c++/10/bits/stl_pair.h:59, from /usr/include/c++/10/bits/stl_algobase.h:64, from /usr/include/c++/10/bits/char_traits.h:39, from /usr/include/c++/10/string:40, from /hhvm/hphp/runtime/base/stream-wrapper.h:20, from /hhvm/hphp/runtime/base/unit-cache.h:19, from /hhvm/hphp/runtime/base/unit-cache.cpp:16: /usr/include/c++/10/type_traits: In instantiation of ‘struct std::is_default_constructible’: /usr/include/c++/10/type_traits:143:12: required from ‘struct std::_and<std::is_default_constructible, std::is_default_constructible<HPHP::RankedCHM<const HPHP::StringData*, HPHP::{anonymous}::CachedUnitNonRepo, HPHP::StringDataHashCompare, HPHP::RankUnitCache>>, std::_not<std::_and<std::__is_implicitly_default_constructible, std::__is_implicitly_default_constructible<HPHP::RankedCHM<const HPHP::StringData, HPHP::{anonymous}::CachedUnitNonRepo, HPHP::StringDataHashCompare, HPHP::RankUnitCache>> > > >’ /usr/include/c++/10/bits/stl_pair.h:244:59: required by substitution of ‘template<class _U1, class _U2, typename std::enable_if<std::_and<std::is_default_constructible<_U1>, std::is_default_constructible<_U2>, std::_not<std::_and<std::__is_implicitly_default_constructible<_U1>, std::__is_implicitly_default_constructible<_U2> > > >::value, bool>::type > constexpr std::pair<const unsigned int, HPHP::RankedCHM<const HPHP::StringData, HPHP::{anonymous}::CachedUnitNonRepo, HPHP::StringDataHashCompare, HPHP::RankUnitCache>>::pair() [with _U1 = const unsigned int; _U2 = HPHP::RankedCHM<const HPHP::StringData, HPHP::{anonymous}::CachedUnitNonRepo, HPHP::StringDataHashCompare, HPHP::RankUnitCache>*; typename std::enable_if<std::_and<std::is_default_constructible<_U1>, std::is_default_constructible<_U2>, std::_not<std::_and<std::__is_implicitly_default_constructible<_U1>, std::__is_implicitly_default_constructible<_U2> > > >::value, bool>::type = ]’ /hhvm/build/third-party/folly/bundled_folly-prefix/include/folly/AtomicHashArray-inl.h:63:19: required from here /usr/include/c++/10/type_traits:918:52: error: non-constant condition for static assertion 918 | static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}), | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~ /usr/include/c++/10/type_traits:918: confused by earlier errors, bailing out make[2]: *** [hphp/runtime/CMakeFiles/hphp_runtime_static.dir/build.make:1733: hphp/runtime/CMakeFiles/hphp_runtime_static.dir/base/unit-cache.cpp.o] Error 1 make[2]: Leaving directory '/hhvm/build' make[1]: *** [CMakeFiles/Makefile2:2550: hphp/runtime/CMakeFiles/hphp_runtime_static.dir/all] Error 2 make[1]: Leaving directory '/hhvm/build' make: *** [Makefile:130: all] Error 2

Standalone code, or other way to reproduce the problem cmake -DMYSQL_UNIX_SOCK_ADDR=/var/run/mysqld/mysqld.sock -DCMAKE_BUILD_TYPE=Debug .. make

Expected behavior

compiles correctly Actual behavior

fails with error above

Environment Ubuntu 20.04 gcc 10.3 aarch64

Additional context This problem does not occur when compiling a non-debug build