#30612 with changes made.
GCC 15 introduces three build failures:
-
Two are related to missing includes. You can’t use
uint16_tet al. without including<cstdint>. -
The third is harder to understand but easy to fix. GCC changed something about the way templates are instantiated when checking type constraints, and now there is a dependency loop while checking
std::optional<CFeeRate>. This manifests as the following compile-time mess:0In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/format:48, 1 from /usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/bits/chrono_io.h:39, 2 from /usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/chrono:3362, 3 from ./util/time.h:9, 4 from ./primitives/block.h:12, 5 from ./blockencodings.h:8, 6 from blockencodings.cpp:5: 7/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/type_traits: In substitution of 'template<class _Up> requires !(is_same_v<std::optional<_Tp>, typename std::remove_cvref<_It2>::type>) && (is_constructible_v<_Tp, const _Up&>) && (__construct_from_contained_value<_Up, typename std::remove_cv< <template-parameter-1-1> >::type>) constexpr std::optional<CFeeRate>::optional(const std::optional<_Tp>&) [with _Up = CFeeRate]': 8/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/type_traits:1140:25: required by substitution of 'template<class _Tp, class ... _Args> using std::__is_constructible_impl = std::__bool_constant<__is_constructible(_Tp, _Args ...)> [with _Tp = CFeeRate; _Args = {std::optional<CFeeRate>&}]' 9 1140 | = __bool_constant<__is_constructible(_Tp, _Args...)>; 10 | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/type_traits:1145:12: required from 'struct std::is_constructible<CFeeRate, std::optional<CFeeRate>&>' 12 1145 | struct is_constructible 13 | ^~~~~~~~~~~~~~~~ 14/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/type_traits:178:35: required by substitution of 'template<class ... _Bn> std::__detail::__first_t<std::integral_constant<bool, false>, typename std::enable_if<(!(bool)(_Bn::value)), void>::type ...> std::__detail::__or_fn(int) [with _Bn = {std::is_constructible<CFeeRate, std::optional<CFeeRate>&>, std::is_convertible<std::optional<CFeeRate>&, CFeeRate>, std::is_constructible<CFeeRate, std::optional<CFeeRate> >, std::is_convertible<std::optional<CFeeRate>, CFeeRate>, std::is_constructible<CFeeRate, const std::optional<CFeeRate>&>, std::is_convertible<const std::optional<CFeeRate>&, CFeeRate>, std::is_constructible<CFeeRate, const std::optional<CFeeRate> >, std::is_convertible<const std::optional<CFeeRate>, CFeeRate>}]' 15 178 | __enable_if_t<!bool(_Bn::value)>...>; 16 | ^~~~~ 17/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/type_traits:196:41: required from 'struct std::__or_<std::is_constructible<CFeeRate, std::optional<CFeeRate>&>, std::is_convertible<std::optional<CFeeRate>&, CFeeRate>, std::is_constructible<CFeeRate, std::optional<CFeeRate> >, std::is_convertible<std::optional<CFeeRate>, CFeeRate>, std::is_constructible<CFeeRate, const std::optional<CFeeRate>&>, std::is_convertible<const std::optional<CFeeRate>&, CFeeRate>, std::is_constructible<CFeeRate, const std::optional<CFeeRate> >, std::is_convertible<const std::optional<CFeeRate>, CFeeRate> >' 18 196 | : decltype(__detail::__or_fn<_Bn...>(0)) 19 | ~~~~~~~~~~~~~~~~~~~~~~~~~^~~ 20/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/optional:824:45: required from 'constexpr const bool std::optional<CFeeRate>::__construct_from_contained_value<CFeeRate, CFeeRate>' 21 824 | = !__converts_from_optional<_Tp, _From>::value; 22 | ^~~~~ 23/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/optional:884:7: required by substitution of 'template<class _Up> requires !(is_same_v<std::optional<_Tp>, typename std::remove_cvref<_It2>::type>) && (is_constructible_v<_Tp, const _Up&>) && (__construct_from_contained_value<_Up, typename std::remove_cv< <template-parameter-1-1> >::type>) constexpr std::optional<CFeeRate>::optional(const std::optional<_Tp>&) [with _Up = CFeeRate]' 24 884 | && __construct_from_contained_value<_Up> 25 | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 26./validation.h:164:41: required from here 27 164 | return MempoolAcceptResult(state); 28 | ^ 29/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/optional:886:2: required by the constraints of 'template<class _Tp> template<class _Up> requires !(is_same_v<std::optional<_Tp>, typename std::remove_cvref<_It2>::type>) && (is_constructible_v<_Tp, const _Up&>) && (__construct_from_contained_value<_Up, typename std::remove_cv< <template-parameter-1-1> >::type>) constexpr std::optional<_Tp>::optional(const std::optional<_From>&)' 30/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/optional:884:14: error: satisfaction of atomic constraint '__construct_from_contained_value<_Up, typename std::remove_cv< <template-parameter-1-1> >::type> [with _Tp = _Tp; _Up = _Up]' depends on itself 31 884 | && __construct_from_contained_value<_Up> 32 | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~It is easiest to solve this by changing the
static_assertin the explicitCFeeRateconstructor to a SFINAE by using a type constraint on the function template parameter.
We already downstreamed these fixes in Gentoo.
