Improving error interface: Begin working on `Box<T>` to allow any `T` to tell if it is owned by a `Box<T>`.

Fortune for libexopt's current commit: Small blessing − 小吉

include/boxed.h

@@ -10,12 +10,15 @@
 #include "exopt.h"
 
 namespace exopt::types { namespace boxed {
+
 	template<typename T>
 	struct [[gnu::visibility("internal")]]  boxable_value_type { using type = std::conditional_t
 			<std::is_reference_v<T>
 			,std::reference_wrapper<std::remove_cvref_t<T> >
 			,T>; };
 
+	namespace { 
+
 	template<typename T>
 	constexpr std::unique_ptr<T> uniq_clone(std::unique_ptr<T> const& c) noexcept(std::is_nothrow_copy_constructible_v<T>) requires(std::is_copy_constructible_v<T>)
 	{ if(__builtin_expect(bool(c), true)) return std::make_unique<T>(*c); return nullptr; }
@@ -35,10 +38,96 @@ namespace exopt::types { namespace boxed {
 	return std::make_unique<T>(*c); }
 
 
+	template<typename Error = ptr::NullException>
+	constexpr decltype(auto) force_ok(auto&& mv) requires(std::is_convertible_v<decltype(mv), bool> && std::is_default_constructible_v<Error>)
+	{
+		struct err {
+			[[gnu::noinline, gnu::cold, noreturn]]
+			static constexpr void _throw() { throw Error{}; }
+		};
+		if( __builtin_expect(!bool(mv), false)) err::_throw();
+		return std::forward<decltype(mv)>(mv);
+	}
+
+	} // _impl (anon)
+	
+
+	template<typename From, typename To>
+	concept binary_convertible = std::is_convertible_v<From, To> and std::is_convertible_v<To, From>;
+
+	template<typename From, typename To>
+	concept polymorphic_castable = std::derived_from<std::decay_t<To>, std::decay_t<From>> 
+					or std::derived_from<std::decay_t<From>, std::decay_t<To>>
+					or std::is_same_v<std::decay_t<From>, std::decay_t<To>>
+					or requires(std::decay_t<From> && from) {
+		{ static_cast<std::decay_t<To> &&>(from) } -> std::convertible_to<To>;
+	};
+
+	template<typename To, typename From> requires(polymorphic_castable<From, To>)
+	constexpr std::unique_ptr<To> static_uniq_cast(std::unique_ptr<From>&& from) noexcept
+	{
+		return std::unique_ptr<To> { 
+			static_cast<To*>( std::move(from).release() )
+		};
+	}
+
+	template<typename To, typename From> requires(polymorphic_castable<From, To>)
+	constexpr std::unique_ptr<To> dynamic_uniq_cast(std::unique_ptr<From>&& from) noexcept
+	{
+		return std::unique_ptr<To> { 
+			dynamic_cast<To*>( std::move(from).release() )
+		};
+	}
+
+	template<typename To, typename From, bool Check = false> requires(polymorphic_castable<From, To>)
+	constexpr std::unique_ptr<To> uniq_cast(std::unique_ptr<From>&& from) noexcept
+	{
+		if constexpr(Check) return dynamic_uniq_cast(std::move(from));
+		else return static_uniq_cast(std::move(from));
+	}
+
+#if 0
+//TODO: Cannot be implemented with this method
+	constexpr bool is_boxed_value(auto const& value) noexcept {
+		return bool(dynamic_cast<ObjectBase const*>(std::addressof(value)));
+	}
+	template<typename T>
+	constexpr bool is_boxed_type() noexcept {
+		using type = std::remove_reference_t<T>;
+		constexpr type const* VALUE = nullptr;
+		return bool(dynamic_cast<ObjectBase const*>(VALUE));
+	}
+
+// We need either: Tagged pointers (XOR, bit-mangled, manual heap, or GOT (external allocation) kind), \
+	or (preferred): layout of Box<T> to be `{ aligned<T>(T, box_type_tag) } unique*` \
+		box_type_tag should be: One pointer width, starting at offset *T+1 (aligned to T within internal tuple struct), provides a way to access RTTI for `*T`, a pointer to static (non-allocated) type information or dynamic_cast used lambda would be ideal.
+#endif
+
 	template<typename T>
-	struct Box {
+	struct Box final {
 		typedef boxable_value_type<T>::type type;
 
+		template<std::derived_from<T> U, bool RuntimeCheck=false>
+		constexpr static Box<T> new_dynamic(U&& v) noexcept(!RuntimeCheck) {
+			if constexpr(!RuntimeCheck) {
+				auto boxed = std::make_unique<U>(std::move(v));
+				return Box<T>{std::unique_ptr<T>{static_cast<T*>(boxed.release())}};
+			} else
+			return Box<T>{std::make_unique<T>(dynamic_cast<T&&>(std::move(v)))};
+		}
+
+		template<std::derived_from<T> U, bool Check = false>
+		constexpr Box<U> upcast() && noexcept(!Check) 
+		{ return Box<U> { force_ok(uniq_cast<U, T, Check>(std::move(m_ptr))) }; }
+
+		template<typename U, bool Check = true> requires(std::derived_from<T, U>)
+		constexpr Box<U> downcast() && noexcept(!Check)
+		{ return Box<U> { force_ok(uniq_cast<U, T, Check>(std::move(m_ptr))) }; }
+
+		template<polymorphic_castable<T> U, bool Check = !std::derived_from<U, T> > // Default dynamic check set to false only if we can statically determine that T is derived from U and the conversion is therfore infallible
+		constexpr Box<U> polycast() && noexcept(!Check)
+		{ return Box<U> { force_ok(uniq_cast<U, T, Check>(std::move(m_ptr))) }; }
+
 		constexpr Box() noexcept(std::is_nothrow_default_constructible_v<T>) requires(std::is_default_constructible_v<T>)
 			: m_ptr{std::make_unique<T>()} {}
 
@@ -90,9 +179,35 @@ namespace exopt::types { namespace boxed {
 			_EO_ASSUME(m_ptr.get());
 		}
 
+#if 0
+// TODO: Identifying if a value `this` pointer is boxed
+		struct alignas(type) inner_layout {
+			constexpr inner_layout() noexcept = default;
+			constexpr inner_layout(const inner_layout&) noexcept = default;
+			constexpr ~inner_layout() noexcept = default;
+
+			type value;
+			box_type_tag identifier{box_tag_of<T>()};
+		};
+#endif
 		std::unique_ptr<T> m_ptr; // Unique<T> m_ptr;
 	};
 
+#define _EO_ADD_RV std::add_rvalue_reference_v
+
+	template<typename Base, typename T = Base>
+	constexpr inline bool is_boxable_v = binary_convertible<_EO_ADD_RV<T>, _EO_ADD_RV<Base> > and requires(T&& value) { 
+		typename Box<Base>;
+		typename Box<Base>::type;
+		{ std::make_unique<T>(std::move(value)) } -> std::same_as<std::unique_ptr<T>>;
+	};
+	template<typename T> concept is_boxable = is_boxable_v<T>;
+
+	template<typename T>
+	constexpr inline bool is_nothrow_boxable_v = is_boxable_v<T> && std::is_nothrow_constructible_v<Box<T>, T>;
+
+#undef _EO_ADD_RV
+
 	template<typename T, typename U> requires(requires(T&& o) { static_cast<U&&>(o); })
 	constexpr Box<U> static_box_cast(Box<T>&& b) noexcept { return Box<U>::from_raw_ptr(static_cast<U*>(b.release())); }
 
@@ -106,6 +221,44 @@ namespace exopt::types { namespace boxed {
 			throw;
 		}
 	} //TODO: Overload for `const&` that does the type check *before* the copy allocation.
+
+#if 0
+	template<typename T, typename R /*XXX: Maybe remove this, and put the requires after the definition, using `auto&& value` instead of `R&& value`*/> requires(std::derived_from<R, T>)
+	constexpr Box<T> box(R&& value, util::comptime<bool> auto Check = _EO_CONSTANT_VALUE(false)) noexcept(std::is_nothrow_invocable_v< Box<T>::new_dynamic<R, util::comptime_eval_v<bool, Check>>) //XXX: This seems illegal...
+	{ return Box<T>::template new_dynamic<R, Check>(std::move(value)); }
+
+	template<typename T>
+	constexpr Box<T> box(T&& value) noexcept(std::is_nothrow_constructible_v<Box<T>, T>)
+	{ return { std::move(value) }; }
+#endif
+	template<typename T>
+	constexpr Box<T> box(T&& value) noexcept(std::is_nothrow_constructible_v<Box<T>, decltype(value)>)
+	{
+		/*if constexpr(requires(decltype(value) v) { static_cast<T&&>(std::move(v)); }) {
+			return Box<T>::template new_dynamic<T>(std::move(value));
+		} else */return Box<T> { std::move(value) };
+	}
+
+	template<typename T>
+	constexpr Box<T> box(std::unique_ptr<T>&& value) noexcept { return Box<T> { std::move(value) }; }
+
+	template<typename Base, typename T> /*requires(polymorphic_castable<Base, T>)
+	constexpr Box<Base> polybox(T&& value) noexcept
+	{
+		return Box<T>{ std::move(value) }.polycast<Base>()
+	}*/ requires(std::derived_from<T, Base>)
+	constexpr Box<Base> polybox(T&& value) noexcept {
+		return Box<T>{ std::move(value) }.polycast<Base, false>(); // Convertion from derived to base infallible, no need for check.
+	}
+
+	template<typename Base, typename T> /*requires(polymorphic_castable<Base, T>)
+	constexpr Box<Base> polybox(T&& value) noexcept
+	{
+		return Box<T>{ std::move(value) }.polycast<Base>()
+	}*/ requires(std::derived_from<T, Base>)
+	constexpr Box<Base> polybox(std::unique_ptr<T>&& value) noexcept {
+		return Box<T>{ std::move(value) }.polycast<Base, false>(); // Convertion from derived to base infallible, no need for check.
+	}
 }
 using boxed::Box;
 }

include/error.hh

@@ -11,13 +11,24 @@
 #include "util.hh"
 
 
+#define _EO_DEFEXCEPT_BASIC_(NAME, BASE, ...) class NAME : public ::exopt:: BASE { \
+		constexpr static inline auto MESSSAGE = (__VA_ARGS__); \
+		public: \
+		_EO_CLASS_DEFINE(NAME, constexpr, noexcept, virtual, =default); \
+		constexpr virtual std::string_view message() const noexcept override { return { MESSAGE }; } \
+	}
+#define _EO_DEFEXCEPT_BASIC(NAME, MSG) _EO_DEFEXCEPT_BASIC_(NAME, Error, MSG)
+#define _EO_DEFEXCEPT_TRACE_BASIC(NAME, MSG) _EO_DEFEXCEPT_BASIC_(NAME, TracedError, MSG)
+
 namespace exopt {
+
 	// Report generated from an error. (virtual base, not abstract.)
 	class Report {
 	public:
 		virtual ~Report();
 	};
-	// This is propagated returned (base, abstract)
+
+	// This is base thrown (base, abstract)
 	class Error {
 	public:
 		constexpr Error(Error const&) = default;
@@ -25,6 +36,9 @@ namespace exopt {
 		constexpr Error& operator=(Error &&) = default;
 		constexpr Error& operator=(Error const&) = default;
 
+		virtual types::Box<TracedError> into_traced(std::stacktrace trace&&) &&noexcept;// = std::stacktrace::current()) && noexcept;
+		inline typed::Box<TracedError> into_traced(std::stacktrace trace = std::stacktrace::current()) && noexcept
+		{ return std::move(*this).into_traced(std::move(trace)); }
 
 		constexpr virtual std::source_location const& location() const noexcept { return m_location; }
 
@@ -32,8 +46,9 @@ namespace exopt {
 
 		constexpr virtual std::string_view message() const noexcept =0;
 
-		constexpr virtual types::Option<Error&> inner() noexcept { return { std::nullopt }; } 
-		constexpr virtual types::MaybeOwned<Report> into_report() noexcept { /* TODO */ } //TODO: Maybe just use `std::optional<std::reference_wrapper<Error>>`? Or Box<Report&>?
+		//constexpr virtual types::Option<Error&> inner() noexcept { return { std::nullopt }; }
+		constexpr virtual types::Option<Error const&> inner() const noexcept { return { std::nullopt }; }
+		constexpr virtual types::MaybeOwned<Report> into_report() & noexcept { /* TODO */ } //TODO: Maybe just use `std::optional<std::reference_wrapper<Error>>`? Or Box<Report&>?
 		constexpr virtual types::MaybeOwned<Report> into_report() && noexcept { /* TODO: auto{*this}.into_report() */ }
 
 		constexpr virtual ~Error() = default;
@@ -47,7 +62,7 @@ namespace exopt {
 	};
 
 	// This is propagated returned, along with a stack trace. (base, abstract)
-	class TracedError : Error {
+	class TracedError : public Error {
 	public:
 		TracedError(TracedError const &) = default;
 		TracedError(TracedError &&) = default;
@@ -62,13 +77,27 @@ namespace exopt {
 				std::source_location loc = std::source_location::current()
 				, std::stacktrace trace = std::stacktrace::current()) noexcept
 			: Error(std::move(loc)), m_trace(std::move(trace)) {}
+		/*inline TracedError(
+					std::stacktrace&& trace,
+					, std::source_location loc = std::source_location::current()) noexcept
+			: Error(std::move(loc)), m_trace(std::move(trace)) {}*/
+		inline TracedError(
+					std::stacktrace&& trace,
+					, std::source_location&& loc) noexcept
+			: Error(std::move(loc)), m_trace(std::move(trace)) {}
+
 	private:
+		inline types::Box<TracedError> into_traced(std::stacktrace trace&&) &&noexcept override final// = std::stacktrace::current()) && noexcept;
+		{ return typed::Box<TracedError> { std::move(*this) }; } //TODO: use `boxed::is_boxed_value()` to check if *this is boxed... Uhh, actually... XXX: No that doesn't work, since `Box<T>` doesn't make `T` visible to `boxed::ObjectBase`.... Eh...
+		inline typed::Box<TracedError> into_traced(std::stacktrace trace = std::stacktrace::current()) && noexcept override final
+		{ return typed::Box<TracedError> { std::move(*this) }; } 
 		std::stacktrace m_trace; //TODO: Maybe box this? idk how big it is...
 	};
-
+#if 0
 	// This is thrown. (virtual base, abstract)
 	class Panic : /*virtual?? I think it should be XXX*/ Error {
 		//TODO: How to make a `constexpr` deduced panic that has stack-trace at runtime only? Is it needed? Hnm...
 	};
 	//TODO: Fatal(string) : public virtual Panic
+#endif
 }

include/exopt.h

@@ -27,11 +27,43 @@ extern "C" {
 #	define _EO_ASSUME(X) ({ if(! (X)) __builtin_unreachable(); })
 #endif
 
+#define _EO_NOTHING
+
 #if _EO(cpp)
 #	ifndef _EO_ASSUME
 #		define _EO_ASSUME(X) [[gnu::assume(X)]]
 #	endif
 #	define _exopt__restrict __restrict__
+#define _EO_CTORS_BASIC_W(N, constexpr, noexcept, ...) \
+		constexpr N(N const&) noexcept __VA_ARGS__; \
+		constexpr N(N &&) noexcept __VA_ARGS__; \
+		constexpr N & operator=(N const&) noexcept __VA_ARGS__; \
+		constexpr N & operator=(N &&) noexcept __VA_ARGS__
+#define _EO_CTORS_BASIC(...) _EO_CTORS_BASIC_W(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)
+#define _EO_CTORS_BASIC_DEFAULT(...) _EO_CTORS_BASIC(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, = default)
+
+#define _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, noexcept, ...) \
+		constexpr N(N const&) noexcept = default; \
+		constexpr N(N &&) noexcept = default; \
+		constexpr N & operator=(N const&) noexcept = default; \
+		constexpr N & operator=(N &&) noexcept = default
+
+#define _EO_CTORS_DEFAULT_BASIC(N) _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, _EO_NOTHING, _EO_NOTHING)
+#define _EO_CTORS_DEFAULT_BASIC_RT(N) _EO_CTORS_DEFAULT_BASIC_W(N, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)
+#define _EO_CTORS_DEFAULT_BASIC_NE_W(N, C) _EO_CTORS_DEFAULT_BASIC_W(N, C, noexcept, _EO_NOTHING)
+#define _EO_CTORS_DEFAULT_BASIC_NE(N) _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, noexcept, _EO_NOTHING)
+#define _EO_CTORS_DEFAULT_BASIC_NE_RT(N) _EO_CTORS_DEFAULT_BASIC_W(N, _EO_NOTHING, noexcept, _EO_NOTHING)
+
+#define _EO_CLASS_DEFAULT_(N, ...) N
+#define _EO_CLASS_DEFAULT_2(_, N, ...) N
+#define _EO_CLASS_DEFAULT_3(_, __, N, ...) N
+#define _EO_CLASS_DEFAULT_4(_, __, ___, N, ...) N
+#define _EO_CLASS_DEFAULT_3REST(_, __, ___, ...) __VA_ARGS__
+#define _EO_CLASS_DEFAULT_4REST(_, __, ___, ____, ...) __VA_ARGS__
+// _EO_CLASS_DEFINE(NAME, [constexpr], [noexcept], [virtual], [=default])
+#define _EO_CLASS_DEFINE(...) _EO_CTORS_BASIC(__VA_ARGS__); \
+				_EO_CLASS_DEFAULT_4(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING) _EO_CLASS_DEFAULT_2(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING) ~ _EO_CLASS_DEFAULT_(__VA_ARGS__, _EO_NOTHING)() _EO_CLASS_DEFAULT_3(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)  _EO_CLASS_DEFAULT_4REST(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)
+
 #else
 #	ifndef _EO_ASSUME
 #		define _EO_ASSUME(X) __attribute__((assume(X)))

include/optional.h

@@ -220,6 +220,11 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 		template<typename T>
 		using mut_ref_t = typename mut_ref_or_void<T>::type;
 
+		template<typename T>
+		using remove_ref_keep_const_t = std::conditional_t,
+								<std::is_const_v<std::remove_reference_v<T> >
+								,const std::remove_cvref_t<T>
+								, std::remove_cvref_t<T> >;
 
 		template<typename T> requires(requires(T v) { { v == nullptr } -> std::convertible_to<bool>; })
 		[[gnu::always_inline]]
@@ -268,7 +273,27 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 
 	
 	template<AsOption T>
-	struct Option final {
+	class Option final {
+		using value_type_correct = _details::remove_ref_keep_const_t<T>;// std::remove_cvref_t<T>;
+		constexpr static inline bool is_const_v = std::is_const_v<value_type_correct>; 
+		template<typename U, typename V = const std::remove_const_t<U> >
+		using correct_const_t = std::conditional_t<is_const_v, V, U>;
+
+	public:
+		[[gnu::const]]
+		constexpr bool is_mutable() const noexcept { return !is_const_v; }
+
+		using value_type = std::remove_const_t<value_type_correct>;
+
+		using pointer_type = correct_const_t<value_type*, value_type const*>;
+		using const_pointer_type = value_type const*;
+
+		using reference_type = correct_const_t<value_type*, value_type const&>;
+		using const_reference_type = value_type const&;
+
+		using move_reference_type = std::add_rvalue_reference_t<value_type_correct>;
+		using const_move_reference_type = value_type const&&;
+
 		struct UnwrapError : public OptionUnwrapError
 		{
 			UnwrapError() noexcept =default;
@@ -287,7 +312,9 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 		}
 
 		constexpr Option(std::optional<T>&& opt) noexcept requires(!std::is_void_v<T>)
-			: inner_( bool(opt) ? std::move(*opt) : nullptr ) {}
+			: Option(nullptr) {
+			if(opt) inner_ = decltype(inner_)(std::move(*opt));
+		}
 
 		constexpr explicit Option(std::nullptr_t) noexcept : inner_(nullptr) {}
 		constexpr Option(none_t) noexcept : Option(nullptr) {}
@@ -300,9 +327,28 @@ namespace exopt::types { namespace optional [[gnu::visibility("internal")]] {
 			: inner_(std::move(move.inner_))
 		{}
 
-		constexpr explicit(std::convertible_to<std::add_rvalue_reference_t<T>, Option<T>>) Option(_details::rv_ref_t<T> value) noexcept(std::is_nothrow_invocable_v<convert_to_held_rv, std::add_rvalue_reference_t<T>>) requires(!std::is_void_v<T>)
+		constexpr explicit(std::convertible_to<std::add_rvalue_reference_t<T>, Option<T>>)
+				Option(_details::rv_ref_t<T> value) 
+				noexcept(std::is_nothrow_invocable_v<convert_to_held_rv, std::add_rvalue_reference_t<T>>) 
+				requires(!std::is_void_v<T>)
 			: inner_(convert_to_held_rv(std::forward<decltype(value)>(value)))
 		{}
+		constexpr explicit Option(pointer_type const&& ptr) noexcept(std::is_nothrow_move_constructible_v<decltype(*ptr)>) requires(!std::is_void_v<T>)
+			Option(nullptr) {
+			if(ptr) inner_ = decltype(inner_)(convert_to_held_rv(std::move(*ptr)));
+		}
+		constexpr explicit Option(const_pointer_type ptr) noexcept(std::is_nothrow_copy_constructible_v<decltype(*ptr)>) requires(!std::is_void_v<T>)
+			: Option(nullptr) {
+			if(ptr) inner_ = decltype(inner_)(convert_to_held_rv(auto(*ptr)));
+		}
+
+		template<typename P> requires(!std::is_void_v<T> && (std::is_same_v<std::remove_cvref_t<P>, pointer_type> 
+					or std::is_same_v<std::remove_cvref_t<P>, const_pointer_type>))
+		constexpr Option<T> from_pointer(P ptr) noexcept
+		{ if constexpr(std::is_const_v<decltype(*ptr)> or !std::is_rvalue_reference_v<P>)
+			return Option<T> { static_cast<const_pointer_type>(ptr) }; 	
+		  else  return Option<T> { std::move(static_cast<pointer_type>(ptr)) }; }
+			//: inner_(ptr ? convert_to_held_rv(*ptr) : nullptr) {}
 
 		//TODO: copy/move assign where appropriate
 		constexpr Option& operator=(const Option& copy) noexcept(std::is_void_v<T> || std::is_nothrow_copy_constructible_v<decltype(copy.inner_)::held_type>)

include/util.hh

@@ -12,6 +12,7 @@
 #define _EO_CONSTANT_VALUE(X) ([]() { \
 	struct { \
 		typedef decltype(X) comptime_constant_t; \
+		constexpr static inline auto VALUE = (X); \
 		consteval operator comptime_constant_t() const noexcept { return (X); } \
 	} inner; \
 	return inner; \
@@ -28,7 +29,7 @@ namespace exopt { namespace util [[gnu::visibility("internal")]] {
 
 	constexpr auto comptime_value(auto value) noexcept {
 		using U = decltype(value);
-		struct inner {
+		struct inner final {
 			typedef U comptime_constant_t;
 			consteval operator comptime_constant_t() const noexcept { return std::move(value); }
 			U value;
@@ -38,7 +39,31 @@ namespace exopt { namespace util [[gnu::visibility("internal")]] {
 		};
 		return inner{ std::move(value) };
 	}
+	
+	template<typename T, auto value> requires(comptime<decltype(value), T>)
+	consteval T comptime_eval() noexcept {
+		if constexpr(requires { 
+			{ decltype(value)::VALUE } -> std::convertible_to<decltype(value)::comptime_constant_t>;
+		}) {
+			return decltype(value)::VALUE;
+		} else  return value;
+	
+	}
+
+	template<typename T, auto value> requires(comptime<decltype(value), T>)
+	constexpr inline T comptime_eval_v = comptime_eval<T, value>(); 
+
+	template<typename T>
+	consteval T comptime_eval(comptime<T> auto value) noexcept {
+		return comptime_eval<T, value>();
+	}
+
+	
 
+	static_assert(comptime_eval(comptime_value(5.0)) == 5.0, "Bad comptime_eval() consteval");
+	static_assert(comptime_eval(_EO_CONSTANT_VALUE(3.f)) == 3.f, "Bad comptime_eval() macro");
+	static_assert(std::is_same_v<decltype(comptime_eval(comptime_value(4.f))), float>, "Bad comptime_eval() return type consteval");
+	static_assert(std::is_same_v<decltype(comptime_eval(_EO_CONSTANT_VALUE(4.0))), double>, "Bad comptime_eval() return type macro");
 	static_assert(comptime_value(std::string_view{"hello"}.size()) == 5, "Bad comptime_value()");
 	static_assert(_EO_CONSTANT_VALUE(std::string_view{"hello world"}) == std::string_view{"hello world"}, "Bad CONSTANT_VALUE()");
 

src/error.cpp

@@ -0,0 +1,30 @@
+#include <stdexcept>
+
+#include <error.hh>
+
+using namespace exopt::types;
+
+namespace exopt {
+	Box<TracedError> Error::into_traced(std::stacktrace&& trace) &&noexcept {
+		struct DynamicTracedError final : TracedError {
+			_EO_CTORS_BASIC_DEFAULT(DynamicTracedError, _EO_NOTHING, noexcept);
+			virtual ~DynamicTracedError() noexcept = default;
+
+			DynamicTracedError(Error&& self, std::stacktrace&& trace) noexcept
+				: TracedError(std::move(trace), std::move(self.m_location))
+				, m_error(std::move(self)) {}
+
+			std::string_view message() const noexcept override { return m_error->message(); }
+			Option<Error const&> inner() const noexcept override { return Option<Error const&>(*m_error); }//{ return Option<Error const&>::from_pointer(std::as_const(m_error.get())); }
+			MaybeOwned<Report> into_report() && noexcept override { return std::move(*m_error).into_report(); }
+			MaybeOwned<Report> into_report() & noexcept override { return m_error->into_report(); }
+
+			
+		private:
+			Box<Error> m_error;
+		};
+#define ERR		DynamicTracedError{std::move(*this), std::move(trace)}
+		return Box<TracedError>::template new_dynamic<DynamicTracedError, false>(ERR);
+#undef ERR
+	}
+}