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Merged
mborland merged 3 commits into from
Oct 7, 2025
Merged

Improve message from disallowed 3 arg constructor #1089

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a5581d2
Add test set
mborland Oct 7, 2025
d1c97b6
Add more helpful message to constructor saying it cant be used
mborland Oct 7, 2025
c04034a
Replace false with impossible condition for older compiler support
mborland Oct 7, 2025
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7 changes: 7 additions & 0 deletions include/boost/decimal/decimal128_t.hpp
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Expand Up @@ -257,6 +257,13 @@ BOOST_DECIMAL_EXPORT class decimal128_t final
#endif
constexpr decimal128_t(T1 coeff, T2 exp, bool sign = false) noexcept;

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
#endif
constexpr decimal128_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
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7 changes: 7 additions & 0 deletions include/boost/decimal/decimal32_t.hpp
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Expand Up @@ -282,6 +282,13 @@ BOOST_DECIMAL_EXPORT class decimal32_t final // NOLINT(cppcoreguidelines-special
#endif
constexpr decimal32_t(T1 coeff, T2 exp, bool sign = false) noexcept;

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
#endif
constexpr decimal32_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
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7 changes: 7 additions & 0 deletions include/boost/decimal/decimal64_t.hpp
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Expand Up @@ -319,6 +319,13 @@ BOOST_DECIMAL_EXPORT class decimal64_t final
#endif
constexpr decimal64_t(T1 coeff, T2 exp, bool sign = false) noexcept;

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
#endif
constexpr decimal64_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
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7 changes: 7 additions & 0 deletions include/boost/decimal/decimal_fast128_t.hpp
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Expand Up @@ -157,6 +157,13 @@ BOOST_DECIMAL_EXPORT class decimal_fast128_t final
#endif
constexpr decimal_fast128_t(T1 coeff, T2 exp, bool sign = false) noexcept;

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
#endif
constexpr decimal_fast128_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
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3 changes: 3 additions & 0 deletions include/boost/decimal/decimal_fast32_t.hpp
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Expand Up @@ -150,6 +150,9 @@ BOOST_DECIMAL_EXPORT class decimal_fast32_t final
template <typename T1, typename T2, std::enable_if_t<detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
constexpr decimal_fast32_t(T1 coeff, T2 exp, bool sign = false) noexcept;

template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
constexpr decimal_fast32_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
constexpr decimal_fast32_t(T1 coeff, T2 exp) noexcept;

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7 changes: 7 additions & 0 deletions include/boost/decimal/decimal_fast64_t.hpp
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Expand Up @@ -168,6 +168,13 @@ BOOST_DECIMAL_EXPORT class decimal_fast64_t final
#endif
constexpr decimal_fast64_t(T1 coeff, T2 exp, bool sign = false) noexcept;

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
template <typename T1, typename T2, std::enable_if_t<!detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool> = true>
#endif
constexpr decimal_fast64_t(T1, T2, bool) noexcept { static_assert(detail::is_unsigned_v<T1>, "Construction from signed integer, exponent, and sign is ambiguous, so it is disallowed. You must use an Unsigned Integer for the coefficient to construct from {coefficient, exponent, sign}"); }

#ifdef BOOST_DECIMAL_HAS_CONCEPTS
template <BOOST_DECIMAL_SIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
#else
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1 change: 1 addition & 0 deletions test/Jamfile
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Expand Up @@ -66,6 +66,7 @@ run github_issue_1035.cpp ;
run github_issue_1054.cpp ;
run github_issue_1055.cpp ;
run github_issue_1057.cpp ;
compile-fail github_issue_1087.cpp ;
run link_1.cpp link_2.cpp link_3.cpp ;
run quick.cpp ;
run random_decimal32_comp.cpp ;
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30 changes: 30 additions & 0 deletions test/github_issue_1087.cpp
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@@ -0,0 +1,30 @@
// Copyright 2025 Matt Borland
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
//
// See: https://github.com/cppalliance/decimal/issues/1087

#include <boost/decimal.hpp>
#include <boost/core/lightweight_test.hpp>

using namespace boost::decimal;

template <typename T>
void test()
{
T val {-3, 3, true};
BOOST_TEST_EQ(val, T(UINT32_C(3), 3, true));
}

int main()
{
test<decimal32_t>();
test<decimal64_t>();
test<decimal128_t>();

test<decimal_fast32_t>();
test<decimal_fast64_t>();
test<decimal_fast128_t>();

return 0;
}