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gsl::not_null: C.89: Make a hash noexcept #1236

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Merged
carsonRadtke merged 1 commit into from
Mar 23, 2026
+17 −1
Merged

gsl::not_null: C.89: Make a hash noexcept #1236

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2 changes: 1 addition & 1 deletion include/gsl/pointers
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Original file line number Diff line number Diff line change
Expand Up @@ -235,7 +235,7 @@ not_null<T> operator+(std::ptrdiff_t, const not_null<T>&) = delete;
template <class T, class U = typename T::element_type, bool = std::is_default_constructible<std::hash<U>>::value>
struct not_null_hash
{
std::size_t operator()(const T& value) const { return std::hash<U>{}(value.get()); }
std::size_t operator()(const T& value) const noexcept { return std::hash<U>{}(value.get()); }
};

template <class T, class U>
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16 changes: 16 additions & 0 deletions tests/pointers_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

#include <gsl/pointers>

#include <functional>
#include <memory>
#include <type_traits>
#include <utility>
Expand Down Expand Up @@ -94,4 +95,19 @@ TEST(pointers_test, member_types)
"check member type: element_type");
}

TEST(pointers_test, hash_noexcept_compiles)
{
{
using Key = gsl::not_null<std::shared_ptr<int>>;
static_assert(noexcept(std::hash<Key>{}(std::declval<Key>())),
"gsl::not_null hash operator must be noexcept");
}

{
using Key = gsl::strict_not_null<std::shared_ptr<int>>;
static_assert(noexcept(std::hash<Key>{}(std::declval<Key>())),
"gsl::strict_not_null hash operator must be noexcept");
}
}

} // namespace
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