[committed] libstdc++: Add static_assert to std::integer_sequence [PR112473]
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Commit Message
Tested x86_64-linux. Pushed to trunk.
-- >8 --
C++20 allows class types as non-type template parameters, but
std::integer_sequence explicitly disallows them. Enforce that.
libstdc++-v3/ChangeLog:
PR libstdc++/112473
* include/bits/utility.h (integer_sequence): Add static_assert.
* testsuite/20_util/integer_sequence/112473.cc: New test.
---
libstdc++-v3/include/bits/utility.h | 3 +++
libstdc++-v3/testsuite/20_util/integer_sequence/112473.cc | 8 ++++++++
2 files changed, 11 insertions(+)
create mode 100644 libstdc++-v3/testsuite/20_util/integer_sequence/112473.cc
@@ -166,6 +166,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp, _Tp... _Idx>
struct integer_sequence
{
+#if __cplusplus >= 202002L
+ static_assert(is_integral_v<_Tp>);
+#endif
typedef _Tp value_type;
static constexpr size_t size() noexcept { return sizeof...(_Idx); }
};
new file mode 100644
@@ -0,0 +1,8 @@
+// { dg-do compile { target c++20 } }
+
+// PR libstdc++/112473 - integer_sequence accepts non-integer types
+
+#include <utility>
+
+std::integer_sequence<std::pair<int, int>, std::pair<int, int>{0, 0}> ic;
+// { dg-error "static assertion failed" "" { target *-*-* } 0 }