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      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - is_trivial not always equal to is_trivially_default_constructible && is_trivially_copyable"
   href="https://bugs.llvm.org/show_bug.cgi?id=51054">51054</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>is_trivial not always equal to is_trivially_default_constructible && is_trivially_copyable
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>C++
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>oliverzlee@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>std::is_trivial_v<T> can be false when both
std::is_trivially_default_constructible_v<T> and
std::is_trivially_copyable_v<T> are true.

-----
#include <array>
#include <type_traits>

template <class T>
struct S 
 {
  std::array<T, 3> data;

  S() = default;

  template <class... Args, class = typename std::enable_if<sizeof...(Args) ==
3>::type>
  constexpr S(Args... args) : data{args...} {}
};

static_assert(std::is_trivially_default_constructible<S<int>>::value, "");
static_assert(std::is_trivially_copyable<S<int>>::value, "");
static_assert(std::is_trivial<S<int>>::value, "");
----

Compiler explorer link: <a href="https://godbolt.org/z/Wczr1vPhb">https://godbolt.org/z/Wczr1vPhb</a>

This builds successfully with GCC and Clang 10.x and earlier with C++11/14/17.</pre>
        </div>
      </p>


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