[Bug libstdc++/85517] std::variant exception safety problems

[metaprogrammingtheworld at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85517

Matt Calabrese <metaprogrammingtheworld at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |metaprogrammingtheworld@gma
                   |                            |il.com

--- Comment #2 from Matt Calabrese <metaprogrammingtheworld at gmail dot com> ---
Example copy-assign non-compliance:

//////////

#include <variant>

struct bar
{
  bar() noexcept = default; 
  bar(bar&&) { /*never throws, but not noexcept*/ }
  bar(bar const&)  // A copy constructor that throws.
  {
    throw 0;
  }

  bar& operator=(bar&&) noexcept = default;
  bar& operator=(bar const&) noexcept = default;
};

int main()
{
  std::variant<int, bar> v1, v2 = bar();

  try
  {
    v1 = v2;
  }
  catch( int )
  {
    return 0;
  }

  return 1;
}