references in structs and temporary lifetime extension

temporary_lifetime_extension.cpp

#include <iostream>

struct Foo {
  const int &x;
};

struct ConvertedFoo {
  const int &x;

  // Foo is implicitly convertible to ConvertedFoo
  ConvertedFoo(const Foo &foo) : x(foo.x) {}
};

int main() {
  // works
  const Foo &foo42 = Foo{42};
  std::cout << foo42.x;

  // ASan error
  // const ConvertedFoo &foo43 = Foo{43};
  // std::cout << foo43.x;

  // ASan error in Clang but not GCC
  // auto foo44 = Foo{44};
  // std::cout << foo44.x;
}

https://godbolt.org/z/eb9WEPzMP