first attempt

Author: moar55

libcxx/include/complex

@@ -1100,18 +1100,38 @@ inline _LIBCPP_HIDE_FROM_ABI complex<_Tp> pow(const complex<_Tp>& __x, const com
   return std::exp(__y * std::log(__x));
 }
 
+#  if _LIBCPP_STD_VER >= 26
+template <class _Tp, class _Up, __enable_if_t<is_floating_point<_Tp>::value && is_floating_point<_Up>::value, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI complex<typename __promote<_Tp, conditional_t<is_integral_v<_Up>, double, _Up>>::type>
+pow(const complex<_Tp>& __x, const complex<_Up>& __y) {
+  using _Yp = conditional_t<is_integral_v<_Up>, double, _Up>;
+  typedef complex<typename __promote<_Tp, _Yp>::type> result_type;
+  return std::pow(result_type(__x), result_type(__y));
+}
+#  else
 template <class _Tp, class _Up, __enable_if_t<is_floating_point<_Tp>::value && is_floating_point<_Up>::value, int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI complex<typename __promote<_Tp, _Up>::type>
 pow(const complex<_Tp>& __x, const complex<_Up>& __y) {
   typedef complex<typename __promote<_Tp, _Up>::type> result_type;
   return std::pow(result_type(__x), result_type(__y));
 }
+#  endif
 
+#  if _LIBCPP_STD_VER >= 26
+template <class _Tp, class _Up, __enable_if_t<is_floating_point<_Tp>::value && is_arithmetic<_Up>::value, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI complex<typename __promote<_Tp, conditional_t<is_integral_v<_Up>, double, _Up>>::type>
+pow(const complex<_Tp>& __x, const _Up& __y) {
+  using _Yp = conditional_t<is_integral_v<_Up>, double, _Up>;
+  typedef complex<typename __promote<_Tp, _Yp>::type> result_type;
+  return std::pow(result_type(__x), result_type(__y));
+}
+#  else
 template <class _Tp, class _Up, __enable_if_t<is_floating_point<_Tp>::value && is_arithmetic<_Up>::value, int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI complex<typename __promote<_Tp, _Up>::type> pow(const complex<_Tp>& __x, const _Up& __y) {
   typedef complex<typename __promote<_Tp, _Up>::type> result_type;
   return std::pow(result_type(__x), result_type(__y));
 }
+#  endif
 
 template <class _Tp, class _Up, __enable_if_t<is_arithmetic<_Tp>::value && is_floating_point<_Up>::value, int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI complex<typename __promote<_Tp, _Up>::type> pow(const _Tp& __x, const complex<_Up>& __y) {

libcxx/test/libcxx/numerics/complex.number/cmplx.over.pow.pass.cpp

@@ -82,5 +82,8 @@ int main(int, char**) {
   assert(pow(ctag, std::complex<long double>(1.0l)) == 4);
   assert(pow(std::complex<long double>(1.0l), ctag) == 5);
 
+  // Make sure LWG4191: P1467 is respected.
+  static_assert(std::is_same_v<decltype(std::pow(std::complex<float>(), int())), std::complex<double>>, "");
+
   return 0;
 }

libcxx/test/std/numerics/complex.number/cmplx.over/pow.pass.cpp

@@ -101,6 +101,9 @@ int main(int, char**)
 
     test<long double, float>();
     test<long double, double>();
+    
+    // Make sure LWG4191: P1467 is respected.
+    static_assert(std::is_same_v<decltype(std::pow(std::complex<float>(), int())), std::complex<double>>, "");
 
   return 0;
 }