Revert "Workaround for Hipcc error (reference to host function in host device function) (#1754)"

This reverts commit 257cf87.

Author: franzpoeschel

include/openPMD/snapshots/RandomAccessIterator.hpp

@@ -72,15 +72,14 @@ class RandomAccessIterator
 
     ~RandomAccessIterator() override;
 
-    RandomAccessIterator(RandomAccessIterator const &other) = default;
+    RandomAccessIterator(RandomAccessIterator const &other);
     RandomAccessIterator(RandomAccessIterator &&other) noexcept(
-        noexcept(iterator_t(std::declval<iterator_t &&>()))) = default;
+        noexcept(iterator_t(std::declval<iterator_t &&>())));
 
+    RandomAccessIterator &operator=(RandomAccessIterator const &other);
     RandomAccessIterator &
-    operator=(RandomAccessIterator const &other) = default;
-    RandomAccessIterator &operator=(RandomAccessIterator &&other) noexcept(
-        noexcept(std::declval<iterator_t>().operator=(
-            std::declval<iterator_t &&>()))) = default;
+    operator=(RandomAccessIterator &&other) noexcept(noexcept(
+        std::declval<iterator_t>().operator=(std::declval<iterator_t &&>())));
 
     auto operator*() -> value_type &;
     auto operator*() const -> value_type const &;

src/snapshots/RandomAccessIterator.cpp

@@ -9,6 +9,24 @@ inline RandomAccessIterator<iterator_t>::RandomAccessIterator(iterator_t it)
 template <typename iterator_t>
 RandomAccessIterator<iterator_t>::~RandomAccessIterator() = default;
 
+template <typename iterator_t>
+RandomAccessIterator<iterator_t>::RandomAccessIterator(
+    RandomAccessIterator const &other) = default;
+template <typename iterator_t>
+RandomAccessIterator<iterator_t>::RandomAccessIterator(
+    RandomAccessIterator
+        &&other) noexcept(noexcept(iterator_t(std::declval<iterator_t &&>()))) =
+    default;
+template <typename iterator_t>
+RandomAccessIterator<iterator_t> &RandomAccessIterator<iterator_t>::operator=(
+    RandomAccessIterator const &other) = default;
+template <typename iterator_t>
+RandomAccessIterator<iterator_t> &RandomAccessIterator<iterator_t>::operator=(
+    RandomAccessIterator
+        &&other) noexcept(noexcept(std::declval<iterator_t>().
+                                   operator=(std::declval<iterator_t &&>()))) =
+    default;
+
 template <typename iterator_t>
 auto RandomAccessIterator<iterator_t>::operator*() -> value_type &
 {