3 files changed, 10 insertions, 8 deletions
diff --git a/include/unicode/type_traits.h b/include/unicode/type_traits.h
index c3507e7..63c7d69 100644
--- a/include/unicode/type_traits.h
+++ b/include/unicode/type_traits.h
@@ -50,7 +50,7 @@ namespace unicode {
  template<typename T>
  struct is_utf_8
  {
-  static const bool value{std::is_trivial_v<T> && sizeof(T) == 1};
+  static const bool value{std::is_same_v<T, UTF_8> || (std::is_trivial_v<T> && sizeof(T) == 1)};
  };
  
  template<typename T>
@@ -59,7 +59,7 @@ namespace unicode {
  template<typename T>
  struct is_utf_16
  {
-  static const bool value{std::is_trivial_v<T> && sizeof(T) == 2};
+  static const bool value{std::is_same_v<T, UTF_16> || (std::is_trivial_v<T> && sizeof(T) == 2)};
  };
  
  template<typename T>
@@ -68,7 +68,7 @@ namespace unicode {
  template<typename T>
  struct is_utf_32
  {
-  static const bool value{std::is_trivial_v<T> && sizeof(T) == 4};
+  static const bool value{std::is_same_v<T, UTF_32> || (std::is_trivial_v<T> && sizeof(T) == 4)};
  };
  
  template<typename T>
diff --git a/include/unicode/utf.h b/include/unicode/utf.h
index 81e8f2b..046d9c6 100644
--- a/include/unicode/utf.h
+++ b/include/unicode/utf.h
@@ -415,11 +415,6 @@ namespace unicode {
   }
  };
 
- // Encoding for convert()
- typedef UTF<utf_iterator<utf8_t>, utf_back_insert_iterator<utf8_t>> UTF_8;
- typedef UTF<utf_iterator<char16_t>, utf_back_insert_iterator<char16_t>> UTF_16;
- typedef UTF<utf_iterator<char32_t>, utf_back_insert_iterator<char32_t>> UTF_32;
-
  // Helper to get correct Encoding from char type, e.g. Encoding<typename decltype(s)::value_type>::type or Encoding_t<typename decltype(s)::value_type>
  template<typename T>
  struct Encoding
diff --git a/include/unicode/utf_fwd.h b/include/unicode/utf_fwd.h
index f3f6c52..c42dea1 100644
--- a/include/unicode/utf_fwd.h
+++ b/include/unicode/utf_fwd.h
@@ -2,6 +2,8 @@
 
 // Forward declarations
 
+#include "types.h"
+
 #include <string>
 
 namespace unicode::detail {
@@ -19,5 +21,10 @@ namespace unicode {
  template<typename InputIt, typename OutputIt>
  struct UTF;
 
+ // Encoding for convert()
+ typedef UTF<utf_iterator<utf8_t>, utf_back_insert_iterator<utf8_t>> UTF_8;
+ typedef UTF<utf_iterator<char16_t>, utf_back_insert_iterator<char16_t>> UTF_16;
+ typedef UTF<utf_iterator<char32_t>, utf_back_insert_iterator<char32_t>> UTF_32;
+
 } // namespace unicode