4 files changed, 14 insertions, 8 deletions
diff --git a/src/u.hh b/src/u.hh
index 583b67b..101dec8 100644
--- a/src/u.hh
+++ b/src/u.hh
@@ -3,13 +3,13 @@
 
 namespace u {
 
-enum class ReadError {
+enum class ReadError : uint8_t {
   Invalid,    // Invalid sequence
   End,        // At end (it == end)
   Incomplete, // Too few bytes
 };
 
-enum class ReadErrorReplace {
+enum class ReadErrorReplace : uint8_t {
   End,        // At end (it == end)
   Incomplete, // Too few bytes
 };
diff --git a/src/u16.hh b/src/u16.hh
index c23a366..781e6a4 100644
--- a/src/u16.hh
+++ b/src/u16.hh
@@ -1,12 +1,13 @@
 #ifndef U16_HH
 #define U16_HH
 
+#include "u.hh" // IWYU pragma: export
+
 #include <cstdint> // IWYU pragma: export
 #include <expected>
 #include <iterator>
 #include <type_traits>
-
-#include "u.hh" // IWYU pragma: export
+#include <utility>
 
 namespace u16 {
 
@@ -49,6 +50,7 @@ std::expected<uint32_t, u::ReadErrorReplace> read_replace(T& start,
     case u::ReadError::Invalid:
       return 0xfffd;
   }
+  std::unreachable();
 }
 
 template<std::forward_iterator T>
diff --git a/src/u8.hh b/src/u8.hh
index 048af4f..3c1d19e 100644
--- a/src/u8.hh
+++ b/src/u8.hh
@@ -1,12 +1,13 @@
 #ifndef U8_HH
 #define U8_HH
 
+#include "u.hh" // IWYU pragma: export
+
 #include <cstdint> // IWYU pragma: export
 #include <expected>
 #include <iterator>
 #include <type_traits>
-
-#include "u.hh" // IWYU pragma: export
+#include <utility>
 
 namespace u8 {
 
@@ -116,6 +117,7 @@ std::expected<uint32_t, u::ReadErrorReplace> read_replace(T& start,
     case u::ReadError::Invalid:
       return 0xfffd;
   }
+  std::unreachable();
 }
 
 template<std::forward_iterator T>
diff --git a/src/umod8.hh b/src/umod8.hh
index 14406c4..117591f 100644
--- a/src/umod8.hh
+++ b/src/umod8.hh
@@ -1,12 +1,13 @@
 #ifndef UMOD8_HH
 #define UMOD8_HH
 
+#include "u.hh" // IWYU pragma: export
+
 #include <cstdint> // IWYU pragma: export
 #include <expected>
 #include <iterator>
 #include <type_traits>
-
-#include "u.hh" // IWYU pragma: export
+#include <utility>
 
 namespace umod8 {
 
@@ -124,6 +125,7 @@ std::expected<uint32_t, u::ReadErrorReplace> read_replace(T& start,
     case u::ReadError::Invalid:
       return 0xfffd;
   }
+  std::unreachable();
 }
 
 template<std::forward_iterator T>