diff --git a/include/boost/charconv/from_chars.hpp b/include/boost/charconv/from_chars.hpp
index 4fe1f93..ae1d6cb 100644
--- a/include/boost/charconv/from_chars.hpp
+++ b/include/boost/charconv/from_chars.hpp
@@ -12,7 +12,6 @@
 #include <boost/config.hpp>
 #include <type_traits>
 #include <limits>
-#include <array>
 #include <cstdlib>
 #include <cerrno>
 #include <cstddef>
@@ -63,6 +62,8 @@ static constexpr unsigned char uchar_values[] =
       255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
       255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255};
 
+static_assert(sizeof(uchar_values) == 256, "uchar_values should represent all 256 values of unsigned char");
+
 // Convert characters for 0-9, A-Z, a-z to 0-35. Anything else is 255
 constexpr unsigned char digit_from_char(char val) noexcept
 {