diff --git a/include/papilio/detail/prefix.hpp b/include/papilio/detail/prefix.hpp
index 429b62d..2730986 100644
--- a/include/papilio/detail/prefix.hpp
+++ b/include/papilio/detail/prefix.hpp
@@ -12,4 +12,5 @@
 #    pragma clang diagnostic ignored "-Wc++20-compat"
 
 #    pragma clang diagnostic ignored "-Wpadded"
+#    pragma clang diagnostic ignored "-Wcovered-switch-default"
 #endif
diff --git a/include/papilio/format/fundamental.inl b/include/papilio/format/fundamental.inl
index 7b60cd7..9216cc4 100644
--- a/include/papilio/format/fundamental.inl
+++ b/include/papilio/format/fundamental.inl
@@ -5,11 +5,6 @@
 #include <cmath>
 #include "helper.hpp"
 
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic push
-#    pragma clang diagnostic ignored "-Wcovered-switch-default"
-#endif
-
 namespace papilio
 {
 namespace detail
@@ -44,7 +39,7 @@ namespace detail
             using context_t = format_context_traits<FormatContext>;
 
             PAPILIO_ASSERT(m_data.fill != U'\0');
-            context_t::append(ctx, utf::codepoint(m_data.fill), count);
+            context_t::append(ctx, m_data.fill, count);
         }
     };
 
@@ -469,6 +464,7 @@ namespace detail
     class string_formatter : public std_formatter_base
     {
     public:
+        using string_ref_type = utf::basic_string_ref<CharT>;
         using string_container_type = utf::basic_string_container<CharT>;
 
         void set_data(const std_formatter_data& data)
@@ -483,15 +479,13 @@ namespace detail
         }
 
         template <typename FormatContext>
-        auto format(string_container_type str, FormatContext& ctx)
+        auto format(string_ref_type str, FormatContext& ctx)
         {
-            PAPILIO_ASSERT(!str.has_ownership());
-
             using context_t = format_context_traits<FormatContext>;
 
-            std::size_t used = 0;
-
+            std::size_t used = 0; // Used width
 
+            // The "precision" for a string means the max width can be used.
             if(m_data.precision != 0)
             {
                 for(auto it = str.begin(); it != str.end(); ++it)
@@ -857,7 +851,3 @@ requires std::is_enum_v<T>
 class formatter<T, CharT> : public detail::enum_formatter<T, CharT>
 {};
 } // namespace papilio
-
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic pop
-#endif
diff --git a/include/papilio/script/interpreter.hpp b/include/papilio/script/interpreter.hpp
index 5f11cc7..89c808f 100644
--- a/include/papilio/script/interpreter.hpp
+++ b/include/papilio/script/interpreter.hpp
@@ -672,11 +672,6 @@ class basic_interpreter_base : public script_base
 
     static bool execute_op(op_id op, const variable_type& lhs, const variable_type& rhs)
     {
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic push
-#    pragma clang diagnostic ignored "-Wcovered-switch-default"
-#endif
-
         switch(op)
         {
         case op_id::equal:
@@ -695,10 +690,6 @@ class basic_interpreter_base : public script_base
         default:
             PAPILIO_UNREACHABLE();
         }
-
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic pop
-#endif
     }
 
     // Parses integer value
diff --git a/include/papilio/utf/string.hpp b/include/papilio/utf/string.hpp
index e299f1b..2d9d0fc 100644
--- a/include/papilio/utf/string.hpp
+++ b/include/papilio/utf/string.hpp
@@ -485,6 +485,12 @@ class basic_string_ref<CharT> : public detail::str_impl<CharT, basic_string_ref<
         return *this;
     }
 
+    constexpr basic_string_ref& assign(const_iterator start, const_iterator stop) noexcept
+    {
+        this->set_view(start, stop);
+        return *this;
+    }
+
     using my_base::find;
 
     [[nodiscard]]
@@ -661,6 +667,7 @@ class basic_string_ref<CharT> : public detail::str_impl<CharT, basic_string_ref<
 
     constexpr void set_view(const_iterator start, const_iterator stop) noexcept
     {
+        PAPILIO_ASSERT(start <= stop);
         set_view(string_view_type(start.base(), stop.base()));
     }
 
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index f1558bb..a3cae4c 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -10,11 +10,6 @@ static const char* to_cstr(script_error_code ec) noexcept
 #define PAPILIO_SCRIPT_ERR(code, msg) \
     case code: return msg
 
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic push
-#    pragma clang diagnostic ignored "-Wcovered-switch-default"
-#endif
-
     switch(ec)
     {
         PAPILIO_SCRIPT_ERR(no_error, "no error");
@@ -30,10 +25,6 @@ static const char* to_cstr(script_error_code ec) noexcept
     [[unlikely]] default:
         PAPILIO_SCRIPT_ERR(unknown_error, "unknown error");
     }
-
-#ifdef PAPILIO_COMPILER_CLANG
-#    pragma clang diagnostic pop
-#endif
 }
 
 std::string to_string(script_error_code ec)