@@ -1020,7 +1020,7 @@ TOML_ANON_NAMESPACE_START
 
 	TOML_ATTR(nonnull)
 	TOML_INTERNAL_LINKAGE
-	void concatenate(char*& write_pos, char* const buf_end, std::string_view text) noexcept
+	void concatenate(char*& write_pos, const char* const buf_end, std::string_view text) noexcept
 	{
 		if TOML_UNLIKELY(write_pos >= buf_end)
 			return;
@@ -1038,7 +1038,7 @@ TOML_ANON_NAMESPACE_START
 
 	TOML_ATTR(nonnull)
 	TOML_INTERNAL_LINKAGE
-	void concatenate(char*& write_pos, char* const buf_end, uint64_t magnitude) noexcept
+	void concatenate(char*& write_pos, const char* const buf_end, uint64_t magnitude) noexcept
 	{
 		char text[max_decimal_digits];
 		char* const text_end		 = text + sizeof(text);
@@ -1048,7 +1048,7 @@ TOML_ANON_NAMESPACE_START
 
 	TOML_ATTR(nonnull)
 	TOML_INTERNAL_LINKAGE
-	void concatenate(char*& write_pos, char* const buf_end, const utf8_codepoint& cp) noexcept
+	void concatenate(char*& write_pos, const char* const buf_end, const utf8_codepoint& cp) noexcept
 	{
 		if (cp.value <= U'\x1F')
 			concatenate(write_pos, buf_end, impl::control_char_escapes[cp.value]);
@@ -1075,7 +1075,7 @@ TOML_ANON_NAMESPACE_START
 
 	// anything else would convert to one of the three
 	template <typename T>
-	void concatenate(char*&, char*, const T&) = delete;
+	void concatenate(char*&, const char*, const T&) = delete;
 
 	struct error_arg
 	{
@@ -2716,10 +2716,9 @@ TOML_IMPL_NAMESPACE_START
 
 			const std::string_view sign_text =
 				traits::is_signed && is_match(*cp, U'+', U'-') ? (*cp == U'-' ? "-"sv : "+"sv) : ""sv;
-			bool negative = {};
+			const bool negative = traits::is_signed && *cp == U'-';
 			if constexpr (traits::is_signed)
 			{
-				negative = *cp == U'-';
 				if (is_match(*cp, U'+', U'-'))
 					advance_and_return_if_error_or_unexpected_eof({});
 			}