+void lex_error_expecting (struct lexer *, ...) SENTINEL(0);
+#define lex_error_expecting(...) \
+ lex_error_expecting(__VA_ARGS__, NULL_SENTINEL)
+void lex_error_expecting_valist (struct lexer *, va_list);
+void lex_error_expecting_array (struct lexer *, const char **, size_t n);