+type_t *revert_automatic_type_conversion(const expression_t *expression);
+declaration_t *expr_is_variable(const expression_t *expression);
+
+/* some builtin types */
+extern type_t *type_wchar_t;
+extern type_t *type_size_t;
+extern type_t *type_ptrdiff_t;
+extern type_t *type_wchar_ptr_t;
+