- /* Confirm that VAL can surely encode the current region. */
- val = call5 (Vselect_safe_coding_system_function,
- start, end, val, Qnil, filename);
+ {
+ /* Confirm that VAL can surely encode the current region. */
+ val = call5 (Vselect_safe_coding_system_function,
+ start, end, val, Qnil, filename);
+ /* As the function specified by select-safe-coding-system-function
+ is out of our control, make sure we are not fed by bogus
+ values. */
+ if (!NILP (val))
+ CHECK_CODING_SYSTEM (val);
+ }