Also, in things like rust you can just do result.unwrap() if you want. In general, language constructs don't really save you from bad programmers.
But it crashes at runtime, so such a bug can exist for years with nobody noticing.
The existence of such bugs is what motivated the musl developers to return "*" instead of NULL.
In practice, that's less of a risk than:
char* x = function_that_might_return_null_and_error();
dangerous_function();
if (x == NULL) {...}
char* x = returns_null_or_a_slice_pointer(data_structure);
char* y = other_function_that_returns_null_or_a_slice_pointer(data_structure);
if (x == y) { puts("you're fucked now!"); }
x : Result<string, err> = function...
dangerous_function();
switch(x) {
Ok() ...
Error() ...
}
To be clear, I strongly prefer Result<> because of the readability, but any dumb thing you can write with NULL + errno can be written with Result (and vice versa).