why the type of `nil` is not `id` but `void *`

Question

In this code

id (^block)(void) = ^(void) {
    return nil;
};

I have this error

Incompatible block pointer types ini

Answer 1

You're using an inferred return type for your block literal, but you don't have to.

The correct way to remove that error is to provide a return type for the block literal:

id (^block)(void) = ^id{
    return nil;
};