[Bug 18] New: int foo[0] accept -- what's its semantics?

[Chris Miller]

> void main() {
>     int foo[0];
> }
>
> dmd 0.148 accepts this gdc 0.17 and my 0.18 work in progress both segv  
> off in
> gcc land where it's assumed that variables passed into the middle end  
> all have
> space associated with them.  What are the right semantics for this  
> situation?

I'd like it to be allowed and completely disable bounds checking on that  
array, so that the old C trick can work: putting an array as the last  
field in a struct so that extra memory can be allocated after the struct  
to add more elements to the array at runtime. To further support this,  
'new' for structs could be overloaded to take a parameter specifying how  
many elements are to be allocated for that last array field, for example:

struct Foo
{
    char* bar; // GC should know about this.
    int[0] baz; // Actual number of elements specified in new().
}
    ...
Foo* f = new(3) Foo; // Allocates 3 ints for Foo.baz for this instance.