headerstackvar.size is it really a compile time constant or not?

[apinski-cavium]

Take:

header h{}
struct s { h[2] f; }
void func(s v)
{
  bit<(v.f.size)> v1;
}

The current specifications has:

- `hs.size`: produces a 32-bit unsigned integer that returns the
  size of the header stack (a compile-time constant).

....

The following are compile-time known values:
...
- The `size` field of a value with type header stack.

Is the value a constant or just a known value at compile time? Yes there can be (and should be) slight difference between the two?

This is related to https://github.com/p4lang/p4-spec/issues/932 too. I don't expect an answer right away since this can get complex really.

[mihaibudiu]

Can we fix this while leaving #932 open?

[jnfoster]

In the interest of tidying up the set of active issues on the P4 specification repository, I'm marking this as "stalled" and closing it. Of course, we can always re-open it in the future if there is interest in resurrecting it.