Type inference in loops with immediate constants

[Guillaume Foliard <guifo@wanadoo.fr>]

Hi,

I'm currently chasing down a Constraint_Error exception and while I was
reading one loop statement I wondered about the type inference in such a
place. Here is the snippet :

---

Length : Positive; -- reminder : subtype Integer range 1 .. Integer'Last

for Index in 0 .. Length - 1 loop

---

Then what type Index should be ?

Positive ?

Obviously not, because of the 0, which is not a Positive, as a starting
value.

Integer ?

Is the compiler using the fact that a positive is derived from an universal
integer and thus decides to give the base type to the loop variable ?

-- 
Guillaume