[Ada] Attributes on predicated subtypes

[Arnaud Charlet <charlet at adacore dot com>]

To prevent anomalies with enumeration types with holes and scalar types with
complex predicates, the attributes First, Last, and Range cannot be applied to
subtypes with predicates. This rule applies only to scalar types.

The following must compile quietly in Ada2012 mode:

package Pred is
   type A is array (Integer range <>) of Integer
     with Predicate => (for all J in A'Range =>
                          (for all K in A'Range =>
                             (if J /= K then A (J) /= A (K))));
end Pred;

Tested on x86_64-pc-linux-gnu, committed on trunk

2011-08-04  Ed Schonberg  <schonberg@adacore.com>

	* sem_attr.adb (Bad_Attribute_For_Predicate): flag illegal use of
	attribute only if prefix type is scalar.

Attachment: difs
Description: Text document