[Ada] Inheritance of predicates in derived scalar types.

[Arnaud Charlet <charlet at adacore dot com>]

This patch fixes an omission in the inheritance of predicate aspects in type
derivations. The parent type may be a subtype declaration or a type declaration
with a dynamic predicate aspect, and the aspect applies to a first subtype, not
to its anonymous parent type.

Eecuting:

   gnatmake -q -gnata test_it
   test_it

must yield:

   2 in Even is TRUE
   3 in Even is FALSE
   2 in New_Even is TRUE
   3 in New_Even is FALSE
   2 in Newer_Even is TRUE
   3 in Newer_Even is FALSE
   OK

---
with Text_IO; use Text_IO;
procedure Test_It is
    type Even is new Integer with
      Dynamic_Predicate => Even mod 2 = 0;

    subtype Other_Even is Integer with
      Dynamic_Predicate => Other_Even mod 2 = 0;

    type New_Even is new Even;
    type Newer_Even is new Other_Even;
    B : Boolean;

    subtype Small is Integer range -5 .. 5;
    type New_Small is new Small;

begin
    B := 2 in Even;
    Put_Line ("2 in Even is " & B'Img);

    B := 3 in Even;
    Put_Line ("3 in Even is " & B'Img);

    B := 2 in New_Even;
    Put_Line ("2 in New_Even is " & B'Img);

    B := 3 in New_Even;
    Put_Line ("3 in New_Even is " & B'Img);

    B := 2 in Newer_Even;
    Put_Line ("2 in Newer_Even is " & B'Img);

    B := 3 in Newer_Even;
    Put_Line ("3 in Newer_Even is " & B'Img);

    declare
       X : New_Even;
    begin
       X := 13;
    exception
       when Others => Put_Line ("OK");
    end;
end;

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

2017-01-12  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch3.adb (Build_Derived_Type): For a scalar derived type,
	inherit predicates if any from the first_subtype of the parent,
	not from the anonymous parent type.
	* sem_eval.adb (Is_Static_Subtype): A type that inherits a dynamic
	predicate is not a static subtype.

Attachment: difs
Description: Text document