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[Ada] Implementation of AI12-0131: legality of class-wide precondition
- From: Pierre-Marie de Rodat <derodat at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Ed Schonberg <schonberg at adacore dot com>
- Date: Wed, 23 May 2018 06:34:37 -0400
- Subject: [Ada] Implementation of AI12-0131: legality of class-wide precondition
This patch refines the legality check on a class-wide precondition on a type
extension when ancestor does not have a class-wide precondition. Previously the
compiler accepted such a precondition when the ancestor had a class-wide
postcondition.
Compiling pck.ads must yield:
pck.ads:7:04: illegal class-wide precondition on overriding operation
----
package Pck is
type Parent is tagged null record;
procedure Init (P : Parent) with Post'Class => True;
type Child is new Parent with null record;
overriding procedure Init (C : Child) with
Pre'Class => True;
end Pck;
Tested on x86_64-pc-linux-gnu, committed on trunk
2018-05-23 Ed Schonberg <schonberg@adacore.com>
gcc/ada/
* sem_prag.adb (Inherit_Class_Wide_Pre): Refine legality check on
class-wide precondition on a type extension when ancestor does not have
a class-wide precondition. Previously the compiler accepted such a
precondition when the ancestor had a class-wide postcondition.
--- gcc/ada/sem_prag.adb
+++ gcc/ada/sem_prag.adb
@@ -4444,7 +4444,9 @@ package body Sem_Prag is
if Present (Cont) then
Prag := Pre_Post_Conditions (Cont);
while Present (Prag) loop
- if Class_Present (Prag) then
+ if Pragma_Name (Prag) = Name_Precondition
+ and then Class_Present (Prag)
+ then
return True;
end if;