[COMMITTED] ada: Allow attributes like First and Last to be read in Exceptional_Cases
Commit Message
From: Piotr Trojanek <trojanek@adacore.com>
Attributes that do not read data from the object can be safely used in
consequences of Exceptional_Cases regardless of the parameter passing
mode.
gcc/ada/
* sem_res.adb (Resolve_Entity_Name): Relax rules for Exceptional_Cases.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_res.adb | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
@@ -8117,11 +8117,19 @@ package body Sem_Res is
-- Parameters of modes OUT or IN OUT of the subprogram shall not
-- occur in the consequences of an exceptional contract unless
-- they are either passed by reference or occur in the prefix
- -- of a reference to the 'Old attribute.
+ -- of a reference to the 'Old attribute. For convenience, we also
+ -- allow them as prefixes of attributes that do not actually read
+ -- data from the object.
if Ekind (E) in E_Out_Parameter | E_In_Out_Parameter
and then Within_Exceptional_Cases_Consequence (N)
and then not In_Attribute_Old (N)
+ and then not (Nkind (Parent (N)) = N_Attribute_Reference
+ and then
+ Attribute_Name (Parent (N)) in Name_Constrained
+ | Name_First
+ | Name_Last
+ | Name_Length)
and then not Is_By_Reference_Type (Etype (E))
and then not Is_Aliased (E)
then