From ad323bbf943820aab97a06d318aadd003f8b978e Mon Sep 17 00:00:00 2001 From: Bob Duff Date: Mon, 8 Jun 2020 13:54:27 -0400 Subject: [PATCH] [Ada] Ada2020: AI12-0289 Implicitly null excluding anon access gcc/ada/ * sem_ch6.adb (Null_Exclusions_Match): New function to check that the null exclusions match, including in the case addressed by this AI. (Check_Conformance): Remove calls to Comes_From_Source when calling Null_Exclusions_Match. These are not needed, as indicated by an ancient "???" comment. --- gcc/ada/sem_ch6.adb | 76 ++++++++++++++++++++++++++++++++------------- 1 file changed, 55 insertions(+), 21 deletions(-) diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb index 1988684b674..cd108d8b733 100644 --- a/gcc/ada/sem_ch6.adb +++ b/gcc/ada/sem_ch6.adb @@ -5605,10 +5605,11 @@ package body Sem_Ch6 is -- in the message, and also provides the location for posting the -- message in the absence of a specified Err_Loc location. - function Conventions_Match - (Id1 : Entity_Id; - Id2 : Entity_Id) return Boolean; - -- Determine whether the conventions of arbitrary entities Id1 and Id2 + function Conventions_Match (Id1, Id2 : Entity_Id) return Boolean; + -- True if the conventions of entities Id1 and Id2 match. + + function Null_Exclusions_Match (F1, F2 : Entity_Id) return Boolean; + -- True if the null exclusions of two formals of anonymous access type -- match. ----------------------- @@ -5699,6 +5700,50 @@ package body Sem_Ch6 is end if; end Conventions_Match; + --------------------------- + -- Null_Exclusions_Match -- + --------------------------- + + function Null_Exclusions_Match (F1, F2 : Entity_Id) return Boolean is + begin + if not Is_Anonymous_Access_Type (Etype (F1)) + or else not Is_Anonymous_Access_Type (Etype (F2)) + then + return True; + end if; + + -- AI12-0289-1: Case of controlling access parameter; False if the + -- partial view is untagged, the full view is tagged, and no explicit + -- "not null". Note that at this point, we're processing the package + -- body, so private/full types have been swapped. The Sloc test below + -- is to detect the (legal) case where F1 comes after the full type + -- declaration. This part is disabled pre-2005, because "not null" is + -- not allowed on those language versions. + + if Ada_Version >= Ada_2005 + and then Is_Controlling_Formal (F1) + and then not Null_Exclusion_Present (Parent (F1)) + and then not Null_Exclusion_Present (Parent (F2)) + then + declare + D : constant Entity_Id := Directly_Designated_Type (Etype (F1)); + Partial_View_Of_Desig : constant Entity_Id := + Incomplete_Or_Partial_View (D); + begin + return No (Partial_View_Of_Desig) + or else Is_Tagged_Type (Partial_View_Of_Desig) + or else Sloc (D) < Sloc (F1); + end; + + -- Not a controlling parameter, or one or both views have an explicit + -- "not null". + + else + return Null_Exclusion_Present (Parent (F1)) = + Null_Exclusion_Present (Parent (F2)); + end if; + end Null_Exclusions_Match; + -- Local Variables Old_Type : constant Entity_Id := Etype (Old_Id); @@ -5868,25 +5913,14 @@ package body Sem_Ch6 is -- Null exclusion must match - if Null_Exclusion_Present (Parent (Old_Formal)) - /= - Null_Exclusion_Present (Parent (New_Formal)) - then - -- Only give error if both come from source. This should be - -- investigated some time, since it should not be needed ??? - - if Comes_From_Source (Old_Formal) - and then - Comes_From_Source (New_Formal) - then - Conformance_Error - ("\null exclusion for& does not match", New_Formal); + if not Null_Exclusions_Match (Old_Formal, New_Formal) then + Conformance_Error + ("\null exclusion for& does not match", New_Formal); - -- Mark error posted on the new formal to avoid duplicated - -- complaint about types not matching. + -- Mark error posted on the new formal to avoid duplicated + -- complaint about types not matching. - Set_Error_Posted (New_Formal); - end if; + Set_Error_Posted (New_Formal); end if; end if; -- 2.30.2