| Message ID | 20101019105507.GA8759@adacore.com |
|---|---|
| State | New |
| Headers | show |
Hi Arnaud, this patch seems to only contain formatting changes. The meat of it is commented out: + -- Also check that null exclusion matches (AI05-0086-1) + -- commented out because this causes many mail test failures ??? + + -- and then Can_Never_Be_Null (T1) = Can_Never_Be_Null (T2); So I'm not sure how it can cause the testcase to pass :) Ciao, Duncan.
> Hi Arnaud, this patch seems to only contain formatting changes. > The meat of it is commented out: > > + -- Also check that null exclusion matches (AI05-0086-1) > + -- commented out because this causes many mail test failures ??? > + > + -- and then Can_Never_Be_Null (T1) = Can_Never_Be_Null (T2); > > So I'm not sure how it can cause the testcase to pass :) Indeed, the code has been disabled at the last minute because of unexpected errors, sorry for the confusion. Arno
Index: sem_eval.adb =================================================================== --- sem_eval.adb (revision 165687) +++ sem_eval.adb (working copy) @@ -4548,6 +4548,8 @@ T2 : Entity_Id) return Boolean is begin + -- Scalar types + if Is_Scalar_Type (T1) then -- Definitely compatible if we match @@ -4606,11 +4608,20 @@ end; end if; + -- Access types + elsif Is_Access_Type (T1) then return not Is_Constrained (T2) - or else Subtypes_Statically_Match - (Designated_Type (T1), Designated_Type (T2)); + or else Subtypes_Statically_Match + (Designated_Type (T1), Designated_Type (T2)); + -- Also check that null exclusion matches (AI05-0086-1) + -- commented out because this causes many mail test failures ??? + + -- and then Can_Never_Be_Null (T1) = Can_Never_Be_Null (T2); + + -- All other cases + else return (Is_Composite_Type (T1) and then not Is_Constrained (T2)) or else Subtypes_Statically_Match (T1, T2);
This patch implements the requirement of AI05-0086-1 that access types are only to be considered statically matching if their null exclusion status matches. The following shows the new error message resulting from this check (compiled with -gnat05): 1. procedure StatCompat is 2. begin 3. declare 4. type Ref is access Integer; 5. type R1 (D1 : not null Ref) is null record; 6. type R2 (D2 : Ref) is new R1 (D1 => D2); | >>> subtype must be compatible with parent discriminant 7. begin 8. null; 9. end; 10. end; Tested on x86_64-pc-linux-gnu, committed on trunk 2010-10-19 Robert Dewar <dewar@adacore.com> * sem_eval.adb: Minor reformatting.