This change fixes the circuitry that handles record representation
clauses so that a component clause for an inherited component in
a record extension is properly rejected (such a clause is illegal
per 13.5.1(9)).
The following compilation must be rejected with the indicated error:
$ gcc -c illegal_clause_for_inherited_comp.ads
illegal_clause_for_inherited_comp.ads:7:08: component clause not allowed for
inherited component "B"
package Illegal_Clause_For_Inherited_Comp is
type R1 is tagged record
B : Boolean;
end record;
type R1_Ext is new R1 with null record;
for R1_Ext use record
B at 2 range 63 .. 63;
end record;
end;
Tested on x86_64-pc-linux-gnu, committed on trunk
2013-01-03 Thomas Quinot <[email protected]>
* sem_ch13.adb (Analyze_Record_Representation_Clause): Reject
an illegal component clause for an inherited component in a
record extension.
Index: sem_ch13.adb
===================================================================
--- sem_ch13.adb (revision 194847)
+++ sem_ch13.adb (working copy)
@@ -4663,10 +4663,34 @@
Ocomp : Entity_Id;
Posit : Uint;
Rectype : Entity_Id;
+ Recdef : Node_Id;
+ function Is_Inherited (Comp : Entity_Id) return Boolean;
+ -- True if Comp is an inherited component in a record extension
+
+ ------------------
+ -- Is_Inherited --
+ ------------------
+
+ function Is_Inherited (Comp : Entity_Id) return Boolean is
+ Comp_Base : Entity_Id;
+ begin
+ if Ekind (Rectype) = E_Record_Subtype then
+ Comp_Base := Original_Record_Component (Comp);
+ else
+ Comp_Base := Comp;
+ end if;
+ return Comp_Base /= Original_Record_Component (Comp_Base);
+ end Is_Inherited;
+
+ Is_Record_Extension : Boolean;
+ -- True if Rectype is a record extension
+
CR_Pragma : Node_Id := Empty;
-- Points to N_Pragma node if Complete_Representation pragma present
+ -- Start of processing for Analyze_Record_Representation_Clause
+
begin
if Ignore_Rep_Clauses then
return;
@@ -4706,6 +4730,14 @@
return;
end if;
+ -- We know we have a first subtype, now possibly go the the anonymous
+ -- base type to determine whether Rectype is a record extension.
+
+ Recdef := Type_Definition (Declaration_Node (Base_Type (Rectype)));
+ Is_Record_Extension :=
+ Nkind (Recdef) = N_Derived_Type_Definition
+ and then Present (Record_Extension_Part (Recdef));
+
if Present (Mod_Clause (N)) then
declare
Loc : constant Source_Ptr := Sloc (N);
@@ -4881,6 +4913,11 @@
("cannot reference discriminant of unchecked union",
Component_Name (CC));
+ elsif Is_Record_Extension and then Is_Inherited (Comp) then
+ Error_Msg_NE
+ ("component clause not allowed for inherited "
+ & "component&", CC, Comp);
+
elsif Present (Component_Clause (Comp)) then
-- Diagnose duplicate rep clause, or check consistency
@@ -4908,10 +4945,11 @@
Error_Msg_N
("component clause inconsistent "
& "with representation of ancestor", CC);
+
elsif Warn_On_Redundant_Constructs then
Error_Msg_N
- ("?r?redundant component clause "
- & "for inherited component!", CC);
+ ("?r?redundant confirming component clause "
+ & "for component!", CC);
end if;
end;
end if;
@@ -7346,7 +7384,7 @@
begin
if Present (CC1) and then Present (CC2) then
- -- Exclude odd case where we have two tag fields in the same
+ -- Exclude odd case where we have two tag components in the same
-- record, both at location zero. This seems a bit strange, but
-- it seems to happen in some circumstances, perhaps on an error.
@@ -7387,7 +7425,7 @@
procedure Find_Component is
procedure Search_Component (R : Entity_Id);
- -- Search components of R for a match. If found, Comp is set.
+ -- Search components of R for a match. If found, Comp is set
----------------------
-- Search_Component --
@@ -7426,8 +7464,8 @@
Search_Component (Rectype);
- -- If not found, maybe component of base type that is absent from
- -- statically constrained first subtype.
+ -- If not found, maybe component of base type discriminant that is
+ -- absent from statically constrained first subtype.
if No (Comp) then
Search_Component (Base_Type (Rectype));
@@ -7555,7 +7593,7 @@
("bit number out of range of specified size",
Last_Bit (CC));
- -- Check for overlap with tag field
+ -- Check for overlap with tag component
else
if Is_Tagged_Type (Rectype)
