+2012-06-12 Thomas Quinot <quinot@adacore.com>
+
+ * sem_prag.adb (Analyze_Pragma, case Unchecked_Union): Do
+ not crash on illegal unchecked union that is a null record.
+
+2012-06-12 Thomas Quinot <quinot@adacore.com>
+
+ * exp_ch4.adb (Has_Inferable_Discriminants): Reorganize code to
+ treat implicit dereferences with a constrained unchecked union
+ nominal subtype as having inferable discriminants.
+
2012-06-12 Robert Dewar <dewar@adacore.com>
* sem_ch6.adb: Minor reformatting.
--------------------------------
function Prefix_Is_Formal_Parameter (N : Node_Id) return Boolean is
- Sel_Comp : Node_Id := N;
+ Sel_Comp : Node_Id;
begin
-- Move to the left-most prefix by climbing up the tree
+ Sel_Comp := N;
while Present (Parent (Sel_Comp))
and then Nkind (Parent (Sel_Comp)) = N_Selected_Component
loop
-- Start of processing for Has_Inferable_Discriminants
begin
- -- For identifiers and indexed components, it is sufficient to have a
- -- constrained Unchecked_Union nominal subtype.
-
- if Nkind_In (N, N_Identifier, N_Indexed_Component) then
- return Is_Unchecked_Union (Base_Type (Etype (N)))
- and then
- Is_Constrained (Etype (N));
-
-- For selected components, the subtype of the selector must be a
-- constrained Unchecked_Union. If the component is subject to a
-- per-object constraint, then the enclosing object must have inferable
-- discriminants.
- elsif Nkind (N) = N_Selected_Component then
+ if Nkind (N) = N_Selected_Component then
if Has_Per_Object_Constraint (Entity (Selector_Name (N))) then
-- A small hack. If we have a per-object constrained selected
if Prefix_Is_Formal_Parameter (N) then
return True;
- end if;
-- Otherwise, check the enclosing object and the selector
- return Has_Inferable_Discriminants (Prefix (N))
- and then
- Has_Inferable_Discriminants (Selector_Name (N));
- end if;
+ else
+ return Has_Inferable_Discriminants (Prefix (N))
+ and then Has_Inferable_Discriminants (Selector_Name (N));
+ end if;
-- The call to Has_Inferable_Discriminants will determine whether
-- the selector has a constrained Unchecked_Union nominal type.
- return Has_Inferable_Discriminants (Selector_Name (N));
+ else
+ return Has_Inferable_Discriminants (Selector_Name (N));
+ end if;
-- A qualified expression has inferable discriminants if its subtype
-- mark is a constrained Unchecked_Union subtype.
elsif Nkind (N) = N_Qualified_Expression then
return Is_Unchecked_Union (Etype (Subtype_Mark (N)))
and then Is_Constrained (Etype (Subtype_Mark (N)));
- end if;
- return False;
+ -- For all other names, it is sufficient to have a constrained
+ -- Unchecked_Union nominal subtype.
+
+ else
+ return Is_Unchecked_Union (Base_Type (Etype (N)))
+ and then Is_Constrained (Etype (N));
+ end if;
end Has_Inferable_Discriminants;
-------------------------------
Tdef := Type_Definition (Declaration_Node (Typ));
Clist := Component_List (Tdef);
+ -- Check presence of component list and variant part
+
+ if No (Clist) or else No (Variant_Part (Clist)) then
+ Error_Msg_N
+ ("Unchecked_Union must have variant part", Tdef);
+ return;
+ end if;
+
+ -- Check components
+
Comp := First (Component_Items (Clist));
while Present (Comp) loop
Check_Component (Comp, Typ);
Next (Comp);
end loop;
- if No (Clist) or else No (Variant_Part (Clist)) then
- Error_Msg_N
- ("Unchecked_Union must have variant part",
- Tdef);
- return;
- end if;
+ -- Check variant part
Vpart := Variant_Part (Clist);