Iterator of the form "of" generate renamings for the container elements. If
the container that is the domain of iteration is a subcomponent of a larger
object, and an assignment is performed on the element, the larger object must
be marked as modified as well.
The following must compile quietly:
gcc -c -gnatwa -gnat12 loop_for_of_false_warning.adb
---
procedure Loop_For_Of_False_Warning is
type Discri_Type is (Case_A, Case_B);
type Discri2_Type is (Case2_A, Case2_B);
type R_Type (D : Discri_Type := Case_A) is record
N : Integer;
case D is
when Case_A =>
I : Integer;
when Case_B =>
F : Float;
end case;
end record;
type T_Type is array (Positive range 1 .. 10) of R_Type;
type R2_Type (D : Discri2_Type := Case2_A) is record
case D is
when Case2_A =>
T_A : T_Type;
when Case2_B =>
T_B : T_Type;
end case;
end record;
procedure Process (V : in out R2_Type)
is
begin
if V.D = Case2_B then
for Element of V.T_B
loop
Element.N := 10;
end loop;
end Process;
X : R2_Type;
begin
Process (X);
end Loop_For_Of_False_Warning;
Tested on x86_64-pc-linux-gnu, committed on trunk
2011-09-02 Ed Schonberg <schonb...@adacore.com>
* sem_util.adb (Note_Possible_Modification): If the entity
being modified is the renaming generated for an Ada2012 iterator
element, the enclosing container or array is modified as well.
Index: sem_util.adb
===================================================================
--- sem_util.adb (revision 178381)
+++ sem_util.adb (working copy)
@@ -10711,6 +10711,18 @@
then
Exp := Renamed_Object (Ent);
goto Continue;
+
+ -- The expression may be the renaming of a subcomponent of an
+ -- array or container. The assignment to the subcomponent is
+ -- a modification of the container.
+
+ elsif Comes_From_Source (Original_Node (Exp))
+ and then
+ Nkind_In (Original_Node (Exp),
+ N_Selected_Component, N_Indexed_Component)
+ then
+ Exp := Prefix (Original_Node (Exp));
+ goto Continue;
end if;
-- Generate a reference only if the assignment comes from
