This patch improves the error message on an iterator specification whose name
is a function call that does not yield a type that implements an iterator
interface.
Compiling try_containers.adb must yield:
try_containers.adb:17:18: expect object that implements iterator interface
--
with Ada.Text_Io; use Ada.Text_Io;
with Ada.Containers.Vectors;
procedure Try_Containers
is
package Integer_Vectors is new Ada.Containers.Vectors (Natural, Integer);
use Integer_Vectors;
A : Vector := To_Vector (1, 10);
begin
Loop_1 :
for Element of A loop
Put_Line ("A (i) => " & Integer'Image (Element));
-- can't do Element := 2;
end loop Loop_1;
Loop_2 :
for Cursor in First (A) loop -- oops! should be:
-- for Cursor in Iterate (A) loop
Put_Line ("A (I) => " & Integer'Image (Element (Cursor)));
Replace_Element (A, Cursor, 2);
Reference (A, Cursor) := 2;
end loop Loop_2;
end Try_Containers;
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-10-17 Ed Schonberg <schonb...@adacore.com>
* sem_ch5.adb (Analyze_Iterator_Specification): If the domain
of iteration is given by an expression that is not an array type,
verify that its type implements an iterator iterface.
Index: sem_ch5.adb
===================================================================
--- sem_ch5.adb (revision 216367)
+++ sem_ch5.adb (working copy)
@@ -1838,6 +1838,17 @@
else
Typ := Etype (Iter_Name);
+
+ -- Verify that the expression produces an iterator.
+
+ if not Of_Present (N) and then not Is_Iterator (Typ)
+ and then not Is_Array_Type (Typ)
+ and then No (Find_Aspect (Typ, Aspect_Iterable))
+ then
+ Error_Msg_N
+ ("expect object that implements iterator interface",
+ Iter_Name);
+ end if;
end if;
-- Protect against malformed iterator
