The pragma Check_Poliy and the names Precondition / Postcondition were
introduced in GNAT before the Ada2012 standardization, and they have a
different behavior from that of the standardized pragma Assertion_Policy.
Rather than making the behavior of both more conformant we choose to preserve
the original semantics but indicate that these are deprecated constructs.
Compiling p.adb must yield:
p.ads:2:25: warning: Check_Policy is a non-standard pragma
p.ads:2:25: warning:
use Assertion_Policy and aspect names Pre/Post for Ada2012 conformance
---
package body P is
Last_X : Integer;
procedure Latch (X : Integer) is
begin
Last_X := X;
end;
end;
--
package P is
pragma Check_Policy (Precondition, On);
procedure Latch (X : Integer)
with Pre => (X > 0);
end;
Tested on x86_64-pc-linux-gnu, committed on trunk
2017-01-20 Ed Schonberg <schonb...@adacore.com>
* sem_prag.adb (Rewrite_Assertion_Kind): If the name is
Precondition or Postcondition, and the context is pragma
Check_Policy, indicate that this Pre-Ada2012 usage is deprecated
and suggest the standard names Assertion_Policy /Pre /Post
instead.
Index: sem_prag.adb
===================================================================
--- sem_prag.adb (revision 244699)
+++ sem_prag.adb (working copy)
@@ -282,11 +282,16 @@
-- function, this routine finds the corresponding state and sets the entity
-- of N to that of the state.
- procedure Rewrite_Assertion_Kind (N : Node_Id);
+ procedure Rewrite_Assertion_Kind
+ (N : Node_Id;
+ From_Policy : Boolean := False);
-- If N is Pre'Class, Post'Class, Invariant'Class, or Type_Invariant'Class,
-- then it is rewritten as an identifier with the corresponding special
-- name _Pre, _Post, _Invariant, or _Type_Invariant. Used by pragmas Check
- -- and Check_Policy.
+ -- and Check_Policy. If the names are Precondition or Postcondition, this
+ -- combination is deprecated in favor of Assertion_Policy and Ada2012
+ -- Aspect names. The parameter From_Policy indicates that the pragma
+ -- is the old non-standard Check_Policy and not a rewritten pragma.
procedure Set_Elab_Unit_Name (N : Node_Id; With_Item : Node_Id);
-- Place semantic information on the argument of an Elaborate/Elaborate_All
@@ -12807,7 +12812,8 @@
Check_Arg_Count (2);
Check_Optional_Identifier (Arg1, Name_Name);
Kind := Get_Pragma_Arg (Arg1);
- Rewrite_Assertion_Kind (Kind);
+ Rewrite_Assertion_Kind (Kind,
+ From_Policy => Comes_From_Source (N));
Check_Arg_Is_Identifier (Arg1);
-- Check forbidden check kind
@@ -29448,10 +29454,14 @@
-- Rewrite_Assertion_Kind --
----------------------------
- procedure Rewrite_Assertion_Kind (N : Node_Id) is
+ procedure Rewrite_Assertion_Kind
+ (N : Node_Id;
+ From_Policy : Boolean := False)
+ is
Nam : Name_Id;
begin
+ Nam := No_Name;
if Nkind (N) = N_Attribute_Reference
and then Attribute_Name (N) = Name_Class
and then Nkind (Prefix (N)) = N_Identifier
@@ -29473,6 +29483,25 @@
return;
end case;
+ -- Recommend standard use of aspect names Pre/Post
+
+ elsif Nkind (N) = N_Identifier
+ and then From_Policy
+ and then Serious_Errors_Detected = 0
+ and then not ASIS_Mode
+ then
+ if Chars (N) = Name_Precondition
+ or else Chars (N) = Name_Postcondition
+ then
+ Error_Msg_N (" Check_Policy is a non-standard pragma??", N);
+ Error_Msg_N
+ (" \use Assertion_Policy and aspect names Pre/Post"
+ & " for Ada2012 conformance?", N);
+ end if;
+ return;
+ end if;
+
+ if Nam /= No_Name then
Rewrite (N, Make_Identifier (Sloc (N), Chars => Nam));
end if;
end Rewrite_Assertion_Kind;
