An expression function does not freeze the corresponding expression. The
function and the expression are frozen by a call, or by the end of the
enclosing declarative part. If the expression includes attribute references
to outer types, these must be frozen at that point. This patch ensures that
freeze nodes for such types are generated properly.
Executing the following::
gnatmake -q bad_main.adb
bad_main
must yield:
bad main OK
---
with Text_IO; use Text_IO;
with Bad_Gen;
procedure Bad_Main is
package Test is new Bad_Gen ("Test");
begin
Put_Line
("bad main " & (if Test.Names.Max_Length > 2 then "OK" else "Fails"));
end Bad_Main;
---
with Ada.Strings.Bounded;
generic
Name: String := "";
package Bad_Gen is
type Desc is tagged null record;
-- D : Desc;
function Size return Natural is ( if Desc'External_Tag'Length > 2 then
Desc'External_Tag'Length
else
Name'Length
);
package Names is new Ada.Strings.Bounded.Generic_Bounded_Length (Size);
Test: Names.Bounded_String := Names.To_Bounded_String (Desc'External_Tag);
end Bad_Gen;
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-10-23 Ed Schonberg <schonb...@adacore.com>
* sem_ch12.adb (Analyze_Associations): If an actual for a formal
object is a call to a parameterless expression function, add
the function to the list of actuals to freeze.
* freeze.adb (Check_Expression_Function): Create freeze nodes of
outer types that may be references in the body of the expression.
Index: sem_ch12.adb
===================================================================
--- sem_ch12.adb (revision 216574)
+++ sem_ch12.adb (working copy)
@@ -1664,6 +1664,18 @@
Assoc);
end if;
+ -- If the object is a call to an expression function, this
+ -- is a freezing point for it.
+
+ if Is_Entity_Name (Match)
+ and then Present (Entity (Match))
+ and then Nkind
+ (Original_Node (Unit_Declaration_Node (Entity (Match))))
+ = N_Expression_Function
+ then
+ Append_Elmt (Entity (Match), Actuals_To_Freeze);
+ end if;
+
when N_Formal_Type_Declaration =>
Match :=
Matching_Actual (
Index: freeze.adb
===================================================================
--- freeze.adb (revision 216574)
+++ freeze.adb (working copy)
@@ -112,6 +112,11 @@
-- to deferred constants without completion. We report this at the freeze
-- point of the function, to provide a better error message.
+ -- In most cases the expression itself is frozen by the time the function
+ -- itself is frozen, because the formals will be frozen by then. However,
+ -- Attribute references to outer types are freeze points for those types;
+ -- this routine generates the required freeze nodes for them.
+
procedure Check_Strict_Alignment (E : Entity_Id);
-- E is a base type. If E is tagged or has a component that is aliased
-- or tagged or contains something this is aliased or tagged, set
@@ -1272,6 +1277,14 @@
then
Error_Msg_NE
("premature use of& in call or instance", N, Entity (Nod));
+
+ elsif Nkind (Nod) = N_Attribute_Reference then
+ Analyze (Prefix (Nod));
+ if Is_Entity_Name (Prefix (Nod))
+ and then Is_Type (Entity (Prefix (Nod)))
+ then
+ Freeze_Before (N, Entity (Prefix (Nod)));
+ end if;
end if;
return OK;
@@ -5983,7 +5996,7 @@
-- and the expressions include allocators, the designed type is frozen
-- as well.
- function In_Exp_Body (N : Node_Id) return Boolean;
+ function In_Expanded_Body (N : Node_Id) return Boolean;
-- Given an N_Handled_Sequence_Of_Statements node N, determines whether
-- it is the handled statement sequence of an expander-generated
-- subprogram (init proc, stream subprogram, or renaming as body).
@@ -6023,11 +6036,11 @@
return Empty;
end Find_Aggregate_Component_Desig_Type;
- -----------------
- -- In_Exp_Body --
- -----------------
+ ----------------------
+ -- In_Expanded_Body --
+ ----------------------
- function In_Exp_Body (N : Node_Id) return Boolean is
+ function In_Expanded_Body (N : Node_Id) return Boolean is
P : Node_Id;
Id : Entity_Id;
@@ -6044,7 +6057,8 @@
else
Id := Defining_Unit_Name (Specification (P));
- -- Following complex conditional could use comments ???
+ -- The following are expander-created bodies, or bodies that
+ -- are not freeze points.
if Nkind (Id) = N_Defining_Identifier
and then (Is_Init_Proc (Id)
@@ -6061,7 +6075,7 @@
return False;
end if;
end if;
- end In_Exp_Body;
+ end In_Expanded_Body;
-- Start of processing for Freeze_Expression
@@ -6314,7 +6328,7 @@
-- outside this body, not inside it, and we skip past the
-- subprogram body that we are inside.
- if In_Exp_Body (Parent_P) then
+ if In_Expanded_Body (Parent_P) then
declare
Subp : constant Node_Id := Parent (Parent_P);
Spec : Entity_Id;
@@ -6358,7 +6372,7 @@
-- of F (2) would place Hidden's freeze node (1) in the
-- wrong place. Avoid explicit freezing and let the usual
-- scenarios do the job - for example, reaching the end
- -- of the private declarations.
+ -- of the private declarations, or a call to F.
if Nkind (Original_Node (Subp)) =
N_Expression_Function
