[Ada] Spurious error with formal incomplete types
Arnaud Charlet
charlet@adacore.com
Wed Sep 6 09:34:00 GMT 2017
This patch fixes a spurious error on the use of of a generic unit with formal
incomplete types, as a formal package in another generic unit, when the
actuals for the incomplete types are themselves formal incomplete types.
The treatment of incomplete subtypes that are created for such formals is now
more consistent with the handling of other subtypes, given their increased
use in Ada2012.
The following must compile quietly:
---
gcc -c promote_2_streams.ads
----
generic
type Data_Stream_Type;
type Data_Type;
with function Has_Data
(Stream : not null access Data_Stream_Type) return Boolean;
with function Consume
(Stream : not null access Data_Stream_Type) return Data_Type;
package Data_Streams is end;
---
with Data_Streams;
generic
type Data1_Type is private;
type Data2_Type is private;
with package DS1 is new Data_Streams (Data_Type => Data1_Type, others => <>);
with package DS2 is new Data_Streams (Data_Type => Data2_Type, others => <>);
package Promote_2_Streams is
type Which_Type is range 1 .. 2;
type Data_Type (Which : Which_Type := 1) is record
case Which is
when 1 => Data1 : Data1_Type;
when 2 => Data2 : Data2_Type;
end case;
end record;
function Consume1 (Stream : not null access DS1.Data_Stream_Type)
return Data_Type is ((Which => 1, Data1 => DS1.Consume (Stream)));
function Consume2 (Stream : not null access DS2.Data_Stream_Type)
return Data_Type is ((Which => 2, Data2 => DS2.Consume (Stream)));
package PS1 is new Data_Streams
(DS1.Data_Stream_Type, Data_Type, DS1.Has_Data, Consume1);
package PS2 is new Data_Streams
(DS2.Data_Stream_Type, Data_Type, DS2.Has_Data, Consume2);
end Promote_2_Streams;
Tested on x86_64-pc-linux-gnu, committed on trunk
2017-09-06 Ed Schonberg <schonberg@adacore.com>
* einfo.adb (Designated_Type): Use Is_Incomplete_Type to handle
properly incomplete subtypes that may be created by explicit or
implicit declarations.
(Is_Base_Type): Take E_Incomplete_Subtype into account.
(Subtype_Kind): Ditto.
* sem_ch3.adb (Build_Discriminated_Subtype): Set properly the
Ekind of a subtype of a discriminated incomplete type.
(Fixup_Bad_Constraint): Use Subtype_Kind in all cases, including
incomplete types, to preserve error reporting.
(Process_Incomplete_Dependents): Do not create a subtype
declaration for an incomplete subtype that is created internally.
* sem_ch7.adb (Analyze_Package_Specification): Handle properly
incomplete subtypes that do not require a completion, either
because they are limited views, of they are generic actuals.
-------------- next part --------------
Index: sem_ch3.adb
===================================================================
--- sem_ch3.adb (revision 251753)
+++ sem_ch3.adb (working copy)
@@ -10094,7 +10094,11 @@
-- elaboration, because only the access type is needed in the
-- initialization procedure.
- Set_Ekind (Def_Id, Ekind (T));
+ if Ekind (T) = E_Incomplete_Type then
+ Set_Ekind (Def_Id, E_Incomplete_Subtype);
+ else
+ Set_Ekind (Def_Id, Ekind (T));
+ end if;
if For_Access and then Within_Init_Proc then
null;
@@ -13629,15 +13633,9 @@
procedure Fixup_Bad_Constraint is
begin
- -- Set a reasonable Ekind for the entity. For an incomplete type,
- -- we can't do much, but for other types, we can set the proper
- -- corresponding subtype kind.
+ -- Set a reasonable Ekind for the entity, including incomplete types.
- if Ekind (T) = E_Incomplete_Type then
- Set_Ekind (Def_Id, Ekind (T));
- else
- Set_Ekind (Def_Id, Subtype_Kind (Ekind (T)));
- end if;
+ Set_Ekind (Def_Id, Subtype_Kind (Ekind (T)));
-- Set Etype to the known type, to reduce chances of cascaded errors
@@ -20802,7 +20800,9 @@
-- Ada 2005 (AI-412): Transform a regular incomplete subtype into a
-- corresponding subtype of the full view.
- elsif Ekind (Priv_Dep) = E_Incomplete_Subtype then
+ elsif Ekind (Priv_Dep) = E_Incomplete_Subtype
+ and then Comes_From_Source (Priv_Dep)
+ then
Set_Subtype_Indication
(Parent (Priv_Dep), New_Occurrence_Of (Full_T, Sloc (Priv_Dep)));
Set_Etype (Priv_Dep, Full_T);
Index: sem_ch7.adb
===================================================================
--- sem_ch7.adb (revision 251753)
+++ sem_ch7.adb (working copy)
@@ -1441,11 +1441,14 @@
-- Check on incomplete types
- -- AI05-0213: A formal incomplete type has no completion
+ -- AI05-0213: A formal incomplete type has no completion,
+ -- and neither does the corresponding subtype in an instance.
- if Ekind (E) = E_Incomplete_Type
+ if Is_Incomplete_Type (E)
and then No (Full_View (E))
and then not Is_Generic_Type (E)
+ and then not From_Limited_With (E)
+ and then not Is_Generic_Actual_Type (E)
then
Error_Msg_N ("no declaration in visible part for incomplete}", E);
end if;
Index: einfo.adb
===================================================================
--- einfo.adb (revision 251758)
+++ einfo.adb (working copy)
@@ -7151,13 +7151,13 @@
begin
Desig_Type := Directly_Designated_Type (Id);
- if Ekind (Desig_Type) = E_Incomplete_Type
+ if Is_Incomplete_Type (Desig_Type)
and then Present (Full_View (Desig_Type))
then
return Full_View (Desig_Type);
elsif Is_Class_Wide_Type (Desig_Type)
- and then Ekind (Etype (Desig_Type)) = E_Incomplete_Type
+ and then Is_Incomplete_Type (Etype (Desig_Type))
and then Present (Full_View (Etype (Desig_Type)))
and then Present (Class_Wide_Type (Full_View (Etype (Desig_Type))))
then
@@ -7364,11 +7364,11 @@
function Get_Full_View (T : Entity_Id) return Entity_Id is
begin
- if Ekind (T) = E_Incomplete_Type and then Present (Full_View (T)) then
+ if Is_Incomplete_Type (T) and then Present (Full_View (T)) then
return Full_View (T);
elsif Is_Class_Wide_Type (T)
- and then Ekind (Root_Type (T)) = E_Incomplete_Type
+ and then Is_Incomplete_Type (Root_Type (T))
and then Present (Full_View (Root_Type (T)))
then
return Class_Wide_Type (Full_View (Root_Type (T)));
@@ -7800,7 +7800,7 @@
Entity_Is_Base_Type : constant array (Entity_Kind) of Boolean :=
(E_Enumeration_Subtype |
- E_Incomplete_Type |
+ E_Incomplete_Subtype |
E_Signed_Integer_Subtype |
E_Modular_Integer_Subtype |
E_Floating_Point_Subtype |
@@ -9174,6 +9174,9 @@
when Enumeration_Kind =>
Kind := E_Enumeration_Subtype;
+ when E_Incomplete_Type =>
+ Kind := E_Incomplete_Subtype;
+
when Float_Kind =>
Kind := E_Floating_Point_Subtype;
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