This patch fixes an issue whereby instantiations of generic packages
were incorrectly allowed despite formal and actual subprograms not
having matching declarations with anonymous constant access type
parameters.
------------
-- Source --
------------
-- gen1.ads
package Gen1 is
generic
with procedure View (IA : not null access constant Integer);
procedure Dispatch (IA : access Integer);
end;
-- gen2.adb
package body Gen1 is
procedure Dispatch (IA : access Integer) is
begin
View (IA);
end;
end;
-- bad1.ads
with Gen1;
package Bad1 is
procedure Bad_View (IA : not null access Integer);
procedure Bad_Dispatch is new Gen1.Dispatch (Bad_View);
end;
-- bad1.adb
package body Bad1 is
procedure Bad_View (IA : not null access Integer) is
begin
IA.all := IA.all + 1;
end;
end;
-- gen2.ads
package Gen2 is
generic
with procedure View (IA : access constant Integer);
procedure Dispatch (IA : access Integer);
end;
-- gen2.adb
package body Gen2 is
procedure Dispatch (IA : access Integer) is
begin
View (IA);
end;
end;
-- bad2.ads
with Gen2;
package Bad2 is
procedure Bad_View (IA : access Integer);
procedure Bad_Dispatch is new Gen2.Dispatch (Bad_View);
end;
-- bad2.adb
package body Bad2 is
procedure Bad_View (IA : access Integer) is
begin
IA.all := IA.all + 1;
end;
end;
-----------------
-- Compilation --
-----------------
$ gnatmake -q bad1.adb
$ bad1.ads:4:04: instantiation error at gen1.ads:3
$ bad1.ads:4:04: not mode conformant with declaration at line 3
$ bad1.ads:4:04: constant modifier does not match
$ gnatmake: "bad1.adb" compilation error
$ gnatmake -q bad2.adb
$ bad2.ads:4:04: instantiation error at gen2.ads:3
$ bad2.ads:4:04: not mode conformant with declaration at line 3
$ bad2.ads:4:04: constant modifier does not match
$ gnatmake: "bad2.adb" compilation error
Tested on x86_64-pc-linux-gnu, committed on trunk
2019-07-03 Justin Squirek <squi...@adacore.com>
gcc/ada/
* sem_ch6.adb (Check_Conformance): Add expression checking for
constant modifiers in anonymous access types (in addition to
"non-null" types) so that they are considered "matching" for
subsequent conformance tests.--- gcc/ada/sem_ch6.adb
+++ gcc/ada/sem_ch6.adb
@@ -5444,10 +5444,14 @@ package body Sem_Ch6 is
and then Directly_Designated_Type (Old_Formal_Base) =
Directly_Designated_Type (New_Formal_Base)
and then ((Is_Itype (Old_Formal_Base)
- and then Can_Never_Be_Null (Old_Formal_Base))
+ and then (Can_Never_Be_Null (Old_Formal_Base)
+ or else Is_Access_Constant
+ (Old_Formal_Base)))
or else
(Is_Itype (New_Formal_Base)
- and then Can_Never_Be_Null (New_Formal_Base)));
+ and then (Can_Never_Be_Null (New_Formal_Base)
+ or else Is_Access_Constant
+ (New_Formal_Base))));
-- Types must always match. In the visible part of an instance,
-- usual overloading rules for dispatching operations apply, and
