The compiler was incorrectly accepting generic instantiations with
formal objects of named access-to-subprogram types associated with an
actual of an anonymous access-to-subprogram type.
Analyze_Object_Declaration tests for objects initialized anonymous
access-to-subprogram values, and wraps a conversion around the argument,
which normally will result in error checks during resolution in
Valid_Conversion, but the conversion was only created when the
initialization expression Comes_From_Source, which prevented the
conversion wrapping from happening for constant declarations resulting
from generic expansion. The test for Comes_From_Source was removed.
The following test must report the error output given further below for
the three constructs marked as errors when compiled with this command:
gcc -c -gnatj70 bad_anon_access_instance.adb
procedure Bad_Anon_Access_Instance (Anon_Acc : access procedure) is
type Ref is access procedure;
Ref_1 : Ref := Anon_Acc; -- ERROR (flagged by GNAT)
Ref_2 : constant Ref := Anon_Acc; -- ERROR (flagged by GNAT)
generic
Formal_Ref : Ref;
package Gen is
end Gen;
package Inst
is new Gen (Formal_Ref => Anon_Acc); -- ERROR (but not flagged by GNAT)
begin
null;
end Bad_Anon_Access_Instance;
-------------
Error output:
-------------
bad_anon_access_instance.adb:4:19: illegal attempt to store anonymous
access to subprogram, value has
deeper accessibility than any
master (RM 3.10.2 (13)), use named
access type for "Anon_Acc" instead
of access parameter
bad_anon_access_instance.adb:6:28: illegal attempt to store anonymous
access to subprogram, value has
deeper accessibility than any
master (RM 3.10.2 (13)), use named
access type for "Anon_Acc" instead
of access parameter
bad_anon_access_instance.adb:14:32: illegal attempt to store
anonymous access to subprogram,
value has deeper accessibility
than any master (RM 3.10.2 (13)),
use named access type for
"Anon_Acc" instead of access
parameter
Tested on x86_64-pc-linux-gnu, committed on trunk
2018-09-26 Gary Dismukes <dismu...@adacore.com>
gcc/ada/
* sem_ch3.adb (Analyze_Object_Declaration): Remove test for
Comes_From_Source, which prevented implicit conversions from
being applied to anonymous access-to-subprogram formals in
constant declartions that arise from instance associations for
generic formal objects. Add RM and AARM references to comment.--- gcc/ada/sem_ch3.adb
+++ gcc/ada/sem_ch3.adb
@@ -4286,12 +4286,11 @@ package body Sem_Ch3 is
else
-- If the expression is a formal that is a "subprogram pointer"
- -- this is illegal in accessibility terms. Add an explicit
- -- conversion to force the corresponding check, as is done for
- -- assignments.
+ -- this is illegal in accessibility terms (see RM 3.10.2 (13.1/2)
+ -- and AARM 3.10.2 (13.b/2)). Add an explicit conversion to force
+ -- the corresponding check, as is done for assignments.
- if Comes_From_Source (N)
- and then Is_Entity_Name (E)
+ if Is_Entity_Name (E)
and then Present (Entity (E))
and then Is_Formal (Entity (E))
and then
