User-Defined Reference in a Task Type Discriminant Compiler Bug?

[Eryndlia Mavourneen <eryndlia@gmail.com>]

Dmitry spurred me to investigate user-defined references.

-----

1) The following code does not compile; however, it seems to abide by the LRM rules in 4.1.5:

   type Inc_Type is not null access procedure (To_Increment : in out Integer);
   
   task type T (Incrementing_Procedure : Inc_Type)
   with Implicit_Dereference => Incrementing_Procedure;

and fails with the error

   not an access discriminant of "T"

referencing the aspect clause.

-----

2) Adding "access" before the discriminant type in the task declaration compiles:

   type Inc_Type is not null access procedure (To_Increment : in out Integer);
   
   task type T (Incrementing_Procedure : access Inc_Type)
   with Implicit_Dereference => Incrementing_Procedure;

but I believe that this will produce an access of an access, no?  The declaration of Inc_Type is not possible, of course, without the keyword "access".

-----

3) I tried pleasing the compiler by splitting the declaration, as:

   type Inc_Type is access procedure (To_Increment : in out Integer);
   
   task type T (Incrementing_Procedure : not null Inc_Type)
   with Implicit_Dereference => Incrementing_Procedure;

but Gnat still produces the same error message for the aspect.

-----

Note that the declaration of Inc_Type in (1) is properly recognized as an access-to-subprogram type without the aspect clause.  I find it odd that the declaration of the discriminant + aspect clause given a similar circumstance will not compile.  It appears to prevent implicitly the type of construct in (1), which seems to me to be legal Ada code.

-----

Eryndlia F. Mavourneen