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Subject: [Bug fortran/54286] [4.8 Regression] Accepts invalid proc-pointer assignments involving proc-ptr function result
Date: Wed, 09 Jan 2013 09:44:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54286

--- Comment #3 from Paul Thomas <pault at gcc dot gnu.org> 2013-01-09 09:44:07 UTC ---
Please find below my interpretation of the validity or not of the testcase for
this PR.

> The following test is probably invalid, but not rejected by recent trunk
> versions:
> 
> 
> type :: t
>   procedure(a), pointer, nopass :: p
> end type
> 
> type(t) :: x
> procedure(iabs), pointer :: pp
> 
> x%p => a     ! ok

[A] I believe that this is invalid because the interfaces do not match
procedure(iabs), pointer  =>  integer pointer procedure (integer formal)

It strikes me as being a moot point as to whetehr or not the processor is
required to report it though, on the gorunds that "anything goes" with
pointers! That said, the interface check is easy to implement.

> x%p => a(1)  ! invalid, but not rejected by 4.8

[B] This is valid:
procedure(iabs), pointer  =>  pointer to integer procedure(iabs)

It has the pleasing property of providing the correct result for
print *, x%p(-99) .eq. iabs(-99)

> 
> pp => a(2)   ! ok

[B] applies - it also gives the correct result.

> pp => a      ! invalid, but not rejected by 4.8

[A] applies - invalid.

> 
> contains
> 
>   function a (c) result (b)
>     integer, intent(in) :: c
>     procedure(iabs), pointer :: b
>     b => iabs
>   end function
> 
> end

Interestingly, both invalid lines run and provide results that are consistent
with INT (loc (iabs)) :-)

Paul