[Bug fortran/49112] Missing type-bound procedure, "duplicate save" warnings and internal compiler error

[jwmwalrus at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49112

--- Comment #4 from John <jwmwalrus at gmail dot com> 2011-05-22 17:58:39 UTC ---
(In reply to comment #3)
> (In reply to comment #0)
> > ...:~$ gfortran -c  test_gfortran_ice.f90 
> > test_gfortran_ice.f90:20.41:
> > 
> >         class(DateTime), intent(IN) :: dt
> >                                          1
> > Warning: Duplicate SAVE attribute specified at (1)
> > test_gfortran_ice.f90:20.41:
> > 
> >         class(DateTime), intent(IN) :: dt
> >                                          1
> > Warning: Duplicate SAVE attribute specified at (1)
> 
> 
> Here is a reduced test case for the duplicate SAVE attribute:
> 
> 
> module datetime_mod
> 
>     implicit none
>     save
> 
>     type :: DateTime
>     end type
> 
> contains
> 
>     character function getString (dt)
>         class(DateTime) :: dt
>     end function 
> 
> end module
> 
> 
> At first glance I would save this is invalid, and should be rejected with an
> error. In particular, is it allowed to give a lonely SAVE statement? If yes,
> what effect should this have? Usually SAVE is specified as an attribute for a
> specific variable, right?

SAVE can be either a statement or an attribute.  When it's statement, it
affects all the variables within the containing unit (e.g., in the case of a
module, it affects all the variables declared before the "contains").  When
it's the attribute for a particular variable declaration, it affects the
variable only.

Since in Fortran initialization implies SAVE, and the ISO_REFERENCE_DATE is
being (sort of) initialized, the compiler is assuming a duplicate SAVE.

The standard also allows the confirmation, as an attribute, of the SAVE at the
module level, so, for a "triple save" example:

module t1_mod
    save

    type :: t1
        integer :: dummy = 0
    end type

    type(t1), save :: a = t1(2), b = t1(3)
end type


Which also triggers a duplicate save warning.