[Bug fortran/51652] [F03] ICE with allocatable scalarstype parameter

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51652

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |accepts-invalid,
                   |                            |diagnostic, wrong-code
                 CC|                            |burnus at gcc dot gnu.org
            Summary|[F03] ICE with allocatable  |[F03] ICE with allocatable
                   |scalars                     |scalarstype parameter

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-12-22 08:40:10 UTC ---
(In reply to comment #0)
> type keyword
> !  character(60), allocatable :: c(:)   ! works but should it?
> !  character(80), allocatable :: c(:)   ! works
>    character(:), allocatable :: c(:)
> end type keyword

Unfortunately, deferred-length type parameters (i.e. allocatable string
lengths) are not yet supported for components of derived types. The current
version does not crash (ICE, internal compiler error) but prints an error:
    character(:), allocatable :: c(:)
                                     1
Error: Deferred-length character component 'c' at (1) is not yet supported

As this is already tracked in PR 51550, PR 47545, PR 49050, PR 51075 - and PR
45170, I ignore the issue in this PR and concentrate on your second issue.


 * * *

Regarding the allocation:
  character(60), allocatable :: c(:)
  allocate(character(80) :: c(10))
That's invalid; currently, the value in the allocate statement is ignored by
gfortran. 

The standard requires that this is diagnosed:

"If type-spec appears and the value of a type parameter it specifies differs
from the value of the corresponding nondeferred type parameter specified in the
declaration of any allocate-object, an error condition occurs. If the value of
a nondeferred length type parameter of an allocate-object differs from the
value of the corresponding type parameter of source-expr, an error condition
occurs."

Note that this cannot always diagnosed at compile time, given that also the
following is valid:

subroutine sub(n)
  integer :: n
  character(len=n), allocatable :: str(:)
  allocate(character(n) :: str(1))
  print *, len(str), size(str)
end
call sub(4)
call sub(5)
end