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Bug 51864 - [OOP] ALLOCATE with polymorphic array constructor as SOURCE=
Summary: [OOP] ALLOCATE with polymorphic array constructor as SOURCE=
Alias: None
Product: gcc
Classification: Unclassified
Component: fortran (show other bugs)
Version: 4.7.0
: P3 normal
Target Milestone: 7.0
Assignee: vehre
Keywords: ice-on-valid-code
Depends on:
Reported: 2012-01-15 12:55 UTC by Tobias Burnus
Modified: 2016-11-16 16:40 UTC (History)
2 users (show)

See Also:
Known to work:
Known to fail:
Last reconfirmed: 2014-07-20 00:00:00


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Description Tobias Burnus 2012-01-15 12:55:12 UTC
See also

The following program causes gfortran to ICE with a segfault. The program compiles with NAG f95 5.1 and crayftn 7.1 - though it segfaults at run time.

I think the program is valid F2003/F2008.

type t
  integer :: i = 5
end type t
type, extends(t) :: t2
  integer :: j = 6
end type t2

class(t), allocatable :: a(:), b(:), c(:)
allocate(t2 :: a(3))
allocate(t2 :: b(5))
!allocate(c, source=[ a, b ]) ! F2008, PR 44672
allocate(c(8), source=[ a, b ])
! c = [ a, b ] ! F2008, PR 43366
select type(c)
  type is(t)
    print '(8(i2))', c%i
  type is(t2)
    print '(8(i2))', c%i
    print '(8(i2))', c%j
end select
Comment 1 Tobias Burnus 2012-01-15 23:25:55 UTC
(In reply to comment #0)
> class(t), allocatable :: a(:), b(:), c(:)
> allocate(t2 :: a(3))
> allocate(t2 :: b(5))
> allocate(c(8), source=[ a, b ])

Actually, this part of the program is invalid as Fortran 2008 demands (4.8 Construction of array values):

"The dynamic type of an array constructor is the same as its declared type."

Thus, one can use
 [ a, b ]
but only if both are of the declared and dynamic type "t", cf.

"If type-spec is omitted, each ac-value expression in the array constructor shall have the same length type parameters; in this case, the declared type and type parameters of the array constructor are those of the ac-value expressions."

However, one is still allowed to use:

 [ t2 :: a, b]

in that case, "a" and "b" need to have a declared type "t2" or an extension of "t2" as declared type - and can have any dynamic type.

"If type-spec appears, it specifies the declared type and type parameters of the array constructor. Each ac-value expression in the array-constructor shall be compatible with intrinsic assignment to a variable of this type and type parameters. Each value is converted to the type parameters of the array-constructor in accordance with the rules of intrinsic assignment ("

And in CLASS, one finds "type compatible" defined as:

"A polymorphic entity that is not an unlimited polymorphic entity is type compatible with entities of the same declared type or any of its extensions. Even though an unlimited polymorphic entity is not considered to have a declared type, it is type compatible with all entities. An entity is type compatible with a type if it is type compatible with entities of that type."
Comment 2 Dominique d'Humieres 2014-07-20 08:33:09 UTC
Compiling the code in comment 0 still gives an ICE with gfortran 4.10.0 r212833 (the same ICE as for pr53653):

pr51864.f90: In function 'MAIN__':
pr51864.f90:12:0: internal compiler error: in gfc_conv_array_constructor_expr, at fortran/trans-expr.c:5668
 allocate(c(8), source=[ a, b ])

I also get the same ICE with the following code

  call pr53876

subroutine pr53876
  TYPE :: individual
    integer :: icomp ! Add an extra component to test offset
  CLASS(individual), DIMENSION(:), ALLOCATABLE :: indv, indv1
  allocate (indv(2), source = [individual(1, [99,999]), &
                               individual(2, [999,9999])])
  allocate (indv1(2), source = [indv])

If I understand correctly comment 1, this code should be valid. Replacing '[indv]' with '[indv(1),indv(2)]' does not fix the ICE, but replacing it with 'imdv' does.
Comment 3 vehre 2016-10-22 12:34:10 UTC
Author: vehre
Date: Sat Oct 22 12:33:38 2016
New Revision: 241439


2016-10-22  Andre Vehreschild  <>

	PR fortran/43366
	PR fortran/51864
	PR fortran/57117
	PR fortran/61337
	PR fortran/61376
	* primary.c (gfc_expr_attr): For transformational functions on classes
	get the attrs from the class argument.
	* resolve.c (resolve_ordinary_assign): Remove error message due to
	feature implementation.  Rewrite POINTER_ASSIGNS to ordinary ones when
	the right-hand side is scalar class object (with some restrictions).
	* trans-array.c (trans_array_constructor): Create the temporary from
	class' inner type, i.e., the derived type.
	(build_class_array_ref): Add support for class array's storage of the
	class object or the array descriptor in the decl saved descriptor.
	(gfc_conv_expr_descriptor): When creating temporaries for class objects
	add the class object's handle into the decl saved descriptor.
	(structure_alloc_comps): Use the common way to get the _data component.
	(gfc_is_reallocatable_lhs): Add notion of allocatable class objects.
	* trans-expr.c (gfc_find_and_cut_at_last_class_ref): Remove the only ref
	only when the expression's type is BT_CLASS.
	(gfc_trans_class_init_assign): Correctly handle class arrays.
	(gfc_trans_class_assign): Joined into gfc_trans_assignment_1.
	(gfc_conv_procedure_call): Support for class types as arguments.
	(trans_get_upoly_len): For unlimited polymorphics retrieve the _len
	component's tree.
	(trans_class_vptr_len_assignment): Catch all ways to assign the _vptr
	and _len components of a class object correctly.
	(pointer_assignment_is_proc_pointer): Identify assignments of
	procedure pointers.
	(gfc_trans_pointer_assignment): Enhance support for class object pointer
	(gfc_trans_scalar_assign): Removed assert.
	(trans_class_assignment): Assign to a class object.
	(gfc_trans_assignment_1): Treat class objects correctly.
	(gfc_trans_assignment): Propagate flags to trans_assignment_1.
	* trans-stmt.c (gfc_trans_allocate): Use gfc_trans_assignment now
	instead of copy_class_to_class.
	* trans-stmt.h: Function prototype removed.
	* trans.c (trans_code): Less special casing for class objects.
	* trans.h: Added flags to gfc_trans_assignment () prototype.


2016-10-22  Andre Vehreschild  <>

        Forgot to add on original commit.
        * gfortran.dg/coarray_alloc_comp_2.f08: New test.

2016-10-22  Andre Vehreschild  <>

	PR fortran/43366
	PR fortran/57117
	PR fortran/61337
	* gfortran.dg/alloc_comp_class_5.f03: New test.
	* gfortran.dg/class_allocate_21.f90: New test.
	* gfortran.dg/class_allocate_22.f90: New test.
	* gfortran.dg/realloc_on_assign_27.f08: New test.

Comment 4 vehre 2016-10-24 16:59:23 UTC
Waiting one week for regression reports.
Comment 5 vehre 2016-10-31 16:25:39 UTC
No complaints so far, closing.