[Bug fortran/72832] [OOP] ALLOCATE with SOURCE fails to allocate requested dimensions

[daanvanvugt at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72832

--- Comment #5 from Daan van Vugt  ---
Thanks for the quick responses.
Just out of interest: what is the recommended way to allocate a class(t)
variable of the same type as a but different size?
Do I need to select type and list all of the types? that would be inconvenient.

[Bug fortran/72832] [OOP] ALLOCATE with SOURCE fails to allocate requested dimensions

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72832

--- Comment #4 from Dominique d'Humieres  ---
For the record, the following test

program allocate_source
  type :: t
  end type t
  type, extends(t) :: tt
  end type tt

  type(t), allocatable, dimension(:) :: a, b
  allocate(a(1:2))
  write(*,*) size(a,1)

  allocate(b(1:4), source=a)
  write(*,*) size(b,1)
end program allocate_source

gives the "expected" output and at runtime the error

   2
At line 11 of file pr72832_db_1.f90
Fortran runtime error: Array bound mismatch for dimension 1 of array 'b' (4/2)

when compiled with -fcheck=bounds.

[Bug fortran/72832] [OOP] ALLOCATE with SOURCE fails to allocate requested dimensions

[vehre at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72832

--- Comment #3 from vehre at gcc dot gnu.org ---
This patch fragment fixes the first issue:

diff --git a/gcc/fortran/trans-stmt.c b/gcc/fortran/trans-stmt.c
index 5884e7a..8e5428a 100644
--- a/gcc/fortran/trans-stmt.c
+++ b/gcc/fortran/trans-stmt.c
@@ -5485,7 +5485,8 @@ gfc_trans_allocate (gfc_code * code)
  desc = tmp;
  tmp = gfc_class_data_get (tmp);
}
- e3_is = E3_DESC;
+ if (code->ext.alloc.arr_spec_from_expr3)
+   e3_is = E3_DESC;
}
  else
desc = !is_coarray ? se.expr

[Bug fortran/72832] [OOP] ALLOCATE with SOURCE fails to allocate requested dimensions

[vehre at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72832

vehre at gcc dot gnu.org changed:

   What|Removed |Added

 CC||vehre at gcc dot gnu.org

--- Comment #2 from vehre at gcc dot gnu.org ---
There are two bugs in one here: 

- the shape is selected from source= and not from the b(1:4), and
- the shape of a and new b is not conformable, which can only be deduced at
runtime (and is already when the class(t) is replaced by type(t) and
-fcheck=all is used).

[Bug fortran/72832] [OOP] ALLOCATE with SOURCE fails to allocate requested dimensions

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72832

Dominique d'Humieres  changed:

   What|Removed |Added

 Status|UNCONFIRMED |WAITING
   Last reconfirmed||2016-08-08
 Ever confirmed|0   |1

--- Comment #1 from Dominique d'Humieres  ---
> While I expect the second line to be 4.

From the standard

"If SOURCE= appears, source-expr shall be conformable with allocation."

I think the code is invalid.