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From: "ygalklein at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/103115] New: reallocation of character array fails when
 appending a constant size 4 array
Date: Sun, 07 Nov 2021 11:01:13 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103115

            Bug ID: 103115
           Summary: reallocation of character array fails when appending a
                    constant size 4 array
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ygalklein at gmail dot com
  Target Milestone: ---

The following example program:
```fortran
program reallocationCharacterArray
    implicit none
    character(:), dimension(:), allocatable :: titles
    titles =3D ["1"]
    titles =3D [titles,&
            "2",&
            "3",&
            "4",&
            "5"&
            ]
    block
        integer :: iTitle
        do iTitle =3D 1, size(titles)
            write(*, "('titles(',i2,') =3D ',a)") iTitle, trim(titles(iTitl=
e))
        end do
    end block
end program reallocationCharacterArray
```

when compiled using gfortran 11.1 or 10.3 results with the following output:
`
size(titles) =3D 5
titles( 1) =3D 1
titles( 2) =3D=20
titles( 3) =3D=20
titles( 4) =3D=20
titles( 5) =3D=20
`

which is clearly wrong.
One can see that the reallocation succeded in increasing the size of titles
from 1 to 5 - but the assignment to all the places from 2 to 5 are erronous.

one should note that using intel compiler 2021.4 - results with the followi=
ng
output:
`
size(titles) =3D 5
titles( 1) =3D 1
titles( 2) =3D 2
titles( 3) =3D 3
titles( 4) =3D 4
titles( 5) =3D 5
`

which is the right output.

One should also note that commenting one line from the constant array being
appended - i.e appending an array of size 3 (instead of size 4) results with
the right output when using gfortran, i.e

the following program (note the ! sign commenting one line):
```fortran
program reallocationCharacterArray
    implicit none
    character(:), dimension(:), allocatable :: titles
    titles =3D ["1"]
    titles =3D [titles,&
            ! "2",&
            "3",&
            "4",&
            "5"&
            ]
    write(*, "('size(titles) =3D ',i1)") size(titles)
    block
        integer :: iTitle=20=20=20=20
        do iTitle =3D 1, size(titles)
            write(*, "('titles(',i2,') =3D ',a)") iTitle, trim(titles(iTitl=
e))
        end do
    end block
end program reallocationCharacterArray
```

results with the following right output:
`
size(titles) =3D 4
titles( 1) =3D 1
titles( 2) =3D 3
titles( 3) =3D 4
titles( 4) =3D 5
`

both in gfortran and ifort.=