[Bug fortran/65677] New: Incomplete assignment on deferred-length character variable

["jwmwalrus at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65677

            Bug ID: 65677
           Summary: Incomplete assignment on deferred-length character
                    variable
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jwmwalrus at gmail dot com

The code below fails to produce the expected results.


module mod1
    implicit none
contains
    subroutine getKeyword(string, keyword, rest)
        character(:), allocatable, intent(IN) :: string
        character(:), allocatable, intent(OUT) :: keyword, rest
        integer :: idx
        character(:), allocatable :: text

        keyword = ''
        rest = ''
        text = string
        text = ADJUSTL(text(2:))    !***
        idx = INDEX(text, ' ')

        if (idx == 0) then
            keyword = TRIM(text)
        else
            keyword = text(:idx-1)
            rest = TRIM(ADJUSTL(text(idx+1:)))
        endif
    end subroutine
end module mod1

use mod1
implicit none

character(:), allocatable :: line, keyword, rest

line = '@HERE    IT IS'

call getKeyword(line, keyword, rest)

print *, 'line: ', line
print *, 'keyword: ', keyword
print *, 'rest: ', rest
end


It seems that whenever a deferred-length character variable that's being
assigned something is also a substring in the right-hand side expression,
assignment is wrong/incomplete. The offending line is marked with "!***" in the
code. This is the output I get:


~$ ll `which gfortran-5.0`
lrwxrwxrwx 1 root staff 35 Feb 26 11:01 /usr/local/bin/gfortran-5.0 ->
../../lib/gcc-snapshot/bin/gfortran*
~$ gfortran-5.0 test_deferred.f90 
~$ ./a.out 
 line: @HERE    IT IS
 keyword: HERE
 rest: IT I


So far I've noticed the error occurs only when the substring does not coincide
with the beginning of the string. I get the same error with gfortran 4.9.

The system and compiler information is:

$ lsb_release -rd && gfortran-5.0 -v
Description:    Debian GNU/Linux 8.0 (jessie)
Release:    8.0
Using built-in specs.
COLLECT_GCC=gfortran-5.0
COLLECT_LTO_WRAPPER=/usr/lib/gcc-snapshot/libexec/gcc/x86_64-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 20150404-1'
--with-bugurl=file:///usr/share/doc/gcc-snapshot/README.Bugs
--enable-languages=c,ada,c++,java,go,fortran,objc,obj-c++
--prefix=/usr/lib/gcc-snapshot --enable-shared --enable-linker-build-id
--disable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=c++98
--enable-gnu-unique-object --disable-vtable-verify --enable-libmpx
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-snap-amd64/jre
--enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-snap-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-snap-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --with-arch-32=i586 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--disable-werror --enable-checking=yes --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.0.0 20150404 (experimental) [trunk revision 221867] (Debian
20150404-1)