https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99125
--- Comment #5 from G. Steinmetz <gs...@t-online.de> ---
I also checked this invalid (probably a known issue) :
$ cat za.f90
program p
character(:), allocatable :: a(:)
character(8) :: c(2) = '12 45 78'
a = c
print *, a(7:8)
end
$ gfortran-11-20210221 za.f90 && ./a.out # surprising
12 45 7812 45 78
Detected at runtime :
$ gfortran-11-20210221 za.f90 -Wall -fcheck=all && ./a.out
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
Warning: '.a' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.offset' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].lbound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].ubound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].lbound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].ubound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].ubound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
za.f90:4:8:
4 | a = c
| ^
Warning: 'a.dim[0].lbound' may be used uninitialized [-Wmaybe-uninitialized]
za.f90:2:36:
2 | character(:), allocatable :: a(:)
| ^
note: 'a' declared here
At line 5 of file za.f90
Fortran runtime error: Index '7' of dimension 1 of array 'a' outside of
expected range (1:2)
Error termination. Backtrace:
#0 0x4025d1 in ???
#1 0x402738 in ???
#2 0x7fa0f5697f89 in ???
#3 0x4022b9 in ???
at ../sysdeps/x86_64/start.S:120
#4 0xffffffffffffffff in ???
---
The very basic simplification gives :
$ cat zc.f90
program p
character(8) :: c(2) = '12 45 78'
print *, c(7:8)
end
$ gfortran-11-20210221 zc.f90 -Wall -fcheck=all && ./a.out
zc.f90:3:14:
3 | print *, c(7:8)
| 1
Warning: Lower array reference at (1) is out of bounds (7 > 2) in dimension 1
At line 3 of file zc.f90
Fortran runtime error: Index '7' of dimension 1 of array 'c' outside of
expected range (1:2)
Error termination. Backtrace:
#0 0x4023f7 in ???
#1 0x40242b in ???
#2 0x7fc15fc2af89 in ???
#3 0x4022b9 in ???
at ../sysdeps/x86_64/start.S:120
#4 0xffffffffffffffff in ???
