https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71883
--- Comment #2 from Gerhard Steinmetz <gerhard.steinmetz.fort...@t-online.de> --- Runtime behavior : $ cat y1.f90 program p character(3), allocatable :: z(:,:) z(1:2,1:2) = 'abc' z(2,1) = z(1,2) z(2,1) = z(1,2) end $ gfortran-6 -g -O0 -Wall -fcheck=all -fno-frontend-optimize y1.f90 $ a.out At line 3 of file y1.f90 Fortran runtime error: Index '1' of dimension 2 of array 'z' outside of expected range (47021301956608:0) Error termination. Backtrace: #...