https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83093
--- Comment #1 from G. Steinmetz <gs...@t-online.de> --- These variants are silently accepted : $ cat z4.f90 program p character(:), allocatable :: z allocate (character(z) :: z) end $ cat z5.f90 program p character(:), allocatable :: z allocate (character(z(1:1)) :: z) end $ cat z7.f90 program p character(:), allocatable :: z allocate (character((.true.)) :: z) end $ cat z9.f90 program p character(:), allocatable :: z allocate (character(n) :: z) end $ gfortran-8-20171119 -c z4.f90 $