When compiled with the fortran-dev branch, the tests gfortran.dg/alloc_comp_assign_[234].f90, pr43808.f90, and realloc_on_assign_17.f90 fail at run time. Reduced tests:

  type :: a
    integer, allocatable :: i(:)
  end type a

  type :: b
    type (a), allocatable :: at(:)
  end type b

  type(a) :: x(2)
  type(b) :: y(2), z(2)
  integer i, m(4)

  x = (/a ((/1,2,3,4/)),a ((/5,6,7,8/))/)
  print *, x(1)%i, x(2)%i
  print *, "after x"
  y(1) = b ((/x(i)/))
  print *, "after 2"

end

fails at y(1) = b ((/x(i)/)), and

program allocate_assign
   implicit none
   type label
      integer, allocatable :: parts(:)
   end type label
   type table
      type(label), allocatable :: headers(:)
   end type table
   type(table) x1(2)
   integer i, j!, k
       x1 = [table([(label([(j,j=1,3)]),i=1,3)]), &
             table([(label([(j,j=1,4)]),i=1,4)])]
end program allocate_assign

fails at x1=... .