[flang] Missing diagnostic on invalid DTIO interface

[DanielCChen]

Consider the following code:

module m
    type base
        character(5), allocatable :: data
    end type

    interface write(formatted)
        subroutine formattedRead (dtv, unit, iotype, v_list, iostat, iomsg)
        import base
            class (base), intent(in) :: dtv(10)   !<-- can not be array
            integer, intent(in) :: unit
            character(*), intent(in) :: iotype(2)  !<-- can not be array
            integer, intent(in) :: v_list(:)
            integer, intent(out) :: iostat
            character(*), intent(inout) :: iomsg
        end subroutine
    end interface
end module

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: Daniel Chen (DanielCChen)

Consider the following code: ``` module m type base character(5), allocatable :: data end type

interface write(formatted)
    subroutine formattedRead (dtv, unit, iotype, v_list, iostat, iomsg)
    import base
        class (base), intent(in) :: dtv(10)   !<-- can not be array
        integer, intent(in) :: unit
        character(*), intent(in) :: iotype(2)  !<-- can not be array
        integer, intent(in) :: v_list(:)
        integer, intent(out) :: iostat
        character(*), intent(inout) :: iomsg
    end subroutine
end interface

end module

</details>