错误 1 error #6552: The CALL statement is invoking a function subprogram as a subroutine.   [GET_DISTANCE] 

具体代码为：

module constant

  implicit none
  real, parameter :: PI = 3.14159
  real, parameter :: G  = 9.81
end module

module typedef
  implicit none
  type player
    real :: angle
    real :: speed
    real :: distance
  end type
end module

program ex0836
  use typedef
  use constant
  implicit none
  integer, parameter :: players = 5
  type(player) :: people(players) = (/ player(30.0, 25.0, 0.0),&
                                       player(45.0, 20.0, 0.0),& 
  player(35.0, 21.0, 0.0),&
  player(50.0, 27.0, 0.0),&
  player(40.0, 22.0, 0.0) &
/)
  real :: Get_Distance ! 声明Get_Distance是个函数
  integer :: I
  
  do I=1, players
     call  Get_Distance( people(I) )
write(*,"('Player ',I1,' =',F8.2)") I, people(I)%distance
  end do

  stop
end
! 把0～360的角度转换成0～2PI的弧度
real function Angle_TO_Rad( angle )
  use constant
  implicit none
  real angle
  Angle_TO_Rad = angle*pi/180.0
  return
end

  subroutine Get_Distance(person)
  use constant
  use typedef
  implicit none
  type(player) :: person
  real rad, Vx, time
  real, external  :: Angle_TO_Rad ! 声明Angle_TO_Rad是个函数

  rad  = Angle_TO_Rad( person%angle )      ! 单位转换
  Vx   = person%speed * cos(rad)           ! 水平方向速度
  time = 2.0 * person%speed * sin(rad) / G ! 在空中飞行时间
  person%distance = Vx * time              ! 距离 = 水平方向速度 * 飞行时间
return 
end