! { dg-do run }
!
! Basic test of submodule functionality.
!
! Contributed by Paul Thomas  <pault@gcc.gnu.org>
!
 module foo_interface
   implicit none
   character(len = 100) :: message
   character(len = 100) :: message2

   type foo
     character(len=15) :: greeting = "Hello, world!  "
     character(len=15), private :: byebye = "adieu, world!  "
   contains
     procedure :: greet => say_hello
     procedure :: farewell => bye
     procedure, private :: adieu => byebye
   end type foo

   interface
     module subroutine say_hello(this)
       class(foo), intent(in) :: this
     end subroutine

     module subroutine bye(this)
       class(foo), intent(in) :: this
     end subroutine

     module subroutine byebye(this, that)
       class(foo), intent(in) :: this
       class(foo), intent(inOUT), allocatable :: that
     end subroutine

     module function realf (arg) result (res)
       real :: arg, res
     end function

     integer module function intf (arg)
       integer :: arg
     end function

     real module function realg (arg)
       real :: arg
     end function

     integer module function intg (arg)
       integer :: arg
     end function

   end interface

   integer :: factor = 5

 contains

   subroutine smurf
     class(foo), allocatable :: this
     allocate (this)
     message = "say_hello from SMURF --->"
     call say_hello (this)
   end subroutine
 end module

!
  SUBMODULE (foo_interface) foo_interface_son
!
  contains
! Test module procedure with conventional specification part for dummies
     module subroutine say_hello(this)
       class(foo), intent(in) :: this
       class(foo), allocatable :: that
       allocate (that, source = this)
!       call this%farewell         ! NOTE WELL: This compiles and causes a crash in run-time
!                                               due to recursion through the call to this procedure from
!                                               say hello.
       message = that%greeting

! Check that descendant module procedure is correctly processed
       if (intf (77) .ne. factor*77) call abort
     end subroutine

     module function realf (arg) result (res)
       real :: arg, res
       res = 2*arg
     end function

  end SUBMODULE foo_interface_son

!
! Check that multiple generations of submodules are OK
  SUBMODULE (foo_interface:foo_interface_son) foo_interface_grandson
!
  contains

     module procedure intf
       intf = factor*arg
     end PROCEDURE

  end SUBMODULE foo_interface_grandson

!
  SUBMODULE (foo_interface) foo_interface_daughter
!
  contains
! Test module procedure with abbreviated declaration and no specification of dummies
     module procedure bye
       class(foo), allocatable :: that
       call say_hello (this)
! check access to a PRIVATE procedure pointer that accesses a private component
       call this%adieu (that)
       message2 = that%greeting
     end PROCEDURE

! Test module procedure pointed to by PRIVATE component of foo
     module procedure byebye
       allocate (that, source = this)
! Access a PRIVATE component of foo
       that%greeting = that%byebye
     end PROCEDURE

     module procedure intg
       intg = 3*arg
     end PROCEDURE

     module procedure realg
       realg = 3*arg
     end PROCEDURE

  end SUBMODULE foo_interface_daughter

!
 program try
   use foo_interface
   implicit none
   type(foo) :: bar

   call clear_messages
   call bar%greet ! typebound call
   if (trim (message) .ne. "Hello, world!") call abort

   call clear_messages
   bar%greeting = "G'day, world!"
   call say_hello(bar) ! Checks use association of 'say_hello'
   if (trim (message) .ne. "G'day, world!") call abort

   call clear_messages
   bar%greeting = "Hi, world!"
   call bye(bar) ! Checks use association in another submodule
   if (trim (message) .ne. "Hi, world!") call abort
   if (trim (message2) .ne. "adieu, world!") call abort

   call clear_messages
   call smurf ! Checks host association of 'say_hello'
   if (trim (message) .ne. "Hello, world!") call abort

   call clear_messages
   bar%greeting = "farewell     "
   call bar%farewell
   if (trim (message) .ne. "farewell") call abort
   if (trim (message2) .ne. "adieu, world!") call abort

   if (realf(2.0) .ne. 4.0) call abort ! Check module procedure with explicit result
   if (intf(2) .ne. 10) call abort     ! ditto
   if (realg(3.0) .ne. 9.0) call abort ! Check module procedure with function declaration result
   if (intg(3) .ne. 9) call abort      ! ditto
 contains
   subroutine clear_messages
     message = ""
     message2 = ""
   end subroutine
 end program