[Bug fortran/63797] Bogus ambiguous reference to 'sqrt'

["anlauf at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63797

--- Comment #6 from anlauf at gcc dot gnu.org ---
Steve, can you give an example for the procedure pointer case you mentioned?
I played a bit, but the only valid code that I can think of did not produce
a reference to sqrt in such a way that it needs to show up in the mod.

Extended testcase that compiles and also uses a procedure pointer to sqrt():

! { dg-do compile }
! PR63797 - Bogus ambiguous reference to 'sqrt'

module mod1
  implicit none
  real, parameter :: z = sqrt (0.0)
  real            :: w = sqrt (1.0)
  interface
     pure real function sqrt_ifc (x)
       real, intent(in) :: x
     end function sqrt_ifc
  end interface
contains
  pure function myroot () result (f)
    procedure(sqrt_ifc), pointer :: f
    intrinsic :: sqrt
    f => sqrt
  end function myroot
end module mod1

module mod2
  implicit none
  type t
     real :: a = 0.
  end type
  interface sqrt
     module procedure sqrt
  end interface
contains
  function sqrt (a)
    type(t), intent(in) :: a
    type(t)             :: sqrt
    sqrt% a = a% a
  end function sqrt
end module mod2

program test
  use mod1
  use mod2
  implicit none
  type(t) :: x, y
  procedure(sqrt_ifc), pointer :: root
  root => myroot ()
  y    = sqrt (x)
  y% a = sqrt (x% a) + z - w + root (x% a)
end program test