[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 #4 from anlauf at gcc dot gnu.org ---
The following patch regtests ok and fixes the testcase:

diff --git a/gcc/fortran/module.c b/gcc/fortran/module.c
index 4db0a3ac76d..b4b7b437f86 100644
--- a/gcc/fortran/module.c
+++ b/gcc/fortran/module.c
@@ -6218,6 +6218,9 @@ write_symtree (gfc_symtree *st)
   if (check_unique_name (st->name))
     return;

+  if (strcmp (sym->module, "(intrinsic)") == 0)
+    return;
+
   p = find_pointer (sym);
   if (p == NULL)
     gfc_internal_error ("write_symtree(): Symbol not written");


It even fixes the slightly reduced & refined testcase:

module mod1
  implicit none
  real, parameter :: z = sqrt (0.0)
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
  y = sqrt (x)
end program test