[PATCH] PR fortran/63797 - Bogus ambiguous reference to 'sqrt'

[Harald Anlauf <anlauf@gmx.de>]

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Hello everybody,

we currently write the interface for intrinsic procedures to module
files although that should not be necessary.  (F2018:15.4.2.1 actually
states that interfaces e.g. of intrinsic procedures are 'explicit'.)
This lead to bogus errors due to an apparently bogus ambiguity.
A simple solution is to just avoid writing that (redundant) information
to the module file.

Regtested on x86_64-pc-linux-gnu.  OK for (current) mainline?
Or rather wait after 11 release?

Thanks,
Harald


PR fortran/63797 - Bogus ambiguous reference to 'sqrt'

The interface of an intrinsic procedure is automatically explicit.
Do not write it to the module file.

gcc/fortran/ChangeLog:

	* module.c (write_symtree): Do not write interface of intrinsic
	procedure to module file.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr63797.f90: New test.


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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");
diff --git a/gcc/testsuite/gfortran.dg/pr63797.f90 b/gcc/testsuite/gfortran.dg/pr63797.f90
new file mode 100644
index 00000000000..1131e8167b1
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr63797.f90
@@ -0,0 +1,60 @@
+! { 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
+  elemental function sqrt (a)
+    type(t), intent(in) :: a
+    type(t)             :: sqrt
+    sqrt% a = a% a
+  end function sqrt
+end module mod2
+
+module mod3
+  implicit none
+  abstract interface
+     function real_func (x)
+       real              :: real_func
+       real, intent (in) :: x
+     end function real_func
+  end interface
+  intrinsic :: sqrt
+  procedure(real_func), pointer :: real_root => sqrt
+end module mod3
+
+program test
+  use mod1
+  use mod2
+  use mod3
+  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)
+  y% a = real_root (x% a)
+end program test