re PR fortran/82796 (Private+equivalence in used module breaks compilation of pure function)

2017-11-01  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/82796
	* resolve.c (resolve_equivalence): An entity in a common block within
 	a module cannot appear in an equivalence statement if the entity is
	with a pure procedure.

2017-11-01  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/82796
	* gfortran.dg/equiv_pure.f90: New test.

From-SVN: r254403

gcc/fortran/ChangeLog

+2017-11-03  Steven G. Kargl  <kargl@gcc.gnu.org>
+
+	PR fortran/82796
+	* resolve.c (resolve_equivalence): An entity in a common block within
+ 	a module cannot appear in an equivalence statement if the entity is
+	with a pure procedure.
+
 2017-10-31  Jim Wilson  <wilson@tuliptree.org>
 
 	* parse.c (unexpected_eof): Call gcc_unreachable before return.

gcc/fortran/resolve.c

@@ -15936,8 +15936,21 @@ resolve_equivalence (gfc_equiv *eq)
 	  && sym->ns->proc_name->attr.pure
 	  && sym->attr.in_common)
 	{
-	  gfc_error ("Common block member %qs at %L cannot be an EQUIVALENCE "
-		     "object in the pure procedure %qs",
+	  /* Need to check for symbols that may have entered the pure
+	     procedure via a USE statement.  */
+	  bool saw_sym = false;
+	  if (sym->ns->use_stmts)
+	    {
+	      gfc_use_rename *r;
+	      for (r = sym->ns->use_stmts->rename; r; r = r->next)
+		if (strcmp(r->use_name, sym->name) == 0) saw_sym = true; 
+	    }
+	  else
+	    saw_sym = true;
+
+	  if (saw_sym)
+	    gfc_error ("COMMON block member %qs at %L cannot be an "
+		       "EQUIVALENCE object in the pure procedure %qs",
 		       sym->name, &e->where, sym->ns->proc_name->name);
 	  break;
 	}

gcc/testsuite/ChangeLog

+2017-11-03  Steven G. Kargl  <kargl@gcc.gnu.org>
+
+	PR fortran/82796
+	* gfortran.dg/equiv_pure.f90: New test.
+
 2017-11-03  Jeff Law  <law@redhat.com>
 
 	PR target/82823

gcc/testsuite/gfortran.dg/equiv_pure.f90

+! { dg-do compile }
+! PR fortran/82796
+! Code contributed by ripero84 at gmail dot com 
+module eq
+   implicit none
+   integer :: n1, n2
+   integer, dimension(2) :: a
+   equivalence (a(1), n1)
+   equivalence (a(2), n2)
+   common /a/ a
+end module eq
+
+module m
+   use eq
+   implicit none
+   type, public :: t
+     integer :: i
+   end type t
+end module m
+
+module p
+   implicit none
+   contains
+   pure integer function d(h)
+     use m
+     implicit none
+     integer, intent(in) :: h
+     d = h
+   end function
+end module p
+
+module q
+   implicit none
+   contains
+   pure integer function d(h)
+     use m, only : t
+     implicit none
+     integer, intent(in) :: h
+     d = h
+   end function
+end module q
+
+module r
+   implicit none
+   contains
+   pure integer function d(h)
+     use m, only : a          ! { dg-error "cannot be an EQUIVALENCE object" }
+     implicit none
+     integer, intent(in) :: h
+     d = h
+   end function
+end module r