re PR c++/56380 (Const/reference mutable members are not always rejected in class templates)

/cp
2013-08-22  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/56380
	* class.c (check_field_decls): Check for const mutable and const
	reference data members.

/testsuite
2013-08-22  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/56380
	* g++.dg/template/error54.C: New.

From-SVN: r201925

gcc/cp/ChangeLog

+2013-08-22  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/56380
+	* class.c (check_field_decls): Check for const mutable and const
+	reference data members.
+
 2013-08-22  Gabriel Dos Reis  <gdr@integrable-solutions.net>
 
 	* error.c (init_error): Remove calls to pp_construct and

gcc/cp/class.c

@@ -3500,6 +3500,22 @@ check_field_decls (tree t, tree *access_decls,
       if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
 	CLASSTYPE_HAS_MUTABLE (t) = 1;
 
+      if (DECL_MUTABLE_P (x))
+	{
+	  if (CP_TYPE_CONST_P (type))
+	    {
+	      error ("member %q+D cannot be declared both %<const%> "
+		     "and %<mutable%>", x);
+	      continue;
+	    }
+	  if (TREE_CODE (type) == REFERENCE_TYPE)
+	    {
+	      error ("member %q+D cannot be declared as a %<mutable%> "
+		     "reference", x);
+	      continue;
+	    }
+	}
+
       if (! layout_pod_type_p (type))
 	/* DR 148 now allows pointers to members (which are POD themselves),
 	   to be allowed in POD structs.  */

gcc/testsuite/ChangeLog

+2013-08-22  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/56380
+	* g++.dg/template/error54.C: New.
+
 2013-08-22  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/58185

gcc/testsuite/g++.dg/template/error54.C

+// PR c++/56380
+
+template <typename T>
+struct X {
+  X();
+  mutable T x;  // { dg-error "cannot be declared" }
+};
+
+X<const int> a; // { dg-message "required from here" }
+X<int&> b;      // { dg-message "required from here" }