re PR c++/39560 (Erroneous warnings 'unused variable' in a templated class method with union)

	PR c++/39560
	* decl2.c (build_anon_union_vars): Set DECL_ARTIFICIAL.

From-SVN: r154133

gcc/cp/ChangeLog

 2009-11-12  Jason Merrill  <jason@redhat.com>
 
+	PR c++/39560
+	* decl2.c (build_anon_union_vars): Set DECL_ARTIFICIAL.
+
 	PR c++/37037
 	* decl.c (grokdeclarator): Don't generate a void PARM_DECL.
 

gcc/cp/decl2.c

@@ -1313,6 +1313,7 @@ build_anon_union_vars (tree type, tree object)
 	  decl = build_decl (input_location,
 			     VAR_DECL, DECL_NAME (field), TREE_TYPE (field));
 	  DECL_ANON_UNION_VAR_P (decl) = 1;
+	  DECL_ARTIFICIAL (decl) = 1;
 
 	  base = get_base_address (object);
 	  TREE_PUBLIC (decl) = TREE_PUBLIC (base);

gcc/testsuite/ChangeLog

 2009-11-12  Jason Merrill  <jason@redhat.com>
 
+	PR c++/39560
+	* g++.dg/lookup/anon7.C: New.
+
 	PR c++/37037
 	* g++.dg/template/typedef21.C: New.
 

gcc/testsuite/g++.dg/lookup/anon7.C

+// PR c++/39560
+// { dg-options -Wunused }
+
+struct X { };
+
+class Z {
+public:
+  X* cc(int c);
+};
+
+class F {
+public:
+  typedef X* (Z::*MethO)(int);
+  typedef X* (F::*MethF)(int);
+  template<MethO m>
+  X* xwrapper(int i) {
+    union {
+      Z *z;
+      F *f;
+    };				// { dg-bogus "unused" }
+    f = this;
+    return ((z->*m)(i));
+  }
+};
+
+F::MethF meth = &F::xwrapper<&Z::cc>;