re PR c++/49298 ([C++0x] sorry, unimplemented: unexpected ast of kind field_decl)

	PR c++/49298
	* semantics.c (potential_constant_expression_1): Handle FIELD_DECL.

From-SVN: r174721

gcc/cp/ChangeLog

 2011-06-06  Jason Merrill  <jason@redhat.com>
 
+	PR c++/49298
+	* semantics.c (potential_constant_expression_1): Handle FIELD_DECL.
+
 	PR objc++/49221
 	* decl.c (cp_finish_decl): Check DECL_FUNCTION_SCOPE_P rather than
 	at_function_scope_p.

gcc/cp/semantics.c

@@ -7489,6 +7489,8 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
     case TEMPLATE_PARM_INDEX:
     case TRAIT_EXPR:
     case IDENTIFIER_NODE:
+      /* We can see a FIELD_DECL in a pointer-to-member expression.  */
+    case FIELD_DECL:
       return true;
 
     case PARM_DECL:

gcc/testsuite/ChangeLog

+2011-06-06  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/cpp0x/regress/ptrmem1.C: New.
+
 2011-06-06  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	PR rtl-optimization/49145

gcc/testsuite/g++.dg/cpp0x/regress/ptrmem1.C

+// PR c++/49298
+// { dg-options -std=c++0x }
+
+template <class T, int T::*> struct B { };
+template <class T> struct A
+{
+  int i;
+  B<A,&A::i> b;
+};