Index: src/GenPoly/Box.cc
===================================================================
--- src/GenPoly/Box.cc	(revision 943bfad2c0b8d6d35a71ff04892a3d14825e9dc8)
+++ src/GenPoly/Box.cc	(revision 7ff35e0e9d22f318f67ab6ff6dae531af68e5edc)
@@ -1546,11 +1546,28 @@
 			long i = 0;
 			for(std::list< Declaration* >::const_iterator decl = baseDecls.begin(); decl != baseDecls.end(); ++decl, ++i ) {
-				if ( memberDecl->get_name() != (*decl)->get_name() ) continue;
-
-				if ( DeclarationWithType *declWithType = dynamic_cast< DeclarationWithType* >( *decl ) ) {
-					if ( memberDecl->get_mangleName().empty() || declWithType->get_mangleName().empty()
-					     || memberDecl->get_mangleName() == declWithType->get_mangleName() ) return i;
-					else continue;
-				} else return i;
+				if ( memberDecl->get_name() != (*decl)->get_name() )
+					continue;
+
+				if ( memberDecl->get_name().empty() ) {
+					// plan-9 field: match on unique_id
+					if ( memberDecl->get_uniqueId() == (*decl)->get_uniqueId() )
+						return i;
+					else
+						continue;
+				}
+
+				DeclarationWithType *declWithType = strict_dynamic_cast< DeclarationWithType* >( *decl );
+
+				if ( memberDecl->get_mangleName().empty() || declWithType->get_mangleName().empty() ) {
+					// tuple-element field: expect neither had mangled name; accept match on simple name (like field_2) only
+					assert( memberDecl->get_mangleName().empty() && declWithType->get_mangleName().empty() );
+					return i;
+				}
+
+				// ordinary field: use full name to accommodate overloading
+				if ( memberDecl->get_mangleName() == declWithType->get_mangleName() )
+					return i;
+				else
+					continue;
 			}
 			return -1;