--- Alias.xs.orig	2010-07-25 00:35:27.000000000 +0200
+++ Alias.xs	2010-07-25 01:23:11.000000000 +0200
@@ -366,14 +366,14 @@
 	SSPUSHPTR(gp);
 	SSPUSHINT(SAVEt_DESTRUCTOR_X);
 	++gp->gp_refcnt;
-	*sptr = Nullsv;
+	*sptr = NULL;
 }
 
 STATIC SV *da_refgen(pTHX_ SV *sv) {
 	SV *rv;
 	PREP_ALIAS_INC(sv);
 	rv = sv_newmortal();
-	sv_upgrade(rv, SVt_RV);
+	sv_upgrade(rv, SVt_IV);
 	SvRV(rv) = sv;
 	SvROK_on(rv);
 	SvREADONLY_on(rv);
@@ -1248,7 +1248,7 @@
 		cxstack_ix--;
 		POPSUB(cx, sv);
 	} else {
-		sv = Nullsv;
+		sv = NULL;
 	}
 	PL_curpm = newpm;
 	LEAVESUB(sv);
@@ -1433,7 +1433,7 @@
 	int hits = 0;
 
 	while (op) {
-		OP *kid = Nullop, *tmp;
+		OP *kid = NULL, *tmp;
 		int ksib = TRUE;
 		OPCODE optype;
 
@@ -1447,7 +1447,6 @@
 		default:
 			--hits;
 			switch (optype) {
-			case OP_SETSTATE:
 			case OP_NEXTSTATE:
 			case OP_DBSTATE:
 				PL_curcop = (COP *) op;
@@ -1586,7 +1585,6 @@
 				if (da_peep2(aTHX_ k))
 					return 1;
 			} else switch (o->op_type ? o->op_type : o->op_targ) {
-			case OP_SETSTATE:
 			case OP_NEXTSTATE:
 			case OP_DBSTATE:
 				PL_curcop = (COP *) o;
@@ -1764,7 +1762,7 @@
 	kUNOP->op_first = last;
 	while (kid->op_sibling != last)
 		kid = kid->op_sibling;
-	kid->op_sibling = Nullop;
+	kid->op_sibling = NULL;
 	cLISTOPx(cUNOPo->op_first)->op_last = kid;
 	if (kid->op_type == OP_NULL && inside)
 		kid->op_flags &= ~OPf_SPECIAL;