diff --git a/hscript/Async.hx b/hscript/Async.hx
index de3f264..233a32f 100644
--- a/hscript/Async.hx
+++ b/hscript/Async.hx
@@ -79,8 +79,10 @@ class Async {
 
 	function buildSync( e : Expr, exit : Expr ) : Expr {
 		switch( expr(e) ) {
-		case EFunction(_):
-			return toCps(e, null, null);
+		case EFunction(_,_,name,_):
+			if( name != null )
+				return toCps(e, null, null);
+			return e;
 		case EBlock(el):
 			var v = saveVars();
 			for( e in el )
@@ -96,7 +98,7 @@ class Async {
 		case EBreak if( currentBreak != null ):
 			return currentBreak(e);
 		case EContinue if( currentLoop != null ):
-			return block([call(currentLoop, [nullId], e), mk(EReturn(),e)],e);
+			return block([retNull(currentLoop, e), mk(EReturn(),e)],e);
 		case EFor(_), EWhile(_):
 			var oldLoop = currentLoop, oldBreak = currentBreak;
 			currentLoop = null;
@@ -106,7 +108,7 @@ class Async {
 			currentBreak = oldBreak;
 			return e;
 		case EReturn(eret) if( exit != null ):
-			return block([call(exit,[eret == null ? nullId : eret], e), mk(EReturn(),e)], e);
+			return block([eret == null ? retNull(exit, e) : call(exit,[eret], e), mk(EReturn(),e)], e);
 		default:
 			return Tools.map(e, buildSync.bind(_, exit));
 		}
@@ -133,7 +135,9 @@ class Async {
 		return mk(EFunction([for( a in arg ) { name : a, t : null }], e, name), e);
 	}
 
-	inline function block(arr, e) {
+	inline function block(arr:Array<Expr>, e) {
+		if( arr.length == 1 && expr(arr[0]).match(EBlock(_)) )
+			return arr[0];
 		return mk(EBlock(arr), e);
 	}
 
@@ -149,8 +153,12 @@ class Async {
 		return mk(ECall(e, args), inf);
 	}
 
-	function retNull(e) : Expr {
-		return call(e, [nullId],e);
+	function retNull(e:Expr,?pos) : Expr {
+		switch( expr(e) ) {
+		case EFunction([{name:"_"}], e, _, _): return e;
+		default:
+		}
+		return call(e, [nullId], pos == null ? e : pos);
 	}
 
 	function makeCall( ecall, args : Array<Expr>, rest : Expr, exit, sync = false ) {
@@ -179,7 +187,9 @@ class Async {
 		if( !syncFlag )
 			return;
 		switch( expr(e) ) {
-		case ECall(_), EFunction(_):
+		case ECall(_):
+			syncFlag = false;
+		case EFunction(_,_,name,_) if( name != null ):
 			syncFlag = false;
 		case EMeta("sync" | "async", _, _):
 			// isolated from the sync part
@@ -206,7 +216,7 @@ class Async {
 			// local recursion
 			for( e in el )
 				switch( expr(e) ) {
-				case EFunction(_, _, name, null): varNames.push(name);
+				case EFunction(_, _, name, null): if( name != null ) varNames.push(name);
 				default:
 				}
 			while( el.length > 0 ) {
@@ -250,7 +260,7 @@ class Async {
 			var oldLoop = currentLoop, oldBreak = currentBreak;
 			var loop = ident("_loop" + id,e);
 			currentLoop = loop;
-			currentBreak = function(inf) return block([call(rest, [nullId], inf), mk(EReturn(),inf)], inf);
+			currentBreak = function(inf) return block([retNull(rest, inf), mk(EReturn(),inf)], inf);
 			var efor = block([
 				mk(EVar("_i" + id, call(ident("makeIterator",eit),[eit],eit)),eit),
 				fun("_", block([
@@ -258,7 +268,7 @@ class Async {
 					mk(EVar(v, call(field(it, "next",it), [], it)), it),
 					toCps(eloop, loop, exit),
 				], it),"_loop" + id),
-				call(loop, [nullId], e),
+				retNull(loop, e),
 			], e);
 			currentLoop = oldLoop;
 			currentBreak = oldBreak;
@@ -306,18 +316,18 @@ class Async {
 			var loop = ident("_loop" + id, cond);
 			var oldLoop = currentLoop, oldBreak = currentBreak;
 			currentLoop = loop;
-			currentBreak = function(e) return block([call(rest, [nullId], e), mk(EReturn(),e)],e);
+			currentBreak = function(e) return block([retNull(rest,e), mk(EReturn(),e)],e);
 			var ewhile = block([
 				fun("_r",
-					toCps(cond, fun("_c", mk(EIf(ident("_c", cond), toCps(ewh, loop, exit), call(rest, [nullId], cond)),cond)), exit)
+					toCps(cond, fun("_c", mk(EIf(ident("_c", cond), toCps(ewh, loop, exit), retNull(rest,cond)),cond)), exit)
 				, "_loop"+id),
-				call(loop, [nullId], cond),
+				retNull(loop, cond),
 			],e);
 			currentLoop = oldLoop;
 			currentBreak = oldBreak;
 			return ewhile;
 		case EReturn(eret):
-			return eret == null ? call(exit, [nullId], e) : toCps(eret, exit, exit);
+			return eret == null ? retNull(exit, e) : toCps(eret, exit, exit);
 		case EObject(fields):
 			var id = "_o" + uid++;
 			var rest = call(rest, [ident(id,e)], e);
@@ -353,10 +363,10 @@ class Async {
 			return toCps(earr, fun(id1, toCps(eindex, fun(id2, call(rest, [mk(EArray(ident(id1,e), ident(id2,e)),e)], e)), exit)), exit);
 		case EVar(v, t, ev):
 			if( ev == null )
-				return block([e, call(rest, [nullId],e)], e);
+				return block([e, retNull(rest, e)], e);
 			return block([
 				mk(EVar(v, t),e),
-				toCps(ev, fun("_r", block([binop("=", ident(v,e), ident("_r",e), e), call(rest,[nullId],e)], e)), exit),
+				toCps(ev, fun("_r", block([binop("=", ident(v,e), ident("_r",e), e), retNull(rest,e)], e)), exit),
 			],e);
 		case EConst(_), EIdent(_), EUnop(_), EField(_):
 			return call(rest, [e], e);
@@ -375,7 +385,7 @@ class Async {
 			return currentBreak(e);
 		case EContinue:
 			if( currentLoop == null ) throw "Continue outside loop";
-			return block([call(currentLoop, [nullId], e), mk(EReturn(),e)], e);
+			return block([retNull(currentLoop, e), mk(EReturn(),e)], e);
 		case ESwitch(v, cases, def):
 			var cases = [for( c in cases ) { values : c.values, expr : toCps(c.expr, rest, exit) } ];
 			return toCps(v, mk(EFunction([ { name : "_c", t : null } ], mk(ESwitch(ident("_c",v), cases, def == null ? retNull(rest) : toCps(def, rest, exit)),e)),e), exit );