Fixes #71 (#73)

aqua-src/error.aqua

@@ -1,8 +1,11 @@
-service Local("smth"):
-    getString: -> string
+service Test("test"):
+	getBool: -> bool
+	getList: -> []string
 
-func join() -> string:
-	app <- Local.getString()
-	on "app.user_list.peer_id":
-		res <- Local.getString()
-	<- res
+func f():
+	list <- Test.getList()
+	for user <- list:
+		on "peer" via "relay":
+			isOnline <- Test.getBool()
+		if isOnline:
+			Test.getBool()

parser/src/main/scala/aqua/parser/expr/ForExpr.scala

@@ -10,7 +10,15 @@ import LiftParser._
 
 case class ForExpr[F[_]](item: Name[F], iterable: Value[F], par: Option[F[Unit]]) extends Expr[F]
 
-object ForExpr extends Expr.AndIndented(Expr.defer(OnExpr), ParExpr, CallArrowExpr, AbilityIdExpr) {
+object ForExpr
+    extends Expr.AndIndented(
+      Expr.defer(OnExpr),
+      ParExpr,
+      CallArrowExpr,
+      AbilityIdExpr,
+      Expr.defer(IfExpr),
+      Expr defer ElseOtherwiseExpr
+    ) {
 
   override def p[F[_]: LiftParser: Comonad]: P[ForExpr[F]] =
     ((`for` *> ` ` *> Name.p[F] <* ` <- `) ~ Value.`value`[F] ~ (` ` *> `par`.lift).?).map {