diff --git a/app/src/main/java/org/schabi/newpipe/local/feed/FeedDatabaseManager.kt b/app/src/main/java/org/schabi/newpipe/local/feed/FeedDatabaseManager.kt
index d319c9fa3..f77e13f69 100644
--- a/app/src/main/java/org/schabi/newpipe/local/feed/FeedDatabaseManager.kt
+++ b/app/src/main/java/org/schabi/newpipe/local/feed/FeedDatabaseManager.kt
@@ -50,7 +50,7 @@ class FeedDatabaseManager(context: Context) {
 
         return streams.map<List<StreamInfoItem>> {
             val items = ArrayList<StreamInfoItem>(it.size)
-            for (streamEntity in it) items.add(streamEntity.toStreamInfoItem())
+            it.mapTo(items) { it.toStreamInfoItem() }
             return@map items
         }
     }
diff --git a/app/src/main/java/org/schabi/newpipe/local/feed/service/FeedLoadService.kt b/app/src/main/java/org/schabi/newpipe/local/feed/service/FeedLoadService.kt
index 0181f2711..556c215d9 100644
--- a/app/src/main/java/org/schabi/newpipe/local/feed/service/FeedLoadService.kt
+++ b/app/src/main/java/org/schabi/newpipe/local/feed/service/FeedLoadService.kt
@@ -161,8 +161,8 @@ class FeedLoadService : Service() {
         companion object {
             fun wrapList(subscriptionId: Long, info: ListInfo<StreamInfoItem>): List<Throwable> {
                 val toReturn = ArrayList<Throwable>(info.errors.size)
-                for (error in info.errors) {
-                    toReturn.add(RequestException(subscriptionId, info.serviceId.toString() + ":" + info.url, error))
+                info.errors.mapTo(toReturn) {
+                    RequestException(subscriptionId, info.serviceId.toString() + ":" + info.url, it)
                 }
                 return toReturn
             }
diff --git a/app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupDialogViewModel.kt b/app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupDialogViewModel.kt
index e9a7e4eb7..4b1a4df5e 100644
--- a/app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupDialogViewModel.kt
+++ b/app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupDialogViewModel.kt
@@ -37,8 +37,8 @@ class FeedGroupDialogViewModel(
                 BiFunction { t1: String, t2: Boolean -> Filter(t1, t2) }
         )
         .distinctUntilChanged()
-        .switchMap { filter ->
-            subscriptionManager.getSubscriptions(groupId, filter.query, filter.showOnlyUngrouped)
+        .switchMap { (query, showOnlyUngrouped) ->
+            subscriptionManager.getSubscriptions(groupId, query, showOnlyUngrouped)
         }.map { list -> list.map { PickerSubscriptionItem(it) } }
 
     private val mutableGroupLiveData = MutableLiveData<FeedGroupEntity>()