diff --git a/apps/dav/lib/DAV/SystemPrincipalBackend.php b/apps/dav/lib/DAV/SystemPrincipalBackend.php
index 8c19e92499..7c5bdcab01 100644
--- a/apps/dav/lib/DAV/SystemPrincipalBackend.php
+++ b/apps/dav/lib/DAV/SystemPrincipalBackend.php
@@ -163,7 +163,7 @@ class SystemPrincipalBackend extends AbstractBackend {
 	 * @return array
 	 */
 	function getGroupMembership($principal) {
-		list($prefix, $name) = \Sabre\Uri\split($principal);
+		list($prefix, ) = \Sabre\Uri\split($principal);
 
 		if ($prefix === 'principals/system') {
 			$principal = $this->getPrincipalByPath($principal);
diff --git a/apps/dav/tests/unit/CalDAV/Search/Request/CalendarSearchReportTest.php b/apps/dav/tests/unit/CalDAV/Search/Request/CalendarSearchReportTest.php
index 20bac8aa9f..cbfc2e5549 100644
--- a/apps/dav/tests/unit/CalDAV/Search/Request/CalendarSearchReportTest.php
+++ b/apps/dav/tests/unit/CalDAV/Search/Request/CalendarSearchReportTest.php
@@ -199,7 +199,7 @@ XML;
 </nc:calendar-search>
 XML;
 
-		$result = $this->parse($xml);
+		$this->parse($xml);
 	}
 
 	/**
diff --git a/apps/dav/tests/unit/CardDAV/SyncServiceTest.php b/apps/dav/tests/unit/CardDAV/SyncServiceTest.php
index debc923806..0c0f36d030 100644
--- a/apps/dav/tests/unit/CardDAV/SyncServiceTest.php
+++ b/apps/dav/tests/unit/CardDAV/SyncServiceTest.php
@@ -80,7 +80,7 @@ class SyncServiceTest extends TestCase {
 		$logger = $this->getMockBuilder(ILogger::class)->disableOriginalConstructor()->getMock();
 		$accountManager = $this->getMockBuilder(AccountManager::class)->disableOriginalConstructor()->getMock();
 		$ss = new SyncService($backend, $userManager, $logger, $accountManager);
-		$book = $ss->ensureSystemAddressBookExists('principals/users/adam', 'contacts', []);
+		$ss->ensureSystemAddressBookExists('principals/users/adam', 'contacts', []);
 	}
 
 	public function testUpdateAndDeleteUser() {
diff --git a/apps/files/js/detailsview.js b/apps/files/js/detailsview.js
index a896e84fdc..7bfc3d5ad7 100644
--- a/apps/files/js/detailsview.js
+++ b/apps/files/js/detailsview.js
@@ -78,9 +78,6 @@
 			this._detailFileInfoViews = [];
 
 			this._dirty = true;
-
-			// uncomment to add some dummy tabs for testing
-			//this._addTestTabs();
 		},
 
 		_onClose: function(event) {
@@ -102,21 +99,6 @@
 			this.selectTab(tabId);
 		},
 
-		_addTestTabs: function() {
-			for (var j = 0; j < 2; j++) {
-				var testView = new OCA.Files.DetailTabView({id: 'testtab' + j});
-				testView.index = j;
-				testView.getLabel = function() { return 'Test tab ' + this.index; };
-				testView.render = function() {
-					this.$el.empty();
-					for (var i = 0; i < 100; i++) {
-						this.$el.append('<div>Test tab ' + this.index + ' row ' + i + '</div>');
-					}
-				};
-				this._tabViews.push(testView);
-			}
-		},
-
 		template: function(vars) {
 			if (!this._template) {
 				this._template = Handlebars.compile(TEMPLATE);
diff --git a/apps/files/js/favoritesfilelist.js b/apps/files/js/favoritesfilelist.js
index 4c2cf3ce81..8c9c125d0a 100644
--- a/apps/files/js/favoritesfilelist.js
+++ b/apps/files/js/favoritesfilelist.js
@@ -66,7 +66,6 @@ $(document).ready(function() {
 			},
 
 			reload: function() {
-				var tagName = OC.TAG_FAVORITE;
 				this.showMask();
 				if (this._reloadCall) {
 					this._reloadCall.abort();
diff --git a/apps/files/lib/Command/Scan.php b/apps/files/lib/Command/Scan.php
index d81beb0eaf..4026af2db7 100644
--- a/apps/files/lib/Command/Scan.php
+++ b/apps/files/lib/Command/Scan.php
@@ -322,7 +322,7 @@ class Scan extends Base {
 	 * @return string
 	 */
 	protected function formatExecTime() {
-		list($secs, $tens) = explode('.', sprintf("%.1f", ($this->execTime)));
+		list($secs, ) = explode('.', sprintf("%.1f", ($this->execTime)));
 
 		# if you want to have microseconds add this:   . '.' . $tens;
 		return date('H:i:s', $secs);
diff --git a/apps/files/lib/Command/ScanAppData.php b/apps/files/lib/Command/ScanAppData.php
index 7212717ee4..afcdf999d2 100644
--- a/apps/files/lib/Command/ScanAppData.php
+++ b/apps/files/lib/Command/ScanAppData.php
@@ -240,7 +240,7 @@ class ScanAppData extends Base {
 	 * @return string
 	 */
 	protected function formatExecTime() {
-		list($secs, $tens) = explode('.', sprintf("%.1f", ($this->execTime)));
+		list($secs, ) = explode('.', sprintf("%.1f", ($this->execTime)));
 
 		# if you want to have microseconds add this:   . '.' . $tens;
 		return date('H:i:s', $secs);
diff --git a/lib/private/legacy/files.php b/lib/private/legacy/files.php
index 017691805c..92dbf08bc6 100644
--- a/lib/private/legacy/files.php
+++ b/lib/private/legacy/files.php
@@ -338,7 +338,7 @@ class OC_Files {
 	 *
 	 * @param int $size file size in bytes
 	 * @param array $files override '.htaccess' and '.user.ini' locations
-	 * @return bool false on failure, size on success
+	 * @return bool|int false on failure, size on success
 	 */
 	public static function setUploadLimit($size, $files = []) {
 		//don't allow user to break his config
diff --git a/lib/public/AppFramework/Db/Mapper.php b/lib/public/AppFramework/Db/Mapper.php
index 611791a436..b008702ba5 100644
--- a/lib/public/AppFramework/Db/Mapper.php
+++ b/lib/public/AppFramework/Db/Mapper.php
@@ -244,7 +244,7 @@ abstract class Mapper {
 			}
 		}
 
-		$result = $query->execute();
+		$query->execute();
 
 		return $query;
 	}