diff --git a/api/ApiAbuseFilterCheckMatch.php b/api/ApiAbuseFilterCheckMatch.php
index d13e48c4a..8f704feea 100644
--- a/api/ApiAbuseFilterCheckMatch.php
+++ b/api/ApiAbuseFilterCheckMatch.php
@@ -7,7 +7,11 @@ class ApiAbuseFilterCheckMatch extends ApiBase {
 
 		// "Anti-DoS"
 		if ( !$this->getUser()->isAllowed( 'abusefilter-modify' ) ) {
-			$this->dieUsage( 'You don\'t have permission to test abuse filters', 'permissiondenied' );
+			if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+				$this->dieWithError( 'apierror-abusefilter-canttest', 'permissiondenied' );
+			} else {
+				$this->dieUsage( 'You don\'t have permission to test abuse filters', 'permissiondenied' );
+			}
 		}
 
 		$vars = null;
@@ -27,7 +31,11 @@ class ApiAbuseFilterCheckMatch extends ApiBase {
 			);
 
 			if ( !$row ) {
-				$this->dieUsageMsg( array( 'nosuchrcid', $params['rcid'] ) );
+				if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+					$this->dieWithError( [ 'apierror-nosuchrcid', $params['rcid'] ] );
+				} else {
+					$this->dieUsageMsg( [ 'nosuchrcid', $params['rcid'] ] );
+				}
 			}
 
 			$vars = AbuseFilter::getVarsFromRCRow( $row );
@@ -41,17 +49,25 @@ class ApiAbuseFilterCheckMatch extends ApiBase {
 			);
 
 			if ( !$row ) {
-				$this->dieUsage(
-					"There is no abuselog entry with the id ``{$params['logid']}''",
-					'nosuchlogid'
-				);
+				if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+					$this->dieWithError( [ 'apierror-abusefilter-nosuchlogid', $params['logid'] ], 'nosuchlogid' );
+				} else {
+					$this->dieUsage(
+						"There is no abuselog entry with the id ``{$params['logid']}''",
+						'nosuchlogid'
+					);
+				}
 			}
 
 			$vars = AbuseFilter::loadVarDump( $row->afl_var_dump );
 		}
 
 		if ( AbuseFilter::checkSyntax( $params[ 'filter' ] ) !== true ) {
-			$this->dieUsage( 'The filter has invalid syntax', 'badsyntax' );
+			if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+				$this->dieWithError( 'apierror-abusefilter-badsyntax', 'badsyntax' );
+			} else {
+				$this->dieUsage( 'The filter has invalid syntax', 'badsyntax' );
+			}
 		}
 
 		$result = array(
diff --git a/api/ApiAbuseFilterCheckSyntax.php b/api/ApiAbuseFilterCheckSyntax.php
index dfb8274dd..4f04a589d 100644
--- a/api/ApiAbuseFilterCheckSyntax.php
+++ b/api/ApiAbuseFilterCheckSyntax.php
@@ -5,10 +5,14 @@ class ApiAbuseFilterCheckSyntax extends ApiBase {
 	public function execute() {
 		// "Anti-DoS"
 		if ( !$this->getUser()->isAllowed( 'abusefilter-modify' ) ) {
-			$this->dieUsage(
-				'You don\'t have permission to check syntax of abuse filters',
-				'permissiondenied'
-			);
+			if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+				$this->dieWithError( 'apierror-abusefilter-cantcheck', 'permissiondenied' );
+			} else {
+				$this->dieUsage(
+					'You don\'t have permission to check syntax of abuse filters',
+					'permissiondenied'
+				);
+			}
 		}
 
 		$params = $this->extractRequestParams();
diff --git a/api/ApiAbuseFilterUnblockAutopromote.php b/api/ApiAbuseFilterUnblockAutopromote.php
index 81557472e..04cc945a1 100644
--- a/api/ApiAbuseFilterUnblockAutopromote.php
+++ b/api/ApiAbuseFilterUnblockAutopromote.php
@@ -2,25 +2,42 @@
 
 class ApiAbuseFilterUnblockAutopromote extends ApiBase {
 	public function execute() {
-		if ( !$this->getUser()->isAllowed( 'abusefilter-modify' ) ) {
-			$this->dieUsage( 'You do not have permissions to unblock autopromotion', 'permissiondenied' );
+		if ( is_callable( [ $this, 'checkUserRightsAny' ] ) ) {
+			$this->checkUserRightsAny( 'abusefilter-modify' );
+		} else {
+			if ( !$this->getUser()->isAllowed( 'abusefilter-modify' ) ) {
+				$this->dieUsage( 'You do not have permissions to unblock autopromotion', 'permissiondenied' );
+			}
 		}
 
 		$params = $this->extractRequestParams();
 		$user = User::newFromName( $params['user'] );
 
 		if ( $user === false ) {
-			// Oh god this is so bad but this message uses GENDER
-			$msg = wfMessage( 'abusefilter-reautoconfirm-none', $params['user'] )->text();
-			$this->dieUsage( $msg, 'notsuspended' );
+			$encParamName = $this->encodeParamName( 'user' );
+			if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+				$this->dieWithError(
+					[ 'apierror-baduser', $encParamName, wfEscapeWikiText( $param['user'] ) ],
+					"baduser_{$encParamName}"
+				);
+			} else {
+				$this->dieUsage(
+					"Invalid value '{$param['user']}' for user parameter $encParamName",
+					"baduser_{$encParamName}"
+				);
+			}
 		}
 
 		$key = AbuseFilter::autoPromoteBlockKey( $user );
 		$stash = ObjectCache::getMainStashInstance();
 		if ( !$stash->get( $key ) ) {
-			// Same as above :(
-			$msg = wfMessage( 'abusefilter-reautoconfirm-none', $params['user'] )->text();
-			$this->dieUsage( $msg, 'notsuspended' );
+			if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+				$this->dieWithError( [ 'abusefilter-reautoconfirm-none', $user->getName() ], 'notsuspended' );
+			} else {
+				$msg = wfMessage( 'abusefilter-reautoconfirm-none', $user->getName() )
+					->inLanguage( 'en' )->useDatabase( false )->text();
+				$this->dieUsage( $msg, 'notsuspended' );
+			}
 		}
 
 		$stash->delete( $key );
@@ -40,6 +57,7 @@ class ApiAbuseFilterUnblockAutopromote extends ApiBase {
 	public function getAllowedParams() {
 		return array(
 			'user' => array(
+				ApiBase::PARAM_TYPE => 'user',
 				ApiBase::PARAM_REQUIRED => true
 			),
 			'token' => null,
diff --git a/api/ApiQueryAbuseFilters.php b/api/ApiQueryAbuseFilters.php
index 239ea41fb..d8e390b9b 100644
--- a/api/ApiQueryAbuseFilters.php
+++ b/api/ApiQueryAbuseFilters.php
@@ -36,8 +36,12 @@ class ApiQueryAbuseFilters extends ApiQueryBase {
 
 	public function execute() {
 		$user = $this->getUser();
-		if ( !$user->isAllowed( 'abusefilter-view' ) ) {
-			$this->dieUsage( 'You don\'t have permission to view abuse filters', 'permissiondenied' );
+		if ( is_callable( [ $this, 'checkUserRightsAny' ] ) ) {
+			$this->checkUserRightsAny( 'abusefilter-view' );
+		} else {
+			if ( !$user->isAllowed( 'abusefilter-view' ) ) {
+				$this->dieUsage( 'You don\'t have permission to view abuse filters', 'permissiondenied' );
+			}
 		}
 
 		$params = $this->extractRequestParams();
@@ -79,12 +83,14 @@ class ApiQueryAbuseFilters extends ApiQueryBase {
 
 			/* Check for conflicting parameters. */
 			if ( ( isset( $show['enabled'] ) && isset( $show['!enabled'] ) )
-					|| ( isset( $show['deleted'] ) && isset( $show['!deleted'] ) )
-					|| ( isset( $show['private'] ) && isset( $show['!private'] ) ) ) {
-					$this->dieUsage(
-						'Incorrect parameter - mutually exclusive values may not be supplied',
-						'show'
-					);
+				|| ( isset( $show['deleted'] ) && isset( $show['!deleted'] ) )
+				|| ( isset( $show['private'] ) && isset( $show['!private'] ) )
+			) {
+				if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+					$this->dieWithError( 'apierror-show' );
+				} else {
+					$this->dieUsageMsg( 'show' );
+				}
 			}
 
 			$this->addWhereIf( 'af_enabled = 0', isset( $show['!enabled'] ) );
diff --git a/api/ApiQueryAbuseLog.php b/api/ApiQueryAbuseLog.php
index c7fb112c1..2941e5b0f 100644
--- a/api/ApiQueryAbuseLog.php
+++ b/api/ApiQueryAbuseLog.php
@@ -39,7 +39,11 @@ class ApiQueryAbuseLog extends ApiQueryBase {
 		$errors = $this->getTitle()->getUserPermissionsErrors(
 			'abusefilter-log', $user, true, array( 'ns-specialprotected' ) );
 		if ( count( $errors ) ) {
-			$this->dieUsageMsg( $errors[0] );
+			if ( is_callable( [ $this, 'errorArrayToStatus' ] ) ) {
+				$this->dieStatus( $this->errorArrayToStatus( $errors ) );
+			} else {
+				$this->dieUsageMsg( $errors[0] );
+			}
 			return;
 		}
 
@@ -58,14 +62,23 @@ class ApiQueryAbuseLog extends ApiQueryBase {
 		$fld_hidden = isset( $prop['hidden'] );
 		$fld_revid = isset( $prop['revid'] );
 
-		if ( $fld_ip && !$user->isAllowed( 'abusefilter-private' ) ) {
-			$this->dieUsage( 'You don\'t have permission to view IP addresses', 'permissiondenied' );
-		}
-		if ( $fld_details && !$user->isAllowed( 'abusefilter-log-detail' ) ) {
-			$this->dieUsage(
-				'You don\'t have permission to view detailed abuse log entries',
-				'permissiondenied'
-			);
+		if ( is_callable( [ $this, 'checkUserRightsAny' ] ) ) {
+			if ( $fld_ip ) {
+				$this->checkUserRightsAny( 'abusefilter-private' );
+			}
+			if ( $fld_details ) {
+				$this->checkUserRightsAny( 'abusefilter-log-detail' );
+			}
+		} else {
+			if ( $fld_ip && !$user->isAllowed( 'abusefilter-private' ) ) {
+				$this->dieUsage( 'You don\'t have permission to view IP addresses', 'permissiondenied' );
+			}
+			if ( $fld_details && !$user->isAllowed( 'abusefilter-log-detail' ) ) {
+				$this->dieUsage(
+					'You don\'t have permission to view detailed abuse log entries',
+					'permissiondenied'
+				);
+			}
 		}
 		// Match permissions for viewing events on private filters to SpecialAbuseLog (bug 42814)
 		if ( $params['filter'] &&
@@ -77,10 +90,16 @@ class ApiQueryAbuseLog extends ApiQueryBase {
 			}
 			foreach ( $params['filter'] as $filter ) {
 				if ( AbuseFilter::filterHidden( $filter ) ) {
-					$this->dieUsage(
-						'You don\'t have permission to view log entries for private filters',
-						'permissiondenied'
-					);
+					if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+						$this->dieWithError(
+							[ 'apierror-permissiondenied', $this->msg( 'action-abusefilter-log-private' ) ]
+						);
+					} else {
+						$this->dieUsage(
+							'You don\'t have permission to view log entries for private filters',
+							'permissiondenied'
+						);
+					}
 				}
 			}
 		}
@@ -145,7 +164,11 @@ class ApiQueryAbuseLog extends ApiQueryBase {
 		if ( !is_null( $title ) ) {
 			$titleObj = Title::newFromText( $title );
 			if ( is_null( $titleObj ) ) {
-				$this->dieUsageMsg( array( 'invalidtitle', $title ) );
+				if ( is_callable( [ $this, 'dieWithError' ] ) ) {
+					$this->dieWithError( array( 'apierror-invalidtitle', wfEscapeWikiText( $title ) ) );
+				} else {
+					$this->dieUsageMsg( array( 'invalidtitle', $title ) );
+				}
 			}
 			$this->addWhereFld( 'afl_namespace', $titleObj->getNamespace() );
 			$this->addWhereFld( 'afl_title', $titleObj->getDBkey() );
diff --git a/i18n/en.json b/i18n/en.json
index 96579989f..080466318 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -39,6 +39,7 @@
 	"action-abusefilter-modify-restricted": "modify abuse filters with restricted actions",
 	"action-abusefilter-revert": "revert all changes by a given abuse filter",
 	"action-abusefilter-view-private": "view abuse filters marked as private",
+	"action-abusefilter-log-private": "view logs of abuse filters marked as private",
 	"abusefilter-log": "Abuse filter log",
 	"abusefilter-log-summary": "This log shows a list of all actions caught by the filters.",
 	"abusefilter-log-search": "Search the abuse log",
@@ -438,5 +439,9 @@
 	"apihelp-query+abuselog-param-limit": "The maximum amount of entries to list.",
 	"apihelp-query+abuselog-param-prop": "Which properties to get.",
 	"apihelp-query+abuselog-example-1": "Show recent log entries",
-	"apihelp-query+abuselog-example-2": "Show recent log entries for [[API]]"
+	"apihelp-query+abuselog-example-2": "Show recent log entries for [[API]]",
+	"apierror-abusefilter-canttest": "You don't have permission to test abuse filters.",
+	"apierror-abusefilter-cantcheck": "You don't have permission to check syntax of abuse filters.",
+	"apierror-abusefilter-nosuchlogid": "There is no abuselog entry with the id $1.",
+	"apierror-abusefilter-badsyntax": "The filter has invalid syntax."
 }
diff --git a/i18n/qqq.json b/i18n/qqq.json
index 0b60ff1c4..1a72108e9 100644
--- a/i18n/qqq.json
+++ b/i18n/qqq.json
@@ -70,6 +70,7 @@
 	"action-abusefilter-modify-restricted": "{{doc-action|abusefilter-modify-restricted}}",
 	"action-abusefilter-revert": "{{doc-action|abusefilter-revert}}",
 	"action-abusefilter-view-private": "{{doc-action|abusefilter-view-private}}",
+	"action-abusefilter-log-private": "{{doc-action|abusefilter-log-private}}",
 	"abusefilter-log": "Caption of [[Special:AbuseLog]]",
 	"abusefilter-log-summary": "This message is displayed at the top of the log overview page for extension AbuseFilter.",
 	"abusefilter-log-search": "Caption of a fieldset for filter definition on [[Special:AbuseLog]]",
@@ -417,5 +418,9 @@
 	"apihelp-query+abuselog-param-limit": "{{doc-apihelp-param|query+abuselog|limit}}",
 	"apihelp-query+abuselog-param-prop": "{{doc-apihelp-param|query+abuselog|prop}}",
 	"apihelp-query+abuselog-example-1": "{{doc-apihelp-example|query+abuselog}}",
-	"apihelp-query+abuselog-example-2": "{{doc-apihelp-example|query+abuselog}}"
+	"apihelp-query+abuselog-example-2": "{{doc-apihelp-example|query+abuselog}}",
+	"apierror-abusefilter-badsyntax": "{{doc-apierror}}",
+	"apierror-abusefilter-cantcheck": "{{doc-apierror}}",
+	"apierror-abusefilter-canttest": "{{doc-apierror}}",
+	"apierror-abusefilter-nosuchlogid": "{{doc-apierror}}\n\nParameters:\n* $1 - AbuseFilter log ID number."
 }