diff --git a/src/lint/linter/ArcanistBaseXHPASTLinter.php b/src/lint/linter/ArcanistBaseXHPASTLinter.php
index 7951c62e..80f76bbb 100644
--- a/src/lint/linter/ArcanistBaseXHPASTLinter.php
+++ b/src/lint/linter/ArcanistBaseXHPASTLinter.php
@@ -48,7 +48,7 @@ abstract class ArcanistBaseXHPASTLinter extends ArcanistFutureLinter {
       $replace);
   }
 
-  protected function buildFutures(array $paths) {
+  final protected function buildFutures(array $paths) {
     return $this->getXHPASTLinter()->buildSharedFutures($paths);
   }
 
@@ -69,7 +69,7 @@ abstract class ArcanistBaseXHPASTLinter extends ArcanistFutureLinter {
    * @return ArcanistBaseXHPASTLinter Responsible linter.
    * @task sharing
    */
-  protected function getXHPASTLinter() {
+  final protected function getXHPASTLinter() {
     $resource_key = 'xhpast.linter';
 
     // If we're the first linter to run, share ourselves. Otherwise, grab the
@@ -102,7 +102,7 @@ abstract class ArcanistBaseXHPASTLinter extends ArcanistFutureLinter {
    * @return list<ExecFuture> Futures.
    * @task sharing
    */
-  protected function buildSharedFutures(array $paths) {
+  final protected function buildSharedFutures(array $paths) {
     foreach ($paths as $path) {
       if (!isset($this->futures[$path])) {
         $this->futures[$path] = xhpast_get_parser_future($this->getData($path));
@@ -119,7 +119,7 @@ abstract class ArcanistBaseXHPASTLinter extends ArcanistFutureLinter {
    * @return  XHPASTTree|null  Tree, or null if unparseable.
    * @task sharing
    */
-  protected function getXHPASTTreeForPath($path) {
+  final protected function getXHPASTTreeForPath($path) {
 
     // If we aren't the linter responsible for actually building the parse
     // trees, go get the tree from that linter.
@@ -152,7 +152,7 @@ abstract class ArcanistBaseXHPASTLinter extends ArcanistFutureLinter {
    * @return  Exeption|null   Parse exception, if available.
    * @task sharing
    */
-  protected function getXHPASTExceptionForPath($path) {
+  final protected function getXHPASTExceptionForPath($path) {
     if ($this->getXHPASTLinter() !== $this) {
       return $this->getXHPASTLinter()->getXHPASTExceptionForPath($path);
     }
diff --git a/src/lint/linter/ArcanistLinter.php b/src/lint/linter/ArcanistLinter.php
index 410f0903..5c798ed3 100644
--- a/src/lint/linter/ArcanistLinter.php
+++ b/src/lint/linter/ArcanistLinter.php
@@ -174,7 +174,7 @@ abstract class ArcanistLinter {
     return $this->data[$path];
   }
 
-  public function setEngine(ArcanistLintEngine $engine) {
+  final public function setEngine(ArcanistLintEngine $engine) {
     $this->engine = $engine;
     return $this;
   }
@@ -476,7 +476,7 @@ abstract class ArcanistLinter {
    * @param   wild    Default value to return if key is not present in config.
    * @return  wild    Configured value, or default if no configuration exists.
    */
-  protected function getDeprecatedConfiguration($key, $default = null) {
+  final protected function getDeprecatedConfiguration($key, $default = null) {
 
     // If we're being called in a context without an engine (probably from
     // `arc linters`), just return the default value.