diff --git a/src/lint/linter/ArcanistBaseXHPASTLinter.php b/src/lint/linter/ArcanistBaseXHPASTLinter.php
--- a/src/lint/linter/ArcanistBaseXHPASTLinter.php
+++ b/src/lint/linter/ArcanistBaseXHPASTLinter.php
@@ -157,7 +157,6 @@
    * @task sharing
    */
   final protected function getXHPASTTreeForPath($path) {
-
     // If we aren't the linter responsible for actually building the parse
     // trees, go get the tree from that linter.
     if ($this->getXHPASTLinter() !== $this) {
@@ -165,7 +164,12 @@
     }
 
     if (!array_key_exists($path, $this->trees)) {
+      if (!array_key_exists($path, $this->futures)) {
+        return;
+      }
+
       $this->trees[$path] = null;
+
       try {
         $this->trees[$path] = XHPASTTree::newFromDataAndResolvedExecFuture(
           $this->getData($path),