diff --git a/src/applications/diffusion/controller/symbol/DiffusionSymbolController.php b/src/applications/diffusion/controller/symbol/DiffusionSymbolController.php
index 4d5a69702e..9e4d5a35d1 100644
--- a/src/applications/diffusion/controller/symbol/DiffusionSymbolController.php
+++ b/src/applications/diffusion/controller/symbol/DiffusionSymbolController.php
@@ -65,11 +65,23 @@ final class DiffusionSymbolController extends DiffusionController {
     // For PHP builtins, jump to php.net documentation.
     if ($request->getBool('jump') && count($symbols) == 0) {
       if ($request->getStr('lang') == 'php') {
-        if ($request->getStr('type') == 'function') {
-          if (in_array($this->name, idx(get_defined_functions(), 'internal'))) {
-            return id(new AphrontRedirectResponse())
-              ->setURI('http://www.php.net/function.'.$this->name);
-          }
+        switch ($request->getStr('type')) {
+          case 'function':
+            $functions = get_defined_functions();
+            if (in_array($this->name, $functions['internal'])) {
+              return id(new AphrontRedirectResponse())
+                ->setURI('http://www.php.net/function.'.$this->name);
+            }
+            break;
+          case 'class':
+            if (class_exists($this->name) ||
+                in_array($this->name, get_declared_interfaces())) {
+              if (id(new ReflectionClass($this->name))->isInternal()) {
+                return id(new AphrontRedirectResponse())
+                  ->setURI('http://www.php.net/class.'.$this->name);
+              }
+            }
+            break;
         }
       }
     }