fix(indexing): Files with classes that declare itself to be it's parent can cause an infinite loop when indexing. #669

fixtures/self_referencing_class.php

@@ -0,0 +1,4 @@
+<?php
+class C extends C {}
+$c = new C;
+$c->undef_prop = 1;

src/DefinitionResolver.php

@@ -452,7 +452,9 @@ class DefinitionResolver
             // Repeat for parent class
             if ($implementorDef->extends) {
                 foreach ($implementorDef->extends as $extends) {
-                    $implementorFqns[] = $extends;
+                    if ($extends !== $implementorFqn) {
+                        $implementorFqns[] = $extends;
+                    }
                 }
             }
         }