From 6cf6d2cfda34da038e5cb9015a9f77221cb1a2ed Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Tue, 6 Nov 2018 09:18:39 -0500
Subject: [PATCH] Add null check

---
 src/Psalm/Type/ParseTree.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Psalm/Type/ParseTree.php b/src/Psalm/Type/ParseTree.php
index 72259b7ea..f5c6999a7 100644
--- a/src/Psalm/Type/ParseTree.php
+++ b/src/Psalm/Type/ParseTree.php
@@ -108,6 +108,10 @@ class ParseTree
                     }
 
                     do {
+                        if ($current_leaf->parent === null) {
+                            break;
+                        }
+
                         $current_leaf = $current_leaf->parent;
                     } while (!$current_leaf instanceof ParseTree\EncapsulationTree
                         && !$current_leaf instanceof ParseTree\CallableTree