From 1575b7a77ebe402822b62825a33bbf224a9874fb Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 29 Mar 2018 10:16:31 -0700
Subject: [PATCH] Fix parent node walk termination condition in
 getConstrainedTypeVariable

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b7b5dff3e9d..30ffa37e1eb 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7395,7 +7395,7 @@ namespace ts {
 
         function getConstrainedTypeVariable(typeVariable: TypeVariable, node: Node) {
             let constraints: Type[];
-            while (isPartOfTypeNode(node)) {
+            while (node && !isStatement(node)) {
                 const parent = node.parent;
                 if (parent.kind === SyntaxKind.ConditionalType && node === (<ConditionalTypeNode>parent).trueType) {
                     const constraint = getImpliedConstraint(typeVariable, (<ConditionalTypeNode>parent).checkType, (<ConditionalTypeNode>parent).extendsType);