From 64bbf8925cc91e4fd528584ab9984b7a13f014f0 Mon Sep 17 00:00:00 2001
From: Benjamin Lichtman <belichtm@microsoft.com>
Date: Thu, 30 Aug 2018 16:53:46 -0700
Subject: [PATCH] Allow for undefined in type

---
 src/services/codefixes/convertToAsyncFunction.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/services/codefixes/convertToAsyncFunction.ts b/src/services/codefixes/convertToAsyncFunction.ts
index 6162e311266..76cdf471466 100644
--- a/src/services/codefixes/convertToAsyncFunction.ts
+++ b/src/services/codefixes/convertToAsyncFunction.ts
@@ -43,7 +43,7 @@ namespace ts.codefix {
     function convertToAsyncFunction(changes: textChanges.ChangeTracker, sourceFile: SourceFile, position: number, checker: TypeChecker, context: CodeFixContextBase): void {
         // get the function declaration - returns a promise
         const tokenAtPosition = getTokenAtPosition(sourceFile, position);
-        let functionToConvert: FunctionLikeDeclaration;
+        let functionToConvert: FunctionLikeDeclaration | undefined;
 
         // if the parent of a FunctionLikeDeclaration is a variable declaration, the convertToAsync diagnostic will be reported on the variable name
         if (isIdentifier(tokenAtPosition) && isVariableDeclaration(tokenAtPosition.parent) &&
@@ -51,7 +51,7 @@ namespace ts.codefix {
             functionToConvert = tokenAtPosition.parent.initializer;
         }
         else {
-            functionToConvert = getContainingFunction(getTokenAtPosition(sourceFile, position)) as FunctionLikeDeclaration;
+            functionToConvert = tryCast(getContainingFunction(getTokenAtPosition(sourceFile, position)), isFunctionLikeDeclaration);
         }
 
         if (!functionToConvert) {