From b1ad54b3828dc4acfd8a9fd389f7d12163fae71b Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Wed, 18 Sep 2019 13:22:40 -0700
Subject: [PATCH] Add type annotation

---
 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 64e771c7c9f..aa4796c2c58 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8971,7 +8971,7 @@ namespace ts {
             return undefined;
         }
 
-        function getConstraintDeclaration(type: TypeParameter) {
+        function getConstraintDeclaration(type: TypeParameter): TypeNode | undefined {
             return mapDefined(filter(type.symbol && type.symbol.declarations, isTypeParameterDeclaration), getEffectiveConstraintOfTypeParameter)[0];
         }