From e905ffa0e4258806793667204bccb0605d598640 Mon Sep 17 00:00:00 2001
From: Jack Bates <jack@nottheoilrig.com>
Date: Wed, 28 Aug 2019 16:18:51 -0700
Subject: [PATCH] Higher order this parameter inference, like #31116

---
 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 85c6b695063d7..0d96cb326a128 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -23725,7 +23725,7 @@ namespace ts {
             const thisType = getThisTypeOfSignature(signature);
             if (thisType) {
                 const thisArgumentNode = getThisArgumentOfCall(node);
-                const thisArgumentType = thisArgumentNode ? checkExpression(thisArgumentNode) : voidType;
+                const thisArgumentType = thisArgumentNode ? checkExpressionWithContextualType(thisArgumentNode, thisType, context, checkMode) : voidType;
                 inferTypes(context.inferences, thisArgumentType, thisType);
             }