From c4ed55459773092597d0dc1cb500bf176daa62d0 Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Thu, 24 Aug 2017 10:27:07 -0700
Subject: [PATCH] Simplify `isExpression` check (#17741)

---
 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 4a07f349c9a..24a9a868c4a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -15220,7 +15220,7 @@ namespace ts {
             // example, given a 'function wrap<T, U>(cb: (x: T) => U): (x: T) => U' and a call expression
             // 'let f: (x: string) => number = wrap(s => s.length)', we infer from the declared type of 'f' to the
             // return type of 'wrap'.
-            if (isExpression(node)) {
+            if (node.kind !== SyntaxKind.Decorator) {
                 const contextualType = getContextualType(node);
                 if (contextualType) {
                     // We clone the contextual mapper to avoid disturbing a resolution in progress for an