From cabe4d36060750d742a62f6cd3b27234ee83caf4 Mon Sep 17 00:00:00 2001
From: Yui T <yuisu@microsoft.com>
Date: Thu, 25 May 2017 19:49:04 -0700
Subject: [PATCH] Address PR

---
 src/compiler/binder.ts | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 8870757999f..80bdeae6df5 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2178,11 +2178,10 @@ namespace ts {
                 case SyntaxKind.JSDocRecordMember:
                     return bindPropertyWorker(node as JSDocRecordMember);
                 case SyntaxKind.JSDocPropertyTag:
-                    let optionalType = 0;
-                    if ((node as JSDocPropertyTag).typeExpression.type.kind === SyntaxKind.JSDocOptionalType) {
-                        optionalType = SymbolFlags.Optional;
-                    }
-                    return declareSymbolAndAddToSymbolTable(node as JSDocPropertyTag, SymbolFlags.Property | optionalType, SymbolFlags.PropertyExcludes);
+                    return declareSymbolAndAddToSymbolTable(node as JSDocPropertyTag,
+                        (node as JSDocPropertyTag).typeExpression && (node as JSDocPropertyTag).typeExpression.type.kind === SyntaxKind.JSDocOptionalType ?
+                            SymbolFlags.Property | SymbolFlags.Optional : SymbolFlags.Property,
+                        SymbolFlags.PropertyExcludes);
                 case SyntaxKind.JSDocFunctionType:
                     return bindFunctionOrConstructorType(<SignatureDeclaration>node);
                 case SyntaxKind.JSDocTypeLiteral: