From 5ab5cfd2fd444cf42cc1c56f8b96519644191385 Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <drosen@microsoft.com>
Date: Mon, 4 Jan 2016 22:54:37 -0500
Subject: [PATCH] Contextually type the RHS of logical 'and' and comma
 expressions.

---
 src/compiler/checker.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c2e798659d..fb4af5d729 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7362,6 +7362,12 @@ namespace ts {
                 }
                 return type;
             }
+            else if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.CommaToken) {
+                if (node === binaryExpression.right) {
+                    return getContextualType(binaryExpression);
+                }
+            }
+
             return undefined;
         }