From fe55edc38e69daaca26efd35bdf40bcb8d173bb4 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 29 Nov 2016 13:46:00 -0800
Subject: [PATCH] Rest in an untyped binding pattern should be any

---
 src/compiler/checker.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 527735a3b0f..65bc52fde1f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3099,6 +3099,15 @@ namespace ts {
                         error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
+                    const parent = pattern.parent as VariableLikeDeclaration;
+                        if (parent.kind === SyntaxKind.Parameter &&
+                            !parent.type &&
+                            !parent.initializer &&
+                            !getContextuallyTypedParameterType(parent as ParameterDeclaration)) {
+                            // if this type came from examining the structure of the pattern --
+                            // there was no other information -- then it is not sufficient to determine the rest type, so just return any
+                        return anyType;
+                    }
                     const literalMembers: PropertyName[] = [];
                     for (const element of pattern.elements) {
                         if (!(element as BindingElement).dotDotDotToken) {