From e6bcef7dc59a7bf826783453e08f2e2cf2fc1cb4 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 1 Jun 2017 09:19:34 -0700
Subject: [PATCH] Combining unknown type+value symbol->unknownSymbol

Previously, when getExternalModuleMember tried to combine unknownSymbol
from a type and unknownSymbol from a value, it combineValueAndTypeSymbol
would create a new franken-symbol that was no longer equal to
unknownSymbol.
---
 src/compiler/checker.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cfe2c5a6bf2..11bb737e986 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1364,6 +1364,9 @@ namespace ts {
         // An 'import { Point } from "graphics"' needs to create a symbol that combines the value side 'Point'
         // property with the type/namespace side interface 'Point'.
         function combineValueAndTypeSymbols(valueSymbol: Symbol, typeSymbol: Symbol): Symbol {
+            if (valueSymbol === unknownSymbol && typeSymbol === unknownSymbol) {
+                return unknownSymbol;
+            }
             if (valueSymbol.flags & (SymbolFlags.Type | SymbolFlags.Namespace)) {
                 return valueSymbol;
             }