From 720820487744f302c5831afb5cd9c86c784a5dbf Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 30 Nov 2017 12:33:34 -0800
Subject: [PATCH] Don't mutate symbol flags after creation

---
 src/compiler/binder.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 8145246adbb..71b5e1afbff 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2425,13 +2425,13 @@ namespace ts {
             if (!isPrototypeProperty && (!targetSymbol || !(targetSymbol.flags & SymbolFlags.Namespace)) && isLegalPosition) {
                 Debug.assert(isIdentifier(propertyAccess.expression));
                 const identifier = propertyAccess.expression as Identifier;
+                const flags =  SymbolFlags.Module | SymbolFlags.JSContainer;
+                const excludeFlags = SymbolFlags.ValueModuleExcludes & ~SymbolFlags.JSContainer;
                 if (targetSymbol) {
-                    addDeclarationToSymbol(symbol, identifier, SymbolFlags.Module);
-                    symbol.flags |= SymbolFlags.JSContainer;
+                    addDeclarationToSymbol(symbol, identifier, flags);
                 }
                 else {
-                    targetSymbol = declareSymbol(container.locals, /*parent*/ undefined, identifier, SymbolFlags.Module, SymbolFlags.ValueModuleExcludes);
-                    targetSymbol.flags |= SymbolFlags.JSContainer;
+                    targetSymbol = declareSymbol(container.locals, /*parent*/ undefined, identifier, flags, excludeFlags);
                 }
             }
             if (!targetSymbol || !(targetSymbol.flags & (SymbolFlags.Function | SymbolFlags.Class | SymbolFlags.NamespaceModule))) {