From 403f585622192d2ebf53196354b87cf467ea1908 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Tue, 12 Sep 2017 10:43:24 -0700
Subject: [PATCH] enclosingDeclaration can be undefined within
 getAccessibleSymbolChain (#18400)

---
 src/compiler/checker.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c87062a212f..c169dcb83ca 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2063,7 +2063,7 @@ namespace ts {
             return rightMeaning === SymbolFlags.Value ? SymbolFlags.Value : SymbolFlags.Namespace;
         }
 
-        function getAccessibleSymbolChain(symbol: Symbol, enclosingDeclaration: Node, meaning: SymbolFlags, useOnlyExternalAliasing: boolean): Symbol[] | undefined {
+        function getAccessibleSymbolChain(symbol: Symbol, enclosingDeclaration: Node | undefined, meaning: SymbolFlags, useOnlyExternalAliasing: boolean): Symbol[] | undefined {
             if (!(symbol && !isPropertyOrMethodDeclarationSymbol(symbol))) {
                 return undefined;
             }
@@ -2112,7 +2112,7 @@ namespace ts {
                     if (symbolFromSymbolTable.flags & SymbolFlags.Alias
                         && symbolFromSymbolTable.escapedName !== "export="
                         && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)
-                        && !(isUMDExportSymbol(symbolFromSymbolTable) && isExternalModule(getSourceFileOfNode(enclosingDeclaration)))
+                        && !(isUMDExportSymbol(symbolFromSymbolTable) && enclosingDeclaration && isExternalModule(getSourceFileOfNode(enclosingDeclaration)))
                         // If `!useOnlyExternalAliasing`, we can use any type of alias to get the name
                         && (!useOnlyExternalAliasing || some(symbolFromSymbolTable.declarations, isExternalModuleImportEqualsDeclaration))) {
 
@@ -2132,7 +2132,7 @@ namespace ts {
             }
         }
 
-        function needsQualification(symbol: Symbol, enclosingDeclaration: Node, meaning: SymbolFlags) {
+        function needsQualification(symbol: Symbol, enclosingDeclaration: Node | undefined, meaning: SymbolFlags) {
             let qualify = false;
             forEachSymbolTableInScope(enclosingDeclaration, symbolTable => {
                 // If symbol of this name is not available in the symbol table we are ok