From a6a5b85b522b89d061aaf0baaaaf39103ba0c346 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 1 Nov 2017 10:33:24 -0700
Subject: [PATCH] Switch from undefined guard to asserts

In both fixSpelling and getSuggestionForNonexistentSymbol
---
 src/compiler/checker.ts               | 9 +++------
 src/services/codefixes/fixSpelling.ts | 4 +++-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 738a484d254..b28ecb082a1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -15062,12 +15062,9 @@ namespace ts {
             return suggestion && symbolName(suggestion);
         }
 
-        function getSuggestionForNonexistentSymbol(location: Node, name: __String, meaning: SymbolFlags): string {
-            const result = resolveNameHelper(location, name, meaning, /*nameNotFoundMessage*/ undefined, name, /*isUse*/ false, (symbols, name, meaning) => {
-                // NOTE: `name` from the callback is supposed to  === the outer `name`, but is undefined in some cases
-                if (name === undefined) {
-                    return undefined;
-                }
+        function getSuggestionForNonexistentSymbol(location: Node, outerName: __String, meaning: SymbolFlags): string {
+            const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, (symbols, name, meaning) => {
+                Debug.assert(name !== undefined, "name should always be defined, and equal to " + outerName);
                 const symbol = getSymbol(symbols, name, meaning);
                 // Sometimes the symbol is found when location is a return type of a function: `typeof x` and `x` is declared in the body of the function
                 // So the table *contains* `x` but `x` isn't actually in scope.
diff --git a/src/services/codefixes/fixSpelling.ts b/src/services/codefixes/fixSpelling.ts
index ff3bd455291..e5c15ade5a2 100644
--- a/src/services/codefixes/fixSpelling.ts
+++ b/src/services/codefixes/fixSpelling.ts
@@ -22,7 +22,9 @@ namespace ts.codefix {
         }
         else {
             const meaning = getMeaningFromLocation(node);
-            suggestion = checker.getSuggestionForNonexistentSymbol(node, getTextOfNode(node), convertSemanticMeaningToSymbolFlags(meaning));
+            const name = getTextOfNode(node);
+            Debug.assert(!!name, "name should be defined");
+            suggestion = checker.getSuggestionForNonexistentSymbol(node, name, convertSemanticMeaningToSymbolFlags(meaning));
         }
         if (suggestion) {
             return [{