From 39cd6a395a9ef951c9bc0954772beea76e1b264b Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Tue, 30 Jun 2020 09:36:40 -0700
Subject: [PATCH] Fix crash on completion in jsdoc namepath

contextToken may be undefined, so the isAssertionExpression call in
filterGlobalCompletion needs to check for undefined.
---
 src/services/completions.ts                      |  6 +-----
 tests/cases/fourslash/completionJSDocNamePath.ts | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)
 create mode 100644 tests/cases/fourslash/completionJSDocNamePath.ts

diff --git a/src/services/completions.ts b/src/services/completions.ts
index 989aff628bdf8..88cee321e1023 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -1464,7 +1464,7 @@ namespace ts.Completions {
         function filterGlobalCompletion(symbols: Symbol[]): void {
             const isTypeOnly = isTypeOnlyCompletion();
             if (isTypeOnly) {
-                keywordFilters = isTypeAssertion()
+                keywordFilters = contextToken && isAssertionExpression(contextToken.parent)
                     ? KeywordCompletionFilters.TypeAssertionKeywords
                     : KeywordCompletionFilters.TypeKeywords;
             }
@@ -1494,10 +1494,6 @@ namespace ts.Completions {
             });
         }
 
-        function isTypeAssertion(): boolean {
-            return isAssertionExpression(contextToken.parent);
-        }
-
         function isTypeOnlyCompletion(): boolean {
             return insideJsDocTagTypeExpression
                 || !isContextTokenValueLocation(contextToken) &&
diff --git a/tests/cases/fourslash/completionJSDocNamePath.ts b/tests/cases/fourslash/completionJSDocNamePath.ts
new file mode 100644
index 0000000000000..e15f70eaa472d
--- /dev/null
+++ b/tests/cases/fourslash/completionJSDocNamePath.ts
@@ -0,0 +1,15 @@
+// @noLib: true
+
+/// <reference path='fourslash.ts'/>
+
+// fix crash from #38407
+
+//// /**
+////  * @returns {modu/*1*/le:ControlFlow}
+////  */
+//// export function cargo() {
+//// }
+
+goTo.marker('1');
+verify.completions({ marker: "1", excludes: ["module", "ControlFlow"] });
+