diff --git a/types/atom/atom-tests.ts b/types/atom/atom-tests.ts
index 8995bbd3fa..5fc92880f4 100644
--- a/types/atom/atom-tests.ts
+++ b/types/atom/atom-tests.ts
@@ -3113,7 +3113,9 @@ function testWorkspace() {
 
     obj = atom.workspace.createItemForURI("https://test");
 
-    bool = atom.workspace.isTextEditor(obj);
+    if (atom.workspace.isTextEditor(obj)) {
+      const textEditor: Atom.TextEditor = obj;
+    }
 
     async function workspaceReopen() {
         const result = await atom.workspace.reopenItem();
diff --git a/types/atom/index.d.ts b/types/atom/index.d.ts
index 6cc3a30c77..7ee58bb3b5 100644
--- a/types/atom/index.d.ts
+++ b/types/atom/index.d.ts
@@ -2697,7 +2697,7 @@ export interface Workspace {
     createItemForURI(uri: string): Promise<object|TextEditor>;
 
     /** Returns a boolean that is true if object is a TextEditor. */
-    isTextEditor(object: object): boolean;
+    isTextEditor(object: object): object is TextEditor;
 
     /**
      *  Asynchronously reopens the last-closed item's URI if it hasn't already