From c5b539dcd50407d261d125f864af4adf26bb3d86 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk@outlook.com>
Date: Tue, 21 Mar 2023 22:12:38 +0200
Subject: [PATCH] fix(53372): TypeScript cannot auto-complete keyword extends
 (#53418)

---
 src/services/completions.ts                       | 7 ++++---
 tests/cases/fourslash/extendsKeywordCompletion.ts | 8 ++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)
 create mode 100644 tests/cases/fourslash/extendsKeywordCompletion.ts

diff --git a/src/services/completions.ts b/src/services/completions.ts
index f3a8e5f65a7..bbdf67bb2de 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -165,6 +165,7 @@ import {
     isInJSFile,
     isInRightSideOfInternalImportEqualsDeclaration,
     isInString,
+    isInterfaceDeclaration,
     isIntersectionTypeNode,
     isJSDoc,
     isJSDocAugmentsTag,
@@ -4263,9 +4264,9 @@ function getCompletionData(
         return isDeclarationName(contextToken)
             && !isShorthandPropertyAssignment(contextToken.parent)
             && !isJsxAttribute(contextToken.parent)
-            // Don't block completions if we're in `class C /**/`, because we're *past* the end of the identifier and might want to complete `extends`.
-            // If `contextToken !== previousToken`, this is `class C ex/**/`.
-            && !(isClassLike(contextToken.parent) && (contextToken !== previousToken || position > previousToken.end));
+            // Don't block completions if we're in `class C /**/` or `interface I /**/`, because we're *past* the end of the identifier and might want to complete `extends`.
+            // If `contextToken !== previousToken`, this is `class C ex/**/ or `interface I ex/**/``.
+            && !((isClassLike(contextToken.parent) || isInterfaceDeclaration(contextToken.parent)) && (contextToken !== previousToken || position > previousToken.end));
     }
 
     function isPreviousPropertyDeclarationTerminated(contextToken: Node, position: number) {
diff --git a/tests/cases/fourslash/extendsKeywordCompletion.ts b/tests/cases/fourslash/extendsKeywordCompletion.ts
new file mode 100644
index 00000000000..a0334dfc5db
--- /dev/null
+++ b/tests/cases/fourslash/extendsKeywordCompletion.ts
@@ -0,0 +1,8 @@
+/// <reference path="fourslash.ts" />
+
+////export interface B ex/**/
+
+verify.completions({
+    marker: "",
+    includes: [{ name: "extends", sortText: completion.SortText.GlobalsOrKeywords }]
+});