From bd12ae24540e395a148abd5d748b3c69c40bae63 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk@outlook.com>
Date: Fri, 22 Oct 2021 01:56:45 +0300
Subject: [PATCH] fix(46466): add missing async keyword before type parameters
 (#46467)

---
 src/services/codefixes/fixAwaitInSyncFunction.ts |  3 ++-
 tests/cases/fourslash/codeFixAddMissingAsync3.ts | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/codeFixAddMissingAsync3.ts

diff --git a/src/services/codefixes/fixAwaitInSyncFunction.ts b/src/services/codefixes/fixAwaitInSyncFunction.ts
index bfd68e05d0a..0f0f2880ec3 100644
--- a/src/services/codefixes/fixAwaitInSyncFunction.ts
+++ b/src/services/codefixes/fixAwaitInSyncFunction.ts
@@ -53,7 +53,8 @@ namespace ts.codefix {
                 insertBefore = findChildOfKind(containingFunction, SyntaxKind.FunctionKeyword, sourceFile);
                 break;
             case SyntaxKind.ArrowFunction:
-                insertBefore = findChildOfKind(containingFunction, SyntaxKind.OpenParenToken, sourceFile) || first(containingFunction.parameters);
+                const kind = containingFunction.typeParameters ? SyntaxKind.LessThanToken : SyntaxKind.OpenParenToken;
+                insertBefore = findChildOfKind(containingFunction, kind, sourceFile) || first(containingFunction.parameters);
                 break;
             default:
                 return;
diff --git a/tests/cases/fourslash/codeFixAddMissingAsync3.ts b/tests/cases/fourslash/codeFixAddMissingAsync3.ts
new file mode 100644
index 00000000000..9588556afbe
--- /dev/null
+++ b/tests/cases/fourslash/codeFixAddMissingAsync3.ts
@@ -0,0 +1,16 @@
+/// <reference path="fourslash.ts" />
+
+////const foo = <T>(x: T): string => {
+////    await new Promise(resolve => resolve(true));
+////    return "";
+////}
+
+verify.codeFix({
+    description: ts.Diagnostics.Add_async_modifier_to_containing_function.message,
+    index: 0,
+    newFileContent:
+`const foo = async <T>(x: T): Promise<string> => {
+    await new Promise(resolve => resolve(true));
+    return "";
+}`
+});