From cede745ab3251f0cf186d360d9587ddf1449d345 Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <DanielRosenwasser@users.noreply.github.com>
Date: Mon, 29 May 2023 20:05:35 +0000
Subject: [PATCH] Cherry-picks 544d432 into release-5.1.

---
 package-lock.json   | 16 ++++++++--------
 src/compiler/sys.ts |  4 ++--
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 833297b372004..5190401f6f649 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
     "name": "typescript",
-    "version": "5.1.0",
+    "version": "5.1.1-rc",
     "lockfileVersion": 2,
     "requires": true,
     "packages": {
         "": {
             "name": "typescript",
-            "version": "5.1.0",
+            "version": "5.1.1-rc",
             "license": "Apache-2.0",
             "bin": {
                 "tsc": "bin/tsc",
@@ -809,9 +809,9 @@
             "dev": true
         },
         "node_modules/@types/node": {
-            "version": "20.1.4",
-            "resolved": "https://registry.npmjs.org/@types/node/-/node-20.1.4.tgz",
-            "integrity": "sha512-At4pvmIOki8yuwLtd7BNHl3CiWNbtclUbNtScGx4OHfBd4/oWoJC8KRCIxXwkdndzhxOsPXihrsOoydxBjlE9Q==",
+            "version": "20.2.5",
+            "resolved": "https://registry.npmjs.org/@types/node/-/node-20.2.5.tgz",
+            "integrity": "sha512-JJulVEQXmiY9Px5axXHeYGLSjhkZEnD+MDPDGbCbIAbMslkKwmygtZFy1X6s/075Yo94sf8GuSlFfPzysQrWZQ==",
             "dev": true
         },
         "node_modules/@types/semver": {
@@ -5080,9 +5080,9 @@
             "dev": true
         },
         "@types/node": {
-            "version": "20.1.4",
-            "resolved": "https://registry.npmjs.org/@types/node/-/node-20.1.4.tgz",
-            "integrity": "sha512-At4pvmIOki8yuwLtd7BNHl3CiWNbtclUbNtScGx4OHfBd4/oWoJC8KRCIxXwkdndzhxOsPXihrsOoydxBjlE9Q==",
+            "version": "20.2.5",
+            "resolved": "https://registry.npmjs.org/@types/node/-/node-20.2.5.tgz",
+            "integrity": "sha512-JJulVEQXmiY9Px5axXHeYGLSjhkZEnD+MDPDGbCbIAbMslkKwmygtZFy1X6s/075Yo94sf8GuSlFfPzysQrWZQ==",
             "dev": true
         },
         "@types/semver": {
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index ace8ed10678dc..f0b07b429e33f 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -812,7 +812,7 @@ function createDirectoryWatcherSupportingRecursive({
 }
 
 /** @internal */
-export type FsWatchCallback = (eventName: "rename" | "change", relativeFileName: string | undefined, modifiedTime?: Date) => void;
+export type FsWatchCallback = (eventName: "rename" | "change", relativeFileName: string | undefined | null, modifiedTime?: Date) => void;
 /** @internal */
 export type FsWatch = (fileOrDirectory: string, entryKind: FileSystemEntryKind, callback: FsWatchCallback, recursive: boolean, fallbackPollingInterval: PollingInterval, fallbackOptions: WatchOptions | undefined) => FileWatcher;
 /** @internal */
@@ -1205,7 +1205,7 @@ export function createSystemWatchFunctions({
             }
         }
 
-        function callbackChangingToMissingFileSystemEntry(event: "rename" | "change", relativeName: string | undefined) {
+        function callbackChangingToMissingFileSystemEntry(event: "rename" | "change", relativeName: string | undefined | null) {
             // In some scenarios, file save operation fires event with fileName.ext~ instead of fileName.ext
             // To ensure we see the file going missing and coming back up (file delete and then recreated)
             // and watches being updated correctly we are calling back with fileName.ext as well as fileName.ext~