diff --git a/src/BackgroundCompilation.ts b/src/BackgroundCompilation.ts
index edac4dd24..cc82a2e8c 100644
--- a/src/BackgroundCompilation.ts
+++ b/src/BackgroundCompilation.ts
@@ -19,11 +19,11 @@ import { FolderContext } from "./FolderContext";
 import { TaskOperation } from "./tasks/TaskQueue";
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import debounce = require("lodash.debounce");
+import { validFileTypes } from "./utilities/filesystem";
 
 export class BackgroundCompilation implements vscode.Disposable {
     private workspaceFileWatcher?: vscode.FileSystemWatcher;
     private configurationEventDisposable?: vscode.Disposable;
-    private validFileTypes = ["swift", "c", "cpp", "h", "hpp", "m", "mm"];
     private disposables: vscode.Disposable[] = [];
 
     constructor(private folderContext: FolderContext) {
@@ -44,7 +44,7 @@ export class BackgroundCompilation implements vscode.Disposable {
     }
 
     private setupFileWatching() {
-        const fileTypes = this.validFileTypes.join(",");
+        const fileTypes = validFileTypes.join(",");
         const rootFolders = ["Sources", "Tests", "Snippets", "Plugins"].join(",");
         this.disposables.push(
             (this.workspaceFileWatcher = vscode.workspace.createFileSystemWatcher(
diff --git a/src/DiagnosticsManager.ts b/src/DiagnosticsManager.ts
index b1ccdc343..c7e0914a2 100644
--- a/src/DiagnosticsManager.ts
+++ b/src/DiagnosticsManager.ts
@@ -21,6 +21,7 @@ import configuration from "./configuration";
 import { SwiftExecution } from "./tasks/SwiftExecution";
 import { WorkspaceContext } from "./WorkspaceContext";
 import { checkIfBuildComplete, lineBreakRegex } from "./utilities/tasks";
+import { validFileTypes } from "./utilities/filesystem";
 
 interface ParsedDiagnostic {
     uri: string;
@@ -102,6 +103,17 @@ export class DiagnosticsManager implements vscode.Disposable {
                     context.outputChannel.log(`${e}`, 'Failed to provide "swiftc" diagnostics')
                 );
         });
+        const fileTypes = validFileTypes.join(",");
+        this.workspaceFileWatcher = vscode.workspace.createFileSystemWatcher(
+            `**/*.{${fileTypes}}`,
+            true,
+            true
+        );
+        this.onDidDeleteDisposible = this.workspaceFileWatcher.onDidDelete(uri => {
+            if (this.allDiagnostics.delete(uri.fsPath)) {
+                this.diagnosticCollection.delete(uri);
+            }
+        });
     }
 
     /**
@@ -276,6 +288,8 @@ export class DiagnosticsManager implements vscode.Disposable {
         this.diagnosticCollection.dispose();
         this.onDidStartTaskDisposible.dispose();
         this.onDidChangeConfigurationDisposible.dispose();
+        this.onDidDeleteDisposible.dispose();
+        this.workspaceFileWatcher.dispose();
     }
 
     private includeSwiftcDiagnostics(): boolean {
@@ -454,4 +468,6 @@ export class DiagnosticsManager implements vscode.Disposable {
 
     private onDidStartTaskDisposible: vscode.Disposable;
     private onDidChangeConfigurationDisposible: vscode.Disposable;
+    private onDidDeleteDisposible: vscode.Disposable;
+    private workspaceFileWatcher: vscode.FileSystemWatcher;
 }
diff --git a/src/utilities/filesystem.ts b/src/utilities/filesystem.ts
index b68fcaef6..37c772f7c 100644
--- a/src/utilities/filesystem.ts
+++ b/src/utilities/filesystem.ts
@@ -15,6 +15,8 @@
 import * as fs from "fs/promises";
 import * as path from "path";
 
+export const validFileTypes = ["swift", "c", "cpp", "h", "hpp", "m", "mm"];
+
 /**
  * Checks if a file, directory or symlink exists at the supplied path.
  * @param pathComponents The path to check for existence