diff --git a/src/vs/platform/files/common/files.ts b/src/vs/platform/files/common/files.ts
index baa81ebf30d..ced2d157ff3 100644
--- a/src/vs/platform/files/common/files.ts
+++ b/src/vs/platform/files/common/files.ts
@@ -371,19 +371,14 @@ export const enum FileOperation {
 
 export class FileOperationEvent {
 
-	constructor(private _resource: URI, private _operation: FileOperation, private _target?: IFileStatWithMetadata) {
-	}
+	constructor(resource: URI, operation: FileOperation.DELETE);
+	constructor(resource: URI, operation: FileOperation.CREATE | FileOperation.MOVE | FileOperation.COPY, target: IFileStatWithMetadata);
+	constructor(public readonly resource: URI, public readonly operation: FileOperation, public readonly target?: IFileStatWithMetadata) { }
 
-	get resource(): URI {
-		return this._resource;
-	}
-
-	get target(): IFileStat | undefined {
-		return this._target;
-	}
-
-	get operation(): FileOperation {
-		return this._operation;
+	isOperation(operation: FileOperation.DELETE): boolean;
+	isOperation(operation: FileOperation.MOVE | FileOperation.COPY | FileOperation.CREATE): this is { readonly target: IFileStatWithMetadata };
+	isOperation(operation: FileOperation): boolean {
+		return this.operation === operation;
 	}
 }
 
diff --git a/src/vs/workbench/api/browser/mainThreadFileSystemEventService.ts b/src/vs/workbench/api/browser/mainThreadFileSystemEventService.ts
index bd1d2139202..e35329a9dba 100644
--- a/src/vs/workbench/api/browser/mainThreadFileSystemEventService.ts
+++ b/src/vs/workbench/api/browser/mainThreadFileSystemEventService.ts
@@ -51,8 +51,8 @@ export class MainThreadFileSystemEventService {
 
 		// file operation events - (changes the editor makes)
 		fileService.onAfterOperation(e => {
-			if (e.operation === FileOperation.MOVE) {
-				proxy.$onFileRename(e.resource, e.target!.resource);
+			if (e.isOperation(FileOperation.MOVE)) {
+				proxy.$onFileRename(e.resource, e.target.resource);
 			}
 		}, undefined, this._listener);
 
diff --git a/src/vs/workbench/contrib/files/browser/editors/fileEditorTracker.ts b/src/vs/workbench/contrib/files/browser/editors/fileEditorTracker.ts
index 2f51891a957..9bac952ee64 100644
--- a/src/vs/workbench/contrib/files/browser/editors/fileEditorTracker.ts
+++ b/src/vs/workbench/contrib/files/browser/editors/fileEditorTracker.ts
@@ -111,12 +111,12 @@ export class FileEditorTracker extends Disposable implements IWorkbenchContribut
 	private onFileOperation(e: FileOperationEvent): void {
 
 		// Handle moves specially when file is opened
-		if (e.operation === FileOperation.MOVE && e.target) {
+		if (e.isOperation(FileOperation.MOVE)) {
 			this.handleMovedFileInOpenedEditors(e.resource, e.target.resource);
 		}
 
 		// Handle deletes
-		if (e.operation === FileOperation.DELETE || e.operation === FileOperation.MOVE) {
+		if (e.isOperation(FileOperation.DELETE) || e.isOperation(FileOperation.MOVE)) {
 			this.handleDeletes(e.resource, false, e.target ? e.target.resource : undefined);
 		}
 	}
diff --git a/src/vs/workbench/contrib/files/common/explorerService.ts b/src/vs/workbench/contrib/files/common/explorerService.ts
index 46d87e4d7a8..83421a1613d 100644
--- a/src/vs/workbench/contrib/files/common/explorerService.ts
+++ b/src/vs/workbench/contrib/files/common/explorerService.ts
@@ -182,8 +182,8 @@ export class ExplorerService implements IExplorerService {
 
 	private onFileOperation(e: FileOperationEvent): void {
 		// Add
-		if (e.operation === FileOperation.CREATE || e.operation === FileOperation.COPY) {
-			const addedElement = e.target!;
+		if (e.isOperation(FileOperation.CREATE) || e.isOperation(FileOperation.COPY)) {
+			const addedElement = e.target;
 			const parentResource = dirname(addedElement.resource)!;
 			const parents = this.model.findAll(parentResource);
 
@@ -212,9 +212,9 @@ export class ExplorerService implements IExplorerService {
 		}
 
 		// Move (including Rename)
-		else if (e.operation === FileOperation.MOVE) {
+		else if (e.isOperation(FileOperation.MOVE)) {
 			const oldResource = e.resource;
-			const newElement = e.target!;
+			const newElement = e.target;
 			const oldParentResource = dirname(oldResource);
 			const newParentResource = dirname(newElement.resource);
 
@@ -246,7 +246,7 @@ export class ExplorerService implements IExplorerService {
 		}
 
 		// Delete
-		else if (e.operation === FileOperation.DELETE) {
+		else if (e.isOperation(FileOperation.DELETE)) {
 			const modelElements = this.model.findAll(e.resource);
 			modelElements.forEach(element => {
 				if (element.parent) {