diff --git a/src/vs/workbench/browser/parts/editor/breadcrumbsControl.ts b/src/vs/workbench/browser/parts/editor/breadcrumbsControl.ts
index 7863a8c2c126d3e27e2d09f17681b3b11ee0bf09..6e7ff0f164d6c222982effd607e7d775f6c913cc 100644
--- a/src/vs/workbench/browser/parts/editor/breadcrumbsControl.ts
+++ b/src/vs/workbench/browser/parts/editor/breadcrumbsControl.ts
@@ -38,7 +38,7 @@ import { ResourceLabel } from 'vs/workbench/browser/labels';
 import { BreadcrumbsConfig, IBreadcrumbsService } from 'vs/workbench/browser/parts/editor/breadcrumbs';
 import { BreadcrumbElement, EditorBreadcrumbsModel, FileElement } from 'vs/workbench/browser/parts/editor/breadcrumbsModel';
 import { BreadcrumbsPicker, createBreadcrumbsPicker } from 'vs/workbench/browser/parts/editor/breadcrumbsPicker';
-import { SideBySideEditorInput, IEditorPartOptions } from 'vs/workbench/common/editor';
+import { IEditorPartOptions, toResource, SideBySideEditor } from 'vs/workbench/common/editor';
 import { ACTIVE_GROUP, ACTIVE_GROUP_TYPE, IEditorService, SIDE_GROUP, SIDE_GROUP_TYPE } from 'vs/workbench/services/editor/common/editorService';
 import { IEditorGroupsService } from 'vs/workbench/services/editor/common/editorGroupsService';
 import { ITelemetryService } from 'vs/platform/telemetry/common/telemetry';
@@ -234,12 +234,9 @@ export class BreadcrumbsControl {
 		this._breadcrumbsDisposables.clear();
 
 		// honor diff editors and such
-		let input = this._editorGroup.activeEditor;
-		if (input instanceof SideBySideEditorInput) {
-			input = input.master;
-		}
+		const uri = toResource(this._editorGroup.activeEditor, { supportSideBySide: SideBySideEditor.MASTER });
 
-		if (!input || !input.resource || !this._fileService.canHandleResource(input.resource!)) {
+		if (!uri || !this._fileService.canHandleResource(uri)) {
 			// cleanup and return when there is no input or when
 			// we cannot handle this input
 			this._ckBreadcrumbsPossible.set(false);
@@ -255,7 +252,6 @@ export class BreadcrumbsControl {
 		this._ckBreadcrumbsVisible.set(true);
 		this._ckBreadcrumbsPossible.set(true);
 
-		const uri = input.resource;
 		const editor = this._getActiveCodeEditor();
 		const model = new EditorBreadcrumbsModel(
 			uri, editor,
diff --git a/src/vs/workbench/common/editor.ts b/src/vs/workbench/common/editor.ts
index 22caaaa4e86d05f8afe44a01043a7575129ba7dd..1230e01db48de007aaca3e5c693343a779de5fb2 100644
--- a/src/vs/workbench/common/editor.ts
+++ b/src/vs/workbench/common/editor.ts
@@ -1240,10 +1240,10 @@ export interface IResourceOptions {
 	filterByScheme?: string | string[];
 }
 
-export function toResource(editor: IEditorInput | undefined): URI | undefined;
-export function toResource(editor: IEditorInput | undefined, options: IResourceOptions & { supportSideBySide?: SideBySideEditor.MASTER | SideBySideEditor.DETAILS }): URI | undefined;
-export function toResource(editor: IEditorInput | undefined, options: IResourceOptions & { supportSideBySide: SideBySideEditor.BOTH }): URI | { master?: URI, detail?: URI } | undefined;
-export function toResource(editor: IEditorInput | undefined, options?: IResourceOptions): URI | { master?: URI, detail?: URI } | undefined {
+export function toResource(editor: IEditorInput | undefined | null): URI | undefined;
+export function toResource(editor: IEditorInput | undefined | null, options: IResourceOptions & { supportSideBySide?: SideBySideEditor.MASTER | SideBySideEditor.DETAILS }): URI | undefined;
+export function toResource(editor: IEditorInput | undefined | null, options: IResourceOptions & { supportSideBySide: SideBySideEditor.BOTH }): URI | { master?: URI, detail?: URI } | undefined;
+export function toResource(editor: IEditorInput | undefined | null, options?: IResourceOptions): URI | { master?: URI, detail?: URI } | undefined {
 	if (!editor) {
 		return undefined;
 	}