diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index a32ee44692421..d385d7cb0755e 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -738,4 +738,22 @@ declare module 'vscode' {
 	}
 
 	//#endregion
+
+	//#region Joh: hierarchical document symbols, https://github.com/Microsoft/vscode/issues/34968
+
+	export class HierarchicalSymbolInformation {
+		name: string;
+		kind: SymbolKind;
+		location: Location;
+		range: Range;
+		children: HierarchicalSymbolInformation[];
+
+		constructor(name: string, kind: SymbolKind, location: Location, range: Range);
+	}
+
+	export interface DocumentSymbolProvider {
+		provideDocumentSymbols(document: TextDocument, token: CancellationToken): ProviderResult<HierarchicalSymbolInformation | SymbolInformation[]>;
+	}
+
+	//#endregion
 }
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index d477382fdf990..c3205e53724af 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -666,6 +666,12 @@ export function createApiFactory(
 			SourceBreakpoint: extHostTypes.SourceBreakpoint,
 			StatusBarAlignment: extHostTypes.StatusBarAlignment,
 			SymbolInformation: extHostTypes.SymbolInformation,
+			HierarchicalSymbolInformation: class extends extHostTypes.HierarchicalSymbolInformation {
+				constructor(name, kind, keyof, range) {
+					checkProposedApiEnabled(extension);
+					super(name, kind, keyof, range);
+				}
+			},
 			SymbolKind: extHostTypes.SymbolKind,
 			SourceControlInputBoxValidationType: extHostTypes.SourceControlInputBoxValidationType,
 			TextDocumentSaveReason: extHostTypes.TextDocumentSaveReason,
diff --git a/src/vs/workbench/api/node/extHostLanguageFeatures.ts b/src/vs/workbench/api/node/extHostLanguageFeatures.ts
index 2d14359a8b128..ef8b3280235b6 100644
--- a/src/vs/workbench/api/node/extHostLanguageFeatures.ts
+++ b/src/vs/workbench/api/node/extHostLanguageFeatures.ts
@@ -9,7 +9,7 @@ import { TPromise } from 'vs/base/common/winjs.base';
 import { mixin } from 'vs/base/common/objects';
 import * as vscode from 'vscode';
 import * as TypeConverters from 'vs/workbench/api/node/extHostTypeConverters';
-import { Range, Disposable, CompletionList, SnippetString, CodeActionKind } from 'vs/workbench/api/node/extHostTypes';
+import { Range, Disposable, CompletionList, SnippetString, CodeActionKind, HierarchicalSymbolInformation } from 'vs/workbench/api/node/extHostTypes';
 import { ISingleEditOperation } from 'vs/editor/common/model';
 import * as modes from 'vs/editor/common/modes';
 import { ExtHostHeapService } from 'vs/workbench/api/node/extHostHeapService';
@@ -39,6 +39,9 @@ class OutlineAdapter {
 	provideDocumentSymbols(resource: URI): TPromise<SymbolInformationDto[]> {
 		let doc = this._documents.getDocumentData(resource).document;
 		return asWinJsPromise(token => this._provider.provideDocumentSymbols(doc, token)).then(value => {
+			if (value instanceof HierarchicalSymbolInformation) {
+				value = HierarchicalSymbolInformation.toFlatSymbolInformation(value);
+			}
 			if (Array.isArray(value)) {
 				return value.map(symbol => IdObject.mixin(TypeConverters.fromSymbolInformation(symbol)));
 			}
diff --git a/src/vs/workbench/api/node/extHostTypes.ts b/src/vs/workbench/api/node/extHostTypes.ts
index 491bbf87129bd..32a94c5d0baa6 100644
--- a/src/vs/workbench/api/node/extHostTypes.ts
+++ b/src/vs/workbench/api/node/extHostTypes.ts
@@ -876,6 +876,38 @@ export class SymbolInformation {
 	}
 }
 
+export class HierarchicalSymbolInformation {
+	name: string;
+	location: Location;
+	kind: SymbolKind;
+	range: Range;
+	children: HierarchicalSymbolInformation[];
+
+	constructor(name: string, kind: SymbolKind, location: Location, range: Range) {
+		this.name = name;
+		this.kind = kind;
+		this.location = location;
+		this.range = range;
+		this.children = [];
+	}
+
+	static toFlatSymbolInformation(info: HierarchicalSymbolInformation): SymbolInformation[] {
+		let result: SymbolInformation[] = [];
+		HierarchicalSymbolInformation._toFlatSymbolInformation(info, undefined, result);
+		return result;
+	}
+
+	private static _toFlatSymbolInformation(info: HierarchicalSymbolInformation, containerName: string, bucket: SymbolInformation[]): void {
+		bucket.push(new SymbolInformation(info.name, info.kind, containerName, new Location(info.location.uri, info.range)));
+		if (Array.isArray(info.children)) {
+			for (const child of info.children) {
+				HierarchicalSymbolInformation._toFlatSymbolInformation(child, info.name, bucket);
+			}
+		}
+	}
+
+}
+
 export class CodeAction {
 	title: string;