diff --git a/src/vs/workbench/api/common/extHostApiCommands.ts b/src/vs/workbench/api/common/extHostApiCommands.ts
index db66bcb567f76fcac976b4a8747bab3ca94b7a80..e9022a259d5010553d25557888d3323b943a1cbf 100644
--- a/src/vs/workbench/api/common/extHostApiCommands.ts
+++ b/src/vs/workbench/api/common/extHostApiCommands.ts
@@ -579,7 +579,7 @@ export class ExtHostApiCommands {
 			source: ICallHierarchyItemDto;
 			sourceRanges: IRange[];
 		};
-		const args = { resource, position };
+		const args = { resource, position: typeConverters.Position.from(position) };
 		const calls = await this._commands.executeCommand<IncomingCallDto[]>('_executeCallHierarchyIncomingCalls', args);
 
 		const result: vscode.CallHierarchyIncomingCall[] = [];
@@ -594,7 +594,7 @@ export class ExtHostApiCommands {
 			sourceRanges: IRange[];
 			target: ICallHierarchyItemDto;
 		};
-		const args = { resource, position };
+		const args = { resource, position: typeConverters.Position.from(position) };
 		const calls = await this._commands.executeCommand<OutgoingCallDto[]>('_executeCallHierarchyOutgoingCalls', args);
 
 		const result: vscode.CallHierarchyOutgoingCall[] = [];
diff --git a/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts b/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
index 11000760a44ed0381dcb167178d064abd606d940..c01ed37668345d219a61b804223072091fb3376f 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
@@ -878,12 +878,12 @@ suite('ExtHostLanguageFeatureCommands', function () {
 
 		let incoming = await commands.executeCommand<vscode.CallHierarchyIncomingCall[]>('vscode.executeCallHierarchyProviderIncomingCalls', model.uri, new types.Position(0, 10));
 		assert.equal(incoming.length, 1);
-		assert.ok(incoming[0].source instanceof types.CallHierarchyIncomingCall);
+		assert.ok(incoming[0].source instanceof types.CallHierarchyItem);
 		assert.equal(incoming[0].source.name, 'IN');
 
 		let outgoing = await commands.executeCommand<vscode.CallHierarchyOutgoingCall[]>('vscode.executeCallHierarchyProviderOutgoingCalls', model.uri, new types.Position(0, 10));
 		assert.equal(outgoing.length, 1);
-		assert.ok(outgoing[0].target instanceof types.CallHierarchyOutgoingCall);
+		assert.ok(outgoing[0].target instanceof types.CallHierarchyItem);
 		assert.equal(outgoing[0].target.name, 'OUT');
 	});
 });