Promise.then with Any Return Type Produces Incorrect error #12725

From: microsoft/vscode#16819

TypeScript Version: 2.1.4-insiders.20161206

Code

interface CompletionItem {
	a(): number;
}

function func(item: CompletionItem): Promise<CompletionItem> {
	const temp: Promise<any> = null
	return Promise.resolve('abc').then(service => {
		return temp;
	});
}

Expected behavior:
No errors.

Actual behavior:
Error:

Type 'Promise<string>' is not assignable to type 'Promise<CompletionItem>'.
  Type 'string' is not assignable to type 'CompletionItem'.

I believe the error comes from then selecting the incorrect overload during compilation. Changing the type to Promise.resolve(3) changes the error message to Type Promise<number> is not...