Inferred return types checked against extended (as opposed to specific) declaration's return type. #30096

interface IOnlyBob {bob :string};

//this errors as we expect
//const _errors :IOnlyBob = {bob:'hi', steve:'there'};

//this works fine but should error
let _returnsBob :() => IOnlyBob;
_returnsBob = () => ({bob:'hi', steve:'there'});

//I'd expect this to be the way to do the above, if that's what someone actually wanted
let _returnsNotJustBob :<T extends IOnlyBob>() => T;
_returnsNotJustBob = () => ({bob:'hi', steve:'there'} as any); //have to do any, see https://github.com/Microsoft/TypeScript/issues/28154