This now works as advertised at 4.9.
import Search = require("esri/widgets/Search");
import Locator = require("esri/tasks/Locator");
var sources = [{
locator: new Locator({ url: "https://<url>/AddrComposite/GeocodeServer" }),
name: "AddrComposite",
placeholder: "search addresses",
singleLineFieldName: "SingleLine",
}];
var searchWidget = new Search({
view: view,
includeDefaultSources: false,
suggestionsEnabled: true,
sources:sources
});
var searchExpand = new Expand({
view: view,
content: searchWidget
})
view.ui.add([
{
component: searchExpand,
position: "top-left",
index: 1
}
]);