Languages which use only inference have been written, but it's just not ergonomic, no one wants to use that. So the Widget is always available as an annotation (although I can't read your intent out of one line of Java clearly, and depending on what that is, a cleaner type system than Java's might take care of covariance well enough that we still wouldn't care), or as a cast.

Java itself introduced syntax for eliding the type of simple variables, so this is an old complaint, but yeah: a little bit of inference goes a long way.