Currently, it is not possible to do this:

var x = () => 1;

Instead, you need to declare the type before:

Func<int> x = () => 1;

C# should just assume these kind of lambdas are either Action or Func and infer the type.

Usually these lambdas are used as helpers for the method implementation, so it really wouldn't matter if a (string s) => true is a Func<string, bool> instead of a Predicate<string> as long as the signature matches.