Java. Array type expected in lambda

So, I've got an object constructor:

public Func(Function<Var[], Var<T>> function, Var... arguments) {
   // Function is a standart 1.8 class
   //...
   //secret stuff
}

I call it like that:

return new Func(new Function<Var[], Var>() {
        @Override
        public Var apply(Var[] args) {
            return instance.getAttribute(args[0].value());
        }

    }, arguments[0].unpack(instance)  // unpack(...) returns Var object
);

And it works. Now, my IDE (Intellij IDEA) suggests me to replace Function declaration with lambda. Okay, lets do it:

return new Func(
    args -> instance.getAttribute(args[0].value()), 
    arguments[0].unpack(instance)
);

Now I have an error on args:

Array type expected; found: 'java.lang.Object'

So, apparently args now is Object. Why? Is that a bug in IDE or what?

Entire code:

Template:

public class Template {
public static void main(String[] args) {
    SomeClass someClass = new SomeClass();
    System.out.println(someMethod(someClass).value());
}

private static class SomeClass {
    Var[] var = new Var[12];

    SomeClass() {
        var = new Var[12];

        for ( int i = 0; i < var.length; i++) {
            var[i] = new Var<>(i * 4);
        }
    }

    Var getAttribute(int index) {
        return var[index];
    }
}

public static Var someMethod(SomeClass instance) {
    return new Func(new Function<Var[], Var>() {
        @Override
        public Var apply(Var[] args) {
            return instance.getAttribute((int)args[0].value());
        }
    }, new Var(4));
}
}

Var.java:

public class Var<T> {
private T value;

public Var(T value) {
    this.value = value;
}

public T value() {
    return value;
}
}

Func.java:

public class Func<T> extends Var<T> {
private Function<Var[], Var<T>> function;
private Var[] args;

public Func(Function<Var[], Var<T>> function, Var... args) {
    super(null);

    this.function = function;
    this.args = args;
}

@Override
public T value() {
    return function.apply(args).value();
}
}