Lambda expression as a succinct way to pass in type parameter

[Zhong Yu]

Hi Brian, I think I have an interesting use case, but I need your
confirming that it's viable. Consider a method

    <T> T foo() {...}

Suppose the body of foo() needs to know the runtime value of T, due to
erasure, we must pass in a construct containing the value of T

    <T> T foo(TypeToken<T> type) {...}

    interface TypeToken<T>
    {
        int f(int x); // not really used
    }

We can call foo() this way

    Bar result = foo(x->x);

The lambda expression x->x is compiled into an object of
TypeToken<Bar>, and the body of foo() can use reflection to retrieve
T=Bar.

    // equivalent code
    Bar result = foo(type);

    static TypeToken<Bar> type = new TypeToken<Bar>(){ public int
f(int x){ return x; } }

Question: do you see anything wrong with this usage pattern? (other
than how odd it looks)

cheers,
Zhong Yu