The following program does not compile:

interface F<T extends Throwable> {
   void m() throws T;
}

<Z extends Throwable> m(F<Z> fz) { ... }

m(()->{ }); //error

The problem is caused by the fact that inferred type for Z defaults to the declared bound as no other constraints comes up when examining the lambda body. This causes the 'm' to be instantiated as a Throwable-throwing method, thus requiring the user to catch the exception with a try-catch block. This is completely unnecessary as it can be seen that the lambda doesn't throw any checked exception.