ExceptionInferenceBug.java

package spullara;
 
public class ExceptionInferenceBug {
    interface Function<T, V> extends PartialFunction<T, V> {
      V apply(T paramT);
    }
 
    interface PartialFunction<T, V> {
      V apply(T paramT) throws Exception;
    }
 
    interface O {}
 
    static <T, V> void run(Function<? super O, V> function) {}
    static <T, V> void run(PartialFunction<? super O, V> function) {}
 
    static <T, V> void run2(Function<O, V> function) {}
    static <T, V> void run2(PartialFunction<O, V> function) {}
 
    public static void main(String[] args) {
        run(t -> t.toString()); // causes an assertion error
        run((O t) -> t.toString()); // ambiguous
        run((O t) -> { throw new Exception(); });
        run2(t -> t.toString()); // works
        run2((O t) -> { throw new Exception(); }); // ambiguous
        run2((PartialFunction<O, Void>) (O t) -> { throw new Exception(); }); // works
    }
}