checker/tests/nullness/generics/MethodTypeVars.java

import org.checkerframework.checker.nullness.qual.*;

/*
 * This test is based on Issue 93:
 * https://github.com/typetools/checker-framework/issues/93
 */
public class MethodTypeVars {
  void m() {
    // :: error: (type.argument)
    Object a = A.badMethod(null);
    Object b = A.badMethod(new Object());

    // :: error: (type.argument)
    A.goodMethod(null);
    A.goodMethod(new Object());
  }
}

class A {
  public static <T extends @NonNull Object> T badMethod(T t) {
    // :: warning: [unchecked] unchecked cast
    return (T) new Object();
  }

  public static <T extends @NonNull Object> void goodMethod(T t) {}
}

class B {
  public <T> void indexOf1(T[] a, @Nullable Object elt) {}
  // This is not valid Java syntax.
  // public void indexOf2(?[] a, @Nullable Object elt) {}

  void call() {
    Integer[] arg = new Integer[] {1, 2, 3, 4};
    indexOf1(arg, Integer.valueOf(5));
    // indexOf2(arg, new Integer(5));
  }
}