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import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import org.checkerframework.checker.nullness.qual.*;
import org.checkerframework.framework.qual.SubtypeOf;
import org.checkerframework.framework.qual.Unused;
// TODO: feature request: the Nullness Checker should be aware of
// the @Unused annotation.
// This is difficult to implement: one needs to determine the correct
// AnnotatedTypeFactory for the "when" type system and use it
// to determine the right annotated type. We currently don't have
// a mechanism to do this.
//
// @skip-test
public class UnusedNullness {
@SubtypeOf({})
@Target(ElementType.TYPE_USE)
public @interface Prototype {}
@Unused(when = Prototype.class)
public Object ppt;
protected @Prototype UnusedNullness() {
// It should be legal to initialize an unused field to null in
// a constructor with @Prototype receiver.
this.ppt = null;
}
protected @Prototype UnusedNullness(int disambiguate_overloading) {
// It should be legal to NOT initialize an unused field in
// a constructor with @Prototype receiver.
}
protected void protometh(@Prototype UnusedNullness this) {
// It should be legal to initialize the unused field to null in
// a method with @Prototype receiver.
this.ppt = null;
}
protected void meth() {
// Otherwise it's not legal.
// :: error: (assignment.type.incompatible)
this.ppt = null;
}
protected void useUnusedField1(@Prototype UnusedNullness this) {
// :: error: (assignment.type.incompatible)
@NonNull Object x = this.ppt;
}
protected void useUnusedField2() {
@NonNull Object x = this.ppt;
}
}
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