PostconditionBug.java

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

public class PostconditionBug {

    void a(@UnknownInitialization @Raw PostconditionBug this) {
        @NonNull String f = "abc";
        //:: error: (assignment.type.incompatible)
        f = null;
    }
}