checker/tests/nullness/FinalVar2.java

// Test case for issue 266: https://github.com/typetools/checker-framework/issues/266
// The problem is limited refinement of final variables.

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

public class FinalVar2 {

  static Object method1(@Nullable Object arg) {
    final Object tmp = arg;
    if (tmp == null) {
      return "hello";
    }
    return new Object() {
      public void useFinalVar() {
        // should be OK
        tmp.hashCode();
      }
    };
  }

  static Object method2(final @Nullable Object arg) {
    if (arg == null) {
      return "hello";
    }
    return new Object() {
      public void useFinalVar() {
        // should be OK
        arg.hashCode();
      }
    };
  }

  static Object method3(@Nullable Object arg) {
    final Object tmp = arg;
    Object result =
        new Object() {
          public void useFinalVar() {
            // :: error: (dereference.of.nullable)
            tmp.hashCode();
          }
        };
    if (tmp == null) {
      return "hello";
    }
    return result;
  }
}