docs: private @CheckForNull NullnessAnnotation toNullnessAnnotation(@CheckForNull TypeQualifierAnnotation tqa) {
          if (tqa == null || tqa == TypeQualifierAnnotation.OVERRIDES_BUT_NO_ANNOTATION) {
              return null;
          }
          if (tqa.when == null) {
              new NullPointerException("TGA value with null when field").printStackTrace();
              return null;
          }
  
  
  
          switch (tqa.when) {
          case ALWAYS:
              return NullnessAnnotation.NONNULL;
          case MAYBE:
              return NullnessAnnotation.CHECK_FOR_NULL;
          case NEVER:
              return NullnessAnnotation.CHECK_FOR_NULL;
          case UNKNOWN:
              return NullnessAnnotation.UNKNOWN_NULLNESS;
          }
  
          throw new IllegalStateException();
      }