code: protected LightweightTypeReference getBoundTypeArgument(ParameterizedTypeReference reference, JvmTypeParameter type,
  			Visiting visiting) {
  		LightweightMergedBoundTypeArgument boundTypeArgument = typeParameterMapping.get(type);
  		if (boundTypeArgument != null) {
  			LightweightTypeReference boundReference = boundTypeArgument.getTypeReference();
  			if (boundReference != null && reference != boundReference && boundReference.getType() != type) {
  				return boundReference.accept(this, visiting);
  			}
  		}
  		return null;
  	}
docs: /* @Nullable