public boolean isNonNull(Reference reference) {
        for (ScopeLayer<T> layer : scope) {
            if (layer.containsNonNullReference(reference)) {
                return true;
            }
        }
        return false;
    }
Gets if a reference is non-null in the current scope.

@param reference the reference to check nullability for.
@return true if the reference is non-null, false otherwise.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/evaluation/Scope.java