return extensions.firstOrNull { it.useSiteModule == module }
                ?: extensions.singleOrNull { it.useSiteModule == null }
                ?: error(KtFe10AnalysisHandlerExtension::class.java.name + " should be registered")
        }
    }

    var resolveSession: ResolveSession? = null
        private set

    var deprecationResolver: DeprecationResolver? = null
        private set