import type { ASTVisitor } from '../../language/visitor';
import type {
SDLValidationContext,
ValidationContext,
} from '../ValidationContext';
/**
* Known type names
*
* A GraphQL document is only valid if referenced types (specifically
* variable definitions and fragment conditions) are defined by the type schema.
* See https://spec.graphql.org/draft/#sec-Fragment-Spread-Type-Existence
*/
export declare function KnownTypeNamesRule(
context: ValidationContext | SDLValidationContext,
): ASTVisitor;