import { ASTVisitor } from '../../language/visitor';
import { ASTValidationContext } from '../ValidationContext';

export function duplicateVariableMessage(variableName: string): string;

/**
 * Unique variable names
 *
 * A GraphQL operation is only valid if all its variables are uniquely named.
 */
export function UniqueVariableNames(context: ASTValidationContext): ASTVisitor;