import { GraphQLType, GraphQLCompositeType, GraphQLAbstractType } from "../type/definition";
import { GraphQLSchema } from "../type/schema";

/**
 * Provided two types, return true if the types are equal (invariant).
 */
export function isEqualType(typeA: GraphQLType, typeB: GraphQLType): boolean;

/**
 * Provided a type and a super type, return true if the first type is either
 * equal or a subset of the second super type (covariant).
 */
export function isTypeSubTypeOf(schema: GraphQLSchema, maybeSubType: GraphQLType, superType: GraphQLType): boolean;

/**
 * Provided two composite types, determine if they "overlap". Two composite
 * types overlap when the Sets of possible concrete types for each intersect.
 *
 * This is often used to determine if a fragment of a given type could possibly
 * be visited in a context of another type.
 *
 * This function is commutative.
 */
export function doTypesOverlap(
    schema: GraphQLSchema,
    typeA: GraphQLCompositeType,
    typeB: GraphQLCompositeType
): boolean;