Function getRelationKey

test/fixtures/snapshot/typescript.js:67113–67123

* To improve caching, the relation key for two generic types uses the target's id plus ids of the type parameters. * For other cases, the types ids are used.

(source, target, intersectionState, relation, ignoreConstraints)

         * For other cases, the types ids are used.
         */
        function getRelationKey(source, target, intersectionState, relation, ignoreConstraints) {
            if (relation === identityRelation && source.id > target.id) {
                var temp = source;
                source = target;
                target = temp;
            }
            var postFix = intersectionState ? ":" + intersectionState : "";
            return isTypeReferenceWithGenericArguments(source) && isTypeReferenceWithGenericArguments(target) ?
                getGenericTypeReferenceRelationKey(source, target, postFix, ignoreConstraints) :
                "".concat(source.id, ",").concat(target.id).concat(postFix);
        }
        // Invoke the callback for each underlying property symbol of the given symbol and return the first
        // value that isn't undefined.
        function forEachProperty(prop, callback) {