Function inferTypeForHomomorphicMappedType

test/fixtures/snapshot/typescript.js:68194–68207

* Infer a suitable input type for a homomorphic mapped type { [P in keyof T]: X }. We construct * an object type with the same set of properties as the source type, where the type of each * property is computed by inferring from the source property type to X for the type *

(source, target, constraint)

         * variable T[P] (i.e. we treat the type T[P] as the type variable we're inferring for).
         */
        function inferTypeForHomomorphicMappedType(source, target, constraint) {
            if (inInferTypeForHomomorphicMappedType) {
                return undefined;
            }
            var key = source.id + "," + target.id + "," + constraint.id;
            if (reverseMappedCache.has(key)) {
                return reverseMappedCache.get(key);
            }
            inInferTypeForHomomorphicMappedType = true;
            var type = createReverseMappedType(source, target, constraint);
            inInferTypeForHomomorphicMappedType = false;
            reverseMappedCache.set(key, type);
            return type;
        }
        // We consider a type to be partially inferable if it isn't marked non-inferable or if it is
        // an object literal type with at least one property of an inferable type. For example, an object
        // literal { a: 123, b: x => true } is marked non-inferable because it contains a context sensitive