n1.hashCode() != n2.hashCode()

        n1.toString() == "a"
        n2.toString() == "b"

        n1.is(factory.named(CustomNamed, "a"))
        n2.is(factory.named(CustomNamed, "b"))

        !n1.is(factory.named(Named, "a"))
        !n2.is(factory.named(Named, "b"))

        n1 instanceof Managed
    }

    def "can unpack and recreate instance of subtype of Named"() {

            is ObjectOrigin.NewObjectFromTopLevelFunction,
            is ObjectOrigin.ConstantOrigin,
            is ObjectOrigin.External,
            is ObjectOrigin.NullObjectOrigin,
            is ObjectOrigin.PropertyDefaultValue, // TODO: is it so?
            is ObjectOrigin.TopLevelReceiver -> Ok(objectOrigin)
        }

    private

The build state is managed by the `BuildState` class.
An instance is created for each build in the build definition, once per build execution and is discarded at the end of the execution. 

The build state also includes what is currently called the "Gradle state". The Gradle state is being merged into the build state and is mostly empty.

### Project state

 *
 * <h1>The provider value</h1>
 *
 * <p>The value of a provider may be:</p>
 *
 * <ul>
 *     <li>"fixed", which means that the value is a function only of configuration time inputs.

     * cross-process access.
     */
    CacheBuilder withInitializer(Consumer<? super PersistentCache> initializer);

    /**
     * Specifies an action to execute when the cache needs to be cleaned up. An exclusive lock is held while the cleanup is executing, to prevent cross-process access.
     *

    trace.elements.forEach { element ->
        when (element) {
            is AssignmentTraceElement.UnassignedValueUsed -> {
                val locationString = when (val result = element.assignmentAdditionResult) {
                    is AssignmentResolver.AssignmentAdditionResult.Reassignment,
                    is AssignmentAdded -> error("unexpected")

        // TODO - deal with tree that is not backed by a file
        is ZipFileTree -> ZipTreeSpec(tree.backingFileProvider)
        is TarFileTree -> TarTreeSpec(tree.backingFileProvider)
        is FilteredMinimalFileTree -> toSpecOrNull(tree.tree)?.let { FilteredMinimalFileTreeSpec(it, tree.patterns) }
        is GeneratedSingletonFileTree -> GeneratedTreeSpec(tree.toSpec())

            when (val input = read()) {
                null -> break
                is ProjectSpecificFingerprint.ProjectFingerprint -> input.run {
                    // An input that is specific to a project. If it is out-of-date, then invalidate that project's values and continue checking values
                    // Don't check a value for a project that is already out-of-date
                    val state = projects.entryFor(input.projectPath)

fun DeclarativeDocument.structurallyEqualsAsData(other: DeclarativeDocument): Boolean {
    fun ValueNode.structurallyEquals(other: ValueNode): Boolean = when (this) {
        is LiteralValueNode -> other is LiteralValueNode &&
            value == other.value

        is ValueFactoryNode -> other is ValueFactoryNode &&
            factoryName == other.factoryName &&
            values.matchesPairwise(other.values, ValueNode::structurallyEquals)
    }

public interface BuildLifecycleAwareVirtualFileSystem extends VirtualFileSystem {

    /**
     * Called when the build is started.
     *
     * @return whether watching the file system is currently enabled. This requires that the feature
     * is supported on the current operating system, it is enabled for the build, and has been successfully
     * started.
     */