fun createPreIndex(types: Iterable<KClass<*>>): PreIndex {
        val allTypesToVisit = buildSet {
            fun visit(type: KClass<*>) {
                if (add(type)) {
                    typeDiscovery.getClassesToVisitFrom(type).forEach(::visit)
                }
            }
            types.forEach(::visit)
        }

        return PreIndex().apply {
            allTypesToVisit.forEach { type ->

        this.stopAt = stopAt;
    }

    public void visit(ClassLoader classLoader) {
        if (classLoader == stopAt) {
            visitSpec(SystemClassLoaderSpec.INSTANCE);
            return;
        }

        if (classLoader instanceof ClassLoaderHierarchy) {
            ((ClassLoaderHierarchy) classLoader).visit(this);
        } else {
            if (isPreJava9LauncherAppClassloader(classLoader)) {

            }

            @Override
            public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
                Set<String> allInterfaces = new LinkedHashSet<String>(Arrays.asList(interfaces));
                allInterfaces.add(mixInInterface.replace('.', '/'));
                super.visit(version, access, name, signature, superName, allInterfaces.toArray(new String[0]));

                    assertTrue(details.file.directory)
                }
        ] as FileVisitor

        tree.visit(visitor)

        assertThat(files, equalTo(expectedFiles as Set))
        assertThat(dirs, equalTo(expectedDirs as Set))

        files = [] as Set
        tree.visit {FileVisitDetails details ->
            assertTrue(files.add(details.relativePath.pathString))
        }

        when:
        visit(decorator, dir)

        then:
        1 * delegateAction.processFile(dir)
    }

    def doesNotVisitAnEmptyDirectoryIfCorrespondingOptionIsOff() {
        final FileCopyDetailsInternal dir = file("dir", true, false)

        when:
        visit(decorator, dir)

        then:
        0 * delegateAction._
    }

        @Override
        public void visitExact(NodeAccess value) {
            visit(value);
        }

        @Override
        public void visitAncestor(NodeAccess value, VfsRelativePath pathToVisitedLocation) {
            if (value.accessesChild(pathToVisitedLocation)) {
                visit(value);
            }
        }

        @Override

    return "else";
  }
};

TEST(VisitTest, Test1) {
  TaggedValue a(Int64(1)), b(Float32(1.1f));
  TaggedValue c = TaggedValue::None();

  ASSERT_EQ(a.visit<const char*>(Visitor()), "int64");
  ASSERT_EQ(b.visit<const char*>(Visitor()), "float32");
  ASSERT_EQ(c.visit<const char*>(Visitor()), "else");
}

}  // namespace impl
}  // namespace libtf

// Walk traverses an AST in depth-first order: It starts by calling
// v.Visit(node); node must not be nil. If the visitor w returned by
// v.Visit(node) is not nil, Walk is invoked recursively with visitor
// w for each of the non-nil children of node, followed by a call of
// w.Visit(nil).
func Walk(v Visitor, node Node) {
	if v = v.Visit(node); v == nil {
		return
	}

	// walk children

				changed = true
			}
			return changed
		},
	}
	v.Visit(s)
	return s
}

// StripNullable returns a copy without nullable.
func (s *Structural) StripNullable() *Structural {
	s = s.DeepCopy()
	v := Visitor{
		Structural: func(s *Structural) bool {
			changed := s.Nullable
			s.Nullable = false
			return changed
		},
	}
	v.Visit(s)
	return s

				toVisit = append(toVisit, testPath{path: visit.path + "[*]", value: item})
			} else if !isPrimitive(visit.value.Type().Elem().Kind()) {
				t.Logf("unhandled non-primitive map type %s: %s", visit.path, visit.value.Type().Elem())
			}

		case visit.value.Kind() == reflect.Pointer:
			if visit.value.IsNil() {
				if visit.value.Type().Elem().Kind() == reflect.Struct {