// ReadDir via os.ReadDir
func (fs *DefaultFs) ReadDir(dirname string) ([]os.DirEntry, error) {
	return os.ReadDir(fs.prefix(dirname))
}

// Walk via filepath.Walk
func (fs *DefaultFs) Walk(root string, walkFn filepath.WalkFunc) error {
	return filepath.Walk(fs.prefix(root), walkFn)
}

// defaultFile implements File using same-named functions from "os"
type defaultFile struct {
	file *os.File
}

	// from "os"
	ReadFile(filename string) ([]byte, error)
	TempDir(dir, prefix string) (string, error)
	TempFile(dir, prefix string) (File, error)
	ReadDir(dirname string) ([]os.DirEntry, error)
	Walk(root string, walkFn filepath.WalkFunc) error
}

// File is an interface that we can use to mock various filesystem operations typically
// accessed through the File object from the "os" package
type File interface {

// walked multiple times.
// TODO(gri) Revisit this design. It may make sense to walk those nodes
// only once. A place where this matters is types2.TestResolveIdents.
func Walk(root Node, v Visitor) {
	walker{v}.node(root)
}

// A Visitor's Visit method is invoked for each node encountered by Walk.
// If the result visitor w is not nil, Walk visits each of the children

				break
			}
			return err
		}
	}
	return nil
}

// WalkDir walks the file tree rooted at root, calling fn for each file or
// directory in the tree, including root.
//
// All errors that arise visiting files and directories are filtered by fn:
// see the [fs.WalkDirFunc] documentation for details.
//
// The files are walked in lexical order, which makes the output deterministic

        return new AbstractTypeMetadataWalker.InstanceTypeMetadataWalker(typeMetadataStore, nestedAnnotation);
    }

    /**
     * A factory method for a walker that can visit property hierarchy declared by a type.
     *
     * Type walker can detect a nested property cycle and stop walking the path with a cycle, no exception is thrown.
     */

		if n.Elt != nil {
			Walk(v, n.Elt)
		}

	case *FuncLit:
		Walk(v, n.Type)
		Walk(v, n.Body)

	case *CompositeLit:
		if n.Type != nil {
			Walk(v, n.Type)
		}
		walkList(v, n.Elts)

	case *ParenExpr:
		Walk(v, n.X)

	case *SelectorExpr:
		Walk(v, n.X)
		Walk(v, n.Sel)

	case *IndexExpr:
		Walk(v, n.X)
		Walk(v, n.Index)

	case *IndexListExpr:
		Walk(v, n.X)

	call.Fun = walkExpr(call.Fun, &init)

	if len(init) > 0 {
		init.Append(n)
		return ir.NewBlockStmt(n.Pos(), init)
	}
	return n
}

// walkIf walks an OIF node.
func walkIf(n *ir.IfStmt) ir.Node {
	n.Cond = walkExpr(n.Cond, n.PtrInit())
	walkStmtList(n.Body)
	walkStmtList(n.Else)
	return n

	_q    [20]uint64
	plist []P
}

type P struct {
	tag string
	_x  [10]uint64
	b   bool
}

type M int

//go:noinline
func (w *M) walkP(p *P) *P {
	np := &P{}
	*np = *p
	np.tag += "new"
	return np
}

func (w *M) walkOp(op *Op) *Op {
	if op == nil {
		return nil
	}

	orig := op
	cloned := false
	clone := func() {
		if !cloned {
			cloned = true
			op = &Op{}

    @Rule
    SetSystemProperties setSystemPropertiesRule

    protected abstract List<T> getWalkers()

    def "basic directory walking works - walker: #walkerInstance.class.simpleName"() {
        given:
        def rootDir = tmpDir.createDir("root")
        def rootTextFile = rootDir.file("a.txt").createFile()

		}
		fmt.Printf("visited file or dir: %q\n", path)
		return nil
	})
	if err != nil {
		fmt.Printf("error walking the path %q: %v\n", tmpDir, err)
		return
	}
	// Output:
	// On Unix:
	// visited file or dir: "."
	// visited file or dir: "dir"
	// visited file or dir: "dir/to"
	// visited file or dir: "dir/to/walk"
	// skipping a dir without errors: skip