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)

		if s.walkMu != nil {
			s.walkMu.Unlock()
		}
		if err != nil {
			// Folder could have gone away in-between
			if err != errVolumeNotFound && err != errFileNotFound {
				internalLogOnceIf(ctx, err, "metacache-walk-scan-dir")
			}
			if opts.ReportNotFound && err == errFileNotFound && current == opts.BaseDir {
				err = errFileNotFound
			} else {
				err = nil
			}
			diskHealthCheckOK(ctx, err)
			return err

		}
	}
	return nil
}

// walk recursively descends path, calling walkFn.
func walk(path string, info fs.FileInfo, walkFn WalkFunc) error {
	if !info.IsDir() {
		return walkFn(path, info, nil)
	}

	names, err := readDirNames(path)
	err1 := walkFn(path, info, err)
	// If err != nil, walk can't walk into this directory.
	// err1 != nil means walkFn want walk to skip this directory or stop walking.

	}
	return n
}

// walkDot walks an ODOT or ODOTPTR node.
func walkDot(n *ir.SelectorExpr, init *ir.Nodes) ir.Node {
	usefield(n)
	n.X = walkExpr(n.X, init)
	return n
}

// walkDotType walks an ODOTTYPE or ODOTTYPE2 node.
func walkDotType(n *ir.TypeAssertExpr, init *ir.Nodes) ir.Node {
	n.X = walkExpr(n.X, init)

	extraCalls map[*ir.Func][]nowritebarrierrecCall

	// curfn is the current function during AST walks.
	curfn *ir.Func
}

type nowritebarrierrecCall struct {
	target *ir.Func // caller or callee
	lineno src.XPos // line of call
}

// newNowritebarrierrecChecker creates a nowritebarrierrecChecker. It
// must be called before walk.
func newNowritebarrierrecChecker() *nowritebarrierrecChecker {
	c := &nowritebarrierrecChecker{

  // for such regions to a new unique-id. This is required because walk() walks
  // the attached regions first before visiting the op, so there is no
  // opportunity during the walk to seed region arguments. Also note that walk
  // eventually also visits the Op on which the walk() is called, so make sure
  // we do not overwrite the function argument mapping here.
  func_op.walk([&](Operation* op) {
    if (op == func_op) return;

		if err := walk(filename, fi, walkFn); err != nil {
			if !fi.IsDir() || err != filepath.SkipDir {
				return err
			}
		}
	}
	return nil
}

// Walk walks the file tree rooted at root, calling walkFn for each file or
// directory in the tree, including root.
func Walk(root string, walkFn filepath.WalkFunc) error {
	Trace("Walk", root)
	info, err := Lstat(root)
	if err != nil {

	if as.X != nil && as.Y != nil {
		return convas(as, init)
	}
	return as
}

// walkAssignDotType walks an OAS2DOTTYPE node.
func walkAssignDotType(n *ir.AssignListStmt, init *ir.Nodes) ir.Node {
	walkExprListSafe(n.Lhs, init)
	n.Rhs[0] = walkExpr(n.Rhs[0], init)
	return n
}

// walkAssignFunc walks an OAS2FUNC node.
func walkAssignFunc(init *ir.Nodes, n *ir.AssignListStmt) ir.Node {
	init.Append(ir.TakeInit(n)...)

	r := ir.NewBlockStmt(base.Pos, nil)
	r.List = calls
	return walkStmt(typecheck.Stmt(r))
}

// walkRecoverFP walks an ORECOVERFP node.
func walkRecoverFP(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
	return mkcall("gorecover", nn.Type(), init, walkExpr(nn.Args[0], init))
}

// walkUnsafeData walks an OUNSAFESLICEDATA or OUNSAFESTRINGDATA expression.
func walkUnsafeData(n *ir.UnaryExpr, init *ir.Nodes) ir.Node {

	var files []*ast.File
	for _, f := range fs {
		files = append(files, f)
	}
	return files
}

type collector struct {
	dirs  []string
	regex *regexp.Regexp
}

// handlePath walks the filesystem recursively, collecting directories,
// ignoring some unneeded directories (hidden/vendored) that are handled
// specially later.
func (c *collector) handlePath(path string, info os.FileInfo, err error) error {