// instead of implementing Op itself.
type miniNode struct {
	pos  src.XPos // uint32
	op   Op       // uint8
	bits bitset8
	esc  uint16
}

// posOr returns pos if known, or else n.pos.
// For use in DeepCopy.
func (n *miniNode) posOr(pos src.XPos) src.XPos {
	if pos.IsKnown() {
		return pos
	}
	return n.pos
}

// op can be read, but not written.

var poserPathErr = &fs.PathError{Op: "poser"}

func (p *poser) Error() string     { return p.msg }
func (p *poser) Is(err error) bool { return p.f(err) }
func (p *poser) As(err any) bool {
	switch x := err.(type) {
	case **poser:
		*x = p
	case *errorT:
		*x = errorT{"poser"}
	case **fs.PathError:
		*x = poserPathErr
	default:
		return false
	}
	return true
}

func TestAs(t *testing.T) {
	var errT errorT

	invalidOp  = "invalid operation: "
)

// The poser interface is used to extract the position of type-checker errors.
type poser interface {
	Pos() syntax.Pos
}

func (check *Checker) error(at poser, code Code, msg string) {
	err := check.newError(code)
	err.addf(at, "%s", msg)
	err.report()
}

func (check *Checker) errorf(at poser, code Code, format string, args ...any) {
	err := check.newError(code)

func hasDots(call *syntax.CallExpr) bool { return call.HasDots }

// dddErrPos returns the node (poser) for reporting an invalid ... use in a call.
func dddErrPos(call *syntax.CallExpr) *syntax.CallExpr {
	// TODO(gri) should use "..." instead of call position
	return call
}

// argErrPos returns the node (poser) for reporting an invalid argument count.
func argErrPos(call *syntax.CallExpr) *syntax.CallExpr { return call }

type posMap struct {
	bases map[*syntax.PosBase]*src.PosBase
	cache struct {
		last *syntax.PosBase
		base *src.PosBase
	}
}

type poser interface{ Pos() syntax.Pos }
type ender interface{ End() syntax.Pos }

func (m *posMap) pos(p poser) src.XPos { return m.makeXPos(p.Pos()) }
func (m *posMap) end(p ender) src.XPos { return m.makeXPos(p.End()) }

func (m *posMap) makeXPos(pos syntax.Pos) src.XPos {

// is allowed to use version v. If the position is unknown, the specified
// module version (Config.GoVersion) is used. If that version is invalid,
// allowVersion returns true.
func (check *Checker) allowVersion(at poser, v goVersion) bool {
	fileVersion := check.conf.GoVersion
	if pos := at.Pos(); pos.IsKnown() {
		fileVersion = check.versions[pos.FileBase()]
	}

	// We need asGoVersion (which calls version.Lang) below

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package runtime

//go:nosplit
func cputicks() int64 {
	// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
	return nanotime()

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package runtime

//go:nosplit
func cputicks() int64 {
	// nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
	return nanotime()

It is altogether fitting and proper that we should do this. But, in a larger sense, we can not dedicate - we can not consecrate - we can not hallow - this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far...

		print("atomic synchronization instructions. Recompile using GOARM=7.\n")
		exit(1)
	}
}

//go:nosplit
func cputicks() int64 {
	// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
	return nanotime()