return !v.IsNil()
	}
	return true
}

// Fprint prints the (sub-)tree starting at AST node x to w.
// If fset != nil, position information is interpreted relative
// to that file set. Otherwise positions are printed as integer
// values (file set specific offsets).
//
// A non-nil [FieldFilter] f may be provided to control the output:

	isTerminal    = term.IsTerminal(int(os.Stdout.Fd()))
	logPrefix     = ""
	aliases       = map[*regexp.Regexp]string{}
)

type analyzer struct {
	fset      *token.FileSet // positions are relative to fset
	ctx       build.Context
	failed    bool
	donePaths map[string]interface{}
}

func newAnalyzer() *analyzer {
	ctx := build.Default
	ctx.CgoEnabled = true

	a := &analyzer{

	// some extra working space
	b = b[:end+(n*2)]
	// Copy the block of bytes we want to duplicate to the end of the
	// slice
	copy(b[end+n:], b[src:src+n])
	// Shift the bytes after the splice point n positions to the right
	// to make room for the new block
	copy(b[dst+n:end+n], b[dst:end])
	// Insert the duplicate block into the splice point
	copy(b[dst:], b[end+n:])
	b = b[:end+n]
	return b
}

	methods   []*Func      // ordered list of explicitly declared methods
	embeddeds []Type       // ordered list of explicitly embedded elements
	embedPos  *[]token.Pos // positions of embedded elements; or nil (for error messages) - use pointer to save space
	implicit  bool         // interface is wrapper for type set literal (non-interface T, ~T, or A|B)

	Path       string // Use path of module.
	ModulePath string // Module path in the comment.
	Syntax     *Line
}

// ParseWork parses and returns a go.work file.
//
// file is the name of the file, used in positions and errors.
//
// data is the content of the file.
//
// fix is an optional function that canonicalizes module versions.
// If fix is nil, all module versions must be canonical ([module.CanonicalVersion]

		if isWildcard(name) {
			if old, ok := m[name]; ok {
				return subst(nil, old, reflect.Value{})
			}
		}
	}

	if pos.IsValid() && pattern.Type() == positionType {
		// use new position only if old position was valid in the first place
		if old := pattern.Interface().(token.Pos); !old.IsValid() {
			return pattern
		}
		return pos
	}

	// Otherwise copy.
	switch p := pattern; p.Kind() {

	for id, obj := range info.Uses {
		posn := fset.Position(id.Pos())
		lineCol := fmt.Sprintf("%d:%d", posn.Line, posn.Column)
		usesByObj[obj] = append(usesByObj[obj], lineCol)
	}
	var items []string
	for obj, uses := range usesByObj {
		slices.Sort(uses)
		item := fmt.Sprintf("%s:\n  defined at %s\n  used at %s",
			types.ObjectString(obj, types.RelativeTo(pkg)),
			fset.Position(obj.Pos()),
			strings.Join(uses, ", "))

	BuildID() string

	// SourceLine reports the source line information for a given
	// address in the file. Due to inlining, the source line information
	// is in general a list of positions representing a call stack,
	// with the leaf function first.
	SourceLine(addr uint64) ([]Frame, error)

	// Symbols returns a list of symbols in the object file.

			if hostport[end+1] == ':' {
				return addrErr(hostport, tooManyColons)
			}
			return addrErr(hostport, missingPort)
		}
		host = hostport[1:end]
		j, k = 1, end+1 // there can't be a '[' resp. ']' before these positions
	} else {
		host = hostport[:i]
		if bytealg.IndexByteString(host, ':') >= 0 {
			return addrErr(hostport, tooManyColons)
		}
	}
	if bytealg.IndexByteString(hostport[j:], '[') >= 0 {

		{MakePos(f5, 5, 5), "f5:10:1[f1:5:5]", "f1", 5, 5, "f5", 10, 1},
		{MakePos(f5, 5, 10), "f5:10:6[f1:5:10]", "f1", 5, 10, "f5", 10, 6},
		{MakePos(f5, 6, 10), "f5:11:10[f1:6:10]", "f1", 6, 10, "f5", 11, 10},

		// positions from issue #19392
		{MakePos(fc, 4, 1), "c.go:10:1[p.go:4:1]", "p.go", 4, 1, "c.go", 10, 1},
		{MakePos(ft, 7, 1), "t.go:20:1[p.go:7:1]", "p.go", 7, 1, "t.go", 20, 1},