old, found := check.untyped[x]
	if !found {
		return // nothing to do
	}

	// update operands of x if necessary
	switch x := x.(type) {
	case *syntax.BadExpr,
		*syntax.FuncLit,
		*syntax.CompositeLit,
		*syntax.IndexExpr,
		*syntax.SliceExpr,
		*syntax.AssertExpr,
		*syntax.ListExpr,
		//*syntax.StarExpr,
		*syntax.KeyValueExpr,
		*syntax.ArrayType,

	percentBangString = "%!"
	missingString     = "(MISSING)"
	badIndexString    = "(BADINDEX)"
	panicString       = "(PANIC="
	extraString       = "%!(EXTRA "
	badWidthString    = "%!(BADWIDTH)"
	badPrecString     = "%!(BADPREC)"
	noVerbString      = "%!(NOVERB)"
	invReflectString  = "<invalid reflect.Value>"
)

// State represents the printer state passed to custom formatters.

	REG_EBRACE,	"EBRACE",
	REG_BADBR,	"BADBR",
	REG_ERANGE,	"ERANGE",
	REG_ESPACE,	"ESPACE",
	REG_BADRPT,	"BADRPT",
	REG_ENEWLINE,	"ENEWLINE",
	REG_ENULL,	"ENULL",
	REG_ECOUNT,	"ECOUNT",
	REG_BADESC,	"BADESC",
	REG_EMEM,	"EMEM",
	REG_EHUNG,	"EHUNG",
	REG_EBUS,	"EBUS",
	REG_EFAULT,	"EFAULT",
	REG_EFLAGS,	"EFLAGS",
	REG_EDELIM,	"EDELIM",
};

static struct
{
	regmatch_t	NOMATCH;
	int		errors;

		{"AssignStmt.Tok", Field, 0},
		{"AssignStmt.TokPos", Field, 0},
		{"Bad", Const, 0},
		{"BadDecl", Type, 0},
		{"BadDecl.From", Field, 0},
		{"BadDecl.To", Field, 0},
		{"BadExpr", Type, 0},
		{"BadExpr.From", Field, 0},
		{"BadExpr.To", Field, 0},
		{"BadStmt", Type, 0},
		{"BadStmt.From", Field, 0},
		{"BadStmt.To", Field, 0},
		{"BasicLit", Type, 0},
		{"BasicLit.Kind", Field, 0},

pkg syscall (darwin-arm64), const EAUTH Errno
pkg syscall (darwin-arm64), const EBADARCH = 86
pkg syscall (darwin-arm64), const EBADARCH Errno
pkg syscall (darwin-arm64), const EBADEXEC = 85
pkg syscall (darwin-arm64), const EBADEXEC Errno
pkg syscall (darwin-arm64), const EBADF = 9
pkg syscall (darwin-arm64), const EBADMACHO = 88
pkg syscall (darwin-arm64), const EBADMACHO Errno

pkg go/ast, type BadDecl struct
pkg go/ast, type BadDecl struct, From token.Pos
pkg go/ast, type BadDecl struct, To token.Pos
pkg go/ast, type BadExpr struct
pkg go/ast, type BadExpr struct, From token.Pos
pkg go/ast, type BadExpr struct, To token.Pos
pkg go/ast, type BadStmt struct
pkg go/ast, type BadStmt struct, From token.Pos
pkg go/ast, type BadStmt struct, To token.Pos

pkg syscall (darwin-386), const EAGAIN = 35
pkg syscall (darwin-386), const EALREADY = 37
pkg syscall (darwin-386), const EAUTH = 80
pkg syscall (darwin-386), const EBADARCH = 86
pkg syscall (darwin-386), const EBADEXEC = 85
pkg syscall (darwin-386), const EBADF = 9
pkg syscall (darwin-386), const EBADMACHO = 88
pkg syscall (darwin-386), const EBADMSG = 94
pkg syscall (darwin-386), const EBADRPC = 72