// AlgKind describes the kind of algorithms used for comparing and
// hashing a Type.
type AlgKind int8

//go:generate stringer -type AlgKind -trimprefix A alg.go

const (
	AUNK   AlgKind = iota
	ANOEQ          // Types cannot be compared
	ANOALG         // implies ANOEQ, and in addition has a part that is marked Noalg
	AMEM           // Type can be compared/hashed as regular memory.

	"cmd/go/internal/search"
	"cmd/go/internal/str"
	"cmd/go/internal/trace"
	"cmd/internal/pkgpattern"

	"golang.org/x/mod/module"
)

type stdFilter int8

const (
	omitStd = stdFilter(iota)
	includeStd
)

// matchPackages is like m.MatchPackages, but uses a local variable (rather than
// a global) for tags, can include or exclude packages in the standard library,

func Validate(analyzers []*Analyzer) error {
	// Map each fact type to its sole generating analyzer.
	factTypes := make(map[reflect.Type]*Analyzer)

	// Traverse the Requires graph, depth first.
	const (
		white = iota
		grey
		black
		finished
	)
	color := make(map[*Analyzer]uint8)
	var visit func(a *Analyzer) error
	visit = func(a *Analyzer) error {
		if a == nil {
			return fmt.Errorf("nil *Analyzer")
		}

}

var predeclaredConsts = [...]struct {
	name string
	kind BasicKind
	val  constant.Value
}{
	{"true", UntypedBool, constant.MakeBool(true)},
	{"false", UntypedBool, constant.MakeBool(false)},
	{"iota", UntypedInt, constant.MakeInt64(0)},
}

func defPredeclaredConsts() {
	for _, c := range predeclaredConsts {
		def(NewConst(nopos, nil, c.name, Typ[c.kind], c.val))
	}
}

func defPredeclaredNil() {

}

var predeclaredConsts = [...]struct {
	name string
	kind BasicKind
	val  constant.Value
}{
	{"true", UntypedBool, constant.MakeBool(true)},
	{"false", UntypedBool, constant.MakeBool(false)},
	{"iota", UntypedInt, constant.MakeInt64(0)},
}

func defPredeclaredConsts() {
	for _, c := range predeclaredConsts {
		def(NewConst(nopos, nil, c.name, Typ[c.kind], c.val))
	}
}

func defPredeclaredNil() {

// GoState represents the state of a goroutine.
//
// New GoStates may be added in the future. Users of this type must be robust
// to that possibility.
type GoState uint8

const (
	GoUndetermined GoState = iota // No information is known about the goroutine.
	GoNotExist                    // Goroutine does not exist.
	GoRunnable                    // Goroutine is runnable but not running.

	sema  uint32
}

// A Locker represents an object that can be locked and unlocked.
type Locker interface {
	Lock()
	Unlock()
}

const (
	mutexLocked = 1 << iota // mutex is locked
	mutexWoken
	mutexStarving
	mutexWaiterShift = iota

	// Mutex fairness.
	//
	// Mutex can be in 2 modes of operations: normal and starvation.
	// In normal mode waiters are queued in FIFO order, but a woken up waiter

type ScanToken rune

const (
	// Asm defines some two-character lexemes. We make up
	// a rune/ScanToken value for them - ugly but simple.
	LSH          ScanToken = -1000 - iota // << Left shift.
	RSH                                   // >> Logical right shift.
	ARR                                   // -> Used on ARM for shift type 3, arithmetic right shift.

)

type expr struct {
	node
	typeAndValue // After typechecking, contains the results of typechecking this expression.
}

func (*expr) aExpr() {}

type ChanDir uint

const (
	_ ChanDir = iota
	SendOnly
	RecvOnly
)

// ----------------------------------------------------------------------------
// Statements

type (
	Stmt interface {
		Node
		aStmt()
	}

	// These are the same on Linux, BSD, and OS X.
	LOG_EMERG Priority = iota
	LOG_ALERT
	LOG_CRIT
	LOG_ERR
	LOG_WARNING
	LOG_NOTICE
	LOG_INFO
	LOG_DEBUG
)

const (
	// Facility.

	// From /usr/include/sys/syslog.h.
	// These are the same up to LOG_FTP on Linux, BSD, and OS X.
	LOG_KERN Priority = iota << 3
	LOG_USER
	LOG_MAIL
	LOG_DAEMON
	LOG_AUTH
	LOG_SYSLOG
	LOG_LPR