token.MUL_ASSIGN:     token.MUL,
	token.QUO_ASSIGN:     token.QUO,
	token.REM_ASSIGN:     token.REM,
	token.AND_ASSIGN:     token.AND,
	token.OR_ASSIGN:      token.OR,
	token.XOR_ASSIGN:     token.XOR,
	token.SHL_ASSIGN:     token.SHL,
	token.SHR_ASSIGN:     token.SHR,
	token.AND_NOT_ASSIGN: token.AND_NOT,
}

func TestZeroTok(t *testing.T) {
	// zero value for token.Token must be token.ILLEGAL
	var zero token.Token

	SHR     // >>
	AND_NOT // &^

	ADD_ASSIGN // +=
	SUB_ASSIGN // -=
	MUL_ASSIGN // *=
	QUO_ASSIGN // /=
	REM_ASSIGN // %=

	AND_ASSIGN     // &=
	OR_ASSIGN      // |=
	XOR_ASSIGN     // ^=
	SHL_ASSIGN     // <<=
	SHR_ASSIGN     // >>=
	AND_NOT_ASSIGN // &^=

	LAND  // &&
	LOR   // ||
	ARROW // <-
	INC   // ++
	DEC   // --

	EQL    // ==
	LSS    // <
	GTR    // >
	ASSIGN // =

				checkLongShift(pass, node, node.X, node.Y)
			}
		case *ast.AssignStmt:
			if len(node.Lhs) != 1 || len(node.Rhs) != 1 {
				return
			}
			if node.Tok == token.SHL_ASSIGN || node.Tok == token.SHR_ASSIGN {
				checkLongShift(pass, node, node.Lhs[0], node.Rhs[0])
			}
		}
	})
	return nil, nil
}

// checkLongShift checks if shift or shift-assign operations shift by more than

		case '^':
			tok = s.switch2(token.XOR, token.XOR_ASSIGN)
		case '<':
			if s.ch == '-' {
				s.next()
				tok = token.ARROW
			} else {
				tok = s.switch4(token.LSS, token.LEQ, '<', token.SHL, token.SHL_ASSIGN)
			}
		case '>':
			tok = s.switch4(token.GTR, token.GEQ, '>', token.SHR, token.SHR_ASSIGN)
		case '=':
			tok = s.switch2(token.ASSIGN, token.EQL)
		case '!':
			tok = s.switch2(token.NOT, token.NEQ)

	{token.QUO_ASSIGN, "/=", operator},
	{token.REM_ASSIGN, "%=", operator},

	{token.AND_ASSIGN, "&=", operator},
	{token.OR_ASSIGN, "|=", operator},
	{token.XOR_ASSIGN, "^=", operator},
	{token.SHL_ASSIGN, "<<=", operator},
	{token.SHR_ASSIGN, ">>=", operator},
	{token.AND_NOT_ASSIGN, "&^=", operator},

	{token.LAND, "&&", operator},
	{token.LOR, "||", operator},
	{token.ARROW, "<-", operator},

	switch p.tok {
	case
		token.DEFINE, token.ASSIGN, token.ADD_ASSIGN,
		token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN,
		token.REM_ASSIGN, token.AND_ASSIGN, token.OR_ASSIGN,
		token.XOR_ASSIGN, token.SHL_ASSIGN, token.SHR_ASSIGN, token.AND_NOT_ASSIGN:
		// assignment statement
		pos, tok := p.pos, p.tok
		p.next()
		y := p.parseRhsList()
		return &ast.AssignStmt{x, pos, tok, y}
	}

	if len(x) > 1 {

	switch p.tok {
	case
		token.DEFINE, token.ASSIGN, token.ADD_ASSIGN,
		token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN,
		token.REM_ASSIGN, token.AND_ASSIGN, token.OR_ASSIGN,
		token.XOR_ASSIGN, token.SHL_ASSIGN, token.SHR_ASSIGN, token.AND_NOT_ASSIGN:
		// assignment statement, possibly part of a range clause
		pos, tok := p.pos, p.tok
		p.next()
		var y []ast.Expr
		isRange := false

		{"RBRACK", Const, 0},
		{"REM", Const, 0},
		{"REM_ASSIGN", Const, 0},
		{"RETURN", Const, 0},
		{"RPAREN", Const, 0},
		{"SELECT", Const, 0},
		{"SEMICOLON", Const, 0},
		{"SHL", Const, 0},
		{"SHL_ASSIGN", Const, 0},
		{"SHR", Const, 0},
		{"SHR_ASSIGN", Const, 0},
		{"STRING", Const, 0},
		{"STRUCT", Const, 0},
		{"SUB", Const, 0},
		{"SUB_ASSIGN", Const, 0},
		{"SWITCH", Const, 0},

pkg go/token, const RETURN Token
pkg go/token, const RPAREN Token
pkg go/token, const SELECT Token
pkg go/token, const SEMICOLON Token
pkg go/token, const SHL Token
pkg go/token, const SHL_ASSIGN Token
pkg go/token, const SHR Token
pkg go/token, const SHR_ASSIGN Token
pkg go/token, const STRING Token
pkg go/token, const STRUCT Token
pkg go/token, const SUB Token
pkg go/token, const SUB_ASSIGN Token

pkg go/token, const REM_ASSIGN = 27
pkg go/token, const RETURN = 80
pkg go/token, const RPAREN = 54
pkg go/token, const SELECT = 81
pkg go/token, const SEMICOLON = 57
pkg go/token, const SHL = 20
pkg go/token, const SHL_ASSIGN = 31
pkg go/token, const SHR = 21
pkg go/token, const SHR_ASSIGN = 32
pkg go/token, const STRING = 9
pkg go/token, const STRUCT = 82
pkg go/token, const SUB = 13
pkg go/token, const SUB_ASSIGN = 24