{"ExprStmt", `append@(s, 1, 2, 3)`},

	{"SendStmt", `ch @<- x`},

	{"DeclStmt", `@const x = 0`},
	{"DeclStmt", `@const (x = 0)`},
	{"DeclStmt", `@type T int`},
	{"DeclStmt", `@type T = int`},
	{"DeclStmt", `@type (T1 = int; T2 = float32)`},
	{"DeclStmt", `@var x = 0`},
	{"DeclStmt", `@var x, y, z int`},
	{"DeclStmt", `@var (a, b = 1, 2)`},

	{"AssignStmt", `x @= y`},
	{"AssignStmt", `a, b, x @= 1, 2, 3`},

// If s is labeled, label is the label name; otherwise s
// is "".
func (check *Checker) isTerminating(s syntax.Stmt, label string) bool {
	switch s := s.(type) {
	default:
		panic("unreachable")

	case *syntax.DeclStmt, *syntax.EmptyStmt, *syntax.SendStmt,
		*syntax.AssignStmt, *syntax.CallStmt:
		// no chance

	case *syntax.LabeledStmt:
		return check.isTerminating(s.Stmt, s.Label.Value)

	case *syntax.ExprStmt:

// If s is labeled, label is the label name; otherwise s
// is "".
func (check *Checker) isTerminating(s ast.Stmt, label string) bool {
	switch s := s.(type) {
	default:
		panic("unreachable")

	case *ast.BadStmt, *ast.DeclStmt, *ast.EmptyStmt, *ast.SendStmt,
		*ast.IncDecStmt, *ast.AssignStmt, *ast.GoStmt, *ast.DeferStmt,
		*ast.RangeStmt:
		// no chance

	case *ast.LabeledStmt:
		return check.isTerminating(s.Stmt, s.Label.Name)

		// case *MapType:
		// case *ChanType:

		// statements
		// case *EmptyStmt:
		// case *LabeledStmt:
		// case *BlockStmt:
		// case *ExprStmt:
		case *SendStmt:
			m = n.Chan
		// case *DeclStmt:
		case *AssignStmt:
			m = n.Lhs
		// case *BranchStmt:
		// case *CallStmt:
		// case *ReturnStmt:
		// case *IfStmt:
		// case *ForStmt:
		// case *SwitchStmt:
		// case *SelectStmt:

		return 1 << nCommClause
	case *ast.Comment:
		return 1 << nComment
	case *ast.CommentGroup:
		return 1 << nCommentGroup
	case *ast.CompositeLit:
		return 1 << nCompositeLit
	case *ast.DeclStmt:
		return 1 << nDeclStmt
	case *ast.DeferStmt:
		return 1 << nDeferStmt
	case *ast.Ellipsis:
		return 1 << nEllipsis
	case *ast.EmptyStmt:
		return 1 << nEmptyStmt
	case *ast.ExprStmt:
		return 1 << nExprStmt

		fwdJumps = append(fwdJumps, check.blockBranches(all, b, lstmt, list)...)
	}

	var stmtBranches func(ast.Stmt)
	stmtBranches = func(s ast.Stmt) {
		switch s := s.(type) {
		case *ast.DeclStmt:
			if d, _ := s.Decl.(*ast.GenDecl); d != nil && d.Tok == token.VAR {
				recordVarDecl(d.Pos())
			}

		case *ast.LabeledStmt:
			// declare non-blank label
			if name := s.Label.Name; name != "_" {

		Walk(v, n.Methods)

	case *MapType:
		Walk(v, n.Key)
		Walk(v, n.Value)

	case *ChanType:
		Walk(v, n.Value)

	// Statements
	case *BadStmt:
		// nothing to do

	case *DeclStmt:
		Walk(v, n.Decl)

	case *EmptyStmt:
		// nothing to do

	case *LabeledStmt:
		Walk(v, n.Label)
		Walk(v, n.Stmt)

	case *ExprStmt:
		Walk(v, n.X)

	case *SendStmt:

				if jmp == bad {
					return true
				}
			}
		}
		return false
	}

	var stmtBranches func(syntax.Stmt)
	stmtBranches = func(s syntax.Stmt) {
		switch s := s.(type) {
		case *syntax.DeclStmt:
			for _, d := range s.DeclList {
				if d, _ := d.(*syntax.VarDecl); d != nil {
					recordVarDecl(d.Pos())
				}
			}

		case *syntax.LabeledStmt:
			// declare non-blank label

		List   []Stmt
		Rbrace Pos
		stmt
	}

	ExprStmt struct {
		X Expr
		simpleStmt
	}

	SendStmt struct {
		Chan, Value Expr // Chan <- Value
		simpleStmt
	}

	DeclStmt struct {
		DeclList []Decl
		stmt
	}

	AssignStmt struct {
		Op       Operator // 0 means no operation
		Lhs, Rhs Expr     // Rhs == nil means Lhs++ (Op == Add) or Lhs-- (Op == Sub)
		simpleStmt
	}