KindRangeBody       // body of RangeStmt
	KindRangeDone       // block after RangeStmt
	KindRangeLoop       // head of RangeStmt
	KindSelectCaseBody  // body of SelectStmt
	KindSelectDone      // block after SelectStmt
	KindSelectAfterCase // block after a CommClause
	KindSwitchCaseBody  // body of CaseClause
	KindSwitchDone      // block after {Type.}SwitchStmt

	case *ast.Package:
		return 1 << nPackage
	case *ast.ParenExpr:
		return 1 << nParenExpr
	case *ast.RangeStmt:
		return 1 << nRangeStmt
	case *ast.ReturnStmt:
		return 1 << nReturnStmt
	case *ast.SelectStmt:
		return 1 << nSelectStmt
	case *ast.SelectorExpr:
		return 1 << nSelectorExpr
	case *ast.SendStmt:
		return 1 << nSendStmt
	case *ast.SliceExpr:
		return 1 << nSliceExpr
	case *ast.StarExpr:

		Comm  Stmt      // send or receive statement; nil means default case
		Colon token.Pos // position of ":"
		Body  []Stmt    // statement list; or nil
	}

	// A SelectStmt node represents a select statement.
	SelectStmt struct {
		Select token.Pos  // position of "select" keyword
		Body   *BlockStmt // CommClauses only
	}

	// A ForStmt represents a for statement.
	ForStmt struct {

		if len(init) > 0 {
			init.Append(n)
			return ir.NewBlockStmt(n.Pos(), init)
		}
		return n

	case ir.OINLMARK:
		n := n.(*ir.InlineMarkStmt)
		return n

	case ir.OSELECT:
		n := n.(*ir.SelectStmt)
		walkSelect(n)
		return n

	case ir.OSWITCH:
		n := n.(*ir.SwitchStmt)
		walkSwitch(n)
		return n

	case ir.ORANGE:
		n := n.(*ir.RangeStmt)
		return walkRange(n)
	}

		children = append(children,
			tok(n.For, len("for")),
			tok(n.TokPos, len(n.Tok.String())))

	case *ast.ReturnStmt:
		children = append(children,
			tok(n.Return, len("return")))

	case *ast.SelectStmt:
		children = append(children,
			tok(n.Select, len("select")))

	case *ast.SelectorExpr:
		// nop

	case *ast.SendStmt:
		children = append(children,
			tok(n.Arrow, len("<-")))

				Rbrace: stmt.End(),
			}
			n.Else = block
		case *ast.BlockStmt:
			stmt.Lbrace = pos
		default:
			panic("unexpected node type in if")
		}
		ast.Walk(f, n.Else)
		return nil
	case *ast.SelectStmt:
		// Don't annotate an empty select - creates a syntax error.
		if n.Body == nil || len(n.Body.List) == 0 {
			return nil
		}
	case *ast.SwitchStmt:
		// Don't annotate an empty switch - creates a syntax error.

		w.node(n.Body)

	case *SwitchStmt:
		if n.Init != nil {
			w.node(n.Init)
		}
		if n.Tag != nil {
			w.node(n.Tag)
		}
		for _, s := range n.Body {
			w.node(s)
		}

	case *SelectStmt:
		for _, s := range n.Body {
			w.node(s)
		}

	// helper nodes
	case *RangeClause:
		if n.Lhs != nil {
			w.node(n.Lhs)
		}
		w.node(n.X)

	case *CaseClause:

		if n.Init != nil {
			Walk(v, n.Init)
		}
		Walk(v, n.Assign)
		Walk(v, n.Body)

	case *CommClause:
		if n.Comm != nil {
			Walk(v, n.Comm)
		}
		walkList(v, n.Body)

	case *SelectStmt:
		Walk(v, n.Body)

	case *ForStmt:
		if n.Init != nil {
			Walk(v, n.Init)
		}
		if n.Cond != nil {
			Walk(v, n.Cond)
		}
		if n.Post != nil {
			Walk(v, n.Post)
		}

package walk

import (
	"cmd/compile/internal/base"
	"cmd/compile/internal/ir"
	"cmd/compile/internal/typecheck"
	"cmd/compile/internal/types"
	"cmd/internal/src"
)

func walkSelect(sel *ir.SelectStmt) {
	lno := ir.SetPos(sel)
	if sel.Walked() {
		base.Fatalf("double walkSelect")
	}
	sel.SetWalked(true)

	init := ir.TakeInit(sel)

	init = append(init, walkSelectCases(sel.Cases)...)
	sel.Cases = nil

		s.Body = append(s.Body, p.caseClause())
	}
	s.Rbrace = p.pos()
	p.want(_Rbrace)

	return s
}

func (p *parser) selectStmt() *SelectStmt {
	if trace {
		defer p.trace("selectStmt")()
	}

	s := new(SelectStmt)
	s.pos = p.pos()

	p.want(_Select)
	if !p.got(_Lbrace) {
		p.syntaxError("missing { after select clause")
		p.advance(_Case, _Default, _Rbrace)