return n
}

// rangeAssign returns "n.Key = key".
func rangeAssign(n *ir.RangeStmt, key ir.Node) ir.Node {
	key = rangeConvert(n, n.Key.Type(), key, n.KeyTypeWord, n.KeySrcRType)
	return ir.NewAssignStmt(n.Pos(), n.Key, key)
}

// rangeAssign2 returns "n.Key, n.Value = key, value".
func rangeAssign2(n *ir.RangeStmt, key, value ir.Node) ir.Node {
	// Use OAS2 to correctly handle assignments

	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 *ast.ExprStmt:
		// calling the predeclared (possibly parenthesized) panic() function is terminating

				// whose execution terminates."
				valid := false
				if t := b.enclosingTarget(name); t != nil {
					switch t.Stmt.(type) {
					case *ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt, *ast.ForStmt, *ast.RangeStmt:
						valid = true
					}
				}
				if !valid {
					check.errorf(s.Label, MisplacedLabel, "invalid break label %s", name)
					return
				}

			case token.CONTINUE:

	KindIfThen          // then block of IfStmt
	KindLabel           // labeled block of BranchStmt (Stmt may be nil for dangling label)
	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

		(*ast.CallExpr)(nil),
		(*ast.CompositeLit)(nil),
		(*ast.FuncDecl)(nil),
		(*ast.FuncLit)(nil),
		(*ast.GenDecl)(nil),
		(*ast.RangeStmt)(nil),
		(*ast.ReturnStmt)(nil),
	}
	inspect.Preorder(nodeFilter, func(node ast.Node) {
		switch node := node.(type) {
		case *ast.RangeStmt:
			checkCopyLocksRange(pass, node)
		case *ast.FuncDecl:
			checkCopyLocksFunc(pass, node.Name.Name, node.Recv, node.Type)
		case *ast.FuncLit:

	case *ast.TypeSwitchStmt:
		b.typeSwitchStmt(s, label)

	case *ast.SelectStmt:
		b.selectStmt(s, label)

	case *ast.ForStmt:
		b.forStmt(s, label)

	case *ast.RangeStmt:
		b.rangeStmt(s, label)

	default:
		panic(fmt.Sprintf("unexpected statement kind: %T", s))
	}
}

func (b *builder) stmtList(list []ast.Stmt) {
	for _, s := range list {
		b.stmt(s)
	}
}

	// when the specific type of x is known, so the cases cannot
	// be merged.
	case *ast.ForStmt:
		outer := d.breakTarget
		d.breakTarget = x
		d.findLabels(x.Body)
		d.breakTarget = outer

	case *ast.RangeStmt:
		outer := d.breakTarget
		d.breakTarget = x
		d.findLabels(x.Body)
		d.breakTarget = outer

	case *ast.SelectStmt:
		outer := d.breakTarget
		d.breakTarget = x
		d.findLabels(x.Body)

	Run:      run,
}

func run(pass *analysis.Pass) (interface{}, error) {
	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)

	nodeFilter := []ast.Node{
		(*ast.File)(nil),
		(*ast.RangeStmt)(nil),
		(*ast.ForStmt)(nil),
	}
	inspect.Nodes(nodeFilter, func(n ast.Node, push bool) bool {
		if !push {
			// inspect.Nodes is slightly suboptimal as we only use push=true.
			return true
		}

		return 1 << nLabeledStmt
	case *ast.MapType:
		return 1 << nMapType
	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:

		//       about the lower bound.
		// An example where the 0 helps:
		//       x, y, z := b[0:2], b[2:4], b[4:6]
		// An example where it does not:
		//       x, y := b[:n], b[n:]

	case *ast.RangeStmt:
		// - a range of the form: for x, _ = range v {...}
		// can be simplified to: for x = range v {...}
		// - a range of the form: for _ = range v {...}
		// can be simplified to: for range v {...}
		if isBlank(n.Value) {