// to avoid confusion about what gets returned
	// in the presence of type assertions.
}

func walkStmtList(s []ir.Node) {
	for i := range s {
		s[i] = walkStmt(s[i])
	}
}

// walkFor walks an OFOR node.
func walkFor(n *ir.ForStmt) ir.Node {
	if n.Cond != nil {
		init := ir.TakeInit(n.Cond)
		walkStmtList(init)
		n.Cond = walkExpr(n.Cond, &init)
		n.Cond = ir.InitExpr(init, n.Cond)
	}

	if sel.Walked() {
		base.Fatalf("double walkSelect")
	}
	sel.SetWalked(true)

	init := ir.TakeInit(sel)

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

	sel.Compiled = init
	walkStmtList(sel.Compiled)

	base.Pos = lno
}

func walkSelectCases(cases []*ir.CommClause) []ir.Node {
	ncas := len(cases)
	sellineno := base.Pos

	// optimization: zero-case select
	if ncas == 0 {