base.Errorf("%v is not a top level statement", n.Sym())
		} else {
			base.Errorf("%v is not a top level statement", n.Op())
		}
		ir.Dump("nottop", n)
		return n

	case ir.OAS,
		ir.OASOP,
		ir.OAS2,
		ir.OAS2DOTTYPE,
		ir.OAS2RECV,
		ir.OAS2FUNC,
		ir.OAS2MAPR,
		ir.OCLEAR,
		ir.OCLOSE,
		ir.OCOPY,
		ir.OCALLINTER,
		ir.OCALL,
		ir.OCALLFUNC,
		ir.ODELETE,
		ir.OSEND,
		ir.OPRINT,

			fn := chanfn("selectnbrecv", 2, ch.Type())
			call := mkcall1(fn, fn.Type().ResultsTuple(), r.PtrInit(), elem, ch)
			as := ir.NewAssignListStmt(r.Pos(), ir.OAS2, []ir.Node{cond, n.Lhs[1]}, []ir.Node{call})
			r.PtrInit().Append(typecheck.Stmt(as))
		}

		r.Cond = typecheck.Expr(cond)
		r.Body = cas.Body
		r.Else = append(dflt.Init(), dflt.Body...)