You can add debugging in RTL for simulation, using the following syntax:

object Enum extends SpinalEnum{
    val MIAOU, RAWRR = newElement()

class TopLevel extends Component {
    val a = Enum.RAWRR()
    val b = U(0x42)
    val c = out(Enum.RAWRR())
    val d = out (U(0x42))
    report(Seq("miaou ", a, b, c, d))

It will generate the following Verilog code for example:

$display("NOTE miaou %s%x%s%x", a_string, b, c_string, d);

Since SpinalHDL 1.4.4, the following syntax is also supported:

report(L"miaou $a $b $c $d")