DownValues when using Set and SetDelayed

Question

It is known from several questions asked in SE that one of the basic differences between Set and SetDelayed is that the former evaluates the right hand side at the time of assignment whereas the other is not.

When I looked at the DownValues in both cases I found that both definitions result into same DownValues structures.

For example:

t = x + y
f[x_, y_] := 2 x t
g[x_, y_] = 2 x t

Now:

DownValues/@{f,g}

    (*{{HoldPattern[f[x_, y_]] :> 2 x t}, {HoldPattern[g[x_, y_]] :> 2 x (x + y)}}*)

As you can see here that both Set and SetDelayed transformed into same DownValues structures (HoldPattern[function pattern] :> right hand side)

My questions are:

1-Is it correct that internally both will be treated equally based on DownValues structure.

2- If I want to define function using SetDelayed I can do it like this:

DownValues[h]={HoldPattern[h[x_, y_]] :> 2 x t};

Now how to do same thing with Set

Thanks

Answer 1

To do same thing with Set

DownValues[h] = {First[Hold[HoldPattern[h[x_, y_]] :> 2 x t] /. t -> x + y ]};