alias this/opGet and opCast conversion

[js.mdnq]

This i probably a rather dumb question but I've been up all night 
and therefor have a really good excuse ;) (I can barely see 
straight...)


Is opGet the reverse opAssign? I can't find any docs on it but it 
does let me write converters from my type to another type.

e.g.,

struct X { int value; }

double x = xX;

without an opGet or alias this I get an error about not being 
able to implicitly convert. Using alias this solves the problem. 
Using opGet seems to let me write a converter(which I can't seem 
to do otherwise).

For example, it seems I could use opGet to normalize X's value 
when converting to a double.

That is, the way I see it is

double x = xX;

The compiler checks to see if double has an opAssign that will 
convert X to a double. If not it checks if X has an opGet call(a 
sort of reverse opAssign).

Is this the correct understanding of opGet or is there more too 
it.

What if I have

struct X { int value; X opAssign(Y y); }
struct Y { double value; X opGet(); alias opGet this; }

then

X x; Y y;

what does

x = y;
y = x;

do?

It seems the first will call X's opAssign and Y's opGet unless 
there is precedence?  y = x will fail with the implicit 
conversion error?