At the very least, it's contradicted by the website:
http://dlang.org/expression#CastExpression
"Casting a value v to a struct S, when value is not a struct of the
same type, is equivalent to: S(v)"
In your case, you have no 'this' in Decimal to accept a Decimal with
other arguments. This should not work.
Timon provides a nice example:
struct A{
int a,b;
}
struct B{
long x;
}
void main(){
auto a=A();
auto b=cast(B)a;
}
Here, cast(B)a should be transformed into B(a). AFAICT, this should
not compile, but it does.
