Struct type value as template parameter

[Tommi]

There seem to be two ways to pass struct type value-parameters to 
templates, which according to documentation shouldn't be 
possible. What should I make of this? Should the compiler not 
allow the following code? (which currently works)

struct StructParam
{
    int v;
}
struct TestStructParam1(T, T param)
{
    immutable(T) p = param;
}

struct TestStructParam2(alias param)
{
    immutable(StructParam) p = param;
}

//// Error: arithmetic/string type expected for value-parameter
//struct TestStructParam3(StructParam param)
//{
//    immutable(StructParam) p = param;
//}

void main(string[] args)
{
    static assert(TestStructParam1!(StructParam, 
StructParam(42)).p.v == 42);
    static assert(TestStructParam2!(StructParam(42)).p.v == 42);
}

Also, is there any intention to allow struct type 
value-parameters to templates in the future?