template alias argument accepts only class/interface types.

[Alexandru Ermicioi]

Perhaps I missed somewhere, but it seems that you can pass only 
classes or interfaces to alias argument of a template. Trying to 
pass another type (such as int, int[]) yields an error.

Example of issue:
------------------------
void test(alias T)(int o) {
     import std.stdio;
     writeln("coo");
}

void main() {
     int i;
     test!(Object[])(0);
}
------------------------

Try pass Object or IFoo and everything compiles perfectly.
Link to example: https://run.dlang.io/is/jqr9Zi

According to 
https://dlang.org/spec/template.html#TemplateAliasParameter, 
simple types and arrays are excluded from the list of supported 
"alias X" arguments. I'm wondering why do we have such 
limitation? Is there any reasoning at limiting primitive types 
and arrays?

Thank you,
Alexandru.