Pseudo member aliases

[Deokjae Lee]

void func(K,V)(in K[V] x) {
}

void main(string[] args) {
	auto x = [1:"1", 2:"2"];
	x.func();
}

Ok, the function func can be called like a member function of a type K[V].
Is there any way to do similar work on alias?
Actually I'd like to define aliases ValueType and KeyType on associative 
arrays and plain arrays, so that they are like member aliases of the 
array types.
If it is possible, code like the following would be compiled using them.

writeln(typeid((string[]).KeyType))); //print "int"
writeln(typeid((string[]).ValueType))); //print "immutable(char)[]"
auto x = [1:"hello", 2:"world"];
writeln(typeid(x.ValueType));//print "immutable(char)[]"