For this type : 

```
val t :  (String, Array[((String, String), Double)]) =  ("a", Array((("a", "b"), 1.0), (("a", "c"), 2.0)))

```

should I not be able to use also this type definition : 

```
val t : Tuple2[String , Array[Tuple2[[String , String] , Double]]] = ("a", Array((("a", "b"), 1.0), (("a", "c"), 2.0)))

```

But receive this error : 

```
Multiple markers at this line - identifier expected but '[' found. - wrong number of type arguments for Tuple2, 
 should be 2 - only classes can have declared but undefined members

```

Is Tuple2 (or TupleN) not allowed when defining a type ?