Confusion with Generics and nim typesystem.

[zlash]

Hello, I'm new to the language and I'm having a hard time understanding the 
types system and how they interact with generics (And sadly, there is no much 
stuff in the documentation to follow) For example, I would expect the following 
snippet to not even compile: 
    
    
    import typetraits
    
    type
        TT[T] = ref object of RootObj
            val: T
        CB[T] = proc (v: T): void
    
    proc testGeneric[T](val: TT[T], cb: CB[T]): void =
        echo val.type.name
        echo $val.val
    
    
    var tt = new(TT[seq[string]])
    echo tt.type.name
    tt.testGeneric( proc (v: int): void =
        echo $v )
    

However, it compiles and runs.

And also, I would expect the type of tt to be the same when outputted, instead 
the output is: 
    
    
    TT[seq[string]]
    TT[system.int]
    0
    

Can somebody help me with information as why this is not failing to compile, 
why it is choosing to specialize testGeneric with _int_ (instead of finding a 
conflict of different 'T's), and why it accepts to pass a TT[seq[string]] to a 
function expecting TT[int]? Why type.name differs in both calls?

Any insights are very much appreciated. Thanks.