Hi All.

I am a bit unclear on where and how what appears to be a type conversion takes place in the following example. Let say I define function (all shown in ammonite shell)

```
@ def f(x: Seq[Double]): Double = x.sum
defined function f
```

Then following works

```
@ f(Seq(1, 2, 3))
res4: Double = 6.0
```

But this one does not

```
@ val s = Seq(1, 2, 3)
s: Seq[Int] = List(1, 2, 3)
@ f(s)
cmd11.sc:1: type mismatch;
found : Seq[Int]
required: Seq[Double]
val s = Seq(1, 2, 3); val res11_1 = f(s)
^
Compilation Failed
```

So the question is where is this type conversion defined, why it does not work in the second case and how can it be made to work in the second case?