type parameter inference rules are confusing

list/iter.go

@@ -8,9 +8,46 @@ type Iter[T any] interface {
 	Next(*T) bool
 }
 
-/*
+// This actually works, but for some reason I don't yet understand, defining
-type Iter[T any] interface {
+// Max with a constraint of constrains.Ordered that takes Iterable[T] cannot
-	Done() bool
+// have its type parameter infered, but defining it with the same constraint of
-	Next() T
+// constraints.Ordered and taking List[T] does allow the type parameter to be
-}
+// inferred. Super confusing.
-*/
+//
+// func Max[T constraints.Ordered](l Iterable[T]) T {
+// 	it := l.Iter()
+// 
+// 	var v T
+// 	if !it.Next(&v) {
+// 		return v
+// 	}
+// 	max := v
+// 	for it.Next(&v) {
+// 		if v > max {
+// 			max = v
+// 		}
+// 	}
+// 	return max
+// }
+
+
+// Discarded Iterator types:
+//
+// This was my first attempt. I like to have a method that returns a bool so
+// you can use it succinctly in a for loop, but I didn't love having to call
+// both done and next
+//
+// type Iter[T any] interface {
+// 	Done() bool
+// 	Next() T
+// }
+//
+// I was never optimistic about this. In practice, using this in a for loop is
+// just annoying so I stopped doing it. But also there's another thing I find
+// annoying: it's a copy every time. You're not really iterating over the
+// values, you're iterating over copies of the values, it seemed like a lot of
+// unecessary copying.
+//
+// type Iter[T any] interface {
+//   Next() (T, bool)
+// }

list/list_test.go

@@ -110,7 +110,9 @@ func TestMap(t *testing.T) {
 	eq(t, 20, nums.At(1))
 	eq(t, 30, nums.At(2))
 	eq(t, 0, nums.At(3))
+
 	eq(t, 30, Max(nums))
+
 }
 
 func TestIter(t *testing.T) {