fixes tconfusing_arrow bug

tests/generics/tconfusing_arrow.nim

@@ -0,0 +1,15 @@
+import algorithm, future
+
+type Deck = object
+  value: int
+
+proc sort(h: var seq[Deck]) =
+  # works:
+  h.sort(proc (x, y: Deck): auto = 
+    cmp(x.value, y.value))
+  # fails:
+  h.sort((x, y: Deck) => cmp(ord(x.value), ord(y.value)))
+
+var player: seq[Deck] = @[]
+
+player.sort()