next steps for closure iterators

tests/objects/tobjconstr2.nim

@@ -0,0 +1,22 @@
+type TFoo{.exportc.} = object
+ x:int
+
+var s{.exportc.}: seq[TFoo] = @[]
+
+s.add TFoo(x: 42)
+
+echo s[0].x
+
+
+# bug #563
+type
+  Foo =
+    object {.inheritable.}
+      x: int
+
+  Bar =
+    object of Foo
+      y: int
+
+var a = Bar(y: 100, x: 200) # works
+var b = Bar(x: 100, y: 200) # used to fail