fixes #270

compiler/ccgexprs.nim

@@ -1648,7 +1648,7 @@ proc downConv(p: BProc, n: PNode, d: var TLoc) =
     initLocExpr(p, n.sons[0], a)
     var r = rdLoc(a)
     if skipTypes(n.sons[0].typ, abstractInst).kind in {tyRef, tyPtr, tyVar} and
-        n.sons[0].kind notin {nkHiddenAddr, nkAddr}:
+        n.sons[0].kind notin {nkHiddenAddr, nkAddr, nkObjDownConv}:
       app(r, "->Sup")
       for i in countup(2, abs(inheritanceDiff(dest, src))): app(r, ".Sup")
       r = con("&", r)

tests/compile/tobject3.nim

@@ -0,0 +1,28 @@
+type
+  TFoo = ref object of TObject
+    Data: int  
+  TBar = ref object of TFoo
+    nil
+  TBar2 = ref object of TBar
+    d2: int
+
+template super(self: TBar): TFoo = self
+
+template super(self: TBar2): TBar = self
+
+proc Foo(self: TFoo) =
+  echo "TFoo"
+
+#proc Foo(self: TBar) =
+#  echo "TBar"
+#  Foo(super(self))
+# works when this code is uncommented
+
+proc Foo(self: TBar2) =
+  echo "TBar2"
+  Foo(super(self))
+
+var b: TBar2
+new(b)
+
+Foo(b)