fixes #3794

compiler/ccgtrav.nim

@@ -57,6 +57,8 @@ proc parentObj(accessor: Rope; m: BModule): Rope {.inline.} =
 
 proc genTraverseProc(c: var TTraversalClosure, accessor: Rope, typ: PType) =
   if typ == nil: return
+
+  let typ = getUniqueType(typ)
   var p = c.p
   case typ.kind
   of tyGenericInst, tyGenericBody, tyTypeDesc:

tests/ccgbugs/tmissing_ccgtrav_unique_type.nim

@@ -0,0 +1,12 @@
+
+# bug #3794
+
+
+import options
+
+proc getRef*(): Option[int] =
+  return none(int)
+
+proc getChild*() =
+  let iter = iterator (): int {.closure.} =
+    let reference = getRef()