fixes #3550

compiler/cgmeth.nim

@@ -18,7 +18,12 @@ proc genConv(n: PNode, d: PType, downcast: bool): PNode =
   var source = skipTypes(n.typ, abstractPtrs)
   if (source.kind == tyObject) and (dest.kind == tyObject):
     var diff = inheritanceDiff(dest, source)
-    if diff == high(int): internalError(n.info, "cgmeth.genConv")
+    if diff == high(int):
+      # see bug #3550 which triggers it. XXX This is a hack but I don't know yet
+      # how the real fix looks like:
+      localError(n.info, "there is no subtype relation between " &
+                 typeToString(d) & " and " & typeToString(n.typ))
+      #internalError(n.info, "cgmeth.genConv")
     if diff < 0:
       result = newNodeIT(nkObjUpConv, n.info, d)
       addSon(result, n)

todo.txt

@@ -1,7 +1,7 @@
 essential for 1.0
 =================
 
-- document special cased varargs[untyped] and varargs[typed]
+- introduce newSeqOfCap(10)
 - The remaining bugs of the lambda lifting pass that is responsible to enable
   closures and closure iterators need to be fixed.
 - ``concept`` needs to be refined, a nice name for the feature is not enough.