diff --git a/lib/core/typeinfo.nim b/lib/core/typeinfo.nim
index 26a14f444..eb2a0c9e5 100755
--- a/lib/core/typeinfo.nim
+++ b/lib/core/typeinfo.nim
@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2012 Dominik Picheta, Andreas Rumpf
+#        (c) Copyright 2013 Dominik Picheta, Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -139,12 +139,15 @@ proc invokeNewSeq*(x: TAny, len: int) =
   var z = newSeq(x.rawType, len)
   genericShallowAssign(x.value, addr(z), x.rawType)
 
-proc extendSeq*(x: TAny, elems = 1) =
-  ## performs ``setLen(x, x.len+elems)``. `x` needs to represent a ``seq``.
+proc extendSeq*(x: TAny) =
+  ## performs ``setLen(x, x.len+1)``. `x` needs to represent a ``seq``.
   assert x.rawType.kind == tySequence
   var y = cast[ptr PGenSeq](x.value)[]
-  var z = incrSeq(y, x.rawType.base.size * elems)
-  genericShallowAssign(x.value, addr(z), x.rawType)
+  var z = incrSeq(y, x.rawType.base.size)
+  # 'incrSeq' already freed the memory for us and copied over the RC!
+  # So we simply copy the raw pointer into 'x.value':
+  cast[ppointer](x.value)[] = z
+  #genericShallowAssign(x.value, addr(z), x.rawType)
 
 proc setObjectRuntimeType*(x: TAny) =
   ## this needs to be called to set `x`'s runtime object type field.
diff --git a/lib/pure/htmlparser.nim b/lib/pure/htmlparser.nim
index 4136ecf57..ad952fc41 100755
--- a/lib/pure/htmlparser.nim
+++ b/lib/pure/htmlparser.nim
@@ -123,7 +123,7 @@ type
     tagVar         ## the HTML ``var`` element
 
 const
-  tagStrs = [
+  tagToStr* = [
     "a", "abbr", "acronym", "address", "applet", "area", 
     "b", "base", "basefont", "bdo", "big", "blockquote", "body", 
     "br", "button", "caption", "center", "cite", "code", 
@@ -243,13 +243,13 @@ proc binaryStrSearch(x: openarray[string], y: string): int =
 proc htmlTag*(n: PXmlNode): THtmlTag = 
   ## gets `n`'s tag as a ``THtmlTag``.
   if n.clientData == 0:
-    n.clientData = binaryStrSearch(tagStrs, n.tag)+1
+    n.clientData = binaryStrSearch(tagToStr, n.tag)+1
   result = THtmlTag(n.clientData)
 
 proc htmlTag*(s: string): THtmlTag =
   ## converts `s` to a ``THtmlTag``. If `s` is no HTML tag, ``tagUnknown`` is
   ## returned.
-  result = THtmlTag(binaryStrSearch(tagStrs, s.toLower)+1)
+  result = THtmlTag(binaryStrSearch(tagToStr, s.toLower)+1)
 
 proc entityToUtf8*(entity: string): string = 
   ## converts an HTML entity name like ``Ü`` to its UTF-8 equivalent.
diff --git a/lib/pure/marshal.nim b/lib/pure/marshal.nim
index bffc4ebb6..f52b554cc 100755
--- a/lib/pure/marshal.nim
+++ b/lib/pure/marshal.nim
@@ -1,7 +1,7 @@
 #

 #

 #            Nimrod's Runtime Library

-#        (c) Copyright 2012 Andreas Rumpf

+#        (c) Copyright 2013 Andreas Rumpf

 #

 #    See the file "copying.txt", included in this

 #    distribution, for details about the copyright.

diff --git a/lib/system/debugger.nim b/lib/system/debugger.nim
index 68fbccef6..f234c9daf 100755
--- a/lib/system/debugger.nim
+++ b/lib/system/debugger.nim
@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2012 Andreas Rumpf
+#        (c) Copyright 2013 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -579,6 +579,10 @@ proc hash(Data: Pointer, Size: int): THash =
     Dec(s)
   result = !$h
 
+proc hashGcHeader(data: pointer): THash =
+  const headerSize = sizeof(int)*2
+  result = hash(cast[pointer](cast[int](data) -% headerSize), headerSize)
+
 proc genericHashAux(dest: Pointer, mt: PNimType, shallow: bool,
                     h: THash): THash
 proc genericHashAux(dest: Pointer, n: ptr TNimNode, shallow: bool,
@@ -606,20 +610,22 @@ proc genericHashAux(dest: Pointer, mt: PNimType, shallow: bool,
     result = h
     if x != nil:
       let s = cast[NimString](x)
-      when true:
-        result = result !& hash(x, s.len)
+      when defined(trackGcHeaders):
+        result = result !& hashGcHeader(x)
       else:
-        let y = cast[pointer](cast[int](x) -% 2*sizeof(int))
-        result = result !& hash(y, s.len + 2*sizeof(int))
+        result = result !& hash(x, s.len)
   of tySequence:
     var x = cast[ppointer](dest)
     var dst = cast[taddress](cast[ppointer](dest)[])
     result = h
     if dst != 0:
-      for i in 0..cast[pgenericseq](dst).len-1:
-        result = result !& genericHashAux(
-          cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize),
-          mt.Base, shallow, result)
+      when defined(trackGcHeaders):
+        result = result !& hashGcHeader(cast[ppointer](dest)[])
+      else:
+        for i in 0..cast[pgenericseq](dst).len-1:
+          result = result !& genericHashAux(
+            cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize),
+            mt.Base, shallow, result)
   of tyObject, tyTuple:
     # we don't need to copy m_type field for tyObject, as they are equal anyway
     result = genericHashAux(dest, mt.node, shallow, h)
@@ -630,13 +636,18 @@ proc genericHashAux(dest: Pointer, mt: PNimType, shallow: bool,
       result = result !& genericHashAux(cast[pointer](d +% i*% mt.base.size),
                                         mt.base, shallow, result)
   of tyRef:
-    if shallow:
-      result = h !& hash(dest, mt.size)
-    else:
-      result = h
+    when defined(trackGcHeaders):
       var s = cast[ppointer](dest)[]
       if s != nil:
-        result = result !& genericHashAux(s, mt.base, shallow, result)
+        result = result !& hashGcHeader(s)
+    else:
+      if shallow:
+        result = h !& hash(dest, mt.size)
+      else:
+        result = h
+        var s = cast[ppointer](dest)[]
+        if s != nil:
+          result = result !& genericHashAux(s, mt.base, shallow, result)
         # hash the object header:
         #const headerSize = sizeof(int)*2
         #result = result !& hash(cast[pointer](cast[int](s) -% headerSize),