diff --git a/src/hb-open-type.hh b/src/hb-open-type.hh
index a2521dcea..de2d25638 100644
--- a/src/hb-open-type.hh
+++ b/src/hb-open-type.hh
@@ -298,20 +298,24 @@ struct OffsetTo : Offset<OffsetType, has_null>
   }
 
   template <typename ...Ts>
-  bool serialize_subset (hb_subset_context_t *c, const Type &src, const void *base, Ts&&... ds)
+  bool serialize_subset (hb_subset_context_t *c,
+			 const OffsetTo& src,
+			 const void *src_base,
+			 const void *dst_base,
+			 Ts&&... ds)
   {
     *this = 0;
-    if (has_null && &src == _hb_has_null<Type, has_null>::get_null ())
+    if (src.is_null ())
       return false;
 
     auto *s = c->serializer;
 
     s->push ();
 
-    bool ret = c->dispatch (src, hb_forward<Ts> (ds)...);
+    bool ret = c->dispatch (src_base+src, hb_forward<Ts> (ds)...);
 
     if (ret || !has_null)
-      s->add_link (*this, s->pop_pack (), base);
+      s->add_link (*this, s->pop_pack (), dst_base);
     else
       s->pop_discard ();
 
@@ -683,7 +687,7 @@ struct OffsetListOf : OffsetArrayOf<Type>
     if (unlikely (!out)) return_trace (false);
     unsigned int count = this->len;
     for (unsigned int i = 0; i < count; i++)
-      out->arrayZ[i].serialize_subset (c, (*this)[i], out);
+      out->arrayZ[i].serialize_subset (c, this->arrayZ[i], this, out);
     return_trace (true);
   }
 
diff --git a/src/hb-ot-layout-common.hh b/src/hb-ot-layout-common.hh
index b1f4d06ab..f801f5af8 100644
--- a/src/hb-ot-layout-common.hh
+++ b/src/hb-ot-layout-common.hh
@@ -142,7 +142,7 @@ struct RecordListOf : RecordArrayOf<Type>
     if (unlikely (!out)) return_trace (false);
     unsigned int count = this->len;
     for (unsigned int i = 0; i < count; i++)
-      out->get_offset (i).serialize_subset (c, (*this)[i], out);
+      out->get_offset (i).serialize_subset (c, this->get_offset (i), this, out);
     return_trace (true);
   }
 
@@ -732,7 +732,7 @@ struct Lookup
     OffsetArrayOf<TSubTable>& out_subtables = out->get_subtables<TSubTable> ();
     unsigned int count = subTable.len;
     for (unsigned int i = 0; i < count; i++)
-      out_subtables[i].serialize_subset (c, this+subtables[i], out, get_type ());
+      out_subtables[i].serialize_subset (c, subtables[i], this, out, get_type ());
 
     return_trace (true);
   }
diff --git a/src/hb-ot-layout-gdef-table.hh b/src/hb-ot-layout-gdef-table.hh
index ac1bddb2e..0fca9947d 100644
--- a/src/hb-ot-layout-gdef-table.hh
+++ b/src/hb-ot-layout-gdef-table.hh
@@ -442,16 +442,16 @@ struct GDEF
     auto *out = c->serializer->embed (*this);
     if (unlikely (!out)) return_trace (false);
 
-    out->glyphClassDef.serialize_subset (c, this+glyphClassDef, out);
-    out->attachList = 0;//TODO(subset) serialize_subset (c, this+attachList, out);
-    out->ligCaretList = 0;//TODO(subset) serialize_subset (c, this+ligCaretList, out);
-    out->markAttachClassDef.serialize_subset (c, this+markAttachClassDef, out);
+    out->glyphClassDef.serialize_subset (c, glyphClassDef, this, out);
+    out->attachList = 0;//TODO(subset) serialize_subset (c, attachList, this, out);
+    out->ligCaretList = 0;//TODO(subset) serialize_subset (c, ligCaretList, this, out);
+    out->markAttachClassDef.serialize_subset (c, markAttachClassDef, this, out);
 
     if (version.to_int () >= 0x00010002u)
-      out->markGlyphSetsDef = 0;// TODO(subset) serialize_subset (c, this+markGlyphSetsDef, out);
+      out->markGlyphSetsDef = 0;// TODO(subset) serialize_subset (c, markGlyphSetsDef, this, out);
 
     if (version.to_int () >= 0x00010003u)
-      out->varStore = 0;// TODO(subset) serialize_subset (c, this+varStore, out);
+      out->varStore = 0;// TODO(subset) serialize_subset (c, varStore, this, out);
 
     return_trace (true);
   }
diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index 987689d3b..4bc3d7e15 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -2684,14 +2684,15 @@ struct GSUBGPOS
     auto *out = c->serializer->embed (*this);
     if (unlikely (!out)) return_trace (false);
 
-    out->scriptList.serialize_subset (c, this+scriptList, out);
-    out->featureList.serialize_subset (c, this+featureList, out);
+    out->scriptList.serialize_subset (c, scriptList, this, out);
+    out->featureList.serialize_subset (c, featureList, this, out);
 
     typedef OffsetListOf<TLookup> TLookupList;
     /* TODO Use intersects() to count how many subtables survive? */
     CastR<OffsetTo<TLookupList>> (out->lookupList)
       .serialize_subset (c,
-			 this+CastR<OffsetTo<TLookupList>> (lookupList),
+			 CastR<OffsetTo<TLookupList>> (lookupList),
+			 this,
 			 out);
 
     if (version.to_int () >= 0x00010001u)