diff --git a/.gitattributes b/.gitattributes
index 606f73b31b..04b3b060f2 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -6287,6 +6287,7 @@ tests/webtbs/tw3898.pp svneol=native#text/plain
 tests/webtbs/tw3899.pp svneol=native#text/plain
 tests/webtbs/tw3900.pp svneol=native#text/plain
 tests/webtbs/tw3913.pp svneol=native#text/plain
+tests/webtbs/tw3930.pp -text
 tests/webtbs/tw3931a.pp svneol=native#text/plain
 tests/webtbs/tw3939.pp svneol=native#text/plain
 tests/webtbs/tw3953a.pp svneol=native#text/plain
diff --git a/compiler/symdef.pas b/compiler/symdef.pas
index dd36a9e606..f43d105498 100644
--- a/compiler/symdef.pas
+++ b/compiler/symdef.pas
@@ -283,6 +283,7 @@ interface
           procedure deref;
           { add interface reference loaded from ppu }
           procedure addintf_deref(const d:tderef;iofs:longint);
+          procedure addintf_ioffset(d:tdef;iofs:longint);
 
           procedure clearmappings;
           procedure addmappings(intfindex: longint; const origname, newname: string);
@@ -4275,25 +4276,35 @@ implementation
 
 
     function tobjectdef.getcopy : tstoreddef;
+      var
+        i,
+        implintfcount : longint;
       begin
-        result:=inherited getcopy;
-      (*
         result:=tobjectdef.create(objecttype,objname^,childof);
-          childofderef  : tderef;
-          objname,
-          objrealname   : pstring;
-          objectoptions : tobjectoptions;
-          { to be able to have a variable vmt position }
-          { and no vmt field for objects without virtuals }
-          vmt_offset : longint;
-          writing_class_record_stab : boolean;
-          objecttype : tobjectdeftype;
-          iidguid: pguid;
-          iidstr: pstring;
-          lastvtableindex: longint;
-          { store implemented interfaces defs and name mappings }
-          implementedinterfaces: timplementedinterfaces;
-      *)
+        tobjectdef(result).symtable:=symtable.getcopy;
+        if assigned(objname) then
+          tobjectdef(result).objname:=stringdup(objname^);
+        if assigned(objrealname) then
+          tobjectdef(result).objrealname:=stringdup(objrealname^);
+        tobjectdef(result).objectoptions:=objectoptions;
+        tobjectdef(result).vmt_offset:=vmt_offset;
+        if assigned(iidguid) then
+          begin
+            new(tobjectdef(result).iidguid);
+            move(iidguid^,tobjectdef(result).iidguid^,sizeof(iidguid^));
+          end;
+        if assigned(iidstr) then
+          tobjectdef(result).iidstr:=stringdup(iidstr^);
+        tobjectdef(result).lastvtableindex:=lastvtableindex;
+        if assigned(implementedinterfaces) then
+          begin
+            implintfcount:=implementedinterfaces.count;
+            for i:=1 to implintfcount do
+              begin
+                tobjectdef(result).implementedinterfaces.addintf_ioffset(implementedinterfaces.interfaces(i),
+                    implementedinterfaces.ioffsets(i));
+              end;
+          end;
       end;
 
 
@@ -5222,6 +5233,15 @@ implementation
         finterfaces.insert(hintf);
       end;
 
+    procedure timplementedinterfaces.addintf_ioffset(d:tdef;iofs:longint);
+      var
+        hintf : timplintfentry;
+      begin
+        hintf:=timplintfentry.create(tobjectdef(d));
+        hintf.ioffset:=iofs;
+        finterfaces.insert(hintf);
+      end;
+
     procedure timplementedinterfaces.addintf(def: tdef);
       begin
         if not assigned(def) or (searchintf(def)<>-1) or (def.deftype<>objectdef) or
diff --git a/tests/webtbs/tw3930.pp b/tests/webtbs/tw3930.pp
new file mode 100644
index 0000000000..9b77cb42b3
--- /dev/null
+++ b/tests/webtbs/tw3930.pp
@@ -0,0 +1,19 @@
+{$mode objfpc}
+uses
+  classes;
+  
+type
+  TMyStringList = type TStringlist;
+  
+var
+  list : TMyStringList;
+
+begin
+  list:=TMyStringList.Create;
+  list.Free;
+  if pointer(TMyStringList)=pointer(TStringList) then
+    halt(1);
+  writeln('ok');
+end.
+
+    
\ No newline at end of file