EF CTP5 mapping problem when using a Entity base class -

i'm having odd problem many-to-many relationships in ef ctp5 when base class involved. i'll first show simple mapping works.

i have following 2 classes (entities):

public class product {     public int id { get; set; }     public string name { get; set; }      public virtual icollection<process> processes { get; set; } }  public class process {     public int id { get; set; }     public string name { get; set; }      public virtual icollection<product> products { get; set; } } 

and mapping classes:

public class productmapping : entitytypeconfiguration<product> {     public productmapping()     {         totable("products");         haskey(t => t.id);          property(t => t.id).hascolumnname("product_id");         property(t => t.name).hascolumnname("name");     } }  public class processmapping : entitytypeconfiguration<process> {     public processmapping()     {         totable("processes");         haskey(t => t.id);          property(t => t.id).hascolumnname("process_id");         property(t => t.name).hascolumnname("name");          hasmany(p => p.products)             .withmany(p => p.processes)             .map(m =>             {                 m.totable("product_processes");                 m.mapleftkey(process => process.id, "process_id");                 m.maprightkey(product => product.id, "product_id");             });          } } 

this mapping works perfectly. however, want introduce base class entities. start, created following base class:

public abstract class entity {     public int id { get; set; } } 

i made 2 entities product , process inherit entity base class , of course removed id property each class. 2 entities identical except id property implemented in base class.

after compiling , running project, following "famous" ef runtime error:

"sequence contains more 1 matching element"

i know error related many-to-many association, because if remove many-to-many mapping process class, runs correctly, without association of course.

can see problem here? ctp5 bug or there wrong in implementation? if turns out bug, have suggestion workaround?

i ran same problem, many-to-one association. see this answer

in nutshell: don't use base entity class until fixed; can use interface instead id property.