Here's the scenario i am faced with:
public abstract class Record { } 
public abstract class TableRecord : Record { } 
public abstract class LookupTableRecord : TableRecord { } 
public sealed class UserRecord : LookupTableRecord { } 
public interface IDataAccessLayer<TRecord> 
    where TRecord : Record { } 
public interface ITableDataAccessLayer<TTableRecord> : IDataAccessLayer<TTableRecord> 
    where TTableRecord : TableRecord { } 
public interface ILookupTableDataAccessLayer<TLookupTableRecord> : ITableDataAccessLayer<TLookupTableRecord> 
    where TLookupTableRecord : LookupTableRecord { } 
public abstract class DataAccessLayer<TRecord> : IDataAccessLayer<TRecord> 
    where TRecord : Record, new() { } 
public abstract class TableDataAccessLayer<TTableRecord> : DataAccessLayer<TTableRecord>, ITableDataAccessLayer<TTableRecord> 
    where TTableRecord : TableRecord, new() { } 
public abstract class LookupTableDataAccessLayer<TLookupTableRecord> : TableDataAccessLayer<TLookupTableRecord>, ILookupTableDataAccessLayer<TLookupTableRecord> 
    where TLookupTableRecord : LookupTableRecord, new() { } 
public sealed class UserDataAccessLayer : LookupTableDataAccessLayer<UserRecord> { }
Now when i try to cast UserDataAccessLayer to it's generic base type ITableDataAccessLayer<TableRecord>, the compiler complains that it cannot implicitly convert the type.