VB -> C#: injected base breaks overrides

Input code

Private Sub FillAll()
         Clear()
         If Query IsNot Nothing AndAlso Not String.IsNullOrWhiteSpace(Query.CommandText) Then
            ValidateHelper()
            Try
               Using reader = _Helper.ExecuteReader(Query)
                  Dim fieldNames As New List(Of String)
                  For index = 0 To reader.FieldCount - 1
                     fieldNames.Add(reader.GetName(index))
                  Next
                  While reader.Read
                     Dim entity = BuildNewEntity() 
                     entity.InitializeData(reader, fieldNames)
                     AddNewEntity(entity)
                  End While
               End Using
            Catch ex As Exception
               Throw New DataAccessObjectException(SeikaORMClasses.ErrorOnFillAll, ex, Query, Nothing)
            End Try
         End If
      End Sub

BuildNewEntity is defined as this in the parent object:

        protected internal virtual T BuildNewEntity()
        {
            return new T();
        }

A child object redefines BuildNewEntity:

        protected override TestSEntity BuildNewEntity()
        {
            return new TestSEntity(_BusinessCache);
        }

Erroneous output

        private void FillAll()
        {
            Clear();
            if (Query is object && !string.IsNullOrWhiteSpace(Query.CommandText))
            {
                ValidateHelper();
                try
                {
                    using (var reader = _Helper.ExecuteReader(Query))
                    {
                        var fieldNames = new List<string>();
                        for (int index = 0, loopTo = reader.FieldCount - 1; index <= loopTo; index++)
                            fieldNames.Add(reader.GetName(index));
                        while (reader.Read())
                        {
                            var entity = base.BuildNewEntity(); 
                            entity.InitializeData(reader, fieldNames);
                            AddNewEntity(entity);
                        }
                    }
                }
                catch (Exception ex)
                {
                    throw new DataAccessObjectException(SeikaORMClasses.ErrorOnFillAll, ex, Query, null);
                }
            }
        }

Expected output

        private void FillAll()
        {
            Clear();
            if (Query is object && !string.IsNullOrWhiteSpace(Query.CommandText))
            {
                ValidateHelper();
                try
                {
                    using (var reader = _Helper.ExecuteReader(Query))
                    {
                        var fieldNames = new List<string>();
                        for (int index = 0, loopTo = reader.FieldCount - 1; index <= loopTo; index++)
                            fieldNames.Add(reader.GetName(index));
                        while (reader.Read())
                        {
                            var entity = BuildNewEntity(); 
                            entity.InitializeData(reader, fieldNames);
                            AddNewEntity(entity);
                        }
                    }
                }
                catch (Exception ex)
                {
                    throw new DataAccessObjectException(SeikaORMClasses.ErrorOnFillAll, ex, Query, null);
                }
            }
        }

Details

• VS Extension v81.6.0

base should not be introduced when not needed - it will break the behavior silently when override is involved.

[GrahamTheCoder]

This is caused by a bug in the Roslyn library - one that I’ve actually had to work around before for a slightly different case. I’ll find a way to workaround this one, and then hopefully actually get around to PRing the fix to Roslyn too.

[GrahamTheCoder]

Thanks, that’s great!