Debug.Fail was called

I just upgraded to LinqPad 7 and am receiving this error when executing a simple LINQ query only when a where clause is included:

at LINQPad.ExecutionModel.Server.LINQPadTraceListener.Fail(String message, String detailMessage)
at System.Diagnostics.TraceInternal.Fail(String message, String detailMessage)
at System.Diagnostics.TraceInternal.TraceProvider.Fail(String message, String detailMessage)
at System.Diagnostics.Debug.Fail(String message, String detailMessage)
at System.Diagnostics.Debug.Assert(Boolean condition)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlVisitor.RefersToColumn(SqlExpression exp, SqlColumn col)
at System.Data.Linq.Provider.Visitors.SqlBubbler.VisitRow(SqlRow row)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlBubbler.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitAlias(SqlAlias a)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlBubbler.BubbleUp(SqlColumn col, SqlNode source)
at System.Data.Linq.Provider.Common.SqlResolver.Visitor.BubbleUp(SqlColumnRef cref)
at System.Data.Linq.Provider.Common.SqlResolver.Visitor.VisitColumnRef(SqlColumnRef cref)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitExpression(SqlExpression exp)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitRow(SqlRow row)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlScopedVisitor.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitAlias(SqlAlias a)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlScopedVisitor.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitAlias(SqlAlias a)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlScopedVisitor.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitAlias(SqlAlias a)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlScopedVisitor.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlVisitor.VisitAlias(SqlAlias a)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Visitors.SqlScopedVisitor.VisitSelect(SqlSelect select)
at System.Data.Linq.Provider.Visitors.SqlVisitor.Visit(SqlNode node)
at System.Data.Linq.Provider.Common.SqlResolver.Resolve(SqlNode node)
at System.Data.Linq.DbEngines.SqlServer.SqlProvider.BuildQuery(ResultShape resultShape, Type resultType, SqlNode node, ReadOnlyCollection1 parentParameters, SqlNodeAnnotations annotations) at System.Data.Linq.DbEngines.SqlServer.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations) at System.Data.Linq.DbEngines.SqlServer.SqlProvider.Execute(Expression query) at System.Data.Linq.DbEngines.SqlServer.SqlProvider.System.Data.Linq.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery1.System.Collections.Generic.IEnumerable.GetEnumerator()
at System.Linq.Enumerable.SelectEnumerableIterator2.ToList() at System.Linq.Enumerable.ToList[TSource](IEnumerable1 source)
at LINQPad.ExecutionModel.ClrQueryRunner.Run()
at LINQPad.ExecutionModel.Server.RunQuery(QueryRunner runner)

.Where works fine. These are causing the error:

where cs.DisplayName.Contains("Rental") == false
where ut == null

These worked fine in the previous version.

Thanks
Chris