AsQueryable() on collection throws if applied after Where statement

[lbcsy]

A query (IQueryable) worked in version 4.0.4 but has exception in 5.2.2:

 'query.ToList()' threw an exception of type 'System.NotSupportedException'
    Data: {System.Collections.ListDictionaryInternal}
    HResult: -2146233067
    HelpLink: null
    InnerException: null
    Message: "query ( query ( select_from ( from ( range ( . _0 RolePrivileges ) a ) ) ( select a ) ) ( where ( and ( == ( . a AccessTypeName ) ( : p12 ) ) ( or ( == ( : p13 ) true ) ( == ( . ( . param002 Role ) Id ) ( : p14 ) ) ) ) ) )"
    Source: "NHibernate"
    StackTrace: "   at NHibernate.Hql.Ast.ANTLR.PolymorphicQuerySourceDetector.GetClassName(IASTNode querySource)\r\n   at NHibernate.Hql.Ast.ANTLR.PolymorphicQuerySourceDetector.Process(IASTNode tree)\r\n   at NHibernate.Hql.Ast.ANTLR.AstPolymorphicProcessor.Process()\r\n   at NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IASTNode ast, String queryIdentifier, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)\r\n   at NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters)\r\n   at NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow)\r\n   at NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression queryExpression)\r\n   at NHibernate.Linq.DefaultQueryProvider.PrepareQuery(Expression expression, IQuery& query)\r\n   at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)\r\n   at NHib
ernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)\r\n   at Remotion.Linq.QueryableBase`1.GetEnumerator()\r\n   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)\r\n   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)"

Can be reproduced by adding the following test to WhereSubqueryTests

[Test(Description = "GH-2471")]
public void TimeSheetsWithStringContainsSubQueryWithAsQueryableAfterWhere()
{
	var query = (from timesheet in db.Timesheets
				where timesheet.Entries.Where(e => e.Comments != null).AsQueryable().Any(e => e.Comments.Contains("testing"))
				select timesheet).ToList();

	Assert.That(query.Count, Is.EqualTo(2));
}

[lbcsy]

It fails in both 5.2 and 5.3.
I can now identify the error spot, but don't know why and how to overcome it:

The query seems failed with IEnumerable.AsQueryable:

var predicateReadPrivilege = PredicateBuilder.Create<Resource>(x =>
                x.RType.RolePrivileges.Where(a => a.AccessTypeName == accessLevel).AsQueryable().Where(_ => true).Any());// _predicatePrivilegeOnResourceType).Any());

As you can see, even the criteria is a redundant one, it fails, but if I remove the AsQueryable part, it does not throw the exception.

[bahusoid]

It should work if you apply AsQueryable right after mapped collection x.RType.RolePrivileges.AsQueryable()...

Yeah if such query works in 4.x it looks like a bug. Can be reproduced adding the following test to WhereSubqueryTests

[Test(Description = "GH-2471")]
public void TimeSheetsWithStringContainsSubQueryWithAsQueryableAfterWhere()
{
	var query = (from timesheet in db.Timesheets
				where timesheet.Entries.Where(e => e.Comments != null).AsQueryable().Any(e => e.Comments.Contains("testing"))
				select timesheet).ToList();

	Assert.That(query.Count, Is.EqualTo(2));
}

[fredericDelaporte]

If this is a regression of 5.0, shouldn't we backport its fix down to 5.0.x?

[hazzik]

Yes, we should. But do we want to do it?