public class test
{
    public virtual int id { get; set; }
    public virtual string[] items { get; set; }
}

CREATE TABLE test
(
    id serial,
    items text[],
    primary key(id)
)

var tests = session.Query<test>
    .Where(t => t.items.Any(item => filterItems.Contains(item)))
    .ToList();

NHibernate.PropertyAccessException was unhandled
  HResult=-2146232832
  Message=Exception occurred getter of IntersectionTest.Models.test.id
  Source=NHibernate
  StackTrace:
       at NHibernate.Properties.BasicPropertyAccessor.BasicGetter.Get(Object target)
       at NHibernate.Tuple.Entity.AbstractEntityTuplizer.GetIdentifier(Object entity)
       at NHibernate.Persister.Entity.AbstractEntityPersister.GetIdentifier(Object obj, EntityMode entityMode)
       at NHibernate.Persister.Entity.AbstractEntityPersister.IsTransient(Object entity, ISessionImplementor session)
       at NHibernate.Engine.ForeignKeys.IsTransient(String entityName, Object entity, Nullable`1 assumed, ISessionImplementor session)
       at NHibernate.Engine.ForeignKeys.GetEntityIdentifierIfNotUnsaved(String entityName, Object entity, ISessionImplementor session)
       at NHibernate.Type.EntityType.GetIdentifier(Object value, ISessionImplementor session)
       at NHibernate.Type.ManyToOneType.NullSafeSet(IDbCommand cmd, Object value, Int32 index, ISessionImplementor session)
       at NHibernate.Param.NamedParameterSpecification.Bind(IDbCommand command, IList`1 multiSqlQueryParametersList, Int32 singleSqlParametersOffset, IList`1 sqlQueryParametersList, QueryParameters queryParameters, ISessionImplementor session)
       at NHibernate.Param.NamedParameterSpecification.Bind(IDbCommand command, IList`1 sqlQueryParametersList, QueryParameters queryParameters, ISessionImplementor session)
       at NHibernate.SqlCommand.SqlCommandImpl.Bind(IDbCommand command, ISessionImplementor session)
       at NHibernate.Loader.Loader.PrepareQueryCommand(QueryParameters queryParameters, Boolean scroll, ISessionImplementor session)
       at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer)
       at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer)
       at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters, IResultTransformer forcedResultTransformer)
       at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters)
       at NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor session, QueryParameters queryParameters)
       at NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet`1 querySpaces, IType[] resultTypes)
       at NHibernate.Loader.Hql.QueryLoader.List(ISessionImplementor session, QueryParameters queryParameters)
       at NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.List(ISessionImplementor session, QueryParameters queryParameters)
       at NHibernate.Engine.Query.HQLQueryPlan.PerformList(QueryParameters queryParameters, ISessionImplementor session, IList results)
       at NHibernate.Impl.SessionImpl.List(IQueryExpression queryExpression, QueryParameters queryParameters, IList results)
       at NHibernate.Impl.AbstractSessionImpl.List(IQueryExpression queryExpression, QueryParameters parameters)
       at NHibernate.Impl.AbstractQueryImpl2.List()
       at NHibernate.Linq.DefaultQueryProvider.ExecuteQuery(NhLinqExpression nhLinqExpression, IQuery query, NhLinqExpression nhQuery)
       at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)
       at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)
       at Remotion.Linq.QueryableBase`1.GetEnumerator()
       at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
       at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
       ...
  InnerException: System.Reflection.TargetException
       HResult=-2146232829
       Message=Object does not match target type.
       Source=mscorlib
       StackTrace:
            at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
            at System.Reflection.RuntimeMethodInfo.InvokeArgumentsCheck(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
            at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
            at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
            at NHibernate.Properties.BasicPropertyAccessor.BasicGetter.Get(Object target)

class testMapping : ClassMap<test>
{
    public testMapping()
    {
        Id(x => x.id);
        Map(x => x.items)
            .CustomType<PostgreSqlStringArrayType>()
            .CustomSqlType("text[]");
    }
}

[Serializable]
public class PostgreSqlStringArrayType : IUserType
{
    public SqlType[] SqlTypes
    {
        get
        {
            return new[]
            {
                new SqlType(DbType.Object)
            };
        }
    }

    public Type ReturnedType
    {
        get { return typeof(string[]); }
    }

    public bool IsMutable { get; private set; }

    public object Assemble(object cached, object owner)
    {
        return cached;
    }

    public object DeepCopy(object value)
    {
        return value;
    }

    public object Disassemble(object value)
    {
        return value;
    }

    public int GetHashCode(object x)
    {
        return (x == null) ? 0 : x.GetHashCode();
    }

    public object NullSafeGet(IDataReader rs, string[] names, object owner)
    {
        int index = rs.GetOrdinal(names[0]);
        return rs.GetValue(index) as string[];
    }

    public void NullSafeSet(IDbCommand cmd, object value, int index)
    {
        var parameter = ((NpgsqlParameter) cmd.Parameters[index]);
        parameter.NpgsqlDbType = NpgsqlDbType.Array | NpgsqlDbType.Text;
        parameter.Value = value;
    }

    public object Replace(object original, object target, object owner)
    {
        return original;
    }

    bool IUserType.Equals(object x, object y)
    {
        if (ReferenceEquals(x, y))
        {
            return true;
        }
        return (x != null) && x.Equals(y);
    }
}