Please describe the problem:
In the schema which is as follows, 2 particles with idendical element declarations (same type), one under
'choice', one is from sequence, model is non-deterministic.
So the schema parsing should give an error.

Steps to reproduce:
1. Please parse the schema file given below.


Actual results:
libxml2 parses the schema file without giving any error.

Expected results:
It should give an error saying that "element e1 makes the content model non-deterministic agaist element e1"

Does this happen every time?
yes


Other information:
Schema script:

<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <xsd:element name="doc" type="foo"/>
        <xsd:complexType name="foo">
                <xsd:choice>
                        <xsd:element name="e1" type="xsd:string"/>
                        <xsd:group ref="group"/>
                </xsd:choice>
        </xsd:complexType>
        <xsd:group name="group">
                <xsd:sequence>
                        <xsd:element name="e1" type="xsd:string"/>
                </xsd:sequence>
        </xsd:group>
</xsd:schema>