UriParserStringRep

class StringRepResolver : ODataUriResolver
{
    public override void PromoteBinaryOperandTypes(
        BinaryOperatorKind binaryOperatorKind,
        ref SingleValueNode leftNode,
        ref SingleValueNode rightNode,
        out IEdmTypeReference typeReference)
    {
        if (binaryOperatorKind == BinaryOperatorKind.Multiply
            && leftNode.TypeReference != null
            && leftNode.TypeReference.IsString()
            && rightNode.TypeReference != null
            && rightNode.TypeReference.IsInt32())
        {
            // The result type should be Edm.String, as it could be nullable or not, we just took the left
            // node's type reference.
            typeReference = leftNode.TypeReference;
            return;
        }

        // fallback
        base.PromoteBinaryOperandTypes(binaryOperatorKind, ref leftNode, ref rightNode, out typeReference);
    }
}

UriParserStringRepUsage

// Usage of StringRepResolver

var parser = new ODataUriParser(
    extModel.Model,
    ServiceRoot,
    new Uri("http://demo/odata.svc/People?$filter=Name eq 'Red' mul 3"));
try
{
    // Should throw exception
    var clause = parser.ParseFilter();
}
catch (Exception ex)
{
    Console.WriteLine(ex);
}

var parser2 = new ODataUriParser(
    extModel.Model,
    ServiceRoot,
    new Uri("http://demo/odata.svc/People?$filter=Name eq 'Red' mul 3"))
{
    Resolver = new StringRepResolver()
};

// Should work
var clause2 = parser2.ParseFilter();
Console.WriteLine(clause2.Expression.ToLogString());