As in binding2-spec , providing "Data" & "Grouping" suffixs to resolve confliction of type name in the same package,
but this solution has drawbacks, there still exists confliction.

In my opinion, there should also provide the namesapce 'data' and 'grp' at sub levels, just shown right side of '->' below,
although this may result in an even longer package name but it works correctly.

module namespace-test-foo2 {
namespace "org.test.namespace.foo2";
prefix "foo2";
revision 2017-05-19;
/* by Suffix / / by Sub NameSpace */
container a { // data.A -> data.A
container a { // data.a.A -> data.a.data.A
container a

{ // data.a.a.A -> data.a.data.a.data.A }

grouping a

{ // data.a.a.AGrouping -> data.a.data.a.grp.A }

}

grouping a { // data.a.AGrouping -> data.a.grp.A
container a { // data.a.a.AData -> data.a.grp.a.data.A
container a

{ // data.a.a.a.AData -> data.a.grp.a.data.a.data.A }

grouping a

{ // data.a.a.a.AGrouping -> data.a.grp.a.data.a.grp.A }

}

grouping a { // data.a.a.AGrouping -> data.a.grp.a.grp.A
container a

{ // data.a.a.a.AData -> data.a.grp.a.grp.a.data.A }

grouping a

{ // data.a.a.a.AGrouping -> data.a.grp.a.grp.a.grp.A }

}
}
}

grouping a { // grp.AGrouping -> grp.A
container a { // grp.a.AData -> grp.a.data.A
container a

{ // grp.a.a.AData -> grp.a.data.a.data.A }

grouping a

{ // grp.a.a.AGrouping -> grp.a.data.a.grp.A }

}

grouping a { // grp.a.AGrouping -> grp.a.grp.A
container a

{ // grp.a.a.AData -> grp.a.grp.a.data.A }

grouping a

{ // grp.a.a.AGrouping -> grp.a.grp.a.grp.A }

}
}
}