Cannot select inner entities in Ickle

Consider a proto mapping:

message Parent {
   optional Child child;
}

message Child {
   optional string name = 1;
}

It is not possible to select any of the Child attributes in the query. The following queries fail:

SELECT p.child FROM Parent p

Fails with ISPN028503

SELECT p.child.name FROM Parent p

Fails with ISPN028502: Unknown alias 'child'