When ast_member encounters the result of an ast_entfield it
has to replace the ast_entfield's codegen as we cannot
evaluate the field access first.
We then perform the same action as ast_entfield but call
vectorMember on the field before issuing the load/address
instruction.
This effectively turns the codegen of the following ast
structure:
member_of {
field_of {
entity,
a_vector
}
memberid
}
into the one of this structure:
field_of {
entity,
member_of {
a_vector
memberid
}
}
