Inherited tables and column references

In the following example:

create table parent (
id integer unique not null,
name varchar(24)
);

create table child (
first_name varchar(256),
last_name varchar(256)
) inherits (parent);

create table relations (
id integer references child (id)
);

Creating the relations table fails with:

ERROR: there is no unique constraint maching given keys for
referenced table "child"

If I change the last table to:

create table relations (
id integer references parent (id)
);

it works.

This essentially means that references must point to the real table
where the referenced column is, and cannot point to that same column in
a table that inherits the real table.

is this by design, is it a bug, is it just not implemented yet, or am I
doing this wrong?

/s.