embedded composite types

I have defined a composite type containing attributes of an other composite type, e.g.

create type MyPoint as (
x int,
y int
);

create Type Point2 as (
pt1 MyPoint,
pt2 MyPoint
);

accessing the first level using the dot operator works flawlessly, e.g.

do $$
DECLARE
p MyPoint;
BEGIN
p.x := 1;
p.y := 2;
RAISE NOTICE 'p=%', p;
END;
$$

p=(1,2)

But trying to navigate further gives an error:

do $$
DECLARE
p Point2;
x int;
BEGIN
p.pt1 := (1,2);
p.pt2 := (3,4);
x := p.pt1.x;
END;
$$

[42P01] ERROR: missing FROM-clause entry for table "pt1"
Where: PL/pgSQL function inline_code_block line 8 at assignment

doing it in 2 separate steps works (but is not nice)

do $$
DECLARE
p Point2;
pt1 MyPoint;
x int;
BEGIN
p.pt1 := (1,2);
pt1 := p.pt1;
x := pt1.x;
END;
$$

I’m just wondering whether this is the expected behaviour or if there is any syntactical magic I’m not aware of ....