Weird message when creating PK constraint named like table

When I do this

CREATE TABLE "*T1*"
> (
> "T1_ID" bigint NOT NULL,
> CONSTRAINT "*T1*" PRIMARY KEY ("T1_ID" )
> );

I get the following message:

NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "T1" for
> table "T1"
> ERROR: relation "T1" already exists
> ********** Error **********
> ERROR: relation "T1" already exists
> SQL state: 42P07

It does NOT create either the table or the constraint, and the message is
confusing because there is no relation by that name.

The SQLSTATE 42P07 is described in the manual as only as "table undefined",
and it is not clear if the intent is to allow or
disallow the creation of a constraint called the same as the table in
Postgresql. Oracle 11g allows this, but my feeling is that
doing this should not be allowed, just as Postgresql handles it.

*I am complaining about the confusing error message which IMO is off-topic,
not about how the DB handles this.*

Seen on Postgresql 9.1.2 Linux 64bit.