[HACKERS] temp table oddness?

I found weird behavior with temp tables.

test=> create table u1(i int);
CREATE
test=> insert into u1 values(1);
INSERT 3408201 1
test=> insert into u1 values(1);
INSERT 3408202 1
test=> create temp table u1(i int primary key);
NOTICE:  CREATE TABLE/PRIMARY KEY will create implicit index 'u1_pkey' for table 'u1'
NOTICE:  trying to delete a reldesc that does not exist.
NOTICE:  trying to delete a reldesc that does not exist.
CREATE

Are these notices normal?

Next I exited the session and start psql again.

test=> 
EOF
[t-ishii@ext16 Chapter3]$ !!
psql test
Welcome to the POSTGRESQL interactive sql monitor: Please read the file COPYRIGHT for copyright terms of POSTGRESQL
[PostgreSQL 6.5.1 on powerpc-unknown-linux-gnu, compiled by gcc egcs-2.90.25 980302 (egcs-1.0.2 prerelease)]
  type \? for help on slash commands  type \q to quit  type \g or terminate with semicolon to execute queryYou are
currentlyconnected to the database: test
 

test=> create temp table u1(i int primary key);
NOTICE:  CREATE TABLE/PRIMARY KEY will create implicit index 'u1_pkey' for table 'u1'
ERROR:  Cannot create unique index. Table contains non-unique values

What's this? I thought temp tables completely mask persistent tables.
---
Tatsuo Ishii