create function bug?

Using a snapshot from two days ago on a i586-pc-linux-gnu using
linux-elf template:

test=> create table test (t1 integer);
CREATE
test=> create function myfunc (integer) returns integer
test-> as 'select $1' language 'sql';
ERROR: ProcedureCreate: arg type 'integer' is not defined
test=> create function myfunc(int4) returns int4
test-> as 'select $1' language 'sql';
CREATE

I can use the integer type in tables, but not in functions. Is this a
bug?

Ewan Mellor.