Odd numeric->float4/8 casting behaviour

I noticed this odd discrepancy:

postgres=# select -0.999::numeric(3,3)::float4 = -0.999::numeric(3,3);?column? 
----------f
(1 row)


I believe this is happening because the numeric is being cast to float8 and
then the float4-float8 cross-data-type operator is being used. It seems like
it would be preferable to cast it to float4 and use the non-cross-data-type
operator. They're both marked as implicit casts so I'm unclear what decides
which gets used.

Also, as a side note I was surprised to find the above being parsed as
-(0.999::numeric(3,3)) rather than (-0.999)::numeric(3,3) is that expected?



regression=# create or replace view x as select   -0.999::numeric(3,3)::float4 = -0.999::numeric(3,3);
CREATE VIEW
regression=# \d x       View "public.x" Column  |  Type   | Modifiers 
----------+---------+-----------?column? | boolean | 
View definition:SELECT (- 0.999::numeric(3,3)::real) = (- 0.999::numeric(3,3))::double precision;

regression=# create or replace view x as select   (-0.999)::numeric(3,3)::float4 = (-0.999)::numeric(3,3);
CREATE VIEW
regression=# \d x       View "public.x" Column  |  Type   | Modifiers 
----------+---------+-----------?column? | boolean | 
View definition:SELECT -0.999::numeric(3,3)::real = -0.999::numeric(3,3)::double precision;


--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com