I was surprised to learn that 2 is a valid boolean (thanks Berge):
# select 2::boolean;
bool
──────
t
... while '2' is not:
# select '2'::boolean;
ERROR: 22P02: invalid input syntax for type boolean: "2"
LINE 1: select '2'::boolean;
^
LOCATION: boolin, bool.c:151
The first cast is the int4_bool function, but it isn't covered by the
regression tests at all. The attached patch adds tests.
Christoph
