Precedence of new phrase search tsquery operator

It appears that the new <-> operator has been made to have exactly the
same grammatical precedence as the existing & (AND) operator. Thus,
for example, 'a & b <-> c'::tsquery means something different from
'b <-> c & a'::tsquery:

regression=# select 'a & b <-> c'::tsquery;
tsquery
-----------------------------------
( 'a' <-> 'c' ) & ( 'b' <-> 'c' )
(1 row)

regression=# select 'b <-> c & a'::tsquery;
tsquery
-----------------------
( 'b' <-> 'c' ) & 'a'
(1 row)

I find this surprising. My intuitive feeling is that <-> ought to
bind tighter than & (and therefore also tighter than |). What's
the reasoning for making it act like this?

regards, tom lane