ALTER TABLE INHERIT vs collations

Right at the moment, ALTER INHERIT doesn't verify that collations match
in a proposed inheritance child.  So you can do this:

regression=# create table foo (f1 text collate "C");
CREATE TABLE
regression=# create table bar (f1 text collate "POSIX");
CREATE TABLE
regression=# alter table bar inherit foo;
ALTER TABLE

but then the planner whines about it:

regression=# select * from foo;
ERROR:  attribute "f1" of relation "bar" does not match parent's collation

Does anyone think it's not a bug that ALTER TABLE lets this through?
If so, what do you think the querying semantics ought to be?
        regards, tom lane