Nice catch, Tagir. Historically the @Target meta-anno has been strong
enough to keep people from putting annos in the wrong place, but with
the "clever" handling of annos with records (accepting any of the target
types an anno can be reasonably pushed down to), we don't have any way
of saying "except these, which make no sense."
I agree it is silly to put these annos on record components. On the
other hand, I am not sure the spec should prohibit them -- seems more
the sort of thing an IDE should say "hey, that was probably dumb, are
you sure you want that?"
In any case, it is reasonable for a compiler to error in the case of
@Override on a component whose accessor does not override something --
because we should type-check implicit members as well as explicit.
On 1/22/2020 3:03 AM, Tagir Valeev wrote:
Hello!
It appears that it's possible to annotate record component as
@Override or @SafeVarargs, and spec doesn't explicitly forbid this:
record Test(@SafeVarargs int x, @Override int y) {}
In these cases, it's assumed that the annotation propagates to the
accessor method. However, having @SafeVarargs on the accessor method
is prohibited, so should be in a record component. So I expect to see
in 9.6.4.7 something like this:
It is a compile-time error if a record component (§8.10.1) is annotated with
the annotation @SafeVarargs.
Having the @Override is possible on the accessor if accessor overrides
the interface method (and it's really cool possibility!) Probably it's
ok to allow this annotation on the record component in this case, but
it should be definitely disallowed if the accessor doesn't override
anything. So I expect something like this in 9.6.4.4:
If a record component (§8.10.1) of record R is annotated with the annotation
@Override and the accessor method for that component (§8.10.3) does not
override a method declared in a superinterface of R (§8.4.8.1), then a
compile-time error occurs.
What do you think?
With best regards,
Tagir Valeev.
[1] https://docs.oracle.com/javase/specs/jls/se13/html/jls-9.html#jls-9.6.4.7
[2] https://docs.oracle.com/javase/specs/jls/se13/html/jls-9.html#jls-9.6.4.4
