On 22/03/2021 10:05, Gavin Bierman wrote:
Agreed, Maurizio. Jan has pushed a patch for this. Now if you compile with
`-Xlint:rawtypes` you’ll get a warning for `o instanceof Foo foo` - this was
just an oversight.
Thanks for the clarification
Maurizio
Gavin
On 19 Mar 2021, at 18:52, Maurizio Cimadamore <maurizio.cimadam...@oracle.com>
wrote:
On 15/03/2021 13:28, Brian Goetz wrote:
Unchecked conversions are forbidden because of type pollution, that why you can
not write
if (o instanceof Foo<Integer> foo) {
Raw type conversions also leads to type pollution, so i think that a type
pattern with a raw type should be forbidden too.
Note sure I agree here - they are two very different kind of pollutions.
In the Foo<Integer> case the issue is that we might any type that converts to Foo<Integer> to be
treated as a Foo<Integer>. E.g. Foo<? extends Number> -> Foo<Integer>. That is unsound, and
the unsoundness happens in the conversion itself.
But when you say `o instanceof Foo f`, you are not introducing any pollution.
The pollution will be introduced when (and if) the raw type will be accessed.
Honestly, I'm not even sure this deserves a warning (other than the customary "raw-type
usage" warning - not an "unchecked" warning, to be clear).
Maurizio
