On Mon, 9 Jan 2023 18:26:56 GMT, Stuart Marks <sma...@openjdk.org> wrote:
>> Viktor Klang has updated the pull request incrementally with two additional
>> commits since the last revision:
>>
>> - 8299444: java.util.Set.copyOf allocates needlessly for empty input
>> collections
>>
>> Modifies ImmutableCollections.listCopy:
>> Introduces a check for isEmpty to avoid allocation in the case of an
>> empty input collection.
>> - 8299444: java.util.Set.copyOf allocates needlessly for empty input
>> collections
>>
>> Modifies Map.copyOf:
>> Introduces a check for isEmpty to avoid allocation in the case of an
>> empty input Map.
>
> src/java.base/share/classes/java/util/ImmutableCollections.java line 169:
>
>> 167: @SuppressWarnings("unchecked")
>> 168: static <E> List<E> listCopy(Collection<? extends E> coll) {
>> 169: if (coll instanceof List12 || (coll instanceof ListN && !
>> ((ListN<?>)coll).allowNulls)) {
>
> Maybe replace the cast with an instanceof pattern here?
@stuart-marks Sorry, missed this notification. I initially had the same idea,
but decided against it because it forces me to suppress "rawtypes" since `coll
instanceof ListN` is not considered to be a rawtype, but `coll instanceof ListN
c` is. And currently it won't allow for `coll instanceof ListN<E> c`...
-------------
PR: https://git.openjdk.org/jdk/pull/11847
