fix some iterator stubs

[orklah]

This fixes some iterator stubs, directly inspired from phpstan/phpstan-src#796

@weirdan can you review this? In particular, I was not sure if I should have used @template-covariant somewhere

[weirdan]

I think all of those need to pass through the TIterator type parameter:

./stubs/CoreGenericIterators.phpstub|139| class AppendIterator extends IteratorIterator {
./stubs/CoreGenericIterators.phpstub|325| class FilterIterator extends IteratorIterator {
./stubs/CoreGenericIterators.phpstub|349| class CachingIterator extends IteratorIterator implements OuterIterator , ArrayAccess , Countable  {
./stubs/CoreGenericIterators.phpstub|533| class InfiniteIterator extends IteratorIterator {
./stubs/CoreGenericIterators.phpstub|560| class LimitIterator extends IteratorIterator implements OuterIterator {
./stubs/CoreGenericIterators.phpstub|587| class NoRewindIterator extends IteratorIterator {

[orklah]

I'm out of luck! Some time ago I used one of those in a test(https://github.com/vimeo/psalm/runs/4293084567?check_suite_focus=true#step:7:133) to show we could use a Generator to populate the templates of the Iterator.

This was quite obvious when there was two templates in the Iterator, now that there's three, I'm not sure anymore.

I'll see when PHPStan merge the PR what it looks like when I run the test in it and I'll advise

[orklah]

@weirdan mind looking at this one? If it's okay, I'll merge it

[weirdan]

@orklah it's on my todo list along with several other PRs.

[drupol]

Hey hi,

I'm testing Psalm 5b1 and I have this new issue:

ERROR: MissingTemplateParam - src/SimpleCachingIteratorAggregate.php:30:13 - CachingIterator has missing template params, expecting 3 (see https://psalm.dev/182)

This comes from there: https://github.com/loophp/iterators/blob/main/src/SimpleCachingIteratorAggregate.php#L28

I'm trying to understand why does \CachingIterator needs 3 template parameters ?
Therefore, how to fix this then ? https://psalm.dev/r/17b32189e1