fix: Collection::transform() and Paginator::through() return types (#56273)

Author: calebdw

src/Illuminate/Collections/Collection.php

@@ -1732,7 +1732,9 @@ public function takeWhile($value)
  * @template TMapValue
  *
  * @param callable(TValue, TKey): TMapValue $callback
- * @return $this<TKey, TMapValue>
+ * @return $this
+ *
+ * @phpstan-this-out static<TKey, TMapValue>
  */
  public function transform(callable $callback)
  {

src/Illuminate/Pagination/AbstractCursorPaginator.php

@@ -406,7 +406,7 @@ public function items()
  * @template TThroughValue
  *
  * @param callable(TValue, TKey): TThroughValue $callback
- * @return $this<TKey, TThroughValue>
+ * @return $this
  *
  * @phpstan-this-out static<TKey, TThroughValue>
  */

src/Illuminate/Pagination/AbstractPaginator.php

@@ -356,7 +356,9 @@ public function lastItem()
  * @template TMapValue
  *
  * @param callable(TValue, TKey): TMapValue $callback
- * @return $this<TKey, TMapValue>
+ * @return $this
+ *
+ * @phpstan-this-out static<TKey, TMapValue>
  */
  public function through(callable $callback)
  {

types/Support/Collection.php

@@ -1049,18 +1049,18 @@ function ($collection, $count) {
 assertType('Illuminate\Support\Collection<int, User>', $collection->splice(1));
 assertType('Illuminate\Support\Collection<int, User>', $collection->splice(1, 1, [new User]));
 
-assertType('mixed', $collection->transform(function ($user, $int) {
+assertType('Illuminate\Support\Collection<int, int>', $collection->transform(function ($user, $int): int {
  assertType('User', $user);
  assertType('int', $int);
 
- return new User;
+ return $int * 2;
 }));
 
-assertType('mixed', $collection->transform(function ($user, $int): int {
- assertType('User', $user);
- assertType('int', $int);
+assertType('Illuminate\Support\Collection<int, User>', $collection->transform(function ($value, $key) {
+ assertType('int', $value);
+ assertType('int', $key);
 
- return $int * 2;
+ return new User;
 }));
 
 assertType('Illuminate\Support\Collection<int, User>', $collection->add(new User));