Improves Collection::mapInto types (#40374)

Author: nunomaduro

src/Illuminate/Collections/Enumerable.php

@@ -659,8 +659,10 @@ public function flatMap(callable $callback);
     /**
      * Map the values into a new class.
      *
-     * @param  class-string  $class
-     * @return static<TKey, mixed>
+     * @template TMapIntoValue
+     *
+     * @param  class-string<TMapIntoValue>  $class
+     * @return static<TKey, TMapIntoValue>
      */
     public function mapInto($class);
 

src/Illuminate/Collections/Traits/EnumeratesValues.php

@@ -378,8 +378,10 @@ public function flatMap(callable $callback)
     /**
      * Map the values into a new class.
      *
-     * @param  class-string  $class
-     * @return static<TKey, mixed>
+     * @template TMapIntoValue
+     *
+     * @param  class-string<TMapIntoValue>  $class
+     * @return static<TKey, TMapIntoValue>
      */
     public function mapInto($class)
     {

types/Support/Collection.php

@@ -476,7 +476,7 @@
         return 1;
     }));
 
-assertType('Illuminate\Support\Collection<int, mixed>', $collection->mapInto(User::class));
+assertType('Illuminate\Support\Collection<int, User>', $collection->mapInto(User::class));
 
 assertType('Illuminate\Support\Collection<int, int>', $collection->make([1])->merge([2]));
 assertType('Illuminate\Support\Collection<int, string>', $collection->make(['string'])->merge(['string']));

types/Support/LazyCollection.php

@@ -476,7 +476,7 @@
         return 1;
     }));
 
-assertType('Illuminate\Support\LazyCollection<int, mixed>', $collection->mapInto(User::class));
+assertType('Illuminate\Support\LazyCollection<int, User>', $collection->mapInto(User::class));
 
 assertType('Illuminate\Support\LazyCollection<int, int>', $collection->make([1])->merge([2]));
 assertType('Illuminate\Support\LazyCollection<int, string>', $collection->make(['string'])->merge(['string']));