Fix Collection::concat() return type (#50669)

Author: axlon

src/Illuminate/Collections/Collection.php

@@ -998,8 +998,11 @@ public function push(...$values)
     /**
      * Push all of the given items onto the collection.
      *
-     * @param  iterable<array-key, TValue>  $source
-     * @return static
+     * @template TConcatKey of array-key
+     * @template TConcatValue
+     *
+     * @param  iterable<TConcatKey, TConcatValue>  $source
+     * @return static<TKey|TConcatKey, TValue|TConcatValue>
      */
     public function concat($source)
     {

src/Illuminate/Collections/Enumerable.php

@@ -789,8 +789,11 @@ public function partition($key, $operator = null, $value = null);
     /**
      * Push all of the given items onto the collection.
      *
-     * @param  iterable<array-key, TValue>  $source
-     * @return static
+     * @template TConcatKey of array-key
+     * @template TConcatValue
+     *
+     * @param  iterable<TConcatKey, TConcatValue>  $source
+     * @return static<TKey|TConcatKey, TValue|TConcatValue>
      */
     public function concat($source);
 

src/Illuminate/Collections/LazyCollection.php

@@ -991,8 +991,11 @@ public function select($keys)
     /**
      * Push all of the given items onto the collection.
      *
-     * @param  iterable<array-key, TValue>  $source
-     * @return static
+     * @template TConcatKey of array-key
+     * @template TConcatValue
+     *
+     * @param  iterable<TConcatKey, TConcatValue>  $source
+     * @return static<TKey|TConcatKey, TValue|TConcatValue>
      */
     public function concat($source)
     {

types/Support/Collection.php

@@ -657,6 +657,7 @@ function ($collection, $count) {
 
 assertType('Illuminate\Support\Collection<int, int>', $collection->make([1])->concat([2]));
 assertType('Illuminate\Support\Collection<int, string>', $collection->make(['string'])->concat(['string']));
+assertType('Illuminate\Support\Collection<int, int|string>', $collection->make([1])->concat(['string']));
 
 assertType('Illuminate\Support\Collection<int, int>|int', $collection->make([1])->random(2));
 assertType('Illuminate\Support\Collection<int, string>|string', $collection->make(['string'])->random());

types/Support/LazyCollection.php

@@ -547,6 +547,7 @@
 
 assertType('Illuminate\Support\LazyCollection<int, int>', $collection->make([1])->concat([2]));
 assertType('Illuminate\Support\LazyCollection<int, string>', $collection->make(['string'])->concat(['string']));
+assertType('Illuminate\Support\LazyCollection<int, int|string>', $collection->make([1])->concat(['string']));
 
 assertType('Illuminate\Support\LazyCollection<int, int>|int', $collection->make([1])->random(2));
 assertType('Illuminate\Support\LazyCollection<int, string>|string', $collection->make(['string'])->random());