diff --git a/.github/workflows/types.yml b/.github/workflows/types.yml
new file mode 100644
index 000000000000..2b8d7f717ed3
--- /dev/null
+++ b/.github/workflows/types.yml
@@ -0,0 +1,45 @@
+name: types
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '0 0 * * *'
+
+jobs:
+  linux_tests:
+    runs-on: ubuntu-20.04
+
+    strategy:
+      fail-fast: true
+      matrix:
+        php: ['8.0']
+        stability: [prefer-lowest, prefer-stable]
+        include:
+          - php: '8.1'
+            flags: "--ignore-platform-req=php"
+            stability: prefer-stable
+
+    name: PHP ${{ matrix.php }} - ${{ matrix.stability }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          tools: composer:v2
+          coverage: none
+
+      - name: Install dependencies
+        uses: nick-invision/retry@v1
+        with:
+          timeout_minutes: 5
+          max_attempts: 5
+          command: composer update --${{ matrix.stability }} --prefer-dist --no-interaction --no-progress ${{ matrix.flags }}
+
+      - name: Execute type checking
+        continue-on-error: ${{ matrix.php > 8 }}
+        run: vendor/bin/phpstan
diff --git a/composer.json b/composer.json
index 7ce8aa9e8aca..a817bd44d567 100644
--- a/composer.json
+++ b/composer.json
@@ -86,6 +86,7 @@
         "mockery/mockery": "^1.4.2",
         "orchestra/testbench-core": "^6.23",
         "pda/pheanstalk": "^4.0",
+        "phpstan/phpstan": "^0.12.94",
         "phpunit/phpunit": "^8.5.8|^9.3.3",
         "predis/predis": "^1.1.2",
         "symfony/cache": "^5.1.4"
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 000000000000..609d438c7593
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,4 @@
+parameters:
+  paths:
+    - types
+  level: max
diff --git a/src/Illuminate/Collections/Enumerable.php b/src/Illuminate/Collections/Enumerable.php
index 261a0c856b39..ef927c4f6d7e 100644
--- a/src/Illuminate/Collections/Enumerable.php
+++ b/src/Illuminate/Collections/Enumerable.php
@@ -8,22 +8,32 @@
 use IteratorAggregate;
 use JsonSerializable;
 
+/**
+ * @template TKey of array-key
+ * @template TValue
+ * @template-extends \IteratorAggregate<TKey, TValue>
+ */
 interface Enumerable extends Arrayable, Countable, IteratorAggregate, Jsonable, JsonSerializable
 {
     /**
      * Create a new collection instance if the value isn't one already.
      *
-     * @param  mixed  $items
-     * @return static
+     * @template TMakeKey of array-key
+     * @template TMakeValue
+     *
+     * @param  iterable<TMakeKey, TMakeValue>  $items
+     * @return static<TMakeKey, TMakeValue>
      */
     public static function make($items = []);
 
     /**
      * Create a new instance by invoking the callback a given amount of times.
      *
+     * @template TTimesValue
+     *
      * @param  int  $number
-     * @param  callable|null  $callback
-     * @return static
+     * @param  (callable(int): TTimesValue)|null  $callback
+     * @return static<int, TTimesValue>
      */
     public static function times($number, callable $callback = null);
 
@@ -32,37 +42,45 @@ public static function times($number, callable $callback = null);
      *
      * @param  int  $from
      * @param  int  $to
-     * @return static
+     * @return static<int, int>
      */
     public static function range($from, $to);
 
     /**
      * Wrap the given value in a collection if applicable.
      *
-     * @param  mixed  $value
-     * @return static
+     * @template TWrapValue
+     *
+     * @param  TWrapValue|iterable<TWrapValue>  $value
+     * @return static<array-key, TWrapValue>
      */
     public static function wrap($value);
 
     /**
      * Get the underlying items from the given collection if applicable.
      *
-     * @param  array|static  $value
-     * @return array
+     * @template TUnwrapKey of array-key
+     * @template TUnwrapValue
+     *
+     * @param  array<TUnwrapKey, TUnwrapValue>|static<TUnwrapKey, TUnwrapValue>   $value
+     * @return array<TUnwrapKey, TUnwrapValue>
      */
     public static function unwrap($value);
 
     /**
      * Create a new instance with no items.
      *
-     * @return static
+     * @template TEmptyKey of array-key
+     * @template TEmptyValue
+     *
+     * @return static<TEmptyKey, TEmptyValue>
      */
     public static function empty();
 
     /**
      * Get all items in the enumerable.
      *
-     * @return array
+     * @return array<TKey, TValue>
      */
     public function all();
 
@@ -228,7 +246,7 @@ public function duplicatesStrict($callback = null);
     /**
      * Execute a callback over each item.
      *
-     * @param  callable  $callback
+     * @param  callable(TValue): mixed  $callback
      * @return $this
      */
     public function each(callable $callback);
@@ -425,9 +443,11 @@ public function whereInstanceOf($type);
     /**
      * Get the first item from the enumerable passing the given truth test.
      *
-     * @param  callable|null  $callback
-     * @param  mixed  $default
-     * @return mixed
+     * @template TFirstDefaultValue
+     *
+     * @param  (callable(TValue): bool)|null  $callback
+     * @param  TFirstDefaultValue  $default
+     * @return TValue|TFirstDefaultValue
      */
     public function first(callable $callback = null, $default = null);
 
@@ -459,9 +479,11 @@ public function flip();
     /**
      * Get an item from the collection by key.
      *
-     * @param  mixed  $key
-     * @param  mixed  $default
-     * @return mixed
+     * @template TGetDefaultValue
+     *
+     * @param  TKey  $key
+     * @param  TGetDefaultValue  $default
+     * @return TValue|TGetDefaultValue
      */
     public function get($key, $default = null);
 
diff --git a/types/Support/Enumerable.php b/types/Support/Enumerable.php
new file mode 100644
index 000000000000..67940bf38a9a
--- /dev/null
+++ b/types/Support/Enumerable.php
@@ -0,0 +1,60 @@
+<?php
+
+use Illuminate\Foundation\Auth\User as Authenticatable;
+use Illuminate\Support\Enumerable;
+use function PHPStan\Testing\assertType;
+
+/** @var Enumerable<int, User> $enumerable */
+$enumerable = collect([]);
+class User extends Authenticatable
+{
+}
+
+foreach ($enumerable as $int => $user) {
+    assertType('int', $int);
+    assertType('User', $user);
+}
+
+assertType('Illuminate\Support\Enumerable<int, string>', $enumerable::make(['string']));
+assertType('Illuminate\Support\Enumerable<string, User>', $enumerable::make(['string' => new User]));
+
+assertType('Illuminate\Support\Enumerable<int, User>', $enumerable::times(10, function ($int) {
+    // assertType('int', $int);
+
+    return new User;
+}));
+
+assertType('Illuminate\Support\Enumerable<int, User>', $enumerable->each(function ($user) {
+    assertType('User', $user);
+}));
+
+assertType('Illuminate\Support\Enumerable<int, int>', $enumerable->range(1, 100));
+
+assertType('Illuminate\Support\Enumerable<(int|string), int>', $enumerable->wrap(1));
+assertType('Illuminate\Support\Enumerable<(int|string), string>', $enumerable->wrap('string'));
+assertType('Illuminate\Support\Enumerable<(int|string), string>', $enumerable->wrap(['string']));
+assertType('Illuminate\Support\Enumerable<(int|string), User>', $enumerable->wrap(['string' => new User]));
+
+assertType('array<int, string>', $enumerable->unwrap(['string']));
+assertType('array<int, User>', $enumerable->unwrap(
+    $enumerable
+));
+
+assertType('Illuminate\Support\Enumerable<(int|string), mixed>', $enumerable::empty());
+
+assertType('array<int, User>', $enumerable->all());
+
+assertType('User|null', $enumerable->get(0));
+assertType('string|User', $enumerable->get(0, 'string'));
+
+assertType('User|null', $enumerable->first());
+assertType('User|null', $enumerable->first(function ($user) {
+    assertType('User', $user);
+
+    return true;
+}));
+assertType('string|User', $enumerable->first(function ($user) {
+    assertType('User', $user);
+
+    return false;
+}, 'string'));