diff --git a/src/Illuminate/Cache/CacheManager.php b/src/Illuminate/Cache/CacheManager.php
index 98babebf91fb..a821f9261e13 100755
--- a/src/Illuminate/Cache/CacheManager.php
+++ b/src/Illuminate/Cache/CacheManager.php
@@ -144,7 +144,10 @@ protected function createArrayDriver(array $config)
      */
     protected function createFileDriver(array $config)
     {
-        return $this->repository(new FileStore($this->app['files'], $config['path'], $config['permission'] ?? null));
+        return $this->repository(
+            (new FileStore($this->app['files'], $config['path'], $config['permission'] ?? null))
+                ->setLockDirectory($config['lock_path'] ?? null)
+        );
     }
 
     /**
diff --git a/src/Illuminate/Cache/FileStore.php b/src/Illuminate/Cache/FileStore.php
index 7202ee63bc6a..424ca63d43c6 100755
--- a/src/Illuminate/Cache/FileStore.php
+++ b/src/Illuminate/Cache/FileStore.php
@@ -28,6 +28,13 @@ class FileStore implements Store, LockProvider
      */
     protected $directory;
 
+    /**
+     * The file cache lock directory.
+     *
+     * @var string|null
+     */
+    protected $lockDirectory;
+
     /**
      * Octal representation of the cache file permissions.
      *
@@ -210,7 +217,14 @@ public function forever($key, $value)
      */
     public function lock($name, $seconds = 0, $owner = null)
     {
-        return new FileLock($this, $name, $seconds, $owner);
+        $this->ensureCacheDirectoryExists($this->lockDirectory ?? $this->directory);
+
+        return new FileLock(
+            new static($this->files, $this->lockDirectory ?? $this->directory, $this->filePermission),
+            $name,
+            $seconds,
+            $owner
+        );
     }
 
     /**
@@ -364,6 +378,19 @@ public function getDirectory()
         return $this->directory;
     }
 
+    /**
+     * Set the cache directory where locks should be stored.
+     *
+     * @param  string|null  $lockDirectory
+     * @return $this
+     */
+    public function setLockDirectory($lockDirectory)
+    {
+        $this->lockDirectory = $lockDirectory;
+
+        return $this;
+    }
+
     /**
      * Get the cache key prefix.
      *
diff --git a/src/Illuminate/Database/Eloquent/Concerns/QueriesRelationships.php b/src/Illuminate/Database/Eloquent/Concerns/QueriesRelationships.php
index 2412bc68fd03..5933f192ebb9 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/QueriesRelationships.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/QueriesRelationships.php
@@ -448,7 +448,7 @@ public function orWhereMorphRelation($relation, $types, $column, $operator = nul
      * Add a morph-to relationship condition to the query.
      *
      * @param  \Illuminate\Database\Eloquent\Relations\MorphTo|string  $relation
-     * @param  \Illuminate\Database\Eloquent\Model|string  $model
+     * @param  \Illuminate\Database\Eloquent\Model|string|null  $model
      * @return \Illuminate\Database\Eloquent\Builder|static
      */
     public function whereMorphedTo($relation, $model, $boolean = 'and')
@@ -457,6 +457,10 @@ public function whereMorphedTo($relation, $model, $boolean = 'and')
             $relation = $this->getRelationWithoutConstraints($relation);
         }
 
+        if (is_null($model)) {
+            return $this->whereNull($relation->getMorphType(), $boolean);
+        }
+
         if (is_string($model)) {
             $morphMap = Relation::morphMap();
 
@@ -506,7 +510,7 @@ public function whereNotMorphedTo($relation, $model, $boolean = 'and')
      * Add a morph-to relationship condition to the query with an "or where" clause.
      *
      * @param  \Illuminate\Database\Eloquent\Relations\MorphTo|string  $relation
-     * @param  \Illuminate\Database\Eloquent\Model|string  $model
+     * @param  \Illuminate\Database\Eloquent\Model|string|null  $model
      * @return \Illuminate\Database\Eloquent\Builder|static
      */
     public function orWhereMorphedTo($relation, $model)
diff --git a/tests/Database/DatabaseEloquentBuilderTest.php b/tests/Database/DatabaseEloquentBuilderTest.php
index 2d73e8a7dba6..0584af163d82 100755
--- a/tests/Database/DatabaseEloquentBuilderTest.php
+++ b/tests/Database/DatabaseEloquentBuilderTest.php
@@ -1660,6 +1660,15 @@ public function testWhereMorphedTo()
         $this->assertEquals([$relatedModel->getMorphClass(), $relatedModel->getKey()], $builder->getBindings());
     }
 
+    public function testWhereMorphedToNull()
+    {
+        $model = new EloquentBuilderTestModelParentStub;
+        $this->mockConnectionForModel($model, '');
+
+        $builder = $model->whereMorphedTo('morph', null);
+        $this->assertSame('select * from "eloquent_builder_test_model_parent_stubs" where "morph_type" is null', $builder->toSql());
+    }
+
     public function testWhereNotMorphedTo()
     {
         $model = new EloquentBuilderTestModelParentStub;
@@ -1688,6 +1697,17 @@ public function testOrWhereMorphedTo()
         $this->assertEquals(['baz', $relatedModel->getMorphClass(), $relatedModel->getKey()], $builder->getBindings());
     }
 
+    public function testOrWhereMorphedToNull()
+    {
+        $model = new EloquentBuilderTestModelParentStub;
+        $this->mockConnectionForModel($model, '');
+
+        $builder = $model->where('bar', 'baz')->orWhereMorphedTo('morph', null);
+
+        $this->assertSame('select * from "eloquent_builder_test_model_parent_stubs" where "bar" = ? or "morph_type" is null', $builder->toSql());
+        $this->assertEquals(['baz'], $builder->getBindings());
+    }
+
     public function testOrWhereNotMorphedTo()
     {
         $model = new EloquentBuilderTestModelParentStub;