diff --git a/src/Sandbox/SecurityPolicy.php b/src/Sandbox/SecurityPolicy.php
index 1406e8061a9..d617c381f56 100644
--- a/src/Sandbox/SecurityPolicy.php
+++ b/src/Sandbox/SecurityPolicy.php
@@ -102,7 +102,7 @@ public function checkMethodAllowed($obj, $method)
         }
 
         if (!$allowed) {
-            $class = \get_class($obj);
+            $class = $obj::class;
             throw new SecurityNotAllowedMethodError(sprintf('Calling "%s" method on a "%s" object is not allowed.', $method, $class), $class, $method);
         }
     }
@@ -119,7 +119,7 @@ public function checkPropertyAllowed($obj, $property)
         }
 
         if (!$allowed) {
-            $class = \get_class($obj);
+            $class = $obj::class;
             throw new SecurityNotAllowedPropertyError(sprintf('Calling "%s" property on a "%s" object is not allowed.', $property, $class), $class, $property);
         }
     }
diff --git a/src/Sandbox/SourcePolicyInterface.php b/src/Sandbox/SourcePolicyInterface.php
index b78ac50afd0..96d62386ed4 100644
--- a/src/Sandbox/SourcePolicyInterface.php
+++ b/src/Sandbox/SourcePolicyInterface.php
@@ -24,5 +24,5 @@ interface SourcePolicyInterface
      * @param Source $source
      *
      */
-    public function enableSandbox(Source $source = null) : bool;
+    public function enableSandbox(Source $source = null): bool;
 }
diff --git a/tests/Extension/SandboxTest.php b/tests/Extension/SandboxTest.php
index c5159ea43fa..1a4771b408d 100644
--- a/tests/Extension/SandboxTest.php
+++ b/tests/Extension/SandboxTest.php
@@ -107,7 +107,7 @@ public function testSandboxGloballyFalseUnallowedFilterWithIncludeTemplateFromSt
             $twig->load('1_basic2_include_template_from_string_sandboxed')->render(self::$params);
             $this->fail('Sandbox throws a SecurityError exception if an unallowed filter is called');
         } catch (SecurityError $e) {
-            $this->assertInstanceOf('\Twig\Sandbox\SecurityNotAllowedFilterError', $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
+            $this->assertInstanceOf(SecurityNotAllowedFilterError::class, $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
             $this->assertEquals('upper', $e->getFilterName(), 'Exception should be raised on the "upper" filter');
         }
     }
@@ -120,7 +120,7 @@ public function testSandboxGloballyTrueUnallowedFilterWithIncludeTemplateFromStr
             $twig->load('1_basic2_include_template_from_string_sandboxed')->render(self::$params);
             $this->fail('Sandbox throws a SecurityError exception if an unallowed filter is called');
         } catch (SecurityError $e) {
-            $this->assertInstanceOf('\Twig\Sandbox\SecurityNotAllowedFilterError', $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
+            $this->assertInstanceOf(SecurityNotAllowedFilterError::class, $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
             $this->assertEquals('upper', $e->getFilterName(), 'Exception should be raised on the "upper" filter');
         }
     }
@@ -140,7 +140,7 @@ public function testSandboxGloballyTrueUnallowedFilterWithIncludeTemplateFromStr
             $twig->load('1_basic2_include_template_from_string')->render(self::$params);
             $this->fail('Sandbox throws a SecurityError exception if an unallowed filter is called');
         } catch (SecurityError $e) {
-            $this->assertInstanceOf('\Twig\Sandbox\SecurityNotAllowedFilterError', $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
+            $this->assertInstanceOf(SecurityNotAllowedFilterError::class, $e, 'Exception should be an instance of Twig_Sandbox_SecurityNotAllowedFilterError');
             $this->assertEquals('upper', $e->getFilterName(), 'Exception should be raised on the "upper" filter');
         }
     }
@@ -389,7 +389,7 @@ public function testSandboxDisabledAfterIncludeFunctionError()
 
     public function testSandboxWithNoClosureFilter()
     {
-        $this->expectException('\Twig\Error\RuntimeError');
+        $this->expectException(\Twig\Error\RuntimeError::class);
         $this->expectExceptionMessage('The callable passed to the "filter" filter must be a Closure in sandbox mode in "index" at line 1.');
 
         $twig = $this->getEnvironment(true, ['autoescape' => 'html'], ['index' => <<<EOF
@@ -425,8 +425,9 @@ public function testSandboxSourcePolicyEnableReturningFalse()
         $twig = $this->getEnvironment(false, [], self::$templates, [], [], [], [], [], new class() implements \Twig\Sandbox\SourcePolicyInterface {
             public function enableSandbox($source): bool
             {
-                return $source->getName() != '1_basic';
-            }});
+                return '1_basic' != $source->getName();
+            }
+        });
         $this->assertEquals('FOO', $twig->load('1_basic')->render(self::$params));
     }
 
@@ -435,8 +436,9 @@ public function testSandboxSourcePolicyEnableReturningTrue()
         $twig = $this->getEnvironment(false, [], self::$templates, [], [], [], [], [], new class() implements \Twig\Sandbox\SourcePolicyInterface {
             public function enableSandbox($source): bool
             {
-                return $source->getName() === '1_basic';
-            }});
+                return '1_basic' === $source->getName();
+            }
+        });
         $this->expectException(SecurityError::class);
         $twig->load('1_basic')->render([]);
     }
@@ -447,9 +449,10 @@ public function testSandboxSourcePolicyFalseDoesntOverrideOtherEnables()
             public function enableSandbox($source): bool
             {
                 return false;
-            }});
-            $this->expectException(SecurityError::class);
-            $twig->load('1_basic')->render([]);
+            }
+        });
+        $this->expectException(SecurityError::class);
+        $twig->load('1_basic')->render([]);
     }
 }