diff --git a/docs/documentation/assertions.md b/docs/documentation/assertions.md
index e683ab40..4d3b6a1c 100644
--- a/docs/documentation/assertions.md
+++ b/docs/documentation/assertions.md
@@ -48,7 +48,7 @@ It asserts that the selected classes **do not depend** on the target classes.
 It asserts that the selected classes **do not use the constructor** of the target classes.
 
 ## shouldNotExist()
-It asserts that the selected classes **should not exist**.
+It asserts that the selected classes **do not exist**.
 
 ## shouldApplyAttribute()
 It asserts that the selected classes **apply** the target attributes.
diff --git a/extension.neon b/extension.neon
index 34dbea22..12a5292e 100644
--- a/extension.neon
+++ b/extension.neon
@@ -74,7 +74,7 @@ services:
 
 	# ShouldNotExist rules
 	-
-		class: PHPat\Rule\Assertion\Declaration\ShouldNotExist\ShouldNotExistRule
+		class: PHPat\Rule\Assertion\Declaration\ShouldNotExist\ExistsRule
 		tags:
 			- phpstan.rules.rule
 
diff --git a/src/Rule/Assertion/Declaration/ShouldNotExist/ExistsRule.php b/src/Rule/Assertion/Declaration/ShouldNotExist/ExistsRule.php
new file mode 100644
index 00000000..b00b3750
--- /dev/null
+++ b/src/Rule/Assertion/Declaration/ShouldNotExist/ExistsRule.php
@@ -0,0 +1,15 @@
+<?php declare(strict_types=1);
+
+namespace PHPat\Rule\Assertion\Declaration\ShouldNotExist;
+
+use PHPat\Rule\Extractor\Declaration\ExistsExtractor;
+use PHPStan\Node\InClassNode;
+use PHPStan\Rules\Rule;
+
+/**
+ * @implements Rule<InClassNode>
+ */
+final class ExistsRule extends ShouldNotExist implements Rule
+{
+    use ExistsExtractor;
+}
diff --git a/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExist.php b/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExist.php
index f25d49ed..892d0fe2 100644
--- a/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExist.php
+++ b/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExist.php
@@ -6,7 +6,6 @@
 use PHPat\Rule\Assertion\Declaration\DeclarationAssertion;
 use PHPat\Rule\Assertion\Declaration\ValidationTrait;
 use PHPat\Statement\Builder\StatementBuilderFactory;
-use PHPStan\Node\InClassNode;
 use PHPStan\Reflection\ClassReflection;
 use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Type\FileTypeMapper;
@@ -30,13 +29,16 @@ public function __construct(
         );
     }
 
-    public function getNodeType(): string
+    protected function applyValidation(string $ruleName, ClassReflection $subject, bool $meetsDeclaration, array $tips, array $params = []): array
     {
-        return InClassNode::class;
+        return $this->applyShouldNot($ruleName, $subject, $meetsDeclaration, $tips, $params);
     }
 
-    protected function applyValidation(string $ruleName, ClassReflection $subject, bool $meetsDeclaration, array $tips, array $params = []): array
+    protected function getMessage(string $ruleName, string $subject, array $params = []): string
     {
-        return $this->applyShouldNot($ruleName, $subject, $meetsDeclaration, $tips, $params);
+        return $this->prepareMessage(
+            $ruleName,
+            sprintf('%s should not exist', $subject)
+        );
     }
 }
diff --git a/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExistRule.php b/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExistRule.php
deleted file mode 100644
index c7bdf90f..00000000
--- a/src/Rule/Assertion/Declaration/ShouldNotExist/ShouldNotExistRule.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php declare(strict_types=1);
-
-namespace PHPat\Rule\Assertion\Declaration\ShouldNotExist;
-
-use PhpParser\Node;
-use PHPStan\Analyser\Scope;
-use PHPStan\Node\InClassNode;
-use PHPStan\Rules\Rule;
-
-/**
- * @implements Rule<InClassNode>
- */
-final class ShouldNotExistRule extends ShouldNotExist implements Rule
-{
-    protected function getMessage(string $ruleName, string $subject, array $params = []): string
-    {
-        return $this->prepareMessage(
-            $ruleName,
-            sprintf('%s should not exist', $subject)
-        );
-    }
-
-    protected function meetsDeclaration(Node $node, Scope $scope, array $params = []): bool
-    {
-        return true;
-    }
-}
diff --git a/src/Rule/Extractor/Declaration/ExistsExtractor.php b/src/Rule/Extractor/Declaration/ExistsExtractor.php
new file mode 100644
index 00000000..8f83f522
--- /dev/null
+++ b/src/Rule/Extractor/Declaration/ExistsExtractor.php
@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace PHPat\Rule\Extractor\Declaration;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Node\InClassNode;
+
+trait ExistsExtractor
+{
+    public function getNodeType(): string
+    {
+        return InClassNode::class;
+    }
+
+    /**
+     * @param InClassNode $node
+     */
+    protected function meetsDeclaration(Node $node, Scope $scope, array $params = []): bool
+    {
+        return true;
+    }
+}
diff --git a/tests/unit/rules/ShouldNotExist/ShouldNotExistTest.php b/tests/unit/rules/ShouldNotExist/ShouldNotExistTest.php
index fbf92b29..0c5dc748 100644
--- a/tests/unit/rules/ShouldNotExist/ShouldNotExistTest.php
+++ b/tests/unit/rules/ShouldNotExist/ShouldNotExistTest.php
@@ -3,8 +3,8 @@
 namespace Tests\PHPat\unit\rules\ShouldNotExist;
 
 use PHPat\Configuration;
+use PHPat\Rule\Assertion\Declaration\ShouldNotExist\ExistsRule;
 use PHPat\Rule\Assertion\Declaration\ShouldNotExist\ShouldNotExist;
-use PHPat\Rule\Assertion\Declaration\ShouldNotExist\ShouldNotExistRule;
 use PHPat\Selector\Classname;
 use PHPat\Statement\Builder\StatementBuilderFactory;
 use PHPStan\Rules\Rule;
@@ -38,7 +38,7 @@ protected function getRule(): Rule
             []
         );
 
-        return new ShouldNotExistRule(
+        return new ExistsRule(
             new StatementBuilderFactory($testParser),
             new Configuration(false, true, false),
             $this->createReflectionProvider(),