diff --git a/src/CompareClasses.php b/src/CompareClasses.php
index 0fd69d7..2378ef8 100644
--- a/src/CompareClasses.php
+++ b/src/CompareClasses.php
@@ -92,8 +92,9 @@ private function examineSymbol(
         yield from ($this->classBasedComparisons)($oldSymbol, $newClass);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/ClassBased/ClassBecameInternal.php b/src/DetectChanges/BCBreak/ClassBased/ClassBecameInternal.php
index 5695264..3c9de87 100644
--- a/src/DetectChanges/BCBreak/ClassBased/ClassBecameInternal.php
+++ b/src/DetectChanges/BCBreak/ClassBased/ClassBecameInternal.php
@@ -32,8 +32,9 @@ public function __invoke(ReflectionClass $fromClass, ReflectionClass $toClass):
         return Changes::empty();
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/ClassBased/ExcludeInternalClass.php b/src/DetectChanges/BCBreak/ClassBased/ExcludeInternalClass.php
index c33ba88..a6a8412 100644
--- a/src/DetectChanges/BCBreak/ClassBased/ExcludeInternalClass.php
+++ b/src/DetectChanges/BCBreak/ClassBased/ExcludeInternalClass.php
@@ -26,8 +26,9 @@ public function __invoke(ReflectionClass $fromClass, ReflectionClass $toClass):
         return ($this->check)($fromClass, $toClass);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/ClassBased/MethodRemoved.php b/src/DetectChanges/BCBreak/ClassBased/MethodRemoved.php
index 0e9be95..e6134a7 100644
--- a/src/DetectChanges/BCBreak/ClassBased/MethodRemoved.php
+++ b/src/DetectChanges/BCBreak/ClassBased/MethodRemoved.php
@@ -58,8 +58,9 @@ private function accessibleMethods(ReflectionClass $class): array
         );
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/ClassBased/PropertyRemoved.php b/src/DetectChanges/BCBreak/ClassBased/PropertyRemoved.php
index b3cbb31..ad400fb 100644
--- a/src/DetectChanges/BCBreak/ClassBased/PropertyRemoved.php
+++ b/src/DetectChanges/BCBreak/ClassBased/PropertyRemoved.php
@@ -50,8 +50,9 @@ private function accessibleProperties(ReflectionClass $class): array
         });
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/FunctionBased/ExcludeInternalFunction.php b/src/DetectChanges/BCBreak/FunctionBased/ExcludeInternalFunction.php
index 4cda2f5..8fa713d 100644
--- a/src/DetectChanges/BCBreak/FunctionBased/ExcludeInternalFunction.php
+++ b/src/DetectChanges/BCBreak/FunctionBased/ExcludeInternalFunction.php
@@ -29,8 +29,9 @@ public function __invoke(
         return ($this->check)($fromFunction, $toFunction);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/FunctionBased/FunctionBecameInternal.php b/src/DetectChanges/BCBreak/FunctionBased/FunctionBecameInternal.php
index 354d61f..8dd5d0a 100644
--- a/src/DetectChanges/BCBreak/FunctionBased/FunctionBecameInternal.php
+++ b/src/DetectChanges/BCBreak/FunctionBased/FunctionBecameInternal.php
@@ -43,8 +43,9 @@ public function __invoke(
         return Changes::empty();
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/InterfaceBased/ExcludeInternalInterface.php b/src/DetectChanges/BCBreak/InterfaceBased/ExcludeInternalInterface.php
index 2fc7ccf..46d63f9 100644
--- a/src/DetectChanges/BCBreak/InterfaceBased/ExcludeInternalInterface.php
+++ b/src/DetectChanges/BCBreak/InterfaceBased/ExcludeInternalInterface.php
@@ -26,8 +26,9 @@ public function __invoke(ReflectionClass $fromInterface, ReflectionClass $toInte
         return ($this->check)($fromInterface, $toInterface);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/MethodBased/ExcludeInternalMethod.php b/src/DetectChanges/BCBreak/MethodBased/ExcludeInternalMethod.php
index 5c62cc0..1a2bdf6 100644
--- a/src/DetectChanges/BCBreak/MethodBased/ExcludeInternalMethod.php
+++ b/src/DetectChanges/BCBreak/MethodBased/ExcludeInternalMethod.php
@@ -26,8 +26,9 @@ public function __invoke(ReflectionMethod $fromMethod, ReflectionMethod $toMetho
         return ($this->check)($fromMethod, $toMethod);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/PropertyBased/ExcludeInternalProperty.php b/src/DetectChanges/BCBreak/PropertyBased/ExcludeInternalProperty.php
index 385632d..911646d 100644
--- a/src/DetectChanges/BCBreak/PropertyBased/ExcludeInternalProperty.php
+++ b/src/DetectChanges/BCBreak/PropertyBased/ExcludeInternalProperty.php
@@ -23,8 +23,9 @@ public function __invoke(ReflectionProperty $fromProperty, ReflectionProperty $t
         return ($this->propertyBased)($fromProperty, $toProperty);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/PropertyBased/PropertyBecameInternal.php b/src/DetectChanges/BCBreak/PropertyBased/PropertyBecameInternal.php
index 6968634..3d387c4 100644
--- a/src/DetectChanges/BCBreak/PropertyBased/PropertyBecameInternal.php
+++ b/src/DetectChanges/BCBreak/PropertyBased/PropertyBecameInternal.php
@@ -40,8 +40,9 @@ public function __invoke(ReflectionProperty $fromProperty, ReflectionProperty $t
         return Changes::empty();
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }
diff --git a/src/DetectChanges/BCBreak/TraitBased/ExcludeInternalTrait.php b/src/DetectChanges/BCBreak/TraitBased/ExcludeInternalTrait.php
index 969bfec..9a89fba 100644
--- a/src/DetectChanges/BCBreak/TraitBased/ExcludeInternalTrait.php
+++ b/src/DetectChanges/BCBreak/TraitBased/ExcludeInternalTrait.php
@@ -26,8 +26,9 @@ public function __invoke(ReflectionClass $fromTrait, ReflectionClass $toTrait):
         return ($this->check)($fromTrait, $toTrait);
     }
 
-    private function isInternalDocComment(string $comment): bool
+    private function isInternalDocComment(string|null $comment): bool
     {
-        return Regex\matches($comment, '/\s+@internal\s+/');
+        return $comment !== null
+            && Regex\matches($comment, '/\s+@internal\s+/');
     }
 }