diff --git a/src/Type/StaticType.php b/src/Type/StaticType.php
index c379e5b873..21cf102515 100644
--- a/src/Type/StaticType.php
+++ b/src/Type/StaticType.php
@@ -399,6 +399,15 @@ public function toBoolean(): BooleanType
 
 	public function traverse(callable $cb): Type
 	{
+		$subtractedType = $this->subtractedType !== null ? $cb($this->subtractedType) : null;
+
+		if ($subtractedType !== $this->subtractedType) {
+			return new self(
+				$this->classReflection,
+				$subtractedType,
+			);
+		}
+
 		return $this;
 	}
 
diff --git a/src/Type/ThisType.php b/src/Type/ThisType.php
index 004b5137a3..5a5b00e554 100644
--- a/src/Type/ThisType.php
+++ b/src/Type/ThisType.php
@@ -57,6 +57,20 @@ public function changeSubtractedType(?Type $subtractedType): Type
 		return $type;
 	}
 
+	public function traverse(callable $cb): Type
+	{
+		$subtractedType = $this->getSubtractedType() !== null ? $cb($this->getSubtractedType()) : null;
+
+		if ($subtractedType !== $this->getSubtractedType()) {
+			return new self(
+				$this->getClassReflection(),
+				$subtractedType,
+			);
+		}
+
+		return $this;
+	}
+
 	/**
 	 * @param mixed[] $properties
 	 */