Fix

Author: ondrejmirtes

src/Analyser/Fiber/FiberScope.php

@@ -115,7 +115,7 @@ public function filterByFalseyValue(Expr $expr): self
 		return $scope;
 	}
 
-	private function preprocessScope(Scope $scope): Scope
+	private function preprocessScope(MutatingScope $scope): Scope
 	{
 		if ($this->nativeTypesPromoted) {
 			$scope = $scope->doNotTreatPhpDocTypesAsCertain();

src/Analyser/Scope.php

@@ -168,6 +168,6 @@ public function isInFirstLevelStatement(): bool;
 	public function getPhpVersion(): PhpVersions;
 
 	/** @internal */
-	public function toMutatingScope(): self;
+	public function toMutatingScope(): MutatingScope;
 
 }