diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/MethodCallReturnTypeFetcher.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/MethodCallReturnTypeFetcher.php
index 9f8abaa79..a5dc24d17 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/MethodCallReturnTypeFetcher.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/MethodCallReturnTypeFetcher.php
@@ -98,7 +98,7 @@ class MethodCallReturnTypeFetcher
         if ($premixin_method_id->method_name === 'getcode'
             && $premixin_method_id->fq_class_name !== Exception::class
             && (
-                in_array(Throwable::class, $class_storage->class_implements)
+                $codebase->classImplements($premixin_method_id->fq_class_name, Throwable::class)
                 || $codebase->interfaceExtends($premixin_method_id->fq_class_name, Throwable::class)
             )
         ) {