From 04f3e29f94c81b3d861b9edddac483cab08b48f5 Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Thu, 18 Mar 2021 11:06:54 -0400
Subject: [PATCH] =?UTF-8?q?Expand=20documentation=20method=20return=20type?=
 =?UTF-8?q?=20to=20ensure=20we=E2=80=99re=20giving=20a=20fair=20shot?=
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---
 src/Psalm/Internal/Codebase/Methods.php     | 18 +++++++-
 tests/Template/ClassTemplateExtendsTest.php | 50 +++++++++++++++++++++
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/src/Psalm/Internal/Codebase/Methods.php b/src/Psalm/Internal/Codebase/Methods.php
index 8b1683e55..d76095af2 100644
--- a/src/Psalm/Internal/Codebase/Methods.php
+++ b/src/Psalm/Internal/Codebase/Methods.php
@@ -764,15 +764,29 @@ class Methods
                     return clone $candidate_type;
                 }
 
+                $overridden_class_storage =
+                    $this->classlike_storage_provider->get($overridden_method_id->fq_class_name);
+
+                $overridden_storage_return_type = \Psalm\Internal\Type\TypeExpander::expandUnion(
+                    $source_analyzer->getCodebase(),
+                    clone $overridden_storage->return_type,
+                    $overridden_method_id->fq_class_name,
+                    $appearing_fq_class_name,
+                    $overridden_class_storage->parent_class,
+                    true,
+                    false,
+                    $storage->final
+                );
+
                 $old_contained_by_new = UnionTypeComparator::isContainedBy(
                     $source_analyzer->getCodebase(),
                     $candidate_type,
-                    $overridden_storage->return_type
+                    $overridden_storage_return_type
                 );
 
                 $new_contained_by_old = UnionTypeComparator::isContainedBy(
                     $source_analyzer->getCodebase(),
-                    $overridden_storage->return_type,
+                    $overridden_storage_return_type,
                     $candidate_type
                 );
 
diff --git a/tests/Template/ClassTemplateExtendsTest.php b/tests/Template/ClassTemplateExtendsTest.php
index 677fe1788..265e910ab 100644
--- a/tests/Template/ClassTemplateExtendsTest.php
+++ b/tests/Template/ClassTemplateExtendsTest.php
@@ -4350,6 +4350,56 @@ class ClassTemplateExtendsTest extends TestCase
 
                     $foo = new ObjectStorage();'
             ],
+            'liskovTerminatedByFinalClass' => [
+                '<?php
+                    final class CustomEnum extends Enum
+                    {
+                        public static function all() : CustomEnumSet
+                        {
+                            return new CustomEnumSet();
+                        }
+                    }
+
+                    /**
+                     * @template T of Enum
+                     */
+                    class EnumSet
+                    {
+                        private $type;
+
+                        /**
+                         * @param class-string<T> $type
+                         */
+                        public function __construct(string $type)
+                        {
+                            $this->type = $type;
+                        }
+                    }
+
+                    abstract class Enum {
+                        /**
+                         * @return EnumSet<static>
+                         */
+                        public static function all() : EnumSet
+                        {
+                            return new EnumSet(static::class);
+                        }
+                    }
+
+                    /**
+                     * @extends EnumSet<CustomEnum>
+                     */
+                    final class CustomEnumSet extends EnumSet {
+
+                        public function __construct()
+                        {
+                            parent::__construct(CustomEnum::class);
+                        }
+                    }',
+                [],
+                [],
+                '7.4'
+            ],
         ];
     }