From e6bcbb2421efc593d24c5be4fd4e69bcb7d52613 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Tomulik?= <ptomulik@meil.pw.edu.pl>
Date: Thu, 18 Nov 2021 23:13:08 +0100
Subject: [PATCH] attempt to fix #6937

---
 .../Internal/Analyzer/MethodComparator.php    |  9 +++
 tests/ReturnTypeTest.php                      | 64 +++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/src/Psalm/Internal/Analyzer/MethodComparator.php b/src/Psalm/Internal/Analyzer/MethodComparator.php
index 74fcc847621..15bc9f7cced 100644
--- a/src/Psalm/Internal/Analyzer/MethodComparator.php
+++ b/src/Psalm/Internal/Analyzer/MethodComparator.php
@@ -964,6 +964,15 @@ private static function compareMethodDocblockReturnTypes(
                 $guide_method_storage_return_type,
                 $codebase
             );
+
+            if ($implementer_method_storage->defining_fqcln) {
+                self::transformTemplates(
+                    $implementer_classlike_storage->template_extended_params,
+                    $implementer_method_storage->defining_fqcln,
+                    $implementer_method_storage_return_type,
+                    $codebase
+                );
+            }
         }
 
         if ($implementer_classlike_storage->is_trait) {
diff --git a/tests/ReturnTypeTest.php b/tests/ReturnTypeTest.php
index 2198e88e8fe..e901d595d57 100644
--- a/tests/ReturnTypeTest.php
+++ b/tests/ReturnTypeTest.php
@@ -1002,6 +1002,37 @@ function a($end): void{
                         }
                     }'
             ],
+            'returnTypeOfAbstractAndConcreteMethodFromTemplatedTraits' => [
+                '<?php
+                    /** @template T */
+                    trait AggregateTrait {
+                        /** @var T */
+                        private $value;
+
+                        /** @psalm-return T */
+                        public function getValue() {
+                            return $this->value;
+                        }
+                    }
+
+                    /** @template T */
+                    trait AnotherTrait {
+                        /** @psalm-return T */
+                        abstract public function getValue();
+                    }
+
+                    class Test {
+                        /** @use AggregateTrait<int> */
+                        use AggregateTrait;
+
+                        /** @use AnotherTrait<int> */
+                        use AnotherTrait;
+
+                        public function __construct() {
+                            $this->value = 123;
+                        }
+                    }'
+            ]
         ];
     }
 
@@ -1435,6 +1466,39 @@ function f(): object {
                 ',
                 'error_message' => 'LessSpecificReturnStatement',
             ],
+            'lessSpecificImplementedReturnTypeFromTemplatedTraitMethod' => [
+                '<?php
+                    /** @template T */
+                    trait AggregateTrait {
+                        /** @var T */
+                        private $value;
+
+                        /** @psalm-return T */
+                        public function getValue() {
+                            return $this->value;
+                        }
+                    }
+
+                    /** @template T */
+                    trait AnotherTrait {
+                        /** @psalm-return T */
+                        abstract public function getValue();
+                    }
+
+                    /** @template T */
+                    class Test {
+                        /** @use AggregateTrait<T> */
+                        use AggregateTrait;
+
+                        /** @use AnotherTrait<int> */
+                        use AnotherTrait;
+
+                        public function __construct() {
+                            $this->value = 123;
+                        }
+                    }',
+                    'error_message' => 'LessSpecificImplementedReturnType',
+            ]
         ];
     }
 }