Merge pull request #6327 from boesing/bugfix/class-alias

src/Psalm/Internal/Codebase/ClassLikes.php

@@ -675,7 +675,21 @@ class ClassLikes
         }
         $class_storage = $this->classlike_storage_provider->get($fq_class_name);
 
-        return isset($class_storage->class_implements[$interface_id]);
+        if (isset($class_storage->class_implements[$interface_id])) {
+            return true;
+        }
+
+        foreach ($class_storage->class_implements as $implementing_interface_lc => $_) {
+            $aliased_interface_lc = strtolower(
+                $this->getUnAliasedName($implementing_interface_lc)
+            );
+
+            if ($aliased_interface_lc === $interface_id) {
+                return true;
+            }
+        }
+
+        return false;
     }
 
     public function interfaceExists(

tests/Internal/Codebase/ClassLikesTest.php

@@ -0,0 +1,41 @@
+<?php
+declare(strict_types=1);
+
+namespace Psalm\Tests\Internal\Codebase;
+
+use Psalm\Internal\Codebase\ClassLikes;
+use Psalm\Internal\Provider\ClassLikeStorageProvider;
+use Psalm\Storage\ClassLikeStorage;
+use Psalm\Tests\TestCase;
+
+final class ClassLikesTest extends TestCase
+{
+    /**
+     * @var ClassLikes
+     */
+    private $classlikes;
+
+    /**
+     * @var ClassLikeStorageProvider
+     */
+    private $storage_provider;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+        $this->classlikes = $this->project_analyzer->getCodebase()->classlikes;
+        $this->storage_provider = $this->project_analyzer->getCodebase()->classlike_storage_provider;
+    }
+
+    public function testWillDetectClassImplementingAliasedInterface(): void
+    {
+        $this->classlikes->addClassAlias('Foo', 'bar');
+
+        $classStorage = new ClassLikeStorage('Baz');
+        $classStorage->class_implements['bar'] = 'Bar';
+
+        $this->storage_provider->addMore(['baz' => $classStorage]);
+
+        self::assertTrue($this->classlikes->classImplements('Baz', 'Foo'));
+    }
+}