Merge pull request #8670 from danog/fix_8669

Fix #8669

src/Psalm/Internal/Type/AssertionReconciler.php

@@ -601,7 +601,7 @@ class AssertionReconciler extends Reconciler
             $codebase,
             $type_1_atomic,
             $type_2_atomic,
-            !($type_1_atomic instanceof TNamedObject && $type_2_atomic instanceof TNamedObject),
+            $type_1_atomic instanceof TClassString && $type_2_atomic instanceof TClassString,
             false,
             $atomic_comparison_results
         );

tests/TypeReconciliation/TypeTest.php

@@ -19,6 +19,31 @@ class TypeTest extends TestCase
     public function providerValidCodeParse(): iterable
     {
         return [
+            'instanceOfInterface' => [
+                'code' => '<?php
+                    interface Supplier {
+                        public function get(): iterable;
+                    }
+
+                    class SomeClass {
+                        protected Supplier|iterable $prop;
+
+                        public function __construct(Supplier|iterable $value) {
+                            $this->prop = $value;
+                        }
+
+                        public function do(): void {
+                            $var = $this->prop;
+
+                            if ($var instanceof Supplier) {
+                                $var->get();
+                            }
+                        }
+                    }',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '8.0'
+            ],
             'nullableMethodWithTernaryGuard' => [
                 'code' => '<?php
                     class A {