From 5eb7e4df6ddb22fad2bfd14da255700152a948fe Mon Sep 17 00:00:00 2001
From: tuqqu <artkurbidaev@gmail.com>
Date: Tue, 3 Oct 2023 02:53:51 +0200
Subject: [PATCH] Allow isset check for interface properties

---
 .../Expression/Fetch/AtomicPropertyFetchAnalyzer.php     | 9 ++++++---
 tests/InterfaceTest.php                                  | 8 ++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
index d6289b6687b..9275876612c 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
@@ -192,6 +192,7 @@ public static function analyze(
                 $statements_analyzer,
                 $codebase,
                 $stmt,
+                $context,
                 $lhs_type_part,
                 $intersection_types,
                 $class_exists,
@@ -1127,6 +1128,7 @@ private static function handleNonExistentClass(
         StatementsAnalyzer $statements_analyzer,
         Codebase $codebase,
         PhpParser\Node\Expr\PropertyFetch $stmt,
+        Context $context,
         TNamedObject $lhs_type_part,
         array $intersection_types,
         bool &$class_exists,
@@ -1150,10 +1152,11 @@ private static function handleNonExistentClass(
                 }
             }
 
-            if (!$class_exists &&
+            if (!$class_exists
                 //interfaces can't have properties. Except when they do... In PHP Core, they can
-                !in_array($fq_class_name, ['UnitEnum', 'BackedEnum'], true) &&
-                !in_array('UnitEnum', $codebase->getParentInterfaces($fq_class_name))
+                && !in_array($fq_class_name, ['UnitEnum', 'BackedEnum'], true)
+                && !in_array('UnitEnum', $codebase->getParentInterfaces($fq_class_name))
+                && !$context->inside_isset
             ) {
                 if (IssueBuffer::accepts(
                     new NoInterfaceProperties(
diff --git a/tests/InterfaceTest.php b/tests/InterfaceTest.php
index 91d56c16a64..0a21ebd5894 100644
--- a/tests/InterfaceTest.php
+++ b/tests/InterfaceTest.php
@@ -736,6 +736,14 @@ function takesAorB(SomeClass|SomeInterface $some): void {
                 'ignored_issues' => [],
                 'php_version' => '8.0',
             ],
+            'interfacePropertyIssetCheck' => [
+                'code' => '<?php
+                    interface X {}
+
+                    function foo(X $x): void {
+                        isset($x->x);
+                    }',
+            ],
         ];
     }