From 4d8af74d929225881d4a69c36c5c1f25f3051156 Mon Sep 17 00:00:00 2001
From: Bruce Weirdan <weirdan@gmail.com>
Date: Sat, 3 Dec 2022 00:51:22 -0400
Subject: [PATCH] Don't crash when accessing immutable static property

Fixes vimeo/psalm#8313
---
 .../InstancePropertyAssignmentAnalyzer.php     | 18 ++++++++++--------
 tests/UnusedCodeTest.php                       | 15 +++++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/InstancePropertyAssignmentAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/InstancePropertyAssignmentAnalyzer.php
index f5c2000bac8..d69df245442 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/InstancePropertyAssignmentAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/InstancePropertyAssignmentAnalyzer.php
@@ -524,17 +524,19 @@ private static function taintProperty(
                     }
                 }
 
-                $stmt_var_type = $context->vars_in_scope[$var_id]->setParentNodes(
-                    [$var_node->id => $var_node]
-                );
+                if (isset($context->vars_in_scope[$var_id])) {
+                    $stmt_var_type = $context->vars_in_scope[$var_id]->setParentNodes(
+                        [$var_node->id => $var_node]
+                    );
 
-                if ($context->vars_in_scope[$var_id]->parent_nodes) {
-                    foreach ($context->vars_in_scope[$var_id]->parent_nodes as $parent_node) {
-                        $data_flow_graph->addPath($parent_node, $var_node, '=', $added_taints, $removed_taints);
+                    if ($context->vars_in_scope[$var_id]->parent_nodes) {
+                        foreach ($context->vars_in_scope[$var_id]->parent_nodes as $parent_node) {
+                            $data_flow_graph->addPath($parent_node, $var_node, '=', $added_taints, $removed_taints);
+                        }
                     }
-                }
 
-                $context->vars_in_scope[$var_id] = $stmt_var_type;
+                    $context->vars_in_scope[$var_id] = $stmt_var_type;
+                }
             }
         } else {
             if ($statements_analyzer->data_flow_graph instanceof TaintFlowGraph
diff --git a/tests/UnusedCodeTest.php b/tests/UnusedCodeTest.php
index a7aff4e56e8..9398e66f68a 100644
--- a/tests/UnusedCodeTest.php
+++ b/tests/UnusedCodeTest.php
@@ -1742,6 +1742,21 @@ function f(): void {
                 ',
                 'error_message' => 'UnevaluatedCode',
             ],
+            'noCrashOnReadonlyStaticProp' => [
+                'code' => '<?php
+                    /** @psalm-immutable */
+                    final class C { public int $val = 2; }
+
+                    final class A {
+                        private static C $prop;
+                        public static function f()
+                        {
+                            self::$prop->val = 1;
+                        }
+                    }
+                ',
+                'error_message' => 'InaccessibleProperty',
+            ],
         ];
     }
 }