From 8c93123216e8819128f108afecece07bd4c57c16 Mon Sep 17 00:00:00 2001
From: Abdul Malik Ikhsan <samsonasik@gmail.com>
Date: Sat, 11 Apr 2026 20:28:23 +0700
Subject: [PATCH] [CodeQuality] Skip possibly undefined variable on
 CoalesceToTernaryRector

---
 .../Fixture/skip_possibly_undefined.php.inc       | 15 +++++++++++++++
 .../Rector/Coalesce/CoalesceToTernaryRector.php   |  5 +++++
 2 files changed, 20 insertions(+)
 create mode 100644 rules-tests/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector/Fixture/skip_possibly_undefined.php.inc

diff --git a/rules-tests/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector/Fixture/skip_possibly_undefined.php.inc b/rules-tests/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector/Fixture/skip_possibly_undefined.php.inc
new file mode 100644
index 00000000000..9ebdb4001bf
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector/Fixture/skip_possibly_undefined.php.inc
@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\CodeQuality\Rector\Coalesce\CoalesceToTernaryRector\Fixture;
+
+class SkipPossiblyUndefined
+{
+    public function run()
+    {
+        if (rand(0, 1)) {
+            $name = 'tom';
+        }
+
+        return $name ?? 'tom';
+    }
+}
diff --git a/rules/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector.php b/rules/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector.php
index 2c8c95f00e2..2f57dc6ee5f 100644
--- a/rules/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector.php
+++ b/rules/CodeQuality/Rector/Coalesce/CoalesceToTernaryRector.php
@@ -8,6 +8,7 @@
 use PhpParser\Node\Expr\ArrayDimFetch;
 use PhpParser\Node\Expr\BinaryOp\Coalesce;
 use PhpParser\Node\Expr\Ternary;
+use PhpParser\Node\Expr\Variable;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NullType;
@@ -92,6 +93,10 @@ public function refactor(Node $node): ?Node
             }
         }
 
+        if ($node->left instanceof Variable && ! $scope->hasVariableType((string) $this->getName($node->left))->yes()) {
+            return null;
+        }
+
         return new Ternary($node->left, null, $node->right);
     }
 }