From cd265d1f6026a063d329bf52b0a8505b2e3f9442 Mon Sep 17 00:00:00 2001
From: VincentLanglet <9052536+VincentLanglet@users.noreply.github.com>
Date: Fri, 20 Mar 2026 22:44:10 +0000
Subject: [PATCH 1/2] Fix incorrect type narrowing to *NEVER* for array after
 foreach assignment

- Added hasOffsetValueType check in AssignHandler to prevent using setExistingOffsetValueType when offset is known to not exist in the array
- When the offset definitely doesn't exist (hasOffsetValueType returns no), fall through to setOffsetValueType which correctly widens the key type
- Updated bug-13270b-php8 test expectation to reflect more precise type inference (hasOffsetValue instead of hasOffset)
- New regression test in tests/PHPStan/Analyser/nsrt/bug-13786.php
---
 src/Analyser/ExprHandler/AssignHandler.php    |  1 +
 .../PHPStan/Analyser/nsrt/bug-13270b-php8.php |  2 +-
 tests/PHPStan/Analyser/nsrt/bug-13786.php     | 20 +++++++++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-13786.php

diff --git a/src/Analyser/ExprHandler/AssignHandler.php b/src/Analyser/ExprHandler/AssignHandler.php
index 1a1ed14bae..df779e633e 100644
--- a/src/Analyser/ExprHandler/AssignHandler.php
+++ b/src/Analyser/ExprHandler/AssignHandler.php
@@ -991,6 +991,7 @@ private function produceArrayDimFetchAssignValueToWrite(array $dimFetchStack, ar
 				$offsetType !== null
 				&& $arrayDimFetch !== null
 				&& $scope->hasExpressionType($arrayDimFetch)->yes()
+				&& !$offsetValueType->hasOffsetValueType($offsetType)->no()
 			) {
 				$hasOffsetType = null;
 				if ($offsetType instanceof ConstantStringType || $offsetType instanceof ConstantIntegerType) {
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13270b-php8.php b/tests/PHPStan/Analyser/nsrt/bug-13270b-php8.php
index e2d9e4ea0b..ecab6997b8 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-13270b-php8.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-13270b-php8.php
@@ -19,7 +19,7 @@ public function parseData(array $data): array
 			if (!array_key_exists('priceWithVat', $data['price'])) {
 				$data['price']['priceWithVat'] = null;
 			}
-			assertType("non-empty-array&hasOffset('priceWithVat')", $data['price']);
+			assertType("non-empty-array&hasOffsetValue('priceWithVat', mixed)", $data['price']);
 			if (!array_key_exists('priceWithoutVat', $data['price'])) {
 				$data['price']['priceWithoutVat'] = null;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13786.php b/tests/PHPStan/Analyser/nsrt/bug-13786.php
new file mode 100644
index 0000000000..840bdf9dea
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-13786.php
@@ -0,0 +1,20 @@
+<?php declare(strict_types=1);
+
+namespace Bug13786;
+
+use function PHPStan\Testing\assertType;
+
+/** @var array<mixed> $arr */
+
+/** @var non-empty-list<'a'|'b'|'c'> $cols */
+
+$total = [ ];
+foreach ($arr as $id => $dummy) {
+    $total[$id] = [ ];
+    foreach ($cols as $col) {
+        $total[$id][$col] = '0';
+    }
+    assertType("non-empty-array<'a'|'b'|'c'|'d', '0'>", $total[$id]);
+    $total[$id]['d'] = '0';
+    assertType("non-empty-array<'a'|'b'|'c'|'d', '0'>&hasOffsetValue('d', '0')", $total[$id]);
+}

From 1b7551cc98e4907bd828321ebc04fadf6074893e Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sat, 21 Mar 2026 09:23:18 +0100
Subject: [PATCH 2/2] more asserts

---
 tests/PHPStan/Analyser/nsrt/bug-13786.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/PHPStan/Analyser/nsrt/bug-13786.php b/tests/PHPStan/Analyser/nsrt/bug-13786.php
index 840bdf9dea..0c0e56925e 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-13786.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-13786.php
@@ -18,3 +18,6 @@
     $total[$id]['d'] = '0';
     assertType("non-empty-array<'a'|'b'|'c'|'d', '0'>&hasOffsetValue('d', '0')", $total[$id]);
 }
+
+$total[$id]['e'] = '1';
+assertType("non-empty-array<'a'|'b'|'c'|'d'|'e', '0'|'1'>&hasOffsetValue('e', '1')", $total[$id]);