From 54baab07f1a4f0be6dd645a3b3a644dc20e25ada Mon Sep 17 00:00:00 2001
From: phpstan-bot <79867460+phpstan-bot@users.noreply.github.com>
Date: Tue, 14 Apr 2026 22:03:01 +0000
Subject: [PATCH] Do not create conditional expression when guard type overlaps
 with non-object type in other branch

- In `MutatingScope::createConditionalExpressions()`, add a second skip
  condition for cases where the target expression does not exist in the
  other branch but the guard type overlaps with the other branch's guard
  value (for non-object types where `isSuperTypeOf` gives precise answers)
- This prevents false positive "always true/false" reports when a variable
  is assigned from an array access in one branch and from an independent
  expression in another branch, and the shared variable's truthiness is
  later checked
- The existing skip condition (from bug-14411 fix) only handles the case
  where the target exists in both branches; this extends it to handle the
  case where the target only exists in one branch
- The `isObject()->no()` guard ensures we only apply this for non-object
  types where `isSuperTypeOf` overlap detection is reliable (object types
  can give imprecise Maybe results due to theoretical subclass overlap)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/Analyser/MutatingScope.php                |  9 +++
 .../Analyser/nsrt/bug-14469-variants.php      | 54 +++++++++++++++
 tests/PHPStan/Analyser/nsrt/bug-14469.php     | 19 ++++++
 .../BooleanNotConstantConditionRuleTest.php   |  6 ++
 .../Rules/Comparison/data/bug-14469.php       | 66 +++++++++++++++++++
 5 files changed, 154 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-14469-variants.php
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-14469.php
 create mode 100644 tests/PHPStan/Rules/Comparison/data/bug-14469.php

diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 122340cc27b..4d587050a65 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -3649,6 +3649,15 @@ private function createConditionalExpressions(
 				) {
 					continue;
 				}
+				if (
+					!array_key_exists($exprString, $theirExpressionTypes)
+					&& array_key_exists($guardExprString, $theirExpressionTypes)
+					&& $theirExpressionTypes[$guardExprString]->getCertainty()->yes()
+					&& $theirExpressionTypes[$guardExprString]->getType()->isObject()->no()
+					&& !$guardHolder->getType()->isSuperTypeOf($theirExpressionTypes[$guardExprString]->getType())->no()
+				) {
+					continue;
+				}
 				$conditionalExpression = new ConditionalExpressionHolder([$guardExprString => $guardHolder], $holder);
 				$conditionalExpressions[$exprString][$conditionalExpression->getKey()] = $conditionalExpression;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-14469-variants.php b/tests/PHPStan/Analyser/nsrt/bug-14469-variants.php
new file mode 100644
index 00000000000..b58ca971f7a
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-14469-variants.php
@@ -0,0 +1,54 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14469Variants;
+
+use function PHPStan\Testing\assertType;
+
+// Variant 1: if/else where one branch doesn't access the array key
+function variant1(array $R, bool $cond, int $other): void {
+	$aa = null;
+
+	if ($cond) {
+		$aa = $other;
+	} else {
+		if ($R['key']) {
+			$aa = $R['key'];
+		}
+	}
+
+	if ($aa) {
+		assertType('mixed', $R['key']);
+	}
+}
+
+// Variant 2: Multiple elseif branches
+function variant2(array $R, bool $var1, bool $var2, int $other1, int $other2): void {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $other1;
+	} elseif ($var2) {
+		$aa = $other2;
+	} elseif ($R['key']) {
+		$aa = $R['key'];
+	}
+
+	if ($aa) {
+		assertType('mixed', $R['key']);
+	}
+}
+
+// Variant 3: Nested array access
+function variant3(array $R, bool $cond, int $other): void {
+	$aa = null;
+
+	if ($cond) {
+		$aa = $other;
+	} elseif ($R['nested']['key']) {
+		$aa = $R['nested']['key'];
+	}
+
+	if ($aa) {
+		assertType('mixed', $R['nested']['key']);
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-14469.php b/tests/PHPStan/Analyser/nsrt/bug-14469.php
new file mode 100644
index 00000000000..b33f51591ab
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-14469.php
@@ -0,0 +1,19 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14469Nsrt;
+
+use function PHPStan\Testing\assertType;
+
+function t(array $R, bool $var1, object $user): void {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $user->id  === 10 ? 2 : null;
+	} elseif ($R['aa']) {
+		$aa = $R['aa'];
+	}
+
+	if ($aa) {
+		assertType('mixed', $R['aa']);
+	}
+}
diff --git a/tests/PHPStan/Rules/Comparison/BooleanNotConstantConditionRuleTest.php b/tests/PHPStan/Rules/Comparison/BooleanNotConstantConditionRuleTest.php
index 3cf3f2a8bbc..ee1d1ff12fe 100644
--- a/tests/PHPStan/Rules/Comparison/BooleanNotConstantConditionRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/BooleanNotConstantConditionRuleTest.php
@@ -236,4 +236,10 @@ public function testBug6702(): void
 		$this->analyse([__DIR__ . '/data/bug-6702.php'], []);
 	}
 
+	public function testBug14469(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-14469.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Comparison/data/bug-14469.php b/tests/PHPStan/Rules/Comparison/data/bug-14469.php
new file mode 100644
index 00000000000..d5aea39bee6
--- /dev/null
+++ b/tests/PHPStan/Rules/Comparison/data/bug-14469.php
@@ -0,0 +1,66 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14469;
+
+function t(array $R, bool $var1, object $user, bool $is): array {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $user->id  === 10 ? 2 : null;
+	} elseif ($R['aa']) {
+		$aa = $R['aa'];
+	}
+
+	if ($aa) {
+		if (!$R['aa']) {
+			return [];
+		}
+	}
+	return $R;
+}
+
+function t2(array $R, bool $var1, object $user): array {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $user->id  === 10 ? 2 : null;
+	} elseif ($R['aa']) {
+		$aa = $R['aa'];
+	}
+
+	if ($aa) {
+		if ($R['aa'] === false) {
+			return [];
+		}
+	}
+	return $R;
+}
+
+function t3(array $R, bool $var1, int $other): array {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $other;
+	} elseif ($R['bb']) {
+		$aa = $R['bb'];
+	}
+
+	if ($aa) {
+		if (!$R['bb']) {
+			return [];
+		}
+	}
+	return $R;
+}
+
+function t4(array $R, bool $var1, object $user): string {
+	$aa = null;
+
+	if ($var1) {
+		$aa = $user->id  === 10 ? 2 : null;
+	} elseif ($R['aa']) {
+		$aa = $R['aa'];
+	}
+
+	return $aa ? ($R['aa'] ? 'yes' : 'no') : 'none';
+}