Do not create conditional expression when guard type overlaps with non-object type in other branch

src/Analyser/MutatingScope.php

@@ -3649,6 +3649,15 @@
 				) {
 					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;
 			}

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']);
+	}
+}

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']);
+	}
+}

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'], []);
+	}
+
 }

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';
+}