diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 94510cd3a6..ddd6bd0211 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -3238,6 +3238,9 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 
 				// Pass 2: Supertype match. Only runs when Pass 1 found no exact match for this expression.
 				foreach ($conditionalExpressions as $conditionalExpression) {
+					if ($conditionalExpression->getTypeHolder()->getCertainty()->no()) {
+						continue;
+					}
 					foreach ($conditionalExpression->getConditionExpressionTypeHolders() as $holderExprString => $conditionalTypeHolder) {
 						if (
 							!array_key_exists($holderExprString, $specifiedExpressions)
diff --git a/tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php b/tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php
index d6a06d8581..88af910f2b 100644
--- a/tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php
@@ -387,6 +387,11 @@ public function testBug4846(): void
 		]);
 	}
 
+	public function testBug14458(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14458.php'], []);
+	}
+
 	public function testBug14393(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-14393.php'], [
diff --git a/tests/PHPStan/Rules/Variables/data/bug-14458.php b/tests/PHPStan/Rules/Variables/data/bug-14458.php
new file mode 100644
index 0000000000..552f883e86
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-14458.php
@@ -0,0 +1,50 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14458;
+
+use DateTime;
+
+class Foo
+{
+
+	/**
+	 * @param array<mixed> $payload
+	 * @return array<mixed>
+	 */
+	public function doFoo(array $payload): array
+	{
+		if ($payload['a'] !== 'b') {
+			throw new \Exception();
+		}
+
+		if (isset($payload['c'])) {
+			$c = array_values(array_map(static fn (array $cd) => $cd[0], $payload['c']));
+		}
+
+		$convertedPriceWithVat = null;
+		if (array_key_exists('cpwv', $payload)) {
+			$convertedAmount = (float) $payload['cpwv']['awv'];
+
+		}
+
+		return [
+			$payload['cf'],
+			$payload['n'],
+			$payload['d'] ?? null,
+			$payload['mb'] ?? null,
+			$payload['cr'],
+			new DateTime($payload['p']),
+			$payload['pn'],
+			$payload['pd'] ?? null,
+			$payload['piu'] ?? null,
+			$convertedPriceWithVat,
+			$payload['vi'],
+			$payload['pi'],
+			$payload['user']['name'] ?? null,
+			$payload['user']['phone'] ?? null,
+			$payload['ac'] ?? null,
+			$c ?? null,
+		];
+	}
+
+}