Test more cases related to bug #3636

src/Analyser/NodeScopeResolver.php

@@ -1876,7 +1876,7 @@ static function () use ($expr, $rightResult): MutatingScope {
 		} elseif ($expr instanceof Coalesce) {
 			$nonNullabilityResult = $this->ensureNonNullability($scope, $expr->left, false);
 
-			if ($expr->left instanceof PropertyFetch) {
+			if ($expr->left instanceof PropertyFetch || $expr->left instanceof StaticPropertyFetch) {
 				$scope = $nonNullabilityResult->getScope();
 			} else {
 				$scope = $this->lookForEnterVariableAssign($nonNullabilityResult->getScope(), $expr->left);

tests/PHPStan/Rules/DeadCode/UnusedPrivatePropertyRuleTest.php

@@ -142,7 +142,12 @@ public function testBug3636(): void
 	{
 		$this->alwaysWrittenTags = [];
 		$this->alwaysReadTags = [];
-		$this->analyse([__DIR__ . '/data/bug-3636.php'], []);
+		$this->analyse([__DIR__ . '/data/bug-3636.php'], [
+			[
+				'Property Bug3636\Bar::$date is never written, only read.',
+				22,
+			],
+		]);
 	}
 
 }

tests/PHPStan/Rules/DeadCode/data/bug-3636.php

@@ -14,3 +14,42 @@ public function getDate(): \DateTimeImmutable
 	}
 
 }
+
+class Bar
+{
+
+	/** @var \DateTimeImmutable */
+	private $date;
+
+	public function getDate(): ?\DateTimeImmutable
+	{
+		return $this->date ?? null;
+	}
+
+}
+
+class Baz
+{
+
+	/** @var string */
+	private $date;
+
+	public function getDate(): string
+	{
+		return $this->date ?? ($this->date = random_bytes(16));
+	}
+
+}
+
+class Lorem
+{
+
+	/** @var string */
+	private static $date;
+
+	public function getDate(): string
+	{
+		return self::$date ?? (self::$date = random_bytes(16));
+	}
+
+}