diff --git a/Build/phpstan/phpstan.neon b/Build/phpstan/phpstan.neon
index 0556cc92..83e14fb4 100644
--- a/Build/phpstan/phpstan.neon
+++ b/Build/phpstan/phpstan.neon
@@ -29,6 +29,11 @@ parameters:
       message: '#^Call to static method PHPUnit\\Framework\\Assert\:\:assertInstanceOf\(\) .* will always evaluate to#'
       path: '%currentWorkingDirectory%/tests/'
 
+  # This is a temporary but sadly necessary setting to allow upgrade to PHPStan 2.2.8.
+  # It maintains compatibility with PHPStan 2.2.7.
+  # When it has been bedded in, it can (and should) be removed.
+  reportUnmatchedIgnoredErrors: false
+
 services:
   -
     class: \Sabberworm\CSS\PhpStan\IgnoreBooleanAlways
diff --git a/src/PhpStan/IgnoreBooleanAlways.php b/src/PhpStan/IgnoreBooleanAlways.php
index dbcd499f..fb3a8503 100644
--- a/src/PhpStan/IgnoreBooleanAlways.php
+++ b/src/PhpStan/IgnoreBooleanAlways.php
@@ -10,6 +10,7 @@
 use PHPStan\Analyser\Error;
 use PHPStan\Analyser\IgnoreErrorExtension;
 use PHPStan\Analyser\Scope;
+use PHPStan\Node\FunctionCallExpressionNode;
 
 /**
  * Ignore PHPStan warnings where the DocBlocks indicate that a conditional expression would always be true (or false),
@@ -22,25 +23,50 @@ final class IgnoreBooleanAlways implements IgnoreErrorExtension
 {
     public function shouldIgnore(Error $error, Node $node, Scope $scope): bool
     {
-        $shouldIgnore = false;
-
         switch ($error->getIdentifier()) {
             case 'function.alreadyNarrowedType':
-                // For an `assert()` that the DocBlocks say cannot fail.
-                if ($node instanceof FuncCall) {
-                    $nameNode = $node->name;
-                    if ($nameNode instanceof Name && $nameNode->name === 'assert') {
-                        $shouldIgnore = true;
-                    }
-                }
-                break;
+                return self::shouldIgnoreFunctionAlreadyNarrowedType($node);
             case 'instanceof.alwaysTrue':
-                // For `instanceof` within an `assert()` that the DocBlocks say cannot fail.
-                $functionCallStack = $scope->getFunctionCallStack();
-                if (isset($functionCallStack[0]) && $functionCallStack[0]->getName() === 'assert') {
-                    $shouldIgnore = true;
-                }
-                break;
+                return self::shouldIgnoreInstanceofAlwaysTrue($scope);
+            default:
+                return false;
+        }
+    }
+
+    /**
+     * For an `assert()` that the DocBlocks say cannot fail.
+     */
+    private static function shouldIgnoreFunctionAlreadyNarrowedType(Node $node): bool
+    {
+        $shouldIgnore = false;
+
+        // This is an unstable API that does not adhere to semver.
+        // @phpstan-ignore phpstanApi.classConstant, phpstanApi.class
+        if (\class_exists(FunctionCallExpressionNode::class) && $node instanceof FunctionCallExpressionNode) {
+            // Unwrap for PHPStan >= 2.2.8
+            // @phpstan-ignore phpstanApi.method
+            $node = $node->getOriginalNode();
+        }
+        if ($node instanceof FuncCall) {
+            $nameNode = $node->name;
+            if ($nameNode instanceof Name && $nameNode->name === 'assert') {
+                $shouldIgnore = true;
+            }
+        }
+
+        return $shouldIgnore;
+    }
+
+    /**
+     * For `instanceof` within an `assert()` that the DocBlocks say cannot fail.
+     */
+    private static function shouldIgnoreInstanceofAlwaysTrue(Scope $scope): bool
+    {
+        $shouldIgnore = false;
+
+        $functionCallStack = $scope->getFunctionCallStack();
+        if (isset($functionCallStack[0]) && $functionCallStack[0]->getName() === 'assert') {
+            $shouldIgnore = true;
         }
 
         return $shouldIgnore;