Fix internal error with first-class callable in array_filter

src/Rules/Comparison/ImpossibleCheckTypeHelper.php

@@ -59,6 +59,9 @@ public function findSpecifiedType(
 	): ?bool
 	{
 		if ($node instanceof FuncCall) {
+			if ($node->isFirstClassCallable()) {
+				return null;
+			}
 			$argsCount = count($node->getArgs());
 			if ($node->name instanceof Node\Name) {
 				$functionName = strtolower((string) $node->name);
@@ -361,6 +364,10 @@ private function determineContext(Scope $scope, Expr $node): TypeSpecifierContex
 			return TypeSpecifierContext::createTruthy();
 		}
 
+		if ($node instanceof Expr\CallLike && $node->isFirstClassCallable()) {
+			return TypeSpecifierContext::createTruthy();
+		}
+
 		if ($node instanceof FuncCall && $node->name instanceof Node\Name) {
 			if ($this->reflectionProvider->hasFunction($node->name, $scope)) {
 				$functionReflection = $this->reflectionProvider->getFunction($node->name, $scope);

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -1230,6 +1230,18 @@ public function testBug9690(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testBug9994(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1.');
+		}
+
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-9994.php');
+		$this->assertCount(2, $errors);
+		$this->assertSame('Negated boolean expression is always false.', $errors[0]->getMessage());
+		$this->assertSame('Parameter #2 $callback of function array_filter expects callable(1|2|3|null): mixed, false given.', $errors[1]->getMessage());
+	}
+
 	/**
 	 * @param string[]|null $allAnalysedFiles
 	 * @return Error[]

tests/PHPStan/Analyser/data/bug-9994.php

@@ -0,0 +1,16 @@
+<?php declare(strict_types = 1); // lint >= 8.1
+
+namespace Bug9994;
+
+function (): void {
+
+	$arr = [
+		1,
+		2,
+		3,
+		null,
+	];
+
+
+	var_dump(array_filter($arr, !is_null(...)));
+};