diff --git a/src/Rules/Keywords/RequireFileExistsRule.php b/src/Rules/Keywords/RequireFileExistsRule.php
index b0d4def309..b47817e4d6 100644
--- a/src/Rules/Keywords/RequireFileExistsRule.php
+++ b/src/Rules/Keywords/RequireFileExistsRule.php
@@ -3,7 +3,10 @@
 namespace PHPStan\Rules\Keywords;
 
 use PhpParser\Node;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\Include_;
+use PhpParser\Node\Name\FullyQualified;
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredParameter;
 use PHPStan\DependencyInjection\RegisteredRule;
@@ -41,6 +44,10 @@ public function getNodeType(): string
 
 	public function processNode(Node $node, Scope $scope): array
 	{
+		if ($this->isInFileExists($node, $scope)) {
+			return [];
+		}
+
 		$errors = [];
 		$paths = $this->resolveFilePaths($node, $scope);
 
@@ -140,4 +147,19 @@ private function resolveFilePaths(Include_ $node, Scope $scope): array
 		return $paths;
 	}
 
+	private function isInFileExists(Include_ $node, Scope $scope): bool
+	{
+		foreach (['file_exists', 'is_file'] as $funcName) {
+			$expr = new FuncCall(new FullyQualified($funcName), [
+				new Arg($node->expr),
+			]);
+
+			if ($scope->getType($expr)->isTrue()->yes()) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Keywords/RequireFileExistsRuleTest.php b/tests/PHPStan/Rules/Keywords/RequireFileExistsRuleTest.php
index 732819b506..6599e0defe 100644
--- a/tests/PHPStan/Rules/Keywords/RequireFileExistsRuleTest.php
+++ b/tests/PHPStan/Rules/Keywords/RequireFileExistsRuleTest.php
@@ -136,4 +136,9 @@ public function testBug12203(): void
 		]);
 	}
 
+	public function testInFileExists(): void
+	{
+		$this->analyse([__DIR__ . '/data/include-in-file-exists.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Keywords/data/include-in-file-exists.php b/tests/PHPStan/Rules/Keywords/data/include-in-file-exists.php
new file mode 100644
index 0000000000..f3b1e22633
--- /dev/null
+++ b/tests/PHPStan/Rules/Keywords/data/include-in-file-exists.php
@@ -0,0 +1,23 @@
+<?php
+
+if (file_exists(__DIR__ . '/../vendor/autoload.php')) {
+	require __DIR__ . '/../vendor/autoload.php';
+}
+
+if (is_file(__DIR__ . '/../vendor/autoload.php')) {
+	require __DIR__ . '/../vendor/autoload.php';
+}
+
+foreach ([__DIR__ . '/../../autoload.php', __DIR__ . '/../autoload.php', __DIR__ . '/vendor/autoload.php'] as $file) {
+	if (file_exists($file)) {
+		require $file;
+	}
+}
+
+if (file_exists(__DIR__ . '/vendor/autoload.php')) {
+	require __DIR__ . '/vendor/autoload.php';
+} elseif (file_exists(__DIR__ . '/../../autoload.php')) {
+	require __DIR__ . '/../../autoload.php';
+} else {
+	throw new \RuntimeException("Unable to locate vendor/autoload.php");
+}