diff --git a/conf/bleedingEdge.neon b/conf/bleedingEdge.neon
index f3f31c8c80..d43538fa05 100644
--- a/conf/bleedingEdge.neon
+++ b/conf/bleedingEdge.neon
@@ -3,3 +3,4 @@ parameters:
 		closureUsesThis: true
 		randomIntParameters: true
 		nullCoalesce: true
+		fileWhitespace: true
diff --git a/conf/config.level0.neon b/conf/config.level0.neon
index e7396651e3..97250fcde9 100644
--- a/conf/config.level0.neon
+++ b/conf/config.level0.neon
@@ -7,6 +7,8 @@ conditionalTags:
 		phpstan.rules.rule: %featureToggles.closureUsesThis%
 	PHPStan\Rules\Missing\MissingClosureNativeReturnTypehintRule:
 		phpstan.rules.rule: %checkMissingClosureNativeReturnTypehintRule%
+	PHPStan\Rules\Whitespace\FileWhitespaceRule:
+		phpstan.rules.rule: %featureToggles.fileWhitespace%
 
 parametersSchema:
 	missingClosureNativeReturnCheckObjectTypehint: bool()
@@ -178,3 +180,6 @@ services:
 		class: PHPStan\Rules\Regexp\RegularExpressionPatternRule
 		tags:
 			- phpstan.rules.rule
+
+	-
+		class: PHPStan\Rules\Whitespace\FileWhitespaceRule
diff --git a/conf/config.neon b/conf/config.neon
index fdb6fc70a7..9ad402094f 100644
--- a/conf/config.neon
+++ b/conf/config.neon
@@ -11,6 +11,7 @@ parameters:
 		closureUsesThis: false
 		randomIntParameters: false
 		nullCoalesce: false
+		fileWhitespace: false
 	fileExtensions:
 		- php
 	checkAlwaysTrueCheckTypeFunctionCall: false
@@ -145,7 +146,8 @@ parametersSchema:
 		disableRuntimeReflectionProvider: bool(),
 		closureUsesThis: bool(),
 		randomIntParameters: bool(),
-		nullCoalesce: bool()
+		nullCoalesce: bool(),
+		fileWhitespace: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAlwaysTrueCheckTypeFunctionCall: bool()
diff --git a/src/Rules/Whitespace/FileWhitespaceRule.php b/src/Rules/Whitespace/FileWhitespaceRule.php
new file mode 100644
index 0000000000..49f1ea4128
--- /dev/null
+++ b/src/Rules/Whitespace/FileWhitespaceRule.php
@@ -0,0 +1,91 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Whitespace;
+
+use Nette\Utils\Strings;
+use PhpParser\Node;
+use PhpParser\NodeTraverser;
+use PHPStan\Analyser\Scope;
+use PHPStan\Node\FileNode;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+
+/**
+ * @implements Rule<FileNode>
+ */
+class FileWhitespaceRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return FileNode::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$nodes = $node->getNodes();
+		if (count($nodes) === 0) {
+			return [];
+		}
+
+		$firstNode = $nodes[0];
+		$messages = [];
+		if ($firstNode instanceof Node\Stmt\InlineHTML && $firstNode->value === "\xef\xbb\xbf") {
+			$messages[] = RuleErrorBuilder::message('File begins with UTF-8 BOM character. This may cause problems when running the code in the web browser.')->build();
+		}
+
+		$nodeTraverser = new NodeTraverser();
+		$visitor = new class () extends \PhpParser\NodeVisitorAbstract {
+
+			/** @var \PhpParser\Node[] */
+			private $lastNodes = [];
+
+			/**
+			 * @param Node $node
+			 * @return int|Node|null
+			 */
+			public function enterNode(Node $node)
+			{
+				if ($node instanceof Node\Stmt\Declare_) {
+					if ($node->stmts !== null && count($node->stmts) > 0) {
+						$this->lastNodes[] = $node->stmts[count($node->stmts) - 1];
+					}
+					return null;
+				}
+				if ($node instanceof Node\Stmt\Namespace_) {
+					if (count($node->stmts) > 0) {
+						$this->lastNodes[] = $node->stmts[count($node->stmts) - 1];
+					}
+					return null;
+				}
+				return NodeTraverser::DONT_TRAVERSE_CURRENT_AND_CHILDREN;
+			}
+
+			/**
+			 * @return Node[]
+			 */
+			public function getLastNodes(): array
+			{
+				return $this->lastNodes;
+			}
+
+		};
+		$nodeTraverser->addVisitor($visitor);
+		$nodeTraverser->traverse($nodes);
+
+		$lastNodes = $visitor->getLastNodes();
+		if (count($nodes) > 0) {
+			$lastNodes[] = $nodes[count($nodes) - 1];
+		}
+		foreach ($lastNodes as $lastNode) {
+			if (!$lastNode instanceof Node\Stmt\InlineHTML || Strings::match($lastNode->value, '#(\s+)#') === null) {
+				continue;
+			}
+
+			$messages[] = RuleErrorBuilder::message('File ends with a trailing whitespace. This may cause problems when running the code in the web browser. Remove the closing ?> mark or remove the whitespace.')->line($lastNode->getStartLine())->build();
+		}
+
+		return $messages;
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Whitespace/FileWhitespaceRuleTest.php b/tests/PHPStan/Rules/Whitespace/FileWhitespaceRuleTest.php
new file mode 100644
index 0000000000..7004e69611
--- /dev/null
+++ b/tests/PHPStan/Rules/Whitespace/FileWhitespaceRuleTest.php
@@ -0,0 +1,54 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Whitespace;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<FileWhitespaceRule>
+ */
+class FileWhitespaceRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new FileWhitespaceRule();
+	}
+
+	public function testBom(): void
+	{
+		$this->analyse([__DIR__ . '/data/bom.php'], [
+			[
+				'File begins with UTF-8 BOM character. This may cause problems when running the code in the web browser.',
+				1,
+			],
+		]);
+	}
+
+	public function testCorrectFile(): void
+	{
+		$this->analyse([__DIR__ . '/data/correct.php'], []);
+	}
+
+	public function testTrailingWhitespaceWithoutNamespace(): void
+	{
+		$this->analyse([__DIR__ . '/data/trailing.php'], [
+			[
+				'File ends with a trailing whitespace. This may cause problems when running the code in the web browser. Remove the closing ?> mark or remove the whitespace.',
+				6,
+			],
+		]);
+	}
+
+	public function testTrailingWhitespace(): void
+	{
+		$this->analyse([__DIR__ . '/data/trailing-namespace.php'], [
+			[
+				'File ends with a trailing whitespace. This may cause problems when running the code in the web browser. Remove the closing ?> mark or remove the whitespace.',
+				8,
+			],
+		]);
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Whitespace/data/bom.php b/tests/PHPStan/Rules/Whitespace/data/bom.php
new file mode 100644
index 0000000000..d17f0c1edf
--- /dev/null
+++ b/tests/PHPStan/Rules/Whitespace/data/bom.php
@@ -0,0 +1,3 @@
+<?php
+
+echo 'test';
diff --git a/tests/PHPStan/Rules/Whitespace/data/correct.php b/tests/PHPStan/Rules/Whitespace/data/correct.php
new file mode 100644
index 0000000000..614b720750
--- /dev/null
+++ b/tests/PHPStan/Rules/Whitespace/data/correct.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace Test;
+
+echo 'foo';
diff --git a/tests/PHPStan/Rules/Whitespace/data/trailing-namespace.php b/tests/PHPStan/Rules/Whitespace/data/trailing-namespace.php
new file mode 100644
index 0000000000..6aa51ab137
--- /dev/null
+++ b/tests/PHPStan/Rules/Whitespace/data/trailing-namespace.php
@@ -0,0 +1,8 @@
+<?php declare(strict_types = 1);
+
+namespace Test;
+
+echo 'foo';
+
+?>
+
diff --git a/tests/PHPStan/Rules/Whitespace/data/trailing.php b/tests/PHPStan/Rules/Whitespace/data/trailing.php
new file mode 100644
index 0000000000..37f79ec490
--- /dev/null
+++ b/tests/PHPStan/Rules/Whitespace/data/trailing.php
@@ -0,0 +1,6 @@
+<?php
+
+echo 'foo';
+
+?>
+