diff --git a/Makefile b/Makefile
index f5476d6067..0d4adf8b5f 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,7 @@ lint:
 		--exclude tests/PHPStan/Rules/Names/data \
 		--exclude tests/PHPStan/Rules/Operators/data/invalid-inc-dec.php \
 		--exclude tests/PHPStan/Rules/Arrays/data/offset-access-without-dim-for-reading.php \
+		--exclude tests/PHPStan/Rules/Classes/data/bug-13768.php \
 		--exclude tests/PHPStan/Rules/Classes/data/duplicate-declarations.php \
 		--exclude tests/PHPStan/Rules/Classes/data/duplicate-enum-cases.php \
 		--exclude tests/PHPStan/Rules/Classes/data/enum-sanity.php \
diff --git a/src/Rules/Classes/EnumSanityRule.php b/src/Rules/Classes/EnumSanityRule.php
index fc5d56ba8a..fc454bc696 100644
--- a/src/Rules/Classes/EnumSanityRule.php
+++ b/src/Rules/Classes/EnumSanityRule.php
@@ -6,8 +6,11 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\RegisteredRule;
 use PHPStan\Node\InClassNode;
+use PHPStan\Reflection\InitializerExprContext;
+use PHPStan\Reflection\InitializerExprTypeResolver;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\VerbosityLevel;
@@ -16,6 +19,8 @@
 use function count;
 use function implode;
 use function in_array;
+use function is_int;
+use function is_string;
 use function sprintf;
 
 /**
@@ -31,6 +36,12 @@ final class EnumSanityRule implements Rule
 		'__invoke' => true,
 	];
 
+	public function __construct(
+		private InitializerExprTypeResolver $initializerExprTypeResolver,
+	)
+	{
+	}
+
 	public function getNodeType(): string
 	{
 		return InClassNode::class;
@@ -145,27 +156,20 @@ public function processNode(Node $node, Scope $scope): array
 			}
 			$caseName = $stmt->name->name;
 
-			if ($stmt->expr instanceof Node\Scalar\Int_ || $stmt->expr instanceof Node\Scalar\String_) {
-				if ($enumNode->scalarType === null) {
-					$errors[] = RuleErrorBuilder::message(sprintf(
-						'Enum %s is not backed, but case %s has value %s.',
-						$classReflection->getDisplayName(),
-						$caseName,
-						$stmt->expr->value,
-					))
-						->identifier('enum.caseWithValue')
-						->line($stmt->getStartLine())
-						->nonIgnorable()
-						->build();
-				} else {
-					$caseValue = $stmt->expr->value;
-
-					if (!isset($enumCases[$caseValue])) {
-						$enumCases[$caseValue] = [];
-					}
-
-					$enumCases[$caseValue][] = $caseName;
-				}
+			if ($enumNode->scalarType === null && $stmt->expr !== null) {
+				$errors[] = RuleErrorBuilder::message(sprintf(
+					'Enum %s is not backed, but case %s has value %s.',
+					$classReflection->getDisplayName(),
+					$caseName,
+					$this->initializerExprTypeResolver->getType(
+						$stmt->expr,
+						InitializerExprContext::fromScope($scope),
+					)->describe(VerbosityLevel::value()),
+				))
+					->identifier('enum.caseWithValue')
+					->line($stmt->getStartLine())
+					->nonIgnorable()
+					->build();
 			}
 
 			if ($enumNode->scalarType === null) {
@@ -189,6 +193,20 @@ public function processNode(Node $node, Scope $scope): array
 			$exprType = $scope->getType($stmt->expr);
 			$scalarType = $enumNode->scalarType->toLowerString() === 'int' ? new IntegerType() : new StringType();
 			if ($scalarType->isSuperTypeOf($exprType)->yes()) {
+				$constantValues = $exprType->getConstantScalarValues();
+				if (count($constantValues) === 1) {
+					$caseValue = $constantValues[0];
+					if (!is_string($caseValue) && !is_int($caseValue)) {
+						throw new ShouldNotHappenException();
+					}
+
+					if (!isset($enumCases[$caseValue])) {
+						$enumCases[$caseValue] = [];
+					}
+
+					$enumCases[$caseValue][] = $caseName;
+				}
+
 				continue;
 			}
 
diff --git a/tests/PHPStan/Rules/Classes/EnumSanityRuleTest.php b/tests/PHPStan/Rules/Classes/EnumSanityRuleTest.php
index 22bb10a00e..4ab2c6b842 100644
--- a/tests/PHPStan/Rules/Classes/EnumSanityRuleTest.php
+++ b/tests/PHPStan/Rules/Classes/EnumSanityRuleTest.php
@@ -2,6 +2,7 @@
 
 namespace PHPStan\Rules\Classes;
 
+use PHPStan\Reflection\InitializerExprTypeResolver;
 use PHPStan\Rules\Rule;
 use PHPStan\Testing\RuleTestCase;
 use PHPUnit\Framework\Attributes\RequiresPhp;
@@ -14,7 +15,9 @@ class EnumSanityRuleTest extends RuleTestCase
 
 	protected function getRule(): Rule
 	{
-		return new EnumSanityRule();
+		return new EnumSanityRule(
+			self::getContainer()->getByType(InitializerExprTypeResolver::class),
+		);
 	}
 
 	#[RequiresPhp('>= 8.1')]
@@ -141,4 +144,39 @@ public function testBug11592(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.1')]
+	public function testBug13768(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-13768.php'], [
+			[
+				'Enum Bug13768\Order is not backed, but case A has value 1.5.',
+				7,
+			],
+			[
+				'Enum Bug13768\Order is not backed, but case B has value 2.5.',
+				8,
+			],
+			[
+				'Enum Bug13768\Order is not backed, but case C has value 3.',
+				9,
+			],
+			[
+				'Enum Bug13768\Order is not backed, but case D has value \'3\'.',
+				10,
+			],
+			[
+				'Enum Bug13768\Order is not backed, but case E has value false.',
+				11,
+			],
+			[
+				'Enum Bug13768\Order is not backed, but case F has value 1.',
+				12,
+			],
+			[
+				'Enum Bug13768\Backed has duplicate value 1 for cases One, Two.',
+				20,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Classes/data/bug-13768.php b/tests/PHPStan/Rules/Classes/data/bug-13768.php
new file mode 100644
index 0000000000..6a7ffda48b
--- /dev/null
+++ b/tests/PHPStan/Rules/Classes/data/bug-13768.php
@@ -0,0 +1,23 @@
+<?php // lint >= 8.1
+
+namespace Bug13768;
+
+enum Order {
+	case U;
+	case A = 1.5;
+	case B = 2.5;
+	case C = 3;
+	case D = '3';
+	case E = false;
+	case F = Foo::A;
+}
+
+class Foo
+{
+	public const A = 1;
+}
+
+enum Backed: int {
+	case One = Foo::A;
+	case Two = Foo::A;
+}