diff --git a/generators/Tuple/FragmentGenerator/AppendPrependMethodAbstractGenerator.php b/generators/Tuple/FragmentGenerator/AppendPrependMethodAbstractGenerator.php
index cdac143..62ee7e0 100644
--- a/generators/Tuple/FragmentGenerator/AppendPrependMethodAbstractGenerator.php
+++ b/generators/Tuple/FragmentGenerator/AppendPrependMethodAbstractGenerator.php
@@ -17,19 +17,20 @@ public function append(PhpNamespace $namespace, ClassType $class, int $tupleSize
 
         $method = $class->addMethod($this->methodName());
         $method->addParameter('value');
+        $method->addComment('@template T');
+        $method->addComment(self::EMPTY_COMMENT_LINE);
+        $method->addComment('@param T $value');
+        $method->addComment(self::EMPTY_COMMENT_LINE);
 
         if ($this->isMaxSizeTuple($tupleSize, $maxTupleSize)) {
             $namespace->addUse(UnsupportedOperationException::class);
             $method->setBody($this->getMaxTupleSizeExceptionThrowBody());
+            $method->setReturnType('never');
 
             return;
         }
 
         $method->setReturnType($this->getMethodReturnType($namespace, $resultTupleSize));
-        $method->addComment('@template T');
-        $method->addComment(self::EMPTY_COMMENT_LINE);
-        $method->addComment('@param T $value');
-        $method->addComment(self::EMPTY_COMMENT_LINE);
         $method->addComment($this->getReturnTypeComment($resultTupleSize, $tupleSize));
         $method->setBody($this->getMethodBody($resultTupleSize, $tupleSize));
     }
@@ -49,7 +50,7 @@ private function getMethodReturnType(PhpNamespace $namespace, int $resultTupleSi
 
     private function getReturnTypeComment(int $resultTupleSize, int $tupleSize): string
     {
-        return sprintf('@returns Tuple%s<%s>', $resultTupleSize, $this->listOfTypes($tupleSize));
+        return sprintf('@return Tuple%s<%s>', $resultTupleSize, $this->listOfTypes($tupleSize));
     }
 
     private function getMethodBody(int $resultTupleSize, int $tupleSize): string
diff --git a/generators/Tuple/FragmentGenerator/ConcatMethodGenerator.php b/generators/Tuple/FragmentGenerator/ConcatMethodGenerator.php
index 5e3fb06..415c182 100644
--- a/generators/Tuple/FragmentGenerator/ConcatMethodGenerator.php
+++ b/generators/Tuple/FragmentGenerator/ConcatMethodGenerator.php
@@ -47,7 +47,12 @@ private function generateConcatTupleNMethod(int $n, int $tupleSize, ClassType $c
 
         $concatTupleN->addComment(sprintf('@param Tuple%s%s $tuple', $n, $paramTupleGenerics));
         $concatTupleN->addComment(self::EMPTY_COMMENT_LINE);
-        $concatTupleN->addComment(sprintf('@returns Tuple%s%s', $returnTupleSize, $returnTupleGenerics));
-        $concatTupleN->addBody('return $this->concat($tuple);');
+        $concatTupleN->addComment(sprintf('@return Tuple%s%s', $returnTupleSize, $returnTupleGenerics));
+
+        if ($this->isTupleZero($tupleSize) && $n === 0) {
+            $concatTupleN->addBody('return new Tuple0();');
+        } else {
+            $concatTupleN->addBody('return $this->concat($tuple);');
+        }
     }
 }
diff --git a/generators/Tuple/FragmentGenerator/ToArrayMethodGenerator.php b/generators/Tuple/FragmentGenerator/ToArrayMethodGenerator.php
index 2d39d21..1e7fa9e 100644
--- a/generators/Tuple/FragmentGenerator/ToArrayMethodGenerator.php
+++ b/generators/Tuple/FragmentGenerator/ToArrayMethodGenerator.php
@@ -13,6 +13,11 @@ class ToArrayMethodGenerator extends FragmentGenerator
     public function append(PhpNamespace $namespace, ClassType $class, int $tupleSize, int $maxTupleSize): void
     {
         $toArray = $class->addMethod('toArray');
+        if ($this->isTupleZero($tupleSize)) {
+            $toArray->addComment('@return array{}');
+        } else {
+            $toArray->addComment('@return array{'.join(', ', array_map(fn ($int) => 'T'.$int, range(1, $tupleSize))).'}');
+        }
         $toArray->setReturnType('array');
 
         if ($this->isTupleZero($tupleSize)) {
diff --git a/src/Collection/Stream/Collectors.php b/src/Collection/Stream/Collectors.php
index 79dcb20..5ed4425 100644
--- a/src/Collection/Stream/Collectors.php
+++ b/src/Collection/Stream/Collectors.php
@@ -8,7 +8,6 @@
 use Munus\Collection\Map;
 use Munus\Collection\Set;
 use Munus\Collection\Stream\Collector\GenericCollector;
-use Munus\Tuple;
 use Munus\Tuple\Tuple2;
 
 final class Collectors
@@ -94,17 +93,17 @@ public static function counting(): Collector
     }
 
     /**
-     * @return Collector<mixed,int|float>
+     * @return Collector<mixed,int|float|Tuple2>
      */
     public static function averaging(): Collector
     {
-        return new GenericCollector(Tuple::of(0, 0), /** @param T $value */ function (Tuple2 $acc, $value): Tuple2 {
+        return new GenericCollector(new Tuple2(0, 0), /** @param T $value */ function (Tuple2 $acc, $value): Tuple2 {
             if (!is_numeric($value)) {
                 throw new \InvalidArgumentException(sprintf('Could not convert %s to number', (string) $value));
             }
 
-            return Tuple::of($acc[0] + $value, $acc[1] + 1);
-        }, /** @return int|float */ function (Tuple2 $acc) {
+            return new Tuple2($acc[0] + $value, $acc[1] + 1);
+        }, function (Tuple2 $acc): int|float {
             if ($acc[1] === 0) {
                 return 0;
             }
diff --git a/src/Tuple.php b/src/Tuple.php
index 52e4340..c1057b8 100644
--- a/src/Tuple.php
+++ b/src/Tuple.php
@@ -16,6 +16,9 @@
 use Munus\Tuple\Tuple8;
 use Munus\Value\Comparator;
 
+/**
+ * @implements \ArrayAccess<int, mixed>
+ */
 abstract class Tuple implements \ArrayAccess
 {
     public const TUPLE_MAX_SIZE = 8;
@@ -23,7 +26,7 @@ abstract class Tuple implements \ArrayAccess
     /**
      * @param mixed ...$values
      */
-    public static function of(...$values)
+    public static function of(...$values): self
     {
         return match (count($values)) {
             0 => new Tuple0(),
@@ -41,9 +44,26 @@ public static function of(...$values)
 
     abstract public function arity(): int;
 
+    /**
+     * @return mixed[]
+     */
     abstract public function toArray(): array;
 
-    public function concat(Tuple0|Tuple1|Tuple2|Tuple3|Tuple4|Tuple5|Tuple6|Tuple7|Tuple8 $tuple): Tuple0|Tuple1|Tuple2|Tuple3|Tuple4|Tuple5|Tuple6|Tuple7|Tuple8
+    /**
+     * @template T
+     *
+     * @param T $value
+     */
+    abstract public function append($value): self;
+
+    /**
+     * @template T
+     *
+     * @param T $value
+     */
+    abstract public function prepend($value): self;
+
+    public function concat(self $tuple): self
     {
         return Tuple::of(...$this->toArray(), ...$tuple->toArray());
     }
diff --git a/src/Tuple/Tuple0.php b/src/Tuple/Tuple0.php
index 7e3aef5..d4cb897 100644
--- a/src/Tuple/Tuple0.php
+++ b/src/Tuple/Tuple0.php
@@ -22,6 +22,9 @@ public function arity(): int
         return 0;
     }
 
+    /**
+     * @return array{}
+     */
     public function toArray(): array
     {
         return [];
@@ -32,7 +35,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple1<T>
+     * @return Tuple1<T>
      */
     public function prepend($value): Tuple1
     {
@@ -44,7 +47,7 @@ public function prepend($value): Tuple1
      *
      * @param T $value
      *
-     * @returns Tuple1<T>
+     * @return Tuple1<T>
      */
     public function append($value): Tuple1
     {
@@ -54,11 +57,11 @@ public function append($value): Tuple1
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple0
+     * @return Tuple0
      */
     public function concatTuple0($tuple)
     {
-        return $this->concat($tuple);
+        return new Tuple0();
     }
 
     /**
@@ -66,7 +69,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple1<U1>
+     * @return Tuple1<U1>
      */
     public function concatTuple1($tuple)
     {
@@ -79,7 +82,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple2<U1, U2>
+     * @return Tuple2<U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -93,7 +96,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple3<U1, U2, U3>
+     * @return Tuple3<U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
@@ -108,7 +111,7 @@ public function concatTuple3($tuple)
      *
      * @param Tuple4<U1, U2, U3, U4> $tuple
      *
-     * @returns Tuple4<U1, U2, U3, U4>
+     * @return Tuple4<U1, U2, U3, U4>
      */
     public function concatTuple4($tuple)
     {
@@ -124,7 +127,7 @@ public function concatTuple4($tuple)
      *
      * @param Tuple5<U1, U2, U3, U4, U5> $tuple
      *
-     * @returns Tuple5<U1, U2, U3, U4, U5>
+     * @return Tuple5<U1, U2, U3, U4, U5>
      */
     public function concatTuple5($tuple)
     {
@@ -141,7 +144,7 @@ public function concatTuple5($tuple)
      *
      * @param Tuple6<U1, U2, U3, U4, U5, U6> $tuple
      *
-     * @returns Tuple6<U1, U2, U3, U4, U5, U6>
+     * @return Tuple6<U1, U2, U3, U4, U5, U6>
      */
     public function concatTuple6($tuple)
     {
@@ -159,7 +162,7 @@ public function concatTuple6($tuple)
      *
      * @param Tuple7<U1, U2, U3, U4, U5, U6, U7> $tuple
      *
-     * @returns Tuple7<U1, U2, U3, U4, U5, U6, U7>
+     * @return Tuple7<U1, U2, U3, U4, U5, U6, U7>
      */
     public function concatTuple7($tuple)
     {
@@ -178,7 +181,7 @@ public function concatTuple7($tuple)
      *
      * @param Tuple8<U1, U2, U3, U4, U5, U6, U7, U8> $tuple
      *
-     * @returns Tuple8<U1, U2, U3, U4, U5, U6, U7, U8>
+     * @return Tuple8<U1, U2, U3, U4, U5, U6, U7, U8>
      */
     public function concatTuple8($tuple)
     {
diff --git a/src/Tuple/Tuple1.php b/src/Tuple/Tuple1.php
index 0819fa1..42b2893 100644
--- a/src/Tuple/Tuple1.php
+++ b/src/Tuple/Tuple1.php
@@ -29,6 +29,9 @@ public function arity(): int
         return 1;
     }
 
+    /**
+     * @return array{T1}
+     */
     public function toArray(): array
     {
         return [
@@ -41,7 +44,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple2<T, T1>
+     * @return Tuple2<T, T1>
      */
     public function prepend($value): Tuple2
     {
@@ -53,7 +56,7 @@ public function prepend($value): Tuple2
      *
      * @param T $value
      *
-     * @returns Tuple2<T1, T>
+     * @return Tuple2<T1, T>
      */
     public function append($value): Tuple2
     {
@@ -63,7 +66,7 @@ public function append($value): Tuple2
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple1<T1>
+     * @return Tuple1<T1>
      */
     public function concatTuple0($tuple)
     {
@@ -75,7 +78,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple2<T1, U1>
+     * @return Tuple2<T1, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -88,7 +91,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple3<T1, U1, U2>
+     * @return Tuple3<T1, U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -102,7 +105,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple4<T1, U1, U2, U3>
+     * @return Tuple4<T1, U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
@@ -117,7 +120,7 @@ public function concatTuple3($tuple)
      *
      * @param Tuple4<U1, U2, U3, U4> $tuple
      *
-     * @returns Tuple5<T1, U1, U2, U3, U4>
+     * @return Tuple5<T1, U1, U2, U3, U4>
      */
     public function concatTuple4($tuple)
     {
@@ -133,7 +136,7 @@ public function concatTuple4($tuple)
      *
      * @param Tuple5<U1, U2, U3, U4, U5> $tuple
      *
-     * @returns Tuple6<T1, U1, U2, U3, U4, U5>
+     * @return Tuple6<T1, U1, U2, U3, U4, U5>
      */
     public function concatTuple5($tuple)
     {
@@ -150,7 +153,7 @@ public function concatTuple5($tuple)
      *
      * @param Tuple6<U1, U2, U3, U4, U5, U6> $tuple
      *
-     * @returns Tuple7<T1, U1, U2, U3, U4, U5, U6>
+     * @return Tuple7<T1, U1, U2, U3, U4, U5, U6>
      */
     public function concatTuple6($tuple)
     {
@@ -168,7 +171,7 @@ public function concatTuple6($tuple)
      *
      * @param Tuple7<U1, U2, U3, U4, U5, U6, U7> $tuple
      *
-     * @returns Tuple8<T1, U1, U2, U3, U4, U5, U6, U7>
+     * @return Tuple8<T1, U1, U2, U3, U4, U5, U6, U7>
      */
     public function concatTuple7($tuple)
     {
diff --git a/src/Tuple/Tuple2.php b/src/Tuple/Tuple2.php
index b910361..2bca178 100644
--- a/src/Tuple/Tuple2.php
+++ b/src/Tuple/Tuple2.php
@@ -32,6 +32,9 @@ public function arity(): int
         return 2;
     }
 
+    /**
+     * @return array{T1, T2}
+     */
     public function toArray(): array
     {
         return [
@@ -45,7 +48,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple3<T, T1, T2>
+     * @return Tuple3<T, T1, T2>
      */
     public function prepend($value): Tuple3
     {
@@ -57,7 +60,7 @@ public function prepend($value): Tuple3
      *
      * @param T $value
      *
-     * @returns Tuple3<T1, T2, T>
+     * @return Tuple3<T1, T2, T>
      */
     public function append($value): Tuple3
     {
@@ -67,7 +70,7 @@ public function append($value): Tuple3
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple2<T1, T2>
+     * @return Tuple2<T1, T2>
      */
     public function concatTuple0($tuple)
     {
@@ -79,7 +82,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple3<T1, T2, U1>
+     * @return Tuple3<T1, T2, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -92,7 +95,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple4<T1, T2, U1, U2>
+     * @return Tuple4<T1, T2, U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -106,7 +109,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple5<T1, T2, U1, U2, U3>
+     * @return Tuple5<T1, T2, U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
@@ -121,7 +124,7 @@ public function concatTuple3($tuple)
      *
      * @param Tuple4<U1, U2, U3, U4> $tuple
      *
-     * @returns Tuple6<T1, T2, U1, U2, U3, U4>
+     * @return Tuple6<T1, T2, U1, U2, U3, U4>
      */
     public function concatTuple4($tuple)
     {
@@ -137,7 +140,7 @@ public function concatTuple4($tuple)
      *
      * @param Tuple5<U1, U2, U3, U4, U5> $tuple
      *
-     * @returns Tuple7<T1, T2, U1, U2, U3, U4, U5>
+     * @return Tuple7<T1, T2, U1, U2, U3, U4, U5>
      */
     public function concatTuple5($tuple)
     {
@@ -154,7 +157,7 @@ public function concatTuple5($tuple)
      *
      * @param Tuple6<U1, U2, U3, U4, U5, U6> $tuple
      *
-     * @returns Tuple8<T1, T2, U1, U2, U3, U4, U5, U6>
+     * @return Tuple8<T1, T2, U1, U2, U3, U4, U5, U6>
      */
     public function concatTuple6($tuple)
     {
diff --git a/src/Tuple/Tuple3.php b/src/Tuple/Tuple3.php
index 3558f64..a66af8a 100644
--- a/src/Tuple/Tuple3.php
+++ b/src/Tuple/Tuple3.php
@@ -35,6 +35,9 @@ public function arity(): int
         return 3;
     }
 
+    /**
+     * @return array{T1, T2, T3}
+     */
     public function toArray(): array
     {
         return [
@@ -49,7 +52,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple4<T, T1, T2, T3>
+     * @return Tuple4<T, T1, T2, T3>
      */
     public function prepend($value): Tuple4
     {
@@ -61,7 +64,7 @@ public function prepend($value): Tuple4
      *
      * @param T $value
      *
-     * @returns Tuple4<T1, T2, T3, T>
+     * @return Tuple4<T1, T2, T3, T>
      */
     public function append($value): Tuple4
     {
@@ -71,7 +74,7 @@ public function append($value): Tuple4
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple3<T1, T2, T3>
+     * @return Tuple3<T1, T2, T3>
      */
     public function concatTuple0($tuple)
     {
@@ -83,7 +86,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple4<T1, T2, T3, U1>
+     * @return Tuple4<T1, T2, T3, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -96,7 +99,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple5<T1, T2, T3, U1, U2>
+     * @return Tuple5<T1, T2, T3, U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -110,7 +113,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple6<T1, T2, T3, U1, U2, U3>
+     * @return Tuple6<T1, T2, T3, U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
@@ -125,7 +128,7 @@ public function concatTuple3($tuple)
      *
      * @param Tuple4<U1, U2, U3, U4> $tuple
      *
-     * @returns Tuple7<T1, T2, T3, U1, U2, U3, U4>
+     * @return Tuple7<T1, T2, T3, U1, U2, U3, U4>
      */
     public function concatTuple4($tuple)
     {
@@ -141,7 +144,7 @@ public function concatTuple4($tuple)
      *
      * @param Tuple5<U1, U2, U3, U4, U5> $tuple
      *
-     * @returns Tuple8<T1, T2, T3, U1, U2, U3, U4, U5>
+     * @return Tuple8<T1, T2, T3, U1, U2, U3, U4, U5>
      */
     public function concatTuple5($tuple)
     {
diff --git a/src/Tuple/Tuple4.php b/src/Tuple/Tuple4.php
index 9b6370d..dcacbbc 100644
--- a/src/Tuple/Tuple4.php
+++ b/src/Tuple/Tuple4.php
@@ -38,6 +38,9 @@ public function arity(): int
         return 4;
     }
 
+    /**
+     * @return array{T1, T2, T3, T4}
+     */
     public function toArray(): array
     {
         return [
@@ -53,7 +56,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple5<T, T1, T2, T3, T4>
+     * @return Tuple5<T, T1, T2, T3, T4>
      */
     public function prepend($value): Tuple5
     {
@@ -65,7 +68,7 @@ public function prepend($value): Tuple5
      *
      * @param T $value
      *
-     * @returns Tuple5<T1, T2, T3, T4, T>
+     * @return Tuple5<T1, T2, T3, T4, T>
      */
     public function append($value): Tuple5
     {
@@ -75,7 +78,7 @@ public function append($value): Tuple5
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple4<T1, T2, T3, T4>
+     * @return Tuple4<T1, T2, T3, T4>
      */
     public function concatTuple0($tuple)
     {
@@ -87,7 +90,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple5<T1, T2, T3, T4, U1>
+     * @return Tuple5<T1, T2, T3, T4, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -100,7 +103,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple6<T1, T2, T3, T4, U1, U2>
+     * @return Tuple6<T1, T2, T3, T4, U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -114,7 +117,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple7<T1, T2, T3, T4, U1, U2, U3>
+     * @return Tuple7<T1, T2, T3, T4, U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
@@ -129,7 +132,7 @@ public function concatTuple3($tuple)
      *
      * @param Tuple4<U1, U2, U3, U4> $tuple
      *
-     * @returns Tuple8<T1, T2, T3, T4, U1, U2, U3, U4>
+     * @return Tuple8<T1, T2, T3, T4, U1, U2, U3, U4>
      */
     public function concatTuple4($tuple)
     {
diff --git a/src/Tuple/Tuple5.php b/src/Tuple/Tuple5.php
index 2c5890c..43a5605 100644
--- a/src/Tuple/Tuple5.php
+++ b/src/Tuple/Tuple5.php
@@ -41,6 +41,9 @@ public function arity(): int
         return 5;
     }
 
+    /**
+     * @return array{T1, T2, T3, T4, T5}
+     */
     public function toArray(): array
     {
         return [
@@ -57,7 +60,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple6<T, T1, T2, T3, T4, T5>
+     * @return Tuple6<T, T1, T2, T3, T4, T5>
      */
     public function prepend($value): Tuple6
     {
@@ -69,7 +72,7 @@ public function prepend($value): Tuple6
      *
      * @param T $value
      *
-     * @returns Tuple6<T1, T2, T3, T4, T5, T>
+     * @return Tuple6<T1, T2, T3, T4, T5, T>
      */
     public function append($value): Tuple6
     {
@@ -79,7 +82,7 @@ public function append($value): Tuple6
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple5<T1, T2, T3, T4, T5>
+     * @return Tuple5<T1, T2, T3, T4, T5>
      */
     public function concatTuple0($tuple)
     {
@@ -91,7 +94,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple6<T1, T2, T3, T4, T5, U1>
+     * @return Tuple6<T1, T2, T3, T4, T5, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -104,7 +107,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple7<T1, T2, T3, T4, T5, U1, U2>
+     * @return Tuple7<T1, T2, T3, T4, T5, U1, U2>
      */
     public function concatTuple2($tuple)
     {
@@ -118,7 +121,7 @@ public function concatTuple2($tuple)
      *
      * @param Tuple3<U1, U2, U3> $tuple
      *
-     * @returns Tuple8<T1, T2, T3, T4, T5, U1, U2, U3>
+     * @return Tuple8<T1, T2, T3, T4, T5, U1, U2, U3>
      */
     public function concatTuple3($tuple)
     {
diff --git a/src/Tuple/Tuple6.php b/src/Tuple/Tuple6.php
index 54734a4..951808b 100644
--- a/src/Tuple/Tuple6.php
+++ b/src/Tuple/Tuple6.php
@@ -44,6 +44,9 @@ public function arity(): int
         return 6;
     }
 
+    /**
+     * @return array{T1, T2, T3, T4, T5, T6}
+     */
     public function toArray(): array
     {
         return [
@@ -61,7 +64,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple7<T, T1, T2, T3, T4, T5, T6>
+     * @return Tuple7<T, T1, T2, T3, T4, T5, T6>
      */
     public function prepend($value): Tuple7
     {
@@ -73,7 +76,7 @@ public function prepend($value): Tuple7
      *
      * @param T $value
      *
-     * @returns Tuple7<T1, T2, T3, T4, T5, T6, T>
+     * @return Tuple7<T1, T2, T3, T4, T5, T6, T>
      */
     public function append($value): Tuple7
     {
@@ -83,7 +86,7 @@ public function append($value): Tuple7
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple6<T1, T2, T3, T4, T5, T6>
+     * @return Tuple6<T1, T2, T3, T4, T5, T6>
      */
     public function concatTuple0($tuple)
     {
@@ -95,7 +98,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple7<T1, T2, T3, T4, T5, T6, U1>
+     * @return Tuple7<T1, T2, T3, T4, T5, T6, U1>
      */
     public function concatTuple1($tuple)
     {
@@ -108,7 +111,7 @@ public function concatTuple1($tuple)
      *
      * @param Tuple2<U1, U2> $tuple
      *
-     * @returns Tuple8<T1, T2, T3, T4, T5, T6, U1, U2>
+     * @return Tuple8<T1, T2, T3, T4, T5, T6, U1, U2>
      */
     public function concatTuple2($tuple)
     {
diff --git a/src/Tuple/Tuple7.php b/src/Tuple/Tuple7.php
index 8d63279..fcb2b46 100644
--- a/src/Tuple/Tuple7.php
+++ b/src/Tuple/Tuple7.php
@@ -47,6 +47,9 @@ public function arity(): int
         return 7;
     }
 
+    /**
+     * @return array{T1, T2, T3, T4, T5, T6, T7}
+     */
     public function toArray(): array
     {
         return [
@@ -65,7 +68,7 @@ public function toArray(): array
      *
      * @param T $value
      *
-     * @returns Tuple8<T, T1, T2, T3, T4, T5, T6, T7>
+     * @return Tuple8<T, T1, T2, T3, T4, T5, T6, T7>
      */
     public function prepend($value): Tuple8
     {
@@ -77,7 +80,7 @@ public function prepend($value): Tuple8
      *
      * @param T $value
      *
-     * @returns Tuple8<T1, T2, T3, T4, T5, T6, T7, T>
+     * @return Tuple8<T1, T2, T3, T4, T5, T6, T7, T>
      */
     public function append($value): Tuple8
     {
@@ -87,7 +90,7 @@ public function append($value): Tuple8
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple7<T1, T2, T3, T4, T5, T6, T7>
+     * @return Tuple7<T1, T2, T3, T4, T5, T6, T7>
      */
     public function concatTuple0($tuple)
     {
@@ -99,7 +102,7 @@ public function concatTuple0($tuple)
      *
      * @param Tuple1<U1> $tuple
      *
-     * @returns Tuple8<T1, T2, T3, T4, T5, T6, T7, U1>
+     * @return Tuple8<T1, T2, T3, T4, T5, T6, T7, U1>
      */
     public function concatTuple1($tuple)
     {
diff --git a/src/Tuple/Tuple8.php b/src/Tuple/Tuple8.php
index 2fd845f..cee41d5 100644
--- a/src/Tuple/Tuple8.php
+++ b/src/Tuple/Tuple8.php
@@ -51,6 +51,9 @@ public function arity(): int
         return 8;
     }
 
+    /**
+     * @return array{T1, T2, T3, T4, T5, T6, T7, T8}
+     */
     public function toArray(): array
     {
         return [
@@ -65,12 +68,22 @@ public function toArray(): array
         ];
     }
 
-    public function prepend($value)
+    /**
+     * @template T
+     *
+     * @param T $value
+     */
+    public function prepend($value): never
     {
         throw new UnsupportedOperationException('Can\'t prepend next value. This is biggest possible Tuple');
     }
 
-    public function append($value)
+    /**
+     * @template T
+     *
+     * @param T $value
+     */
+    public function append($value): never
     {
         throw new UnsupportedOperationException('Can\'t append next value. This is biggest possible Tuple');
     }
@@ -78,7 +91,7 @@ public function append($value)
     /**
      * @param Tuple0 $tuple
      *
-     * @returns Tuple8<T1, T2, T3, T4, T5, T6, T7, T8>
+     * @return Tuple8<T1, T2, T3, T4, T5, T6, T7, T8>
      */
     public function concatTuple0($tuple)
     {
diff --git a/tests/TupleTest.php b/tests/TupleTest.php
index f399201..41bed64 100644
--- a/tests/TupleTest.php
+++ b/tests/TupleTest.php
@@ -181,7 +181,7 @@ public function testPrependToTuple8(): void
 
     public function testTupleApply(): void
     {
-        self::assertEquals(6, Tuple::of(1, 2, 3)->apply(function (int $a, int $b, int $c): int {return $a + $b + $c; }));
+        self::assertEquals(6, Tuple::of(1, 2, 3)->apply(function (int $a, int $b, int $c): int {return $a + $b + $c; })); // @phpstan-ignore-line
         self::assertEquals('Munus', Tuple::of('M', 'u', 'n', 'u', 's')->apply(function () {return join('', func_get_args()); }));
     }