upgrade codebase to better php 8.1 compatibility (#101)

phpstan.neon

@@ -1,7 +1,7 @@
 includes:
  - vendor/phpstan/phpstan/conf/bleedingEdge.neon
 parameters:
- phpVersion: 80000
+ phpVersion: 80100
  level: 4
  paths:
  - src

src/Collection/Iterator.php

@@ -17,17 +17,14 @@ class Iterator implements \Iterator
  /**
  * @var Traversable<T>
  */
- private $traversable;
+ private Traversable $traversable;
 
  /**
  * @var Traversable<T>
  */
- private $current;
+ private Traversable $current;
 
- /**
- * @var int
- */
- private $index;
+ private int $index;
 
  /**
  * @param Traversable<T> $traversable
@@ -82,6 +79,7 @@ public function hasNext(): bool
  *
  * @return T
  */
+ #[\ReturnTypeWillChange]
  public function next()
  {
  $result = $this->current->head();
@@ -107,32 +105,31 @@ public function toArray(): array
  /**
  * @return T
  */
- public function current()
+ public function current(): mixed
  {
  return $this->current->head();
  }
 
- /**
- * @return int
- */
- public function key()
+ public function key(): mixed
  {
  return $this->index;
  }
 
- public function valid()
+ public function valid(): bool
  {
  return $this->hasNext();
  }
 
- public function rewind()
+ public function rewind(): void
  {
  $this->current = $this->traversable;
  }
 
  /**
  * @param callable(T,T):T $operation
  *
+ * @throws NoSuchElementException
+ *
  * @return T
  */
  public function reduce(callable $operation)
@@ -165,6 +162,9 @@ public function fold($zero, callable $combine)
  return $zero;
  }
 
+ /**
+ * @return self<T>
+ */
  public function sort(): self
  {
  $array = $this->toArray();

src/Collection/Iterator/ArrayIterator.php

@@ -17,12 +17,9 @@ final class ArrayIterator extends Iterator
  /**
  * @var T[]
  */
- private $elements;
+ private array $elements;
 
- /**
- * @var int
- */
- private $index;
+ private int $index;
 
  /**
  * @param T[] $elements
@@ -39,6 +36,8 @@ public function hasNext(): bool
  }
 
  /**
+ * @throws NoSuchElementException
+ *
  * @return T
  */
  public function next()
@@ -50,12 +49,20 @@ public function next()
  throw new NoSuchElementException();
  }
 
- public function current()
+ /**
+ * @throws NoSuchElementException
+ */
+ public function current(): mixed
  {
  if (isset($this->elements[$this->index])) {
  return $this->elements[$this->index];
  }
 
  throw new NoSuchElementException();
  }
+
+ public function rewind(): void
+ {
+ $this->index = 0;
+ }
 }

src/Collection/Iterator/CompositeIterator.php

@@ -17,12 +17,12 @@ final class CompositeIterator extends Iterator
  /**
  * @var ArrayIterator<Iterator<T>>
  */
- private $iterators;
+ private ArrayIterator $iterators;
 
  /**
  * @var Iterator<T>
  */
- private $current;
+ private mixed $current;
 
  /**
  * @param array<int, Iterator<T>> $iterators
@@ -61,6 +61,8 @@ public function hasNext(): bool
  }
 
  /**
+ * @throws NoSuchElementException
+ *
  * @return T
  */
  public function next()
@@ -72,13 +74,13 @@ public function next()
  return $this->current->next();
  }
 
- public function rewind()
+ public function rewind(): void
  {
  $this->iterators->rewind();
  $this->current = $this->iterators->current();
  }
 
- public function current()
+ public function current(): mixed
  {
  return $this->current->current();
  }

src/Collection/Iterator/MapIterator.php

@@ -11,38 +11,32 @@
 final class MapIterator extends Iterator
 {
  /**
- * @var array
+ * @var mixed[]
  */
- private $map;
+ private array $map;
 
  public function __construct(array $map)
  {
  $this->map = $map;
  reset($this->map);
  }
 
- /**
- * @return int|string|null
- */
- public function key()
+ public function key(): mixed
  {
  return key($this->map);
  }
 
- public function current()
+ public function current(): mixed
  {
  return current($this->map);
  }
 
- public function rewind()
+ public function rewind(): void
  {
  reset($this->map);
  }
 
- /**
- * @return Tuple
- */
- public function next()
+ public function next(): Tuple
  {
  if (!$this->valid()) {
  throw new NoSuchElementException();
@@ -53,7 +47,7 @@ public function next()
  return $next;
  }
 
- public function valid()
+ public function valid(): bool
  {
  return key($this->map) !== null;
  }

src/Collection/Iterator/SingletonIterator.php

@@ -17,10 +17,7 @@ final class SingletonIterator extends Iterator
  */
  private $element;
 
- /**
- * @var bool
- */
- private $hasNext;
+ private bool $hasNext;
 
  /**
  * @param T $element
@@ -37,6 +34,8 @@ public function hasNext(): bool
  }
 
  /**
+ * @throws NoSuchElementException
+ *
  * @return T
  */
  public function next()
@@ -49,12 +48,20 @@ public function next()
  return $this->element;
  }
 
- public function current()
+ /**
+ * @throws NoSuchElementException
+ */
+ public function current(): mixed
  {
  if ($this->hasNext === true) {
  return $this->element;
  }
 
  throw new NoSuchElementException();
  }
+
+ public function rewind(): void
+ {
+ $this->hasNext = true;
+ }
 }

src/Collection/Iterator/StreamIterator.php

@@ -19,7 +19,7 @@ final class StreamIterator extends Iterator
  /**
  * @var Lazy<Stream<T>>
  */
- private $current;
+ private Lazy $current;
 
  /**
  * @param Stream<T> $current
@@ -32,7 +32,7 @@ public function __construct(Stream $current)
  /**
  * @return T
  */
- public function current()
+ public function current(): mixed
  {
  return $this->current->get()->head();
  }

src/Collection/Traversable.php

@@ -286,19 +286,13 @@ public function fold($zero, callable $combine)
  return $this->iterator()->fold($zero, $combine);
  }
 
- /**
- * @return int|float
- */
- public function sum()
+ public function sum(): float|int
  {
  return $this->fold(0,
  /**
- * @param int|float $sum
- * @param T $x
- *
- * @return int|float
+ * @param T $x
  */
- function ($sum, $x) {
+ function (float|int $sum, $x): float|int {
  if (!is_numeric($x)) {
  throw new UnsupportedOperationException('not numeric value');
  }
@@ -308,19 +302,13 @@ function ($sum, $x) {
  );
  }
 
- /**
- * @return int|float
- */
- public function product()
+ public function product(): float|int
  {
  return $this->fold(1,
  /**
- * @param int|float $product
- * @param T $x
- *
- * @return int|float
+ * @param T $x
  */
- function ($product, $x) {
+ function (float|int $product, $x): float|int {
  if (!is_numeric($x)) {
  throw new UnsupportedOperationException('not numeric value');
  }
@@ -330,6 +318,9 @@ function ($product, $x) {
  );
  }
 
+ /**
+ * @throws UnsupportedOperationException
+ */
  public function average(): float
  {
  if ($this->isEmpty()) {
@@ -394,7 +385,7 @@ public function count(callable $predicate): int
  /**
  * @return Iterator<T>
  */
- public function getIterator()
+ public function getIterator(): \Traversable
  {
  return $this->iterator();
  }