diff --git a/src/Functional/Ary.php b/src/Functional/Ary.php
index 404ad130..bef8f83d 100644
--- a/src/Functional/Ary.php
+++ b/src/Functional/Ary.php
@@ -11,11 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Call $func with only abs($count) arguments, taken either from the
  * left or right depending on the sign
+ *
+ * @template V
+ * @template T
+ *
+ * @param callable(T...):V $func
+ * @param non-zero-int $count
+ *
+ * @return callable(T...):V
+ *
  * @no-named-arguments
  */
 function ary(callable $func, int $count): callable
diff --git a/src/Functional/Average.php b/src/Functional/Average.php
index e9915707..0eb68454 100644
--- a/src/Functional/Average.php
+++ b/src/Functional/Average.php
@@ -11,13 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns the average of all numeric values in the array or null if no numeric value was found
  *
- * @param Traversable|array $collection
- * @return null|float|int
+ * @param iterable<mixed> $collection
+ *
+ * @return ($collection is iterable<int> ? float|int : (
+ *     $collection is iterable<float> ? float : (
+ *         $collection is iterable<int|float|numeric-string> ? float|int : null
+ *     )
+ * ))
+ *
  * @no-named-arguments
  */
 function average($collection)
diff --git a/src/Functional/ButLast.php b/src/Functional/ButLast.php
index 4f6d314c..c93484e5 100644
--- a/src/Functional/ButLast.php
+++ b/src/Functional/ButLast.php
@@ -11,13 +11,16 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns an array containing the elements of the list without its last element.
  *
- * @param Traversable|array $collection
- * @return array
+ * @template T
+ *
+ * @param iterable<T> $collection
+ *
+ * @return iterable<T>
+ *
  * @no-named-arguments
  */
 function but_last($collection)
diff --git a/src/Functional/Capture.php b/src/Functional/Capture.php
index a3d9fc9f..217c53af 100644
--- a/src/Functional/Capture.php
+++ b/src/Functional/Capture.php
@@ -11,11 +11,15 @@
 namespace Functional;
 
 /**
- * Return a new function that captures the return value of $callback in $result and returns the callbacks return value
+ * Return a new function that captures the return value of $callback in $result and returns the callback's return value
+ *
+ * @template T
+ *
+ * @param callable():T $callback
+ * @param T $result
+ *
+ * @return callable():T
  *
- * @param callable $callback
- * @param mixed $result
- * @return callable
  * @no-named-arguments
  */
 function capture(callable $callback, &$result)
diff --git a/src/Functional/CompareObjectHashOn.php b/src/Functional/CompareObjectHashOn.php
index c4194479..cf8cf62a 100644
--- a/src/Functional/CompareObjectHashOn.php
+++ b/src/Functional/CompareObjectHashOn.php
@@ -13,9 +13,14 @@
 /**
  * Returns a comparison function that can be used with e.g. `usort()`
  *
- * @param callable $comparison A function that compares the two values. Pick e.g. strcmp() or strnatcasecmp()
- * @param callable $keyFunction A function that takes an argument and returns the value that should be compared
- * @return callable
+ * @template V
+ * @template R of int
+ *
+ * @param callable(string,string):R $comparison A function that compares the two values. Pick e.g. strcmp() or strnatcasecmp()
+ * @param null|callable(V):string $keyFunction A function that takes an argument and returns the value that should be compared
+ *
+ * @return callable(object,object):R
+ *
  * @no-named-arguments
  */
 function compare_object_hash_on(callable $comparison, callable $keyFunction = null)
diff --git a/src/Functional/CompareOn.php b/src/Functional/CompareOn.php
index b0e5cda0..f16a4295 100644
--- a/src/Functional/CompareOn.php
+++ b/src/Functional/CompareOn.php
@@ -13,9 +13,15 @@
 /**
  * Returns a comparison function that can be used with e.g. `usort()`
  *
- * @param callable $comparison A function that compares the two values. Pick e.g. strcmp() or strnatcasecmp()
- * @param callable $reducer A function that takes an argument and returns the value that should be compared
- * @return callable
+ * @template V
+ * @template V2
+ * @template R of int
+ *
+ * @param callable(V,V):R $comparison A function that compares the two values. Pick e.g. strcmp() or strnatcasecmp()
+ * @param null|callable(V2):V $reducer A function that takes an argument and returns the value that should be compared
+ *
+ * @return ($reducer is null ? callable(V,V):R : callable(V2,V2):R)
+ *
  * @no-named-arguments
  */
 function compare_on(callable $comparison, callable $reducer = null)
diff --git a/src/Functional/Concat.php b/src/Functional/Concat.php
index 09426c6e..a54492a4 100644
--- a/src/Functional/Concat.php
+++ b/src/Functional/Concat.php
@@ -13,11 +13,13 @@
 /**
  * Concatenates zero or more strings
  *
- * @param string[] ...$strings
+ * @param string ...$strings
+ *
  * @return string
+ *
  * @no-named-arguments
  */
-function concat(string ...$strings)
+function concat(...$strings)
 {
     return \implode('', $strings);
 }
diff --git a/src/Functional/ConstFunction.php b/src/Functional/ConstFunction.php
index 220cf009..1d1a20d6 100644
--- a/src/Functional/ConstFunction.php
+++ b/src/Functional/ConstFunction.php
@@ -13,8 +13,12 @@
 /**
  * Wrap value within a function, which will return it, without any modifications.
  *
- * @param mixed $value
- * @return callable
+ * @template V
+ *
+ * @param V $value
+ *
+ * @return callable():V
+ *
  * @no-named-arguments
  */
 function const_function($value)
diff --git a/src/Functional/Contains.php b/src/Functional/Contains.php
index b0fd5326..248e59f3 100644
--- a/src/Functional/Contains.php
+++ b/src/Functional/Contains.php
@@ -11,16 +11,20 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns true if the collection contains the given value. If the third parameter is
  * true values will be compared in strict mode
  *
- * @param Traversable|array $collection
- * @param mixed $value
+ * @template V
+ * @template V2 of V
+ *
+ * @param iterable<V> $collection
+ * @param V2 $value
  * @param bool $strict
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function contains($collection, $value, $strict = true)
diff --git a/src/Functional/Converge.php b/src/Functional/Converge.php
index 4bbfc03c..271b659c 100644
--- a/src/Functional/Converge.php
+++ b/src/Functional/Converge.php
@@ -16,9 +16,15 @@
  * The results of each branching function are passed as arguments
  * to the converging function to produce the return value.
  *
- * @param callable $convergingFunction Will be invoked with the return values of all branching functions as its arguments
- * @param callable[] $branchingFunctions A list of functions
- * @return callable A flipped version of the given function
+ * @template V
+ * @template R
+ * @template R2
+ *
+ * @param callable(R...):R2 $convergingFunction Will be invoked with the return values of all branching functions as its arguments
+ * @param array<callable(V):R> $branchingFunctions A list of functions
+ *
+ * @return callable(V...):R2 A flipped version of the given function
+ *
  * @no-named-arguments
  */
 function converge($convergingFunction, array $branchingFunctions)
diff --git a/src/Functional/Curry.php b/src/Functional/Curry.php
index 52099360..7bd65c42 100644
--- a/src/Functional/Curry.php
+++ b/src/Functional/Curry.php
@@ -15,12 +15,17 @@
 use Closure;
 
 /**
- * Return a curryied version of the given function. You can decide if you also
+ * Return a curried version of the given function. You can decide if you also
  * want to curry optional parameters or not.
  *
- * @param callable $function the function to curry
- * @param bool $required curry optional parameters ?
- * @return callable a curryied version of the given function
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $function the function to curry
+ * @param bool $required curry optional parameters?
+ *
+ * @return callable(V...):R a curried version of the given function
+ *
  * @no-named-arguments
  */
 function curry(callable $function, $required = true)
diff --git a/src/Functional/CurryN.php b/src/Functional/CurryN.php
index 780e34c9..fb851869 100644
--- a/src/Functional/CurryN.php
+++ b/src/Functional/CurryN.php
@@ -11,15 +11,20 @@
 namespace Functional;
 
 /**
- * Return a version of the given function where the $count first arguments are curryied.
+ * Return a version of the given function where the $count first arguments are curried.
  *
  * No check is made to verify that the given argument count is either too low or too high.
  * If you give a smaller number you will have an error when calling the given function. If
  * you give a higher number, arguments will simply be ignored.
  *
+ * @template R
+ * @template V
+ *
  * @param int $count number of arguments you want to curry
- * @param callable $function the function you want to curry
- * @return callable a curryied version of the given function
+ * @param callable(V...):R $function the function you want to curry
+ *
+ * @return callable(V...):R a curried version of the given function
+ *
  * @no-named-arguments
  */
 function curry_n($count, callable $function)
diff --git a/src/Functional/Difference.php b/src/Functional/Difference.php
index 8984eb12..d8984738 100644
--- a/src/Functional/Difference.php
+++ b/src/Functional/Difference.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Takes a collection and returns the difference of all elements
  *
- * @param Traversable|array $collection
- * @param integer|float $initial
- * @return integer|float
+ * @template V
+ * @template I of int|float
+ *
+ * @param iterable<V> $collection
+ * @param I $initial
+ *
+ * @return (V is int ? ($initial is int ? int : float) : (V is float ? float : int|float))
+ *
  * @no-named-arguments
  */
 function difference($collection, $initial = 0)
diff --git a/src/Functional/DropFirst.php b/src/Functional/DropFirst.php
index 71249c02..af8f9fb1 100644
--- a/src/Functional/DropFirst.php
+++ b/src/Functional/DropFirst.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Drop all elements from a collection until callback returns false
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K, V> $collection
+ * @param callable(V, K, iterable<K, V>):bool $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function drop_first($collection, callable $callback)
diff --git a/src/Functional/DropLast.php b/src/Functional/DropLast.php
index 666c4e76..82cb286c 100644
--- a/src/Functional/DropLast.php
+++ b/src/Functional/DropLast.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Drop all elements from a collection after callback returns true
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K, V> $collection
+ * @param callable(V, K, iterable<K, V>):bool $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function drop_last($collection, callable $callback)
diff --git a/src/Functional/Each.php b/src/Functional/Each.php
index 3720a725..4686574e 100644
--- a/src/Functional/Each.php
+++ b/src/Functional/Each.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Iterates over a collection of elements, yielding each in turn to a callback function. Each invocation of $callback
  * is called with three arguments: (element, index, collection)
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return null
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):void $callback
+ *
+ * @return void
+ *
  * @no-named-arguments
  */
 function each($collection, callable $callback)
diff --git a/src/Functional/Entries.php b/src/Functional/Entries.php
index 1fc22531..fc47234d 100644
--- a/src/Functional/Entries.php
+++ b/src/Functional/Entries.php
@@ -11,16 +11,21 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Inspired by JavaScript’s `Object.entries`, and Python’s `enumerate`,
  * convert a key-value map into an array of key-value pairs
  *
- * @see Functional\from_entries
- * @param Traversable|array $collection
+ * @see \Functional\from_entries
+ *
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
  * @param int $start
- * @return array
+ *
+ * @return array<int, array{K,V}>
+ *
  * @no-named-arguments
  */
 function entries($collection, int $start = 0)
diff --git a/src/Functional/Equal.php b/src/Functional/Equal.php
index 4a7c2b11..03d56b46 100644
--- a/src/Functional/Equal.php
+++ b/src/Functional/Equal.php
@@ -15,7 +15,8 @@
  *
  * @param mixed $b the value to compare to
  *
- * @return callable the function to perform the comparison
+ * @return callable(mixed):bool the function to perform the comparison
+ *
  * @no-named-arguments
  */
 function equal($b)
diff --git a/src/Functional/ErrorToException.php b/src/Functional/ErrorToException.php
index 5051bc45..60f14035 100644
--- a/src/Functional/ErrorToException.php
+++ b/src/Functional/ErrorToException.php
@@ -15,10 +15,16 @@
 /**
  * Takes a function and returns a new function that wraps the callback and rethrows PHP errors as exception
  *
- * @param callable $callback
- * @throws ErrorException Throws exception if PHP error happened
- * @return mixed
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback
+ *
+ * @return callable(V...):R
+ *
  * @no-named-arguments
+ *@throws ErrorException Throws exception if PHP error happened
+ *
  */
 function error_to_exception(callable $callback)
 {
diff --git a/src/Functional/Every.php b/src/Functional/Every.php
index e4d8ff62..af5d44aa 100644
--- a/src/Functional/Every.php
+++ b/src/Functional/Every.php
@@ -11,27 +11,27 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns true if every value in the collection passes the callback truthy test. Opposite of Functional\none().
  * Callback arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable|null $callback
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param null|callable(V,K,iterable<K,V>):bool $callback
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function every($collection, callable $callback = null)
 {
     InvalidArgumentException::assertCollection($collection, __FUNCTION__, 1);
 
-    if ($callback === null) {
-        $callback = '\Functional\id';
-    }
-
     foreach ($collection as $index => $element) {
-        if (!$callback($element, $index, $collection)) {
+        if (!(null === $callback ? id($element) : $callback($element, $index, $collection))) {
             return false;
         }
     }
diff --git a/src/Functional/False.php b/src/Functional/False.php
index ff41c035..e0d38327 100644
--- a/src/Functional/False.php
+++ b/src/Functional/False.php
@@ -11,13 +11,14 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Returns true if all elements of the collection are strictly false
+ * Returns true if all elements of the collection are strictly false or the collection is empty
+ *
+ * @param iterable<mixed> $collection
  *
- * @param Traversable|array $collection
  * @return bool
+ *
  * @no-named-arguments
  */
 function false($collection)
diff --git a/src/Functional/Falsy.php b/src/Functional/Falsy.php
index e16be719..44d3edb6 100644
--- a/src/Functional/Falsy.php
+++ b/src/Functional/Falsy.php
@@ -11,13 +11,14 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Returns true if all elements of the collection evaluate to false
+ * Returns true if all elements of the collection evaluate to false or the collection is empty
+ *
+ * @param iterable<mixed> $collection
  *
- * @param Traversable|array $collection
  * @return bool
+ *
  * @no-named-arguments
  */
 function falsy($collection)
diff --git a/src/Functional/Filter.php b/src/Functional/Filter.php
index 46e09781..9f93e9ac 100644
--- a/src/Functional/Filter.php
+++ b/src/Functional/Filter.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Alias of Functional\select()
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):mixed $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function filter($collection, callable $callback)
diff --git a/src/Functional/First.php b/src/Functional/First.php
index 87db945e..48331a92 100644
--- a/src/Functional/First.php
+++ b/src/Functional/First.php
@@ -11,16 +11,20 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Looks through each element in the collection, returning the first one that passes a truthy test (callback). The
  * function returns as soon as it finds an acceptable element, and doesn't traverse the entire collection. Callback
  * arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return mixed
+ * @template T
+ * @template I
+ *
+ * @param iterable<T> $collection
+ * @param null|callable(T,I,iterable<T>):bool $callback
+ *
+ * @return  ($collection is non-empty-array ? ($callback is null ? T : T|null) : T|null)
+ *
  * @no-named-arguments
  */
 function first($collection, callable $callback = null)
diff --git a/src/Functional/FirstIndexOf.php b/src/Functional/FirstIndexOf.php
index 0fb5a0ad..f511d4dd 100644
--- a/src/Functional/FirstIndexOf.php
+++ b/src/Functional/FirstIndexOf.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns the first index holding specified value in the collection. Returns false if value was not found
  *
- * @param Traversable|array $collection
- * @param mixed $value
- * @return mixed
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param V $value
+ *
+ * @return false|K
+ *
  * @no-named-arguments
  */
 function first_index_of($collection, $value)
diff --git a/src/Functional/FlatMap.php b/src/Functional/FlatMap.php
index 6a022f49..dcfcf026 100644
--- a/src/Functional/FlatMap.php
+++ b/src/Functional/FlatMap.php
@@ -24,9 +24,15 @@
  * then flat_map(collection, callback) will return [1,2,3,[4]]
  * while flatten(map(collection, callback)) will return [1,2,3,4]
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ * @template V2
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):(V2|iterable<V2>) $callback
+ *
+ * @return list<V2>
+ *
  * @no-named-arguments
  */
 function flat_map($collection, callable $callback)
diff --git a/src/Functional/Flatten.php b/src/Functional/Flatten.php
index 615bfb5e..77818c56 100644
--- a/src/Functional/Flatten.php
+++ b/src/Functional/Flatten.php
@@ -17,8 +17,10 @@
  * Takes a nested combination of collections and returns their contents as a single, flat array.
  * Does not preserve indexes.
  *
- * @param Traversable|array $collection
- * @return array
+ * @param iterable<mixed> $collection
+ *
+ * @return array<mixed>
+ *
  * @no-named-arguments
  */
 function flatten($collection)
diff --git a/src/Functional/Flip.php b/src/Functional/Flip.php
index 9beedc8a..33ebc6b7 100644
--- a/src/Functional/Flip.php
+++ b/src/Functional/Flip.php
@@ -15,8 +15,13 @@
  *
  * If one argument is provided, it is passed to the function without change.
  *
- * @param callable $callback the function you want to flip
- * @return callable a flipped version of the given function
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback the function you want to flip
+ *
+ * @return callable(V...):R a flipped version of the given function
+ *
  * @no-named-arguments
  */
 function flip(callable $callback)
diff --git a/src/Functional/FromEntries.php b/src/Functional/FromEntries.php
index 65dd5ffc..0e12194c 100644
--- a/src/Functional/FromEntries.php
+++ b/src/Functional/FromEntries.php
@@ -11,15 +11,21 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Inspired by JavaScript’s `Object.fromEntries`,
  * convert an array of key-value pairs into a key-value map
  *
- * @see Functional\entries
- * @param Traversable|array $collection
- * @return array
+ * @see \Functional\entries
+ *
+ * @template K of array-key
+ * @template V
+ * @template P of array{K,V}
+ *
+ * @param iterable<P> $collection
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function from_entries($collection)
@@ -30,7 +36,7 @@ function from_entries($collection)
     foreach ($collection as $entry) {
         InvalidArgumentException::assertPair($entry, __FUNCTION__, 1);
         [$key, $value] = $entry;
-        InvalidArgumentException::assertValidArrayKey($key, __FUNCTION__, 1);
+        InvalidArgumentException::assertValidArrayKey($key, __FUNCTION__);
         $aggregation[$key] = $value;
     }
 
diff --git a/src/Functional/GreaterThan.php b/src/Functional/GreaterThan.php
index f3c84583..8014feb5 100644
--- a/src/Functional/GreaterThan.php
+++ b/src/Functional/GreaterThan.php
@@ -14,7 +14,9 @@
  * Returns true if $a is strictly greater than $b.
  *
  * @param mixed $b
- * @return \Closure(mixed)
+ *
+ * @return callable(mixed): bool
+ *
  * @no-named-arguments
  */
 function greater_than($b)
diff --git a/src/Functional/GreaterThanOrEqual.php b/src/Functional/GreaterThanOrEqual.php
index 266fd50f..e51a89ca 100644
--- a/src/Functional/GreaterThanOrEqual.php
+++ b/src/Functional/GreaterThanOrEqual.php
@@ -14,7 +14,9 @@
  * Returns true if $a is greater than or equal to $b.
  *
  * @param mixed $b
- * @return \Closure(mixed)
+ *
+ * @return callable(mixed): bool
+ *
  * @no-named-arguments
  */
 function greater_than_or_equal($b)
diff --git a/src/Functional/Group.php b/src/Functional/Group.php
index af2ed3a1..00ea5ef7 100644
--- a/src/Functional/Group.php
+++ b/src/Functional/Group.php
@@ -11,14 +11,25 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Groups a collection by index returned by callback.
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ * @template G of array-key
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):G $callback
+ *
+ * @return (G is numeric-string
+ *      ? (K is numeric-string
+ *          ? array<int,array<int,V>>
+ *          : array<int,array<K,V>>
+ *      )
+ *      : array<G,array<K,V>>
+ *  )
+ *
  * @no-named-arguments
  */
 function group($collection, callable $callback)
diff --git a/src/Functional/Head.php b/src/Functional/Head.php
index c6de5e86..5dde05d7 100644
--- a/src/Functional/Head.php
+++ b/src/Functional/Head.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Alias for Functional\first
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return mixed
+ * @template T
+ * @template I
+ *
+ * @param iterable<T> $collection
+ * @param null|callable(T,I,iterable<T>):bool $callback
+ *
+ * @return ($collection is non-empty-array ? ($callback is null ? T : T|null) : T|null)
+ *
  * @no-named-arguments
  */
 function head($collection, callable $callback = null)
diff --git a/src/Functional/Id.php b/src/Functional/Id.php
index b7de88dc..a1153b2f 100644
--- a/src/Functional/Id.php
+++ b/src/Functional/Id.php
@@ -13,8 +13,12 @@
 /**
  * Return value itself, without any modifications.
  *
- * @param mixed $value
- * @return mixed
+ * @template T
+ *
+ * @param T $value
+ *
+ * @return T
+ *
  * @no-named-arguments
  */
 function id($value)
diff --git a/src/Functional/Identical.php b/src/Functional/Identical.php
index 07f31501..39853db8 100644
--- a/src/Functional/Identical.php
+++ b/src/Functional/Identical.php
@@ -14,7 +14,9 @@
  * Returns true if $a is equal to $b, and they are of the same type.
  *
  * @param mixed $b
- * @return callable
+ *
+ * @return callable(mixed):bool
+ *
  * @no-named-arguments
  */
 function identical($b)
diff --git a/src/Functional/IfElse.php b/src/Functional/IfElse.php
index 607bd635..c2540b3d 100644
--- a/src/Functional/IfElse.php
+++ b/src/Functional/IfElse.php
@@ -13,11 +13,16 @@
 /**
  * Performs an if/else condition over a value using functions as statements
  *
- * @param callable $if   the condition function
- * @param callable $then function to call if condition is true
- * @param callable $else function to call if condition is false
+ * @template V
+ * @template R1
+ * @template R2
+ *
+ * @param callable(V):mixed $if the condition function
+ * @param callable(V):R1 $then function to call if condition is true
+ * @param callable(V):R2 $else function to call if condition is false
+ *
+ * @return callable(V):(R1|R2) a callback that returns the value of the given $then or $else functions
  *
- * @return mixed the return value of the given $then or $else functions
  * @no-named-arguments
  */
 function if_else(callable $if, callable $then, callable $else)
diff --git a/src/Functional/IndexesOf.php b/src/Functional/IndexesOf.php
index 74f05b77..375b63c8 100644
--- a/src/Functional/IndexesOf.php
+++ b/src/Functional/IndexesOf.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Returns a list of array indexes, either matching the predicate or strictly equal to the the passed value. Returns an
- * empty array if no values were found.
+ * Returns a list of array indexes, either matching the predicate or strictly equal to the passed value.
+ * Returns an empty array if no values were found.
+ *
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param V $value
+ *
+ * @return list<K>
  *
- * @param Traversable|array $collection
- * @param mixed $value
- * @return array
  * @no-named-arguments
  */
 function indexes_of($collection, $value)
diff --git a/src/Functional/Intersperse.php b/src/Functional/Intersperse.php
index 4b325ad2..e082d04b 100644
--- a/src/Functional/Intersperse.php
+++ b/src/Functional/Intersperse.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Insert a given value between each element of a collection.
  * Indices are not preserved.
  *
- * @param Traversable|array $collection
- * @param mixed $glue
- * @return array
+ * @template V
+ * @template G
+ *
+ * @param iterable<V> $collection
+ * @param G $glue
+ *
+ * @return list<V|G>
+ *
  * @no-named-arguments
  */
 function intersperse($collection, $glue)
diff --git a/src/Functional/Invoke.php b/src/Functional/Invoke.php
index 5970ed33..b7c60c11 100644
--- a/src/Functional/Invoke.php
+++ b/src/Functional/Invoke.php
@@ -11,16 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Calls the method named by $methodName on each value in the collection. Any extra arguments passed to invoke will be
- * forwarded on to the method invocation.
+ * Calls the method named by $methodName on each value in the collection.
+ * Any extra arguments passed to invoke will be forwarded on to the method invocation.
  *
- * @param Traversable|array $collection
+ * @template K of array-key
+ *
+ * @param iterable<K,object> $collection
  * @param string $methodName
- * @param array $arguments
- * @return array
+ * @param array<mixed> $arguments
+ *
+ * @return (K is numeric-string ? array<int,mixed> : array<K,mixed>)
+ *
  * @no-named-arguments
  */
 function invoke($collection, $methodName, array $arguments = [])
diff --git a/src/Functional/InvokeFirst.php b/src/Functional/InvokeFirst.php
index 8fc8b935..5dc7368f 100644
--- a/src/Functional/InvokeFirst.php
+++ b/src/Functional/InvokeFirst.php
@@ -11,17 +11,17 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Calls the method named by $methodName on first object in the collection containing a callable method named
  * $methodName. Any extra arguments passed to invoke will be forwarded on to the method invocation.
  *
- * @param Traversable|array $collection
+ * @param iterable<object> $collection
  * @param string $methodName
- * @param array $arguments
+ * @param array<mixed> $arguments
  *
  * @return mixed
+ *
  * @no-named-arguments
  */
 function invoke_first($collection, $methodName, array $arguments = [])
diff --git a/src/Functional/InvokeIf.php b/src/Functional/InvokeIf.php
index 7f0a4b36..eebb1e9f 100644
--- a/src/Functional/InvokeIf.php
+++ b/src/Functional/InvokeIf.php
@@ -14,11 +14,13 @@
  * Calls the method named by $methodName on $object. Any extra arguments passed to invoke_if will be
  * forwarded on to the method invocation. If $method is not callable on $object, $defaultValue is returned.
  *
- * @param mixed $object
+ * @param object $object
  * @param string $methodName
- * @param array $methodArguments
+ * @param array<mixed> $methodArguments
  * @param mixed $defaultValue
+ *
  * @return mixed
+ *
  * @no-named-arguments
  */
 function invoke_if($object, $methodName, array $methodArguments = [], $defaultValue = null)
diff --git a/src/Functional/InvokeLast.php b/src/Functional/InvokeLast.php
index b63cfbfa..d2d51470 100644
--- a/src/Functional/InvokeLast.php
+++ b/src/Functional/InvokeLast.php
@@ -10,17 +10,18 @@
 
 namespace Functional;
 
-use Traversable;
 use Functional\Exceptions\InvalidArgumentException;
 
 /**
  * Calls the method named by $methodName on last object in the collection containing a callable method named
  * $methodName. Any extra arguments passed to invoke will be forwarded on to the method invocation.
  *
- * @param Traversable|array $collection
+ * @param iterable<object> $collection
  * @param string $methodName
- * @param array $arguments
+ * @param array<mixed> $arguments
+ *
  * @return mixed
+ *
  * @no-named-arguments
  */
 function invoke_last($collection, $methodName, array $arguments = [])
diff --git a/src/Functional/Invoker.php b/src/Functional/Invoker.php
index 5236cf49..bcc97dc4 100644
--- a/src/Functional/Invoker.php
+++ b/src/Functional/Invoker.php
@@ -10,15 +10,16 @@
 
 namespace Functional;
 
-use Traversable;
 use Functional\Exceptions\InvalidArgumentException;
 
 /**
  * Returns a function that invokes method `$method` with arguments `$methodArguments` on the object
  *
  * @param string $methodName
- * @param array $arguments
- * @return callable
+ * @param array<mixed> $arguments
+ *
+ * @return callable(object):mixed
+ *
  * @no-named-arguments
  */
 function invoker($methodName, array $arguments = [])
diff --git a/src/Functional/Last.php b/src/Functional/Last.php
index 8989f945..4e4db77b 100644
--- a/src/Functional/Last.php
+++ b/src/Functional/Last.php
@@ -11,15 +11,23 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Looks through each element in the collection, returning the last one that passes a truthy test (callback).
  * Callback arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return mixed
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param null|callable(V,K,iterable<K,V>):bool $callback
+ *
+ * @return (
+ *     $collection is non-empty-array
+ *         ? ($callback is null ? V : null|V)
+ *         : null|V
+ * )
+ *
  * @no-named-arguments
  */
 function last($collection, callable $callback = null)
diff --git a/src/Functional/LastIndexOf.php b/src/Functional/LastIndexOf.php
index fc540193..0bf01994 100644
--- a/src/Functional/LastIndexOf.php
+++ b/src/Functional/LastIndexOf.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns the last index holding specified value in the collection. Returns false if value was not found
  *
- * @param Traversable|array $collection
- * @param mixed $value
- * @return mixed
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param V $value
+ *
+ * @return false|K
+ *
  * @no-named-arguments
  */
 function last_index_of($collection, $value)
diff --git a/src/Functional/LessThan.php b/src/Functional/LessThan.php
index 062dc865..516562d3 100644
--- a/src/Functional/LessThan.php
+++ b/src/Functional/LessThan.php
@@ -14,7 +14,9 @@
  * Returns true if $a is strictly less than $b.
  *
  * @param mixed $b
- * @return \Closure(mixed)
+ *
+ * @return callable(mixed):bool
+ *
  * @no-named-arguments
  */
 function less_than($b)
diff --git a/src/Functional/LessThanOrEqual.php b/src/Functional/LessThanOrEqual.php
index d63cb50b..608f1bd2 100644
--- a/src/Functional/LessThanOrEqual.php
+++ b/src/Functional/LessThanOrEqual.php
@@ -14,7 +14,9 @@
  * Returns true if $a is less than or equal to $b.
  *
  * @param mixed $b
- * @return \Closure(mixed)
+ *
+ * @return callable(mixed):bool
+ *
  * @no-named-arguments
  */
 function less_than_or_equal($b)
diff --git a/src/Functional/LexicographicCompare.php b/src/Functional/LexicographicCompare.php
index c025daea..152d92c2 100644
--- a/src/Functional/LexicographicCompare.php
+++ b/src/Functional/LexicographicCompare.php
@@ -15,7 +15,9 @@
  * $a is respectively less than, equal to, or greater than $b.
  *
  * @param mixed $b
- * @return \Closure(mixed)
+ *
+ * @return callable(mixed):int
+ *
  * @no-named-arguments
  */
 function lexicographic_compare($b)
diff --git a/src/Functional/Map.php b/src/Functional/Map.php
index 1bd577b3..f4a712a4 100644
--- a/src/Functional/Map.php
+++ b/src/Functional/Map.php
@@ -11,15 +11,20 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Produces a new array of elements by mapping each element in collection through a transformation function (callback).
  * Callback arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ * @template V2
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):V2 $callback
+ *
+ * @return (K is numeric-string ? array<int,V2> : array<K,V2>)
+ *
  * @no-named-arguments
  */
 function map($collection, callable $callback)
diff --git a/src/Functional/Matching.php b/src/Functional/Matching.php
index d941f86a..2bcfd98c 100644
--- a/src/Functional/Matching.php
+++ b/src/Functional/Matching.php
@@ -21,9 +21,20 @@
 /**
  * Performs an operation checking for the given conditions
  *
- * @param array $conditions the conditions to check against
+ * @template V
+ * @template R
+ *
+ * @param array<array{
+ *     callable(V):mixed,
+ *     callable(V):R,
+ * }> $conditions the conditions to check against
+ *
+ * @return (
+ *     $conditions is non-empty-array
+ *         ? callable(V):(null|R)
+ *         : callable(V):null
+ * ) the function that calls the callable of the first truthy condition
  *
- * @return callable|null the function that calls the callable of the first truthy condition
  * @no-named-arguments
  */
 function matching(array $conditions)
diff --git a/src/Functional/Maximum.php b/src/Functional/Maximum.php
index 8d8d5fb2..204fb70f 100644
--- a/src/Functional/Maximum.php
+++ b/src/Functional/Maximum.php
@@ -11,13 +11,16 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns the maximum value of a collection
  *
- * @param Traversable|array $collection
- * @return integer|float
+ * @template V
+ *
+ * @param iterable<V> $collection
+ *
+ * @return null|V
+ *
  * @no-named-arguments
  */
 function maximum($collection)
diff --git a/src/Functional/Memoize.php b/src/Functional/Memoize.php
index 3813e3ce..2d28c5a2 100644
--- a/src/Functional/Memoize.php
+++ b/src/Functional/Memoize.php
@@ -15,10 +15,15 @@
 /**
  * Memoizes callbacks and returns their value instead of calling them
  *
- * @param callable|null $callback Callable closure or function. Pass null to reset memory
- * @param array $arguments Arguments
- * @param array|string $key Optional memoize key to override the auto calculated hash
- * @return mixed
+ * @template V
+ * @template R
+ *
+ * @param null|callable(V):R $callback Callable closure or function. Pass null to reset memory
+ * @param array<mixed> $arguments Arguments
+ * @param mixed $key Optional memoize key to override the auto calculated hash
+ *
+ * @return ($callback is null ? null : R)
+ *
  * @no-named-arguments
  */
 function memoize(callable $callback = null, $arguments = [], $key = null)
@@ -34,7 +39,7 @@ function memoize(callable $callback = null, $arguments = [], $key = null)
         \trigger_error('Passing a callable as key is deprecated and will be removed in 2.0', E_USER_DEPRECATED);
         $key = $key();
     } elseif (\is_callable($arguments)) {
-        \trigger_error('Passing a callable as key is deprecated and will be removed in 2.0', E_USER_DEPRECATED);
+        \trigger_error('Passing a callable as arguments is deprecated and will be removed in 2.0', E_USER_DEPRECATED);
         $key = $arguments();
     }
 
diff --git a/src/Functional/Minimum.php b/src/Functional/Minimum.php
index 053b0beb..950d2cd1 100644
--- a/src/Functional/Minimum.php
+++ b/src/Functional/Minimum.php
@@ -11,13 +11,16 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns the minimum value of a collection
  *
- * @param Traversable|array $collection
- * @return integer|float
+ * @template V
+ *
+ * @param iterable<V> $collection
+ *
+ * @return null|V
+ *
  * @no-named-arguments
  */
 function minimum($collection)
@@ -26,7 +29,7 @@ function minimum($collection)
 
     $min = null;
 
-    foreach ($collection as $index => $element) {
+    foreach ($collection as $element) {
         if (!\is_numeric($element)) {
             continue;
         }
diff --git a/src/Functional/None.php b/src/Functional/None.php
index edbd33a9..9b42e163 100644
--- a/src/Functional/None.php
+++ b/src/Functional/None.php
@@ -11,27 +11,28 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Returns true if all of the elements in the collection pass the callback falsy test. Opposite of Functional\all().
+ * Returns true if all of the elements in the collection pass the callback falsy test.
+ * Opposite of Functional\all().
  * Callback arguments will be element, index, collection.
  *
- * @param Traversable|array $collection
- * @param callable|null $callback
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param null|callable(V,K,iterable<K,V>):mixed $callback
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function none($collection, callable $callback = null)
 {
     InvalidArgumentException::assertCollection($collection, __FUNCTION__, 1);
 
-    if ($callback === null) {
-        $callback = '\Functional\id';
-    }
-
     foreach ($collection as $index => $element) {
-        if ($callback($element, $index, $collection)) {
+        if (null === $callback ? id($element) : $callback($element, $index, $collection)) {
             return false;
         }
     }
diff --git a/src/Functional/Noop.php b/src/Functional/Noop.php
index 69f9ee2b..bc5594ca 100644
--- a/src/Functional/Noop.php
+++ b/src/Functional/Noop.php
@@ -26,6 +26,9 @@
 
 /**
  * A no-operation function.
+ *
+ * @return void
+ *
  * @no-named-arguments
  */
 function noop()
diff --git a/src/Functional/Not.php b/src/Functional/Not.php
index 9599bea8..fdb13dea 100644
--- a/src/Functional/Not.php
+++ b/src/Functional/Not.php
@@ -13,8 +13,12 @@
 /**
  * Logical negation of the given $function
  *
- * @param callable $function The function to run value against
- * @return callable A negation version on the given $function
+ * @template V
+ *
+ * @param callable(V):mixed $function The function to run value against
+ *
+ * @return callable(V):bool A negation version on the given $function
+ *
  * @no-named-arguments
  */
 function not(callable $function)
diff --git a/src/Functional/OmitKeys.php b/src/Functional/OmitKeys.php
index c08a69b4..1076a146 100644
--- a/src/Functional/OmitKeys.php
+++ b/src/Functional/OmitKeys.php
@@ -16,9 +16,13 @@
 /**
  * Returns an array with the specified keys omitted from the array
  *
- * @param Traversable|array $collection
- * @param array $keys
- * @return array
+ * @template V
+ *
+ * @param iterable<V> $collection
+ * @param array<array-key> $keys
+ *
+ * @return array<V>
+ *
  * @no-named-arguments
  */
 function omit_keys($collection, array $keys)
diff --git a/src/Functional/PartialAny.php b/src/Functional/PartialAny.php
index 71a481dc..0f852161 100644
--- a/src/Functional/PartialAny.php
+++ b/src/Functional/PartialAny.php
@@ -17,9 +17,14 @@
  *
  * Use Functional\…, Functional\…() or Functional\placeholder() as a placeholder
  *
- * @param callable $callback
- * @param mixed ...$arguments
- * @return callable
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback
+ * @param V ...$arguments
+ *
+ * @return callable(V...):R
+ *
  * @no-named-arguments
  */
 function partial_any(callable $callback, ...$arguments)
@@ -40,6 +45,7 @@ function partial_any(callable $callback, ...$arguments)
 
 /**
  * @return resource
+ *
  * @no-named-arguments
  */
 function …()
@@ -56,6 +62,7 @@ function …()
 
 /**
  * @return resource
+ *
  * @no-named-arguments
  */
 function placeholder()
diff --git a/src/Functional/PartialLeft.php b/src/Functional/PartialLeft.php
index e4ae016c..b66e921e 100644
--- a/src/Functional/PartialLeft.php
+++ b/src/Functional/PartialLeft.php
@@ -15,9 +15,14 @@
  *
  * Use Functional\…, Functional\…() or Functional\placeholder() as a placeholder
  *
- * @param callable $callback
- * @param array ...$arguments
- * @return callable
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback
+ * @param V ...$arguments
+ *
+ * @return callable(V...):R
+ *
  * @no-named-arguments
  */
 function partial_left(callable $callback, ...$arguments)
diff --git a/src/Functional/PartialMethod.php b/src/Functional/PartialMethod.php
index ac1f7239..f17c50bb 100644
--- a/src/Functional/PartialMethod.php
+++ b/src/Functional/PartialMethod.php
@@ -15,10 +15,14 @@
 /**
  * Returns a function that expects an object as the first param and tries to invoke the given method on it
  *
+ * @template V
+ *
  * @param string $methodName
- * @param array $arguments
+ * @param array<V> $arguments
  * @param mixed $defaultValue
- * @return callable
+ *
+ * @return callable(object):mixed
+ *
  * @no-named-arguments
  */
 function partial_method($methodName, array $arguments = [], $defaultValue = null)
diff --git a/src/Functional/PartialRight.php b/src/Functional/PartialRight.php
index 601e990b..a2e9fa6f 100644
--- a/src/Functional/PartialRight.php
+++ b/src/Functional/PartialRight.php
@@ -13,9 +13,14 @@
 /**
  * Return a new function with the arguments partially applied starting from the right
  *
- * @param callable $callback
- * @param array ...$arguments
- * @return callable
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback
+ * @param V ...$arguments
+ *
+ * @return callable(V...):R
+ *
  * @no-named-arguments
  */
 function partial_right(callable $callback, ...$arguments)
diff --git a/src/Functional/Partition.php b/src/Functional/Partition.php
index 11fb36b9..7509d723 100644
--- a/src/Functional/Partition.php
+++ b/src/Functional/Partition.php
@@ -11,7 +11,6 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Partitions a collection by callback predicate results. Returns an
@@ -22,9 +21,14 @@
  * Elements are not re-ordered and have the same index they had in the
  * original array.
  *
- * @param Traversable|array $collection
- * @param callable ...$callbacks
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):mixed ...$callbacks
+ *
+ * @return (K is numeric-string ? list<array<int,V>> : list<array<K,V>>)
+ *
  * @no-named-arguments
  */
 function partition($collection, callable ...$callbacks)
diff --git a/src/Functional/Pick.php b/src/Functional/Pick.php
index b4be3c13..baf1b127 100644
--- a/src/Functional/Pick.php
+++ b/src/Functional/Pick.php
@@ -17,11 +17,17 @@
  * Pick a single element from a collection of objects or arrays by index.
  * If no such index exists, return the default value.
  *
- * @param ArrayAccess|array $collection
- * @param mixed $index
- * @param mixed $default
- * @param callable|null $callback Custom function to check if index exists
- * @return mixed
+ * @template K of array-key
+ * @template V
+ * @template D
+ *
+ * @param array<K,V> $collection
+ * @param K $index
+ * @param D $default
+ * @param null|callable(iterable<K,V>, K):mixed $callback Custom function to check if index exists
+ *
+ * @return D|V
+ *
  * @no-named-arguments
  */
 function pick($collection, $index, $default = null, callable $callback = null)
diff --git a/src/Functional/Pluck.php b/src/Functional/Pluck.php
index dd8f6c24..06b34cbf 100644
--- a/src/Functional/Pluck.php
+++ b/src/Functional/Pluck.php
@@ -12,14 +12,17 @@
 
 use ArrayAccess;
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Extract a property from a collection of objects.
  *
- * @param Traversable|array $collection
+ * @template K of array-key
+ *
+ * @param iterable<K,mixed> $collection
  * @param string $propertyName
- * @return array
+ *
+ * @return (K is numeric-string ? array<int,mixed> : array<K,mixed>)
+ *
  * @no-named-arguments
  */
 function pluck($collection, $propertyName)
diff --git a/src/Functional/Poll.php b/src/Functional/Poll.php
index 7c632d77..1832ec42 100644
--- a/src/Functional/Poll.php
+++ b/src/Functional/Poll.php
@@ -14,19 +14,23 @@
 use ArrayIterator;
 use Functional\Exceptions\InvalidArgumentException;
 use InfiniteIterator;
-use Traversable;
 
 /**
  * Retry a callback until it returns a truthy value or the timeout (in microseconds) is reached
  *
- * @param callable $callback
- * @param integer $timeout Timeout in microseconds
- * @param Traversable|null $delaySequence Default: no delay between calls
- * @throws InvalidArgumentException
- * @return boolean
+ * @template R
+ *
+ * @param callable(int,int):R $callback
+ * @param non-negative-int $timeout Timeout in microseconds
+ * @param null|\Iterator $delaySequence Default: no delay between calls
+ *
+ * @return false|R
+ *
  * @no-named-arguments
+ *@throws InvalidArgumentException
+ *
  */
-function poll(callable $callback, $timeout, Traversable $delaySequence = null)
+function poll(callable $callback, $timeout, \Iterator $delaySequence = null)
 {
     InvalidArgumentException::assertIntegerGreaterThanOrEqual($timeout, 0, __FUNCTION__, 2);
 
@@ -57,4 +61,6 @@ function poll(callable $callback, $timeout, Traversable $delaySequence = null)
 
         ++$retry;
     }
+
+    return false;
 }
diff --git a/src/Functional/Product.php b/src/Functional/Product.php
index 6421b68a..6f324533 100644
--- a/src/Functional/Product.php
+++ b/src/Functional/Product.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Takes a collection and returns the product of all elements
  *
- * @param Traversable|array $collection
- * @param integer|float $initial
- * @return integer|float
+ * @template V of int|float
+ * @template I of int|float
+ *
+ * @param iterable<V> $collection
+ * @param I $initial
+ *
+ * @return (V is int ? ($initial is int ? int : float) : float)
+ *
  * @no-named-arguments
  */
 function product($collection, $initial = 1)
diff --git a/src/Functional/Ratio.php b/src/Functional/Ratio.php
index b9ee83e4..c81a850a 100644
--- a/src/Functional/Ratio.php
+++ b/src/Functional/Ratio.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Takes a collection and returns the quotient of all elements
  *
- * @param Traversable|array $collection
- * @param integer|float $initial
- * @return integer|float
+ * @template V of int|float
+ * @template I of int|float
+ *
+ * @param iterable<V> $collection
+ * @param I $initial
+ *
+ * @return (V is int ? ($initial is int ? int|float : float) : float)
+ *
  * @no-named-arguments
  */
 function ratio($collection, $initial = 1)
diff --git a/src/Functional/ReduceLeft.php b/src/Functional/ReduceLeft.php
index bce30c09..0e1d25a1 100644
--- a/src/Functional/ReduceLeft.php
+++ b/src/Functional/ReduceLeft.php
@@ -11,13 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * @param Traversable|array $collection
- * @param callable $callback
- * @param mixed $initial
- * @return mixed
+ * @template K
+ * @template V
+ * @template V2
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>,V2):V2 $callback
+ * @param V2 $initial
+ *
+ * @return V2
+ *
  * @no-named-arguments
  */
 function reduce_left($collection, callable $callback, $initial = null)
diff --git a/src/Functional/ReduceRight.php b/src/Functional/ReduceRight.php
index 094d570d..d0fe4062 100644
--- a/src/Functional/ReduceRight.php
+++ b/src/Functional/ReduceRight.php
@@ -11,13 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * @param Traversable|array $collection
- * @param callable $callback
- * @param mixed $initial
- * @return mixed
+ * @template K
+ * @template V
+ * @template V2
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>,V2):V2 $callback
+ * @param V2 $initial
+ *
+ * @return V2
+ *
  * @no-named-arguments
  */
 function reduce_right($collection, callable $callback, $initial = null)
@@ -29,6 +34,10 @@ function reduce_right($collection, callable $callback, $initial = null)
         $data[] = [$index, $value];
     }
 
+    if (0 === count($data)) {
+        return $initial;
+    }
+
     while ((list($index, $value) = \array_pop($data))) {
         $initial = $callback($value, $index, $collection, $initial);
     }
diff --git a/src/Functional/Reindex.php b/src/Functional/Reindex.php
index ba6cbdf9..f58cc43e 100644
--- a/src/Functional/Reindex.php
+++ b/src/Functional/Reindex.php
@@ -11,15 +11,20 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Produces a new array of elements by assigning the values to keys generated by a transformation function (callback).
  * Callback arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K
+ * @template V
+ * @template K2 of array-key
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):K2 $callback
+ *
+ * @return array<K2,V>
+ *
  * @no-named-arguments
  */
 function reindex($collection, callable $callback)
diff --git a/src/Functional/Reject.php b/src/Functional/Reject.php
index 505acc91..732ea4c1 100644
--- a/src/Functional/Reject.php
+++ b/src/Functional/Reject.php
@@ -11,15 +11,20 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
- * Returns the elements in list without the elements that the truthy test (callback) passes. The opposite of
- * Functional\select(). Callback arguments will be element, index, collection
+ * Returns the elements in list without the elements that the truthy test (callback) passes.
+ * The opposite of Functional\select().
+ * Callback arguments will be element, index, collection
+ *
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param null|callable(V,K,iterable<K,V>):mixed $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
  *
- * @param Traversable|array $collection
- * @param callable|null $callback
- * @return array
  * @no-named-arguments
  */
 function reject($collection, callable $callback = null)
@@ -28,12 +33,8 @@ function reject($collection, callable $callback = null)
 
     $aggregation = [];
 
-    if ($callback === null) {
-        $callback = '\Functional\id';
-    }
-
     foreach ($collection as $index => $element) {
-        if (!$callback($element, $index, $collection)) {
+        if (!(null === $callback ? id($element) : $callback($element, $index, $collection))) {
             $aggregation[$index] = $element;
         }
     }
diff --git a/src/Functional/Repeat.php b/src/Functional/Repeat.php
index a3d00b95..de2d6d72 100644
--- a/src/Functional/Repeat.php
+++ b/src/Functional/Repeat.php
@@ -10,15 +10,15 @@
 
 namespace Functional;
 
-use Closure;
 use Functional\Exceptions\InvalidArgumentException;
 
 /**
  * Creates a function that can be used to repeat the execution of $callback.
  *
- * @param callable $callback
+ * @param callable():mixed $callback
+ *
+ * @return callable(non-negative-int):void
  *
- * @return Closure
  * @no-named-arguments
  */
 function repeat(callable $callback)
diff --git a/src/Functional/Retry.php b/src/Functional/Retry.php
index 40ef0fa7..d42c935e 100644
--- a/src/Functional/Retry.php
+++ b/src/Functional/Retry.php
@@ -16,20 +16,25 @@
 use Exception;
 use InfiniteIterator;
 use LimitIterator;
-use Traversable;
 
 /**
  * Retry a callback until the number of retries are reached or the callback does no longer throw an exception
  *
- * @param callable $callback
- * @param integer $retries
- * @param Traversable|null $delaySequence Default: no delay between calls
+ * @template R
+ *
+ * @param callable(int,int):R $callback
+ * @param int<-1,max> $retries
+ * @param null|\Iterator $delaySequence Default: no delay between calls
+ *
  * @throws Exception Any exception thrown by the callback
  * @throws InvalidArgumentException
- * @return mixed Return value of the function
+ * @throws \LogicException Reached the end of execution before retries number and before success (should not happen)
+ *
+ * @return R Return value of the function
+ *
  * @no-named-arguments
  */
-function retry(callable $callback, $retries, Traversable $delaySequence = null)
+function retry(callable $callback, $retries, \Iterator $delaySequence = null)
 {
     InvalidArgumentException::assertIntegerGreaterThanOrEqual($retries, 1, __FUNCTION__, 2);
 
@@ -58,4 +63,6 @@ function retry(callable $callback, $retries, Traversable $delaySequence = null)
 
         ++$retry;
     }
+
+    throw new \LogicException();
 }
diff --git a/src/Functional/Select.php b/src/Functional/Select.php
index 93420357..a601d654 100644
--- a/src/Functional/Select.php
+++ b/src/Functional/Select.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Looks through each element in the list, returning an array of all the elements that pass a truthy test (callback).
  * Opposite is Functional\reject(). Callback arguments will be element, index, collection
  *
- * @param Traversable|array $collection
- * @param callable|null $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):mixed $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function select($collection, callable $callback = null)
@@ -28,12 +32,8 @@ function select($collection, callable $callback = null)
 
     $aggregation = [];
 
-    if ($callback === null) {
-        $callback = '\Functional\id';
-    }
-
     foreach ($collection as $index => $element) {
-        if ($callback($element, $index, $collection)) {
+        if (null === $callback ? id($element) : $callback($element, $index, $collection)) {
             $aggregation[$index] = $element;
         }
     }
diff --git a/src/Functional/SelectKeys.php b/src/Functional/SelectKeys.php
index b222631d..eb8f94f3 100644
--- a/src/Functional/SelectKeys.php
+++ b/src/Functional/SelectKeys.php
@@ -16,9 +16,14 @@
 /**
  * Select the specified keys from the array
  *
- * @param Traversable|array $collection
- * @param array $keys
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param array<K> $keys
+ *
+ * @return array<K,V>
+ *
  * @no-named-arguments
  */
 function select_keys($collection, array $keys)
diff --git a/src/Functional/SequenceConstant.php b/src/Functional/SequenceConstant.php
index 568dd86d..6d19c85b 100644
--- a/src/Functional/SequenceConstant.php
+++ b/src/Functional/SequenceConstant.php
@@ -13,13 +13,14 @@
 use ArrayIterator;
 use Functional\Exceptions\InvalidArgumentException;
 use InfiniteIterator;
-use Traversable;
 
 /**
  * Returns an infinite, traversable sequence of constant values
  *
- * @param integer $value
- * @return Traversable
+ * @param int<0,max> $value
+ *
+ * @return \Iterator
+ *
  * @no-named-arguments
  */
 function sequence_constant($value)
diff --git a/src/Functional/SequenceExponential.php b/src/Functional/SequenceExponential.php
index 8e5fc629..77ee2937 100644
--- a/src/Functional/SequenceExponential.php
+++ b/src/Functional/SequenceExponential.php
@@ -16,10 +16,13 @@
 /**
  * Returns an infinite, traversable sequence that exponentially grows by given percentage
  *
- * @param integer $start
- * @param integer $percentage Integer between 1 and 100
+ * @param int<1,max> $start
+ * @param int<1,100> $percentage Integer between 1 and 100
+ *
  * @return ExponentialSequence
+ *
  * @throws InvalidArgumentException
+ *
  * @no-named-arguments
  */
 function sequence_exponential($start, $percentage)
diff --git a/src/Functional/SequenceLinear.php b/src/Functional/SequenceLinear.php
index 822a5794..44b5472a 100644
--- a/src/Functional/SequenceLinear.php
+++ b/src/Functional/SequenceLinear.php
@@ -12,14 +12,15 @@
 
 use Functional\Exceptions\InvalidArgumentException;
 use Functional\Sequences\LinearSequence;
-use Traversable;
 
 /**
  * Returns an infinite, traversable sequence that linearly grows by given amount
  *
- * @param integer $start
- * @param integer $amount
- * @return Traversable
+ * @param int<0,max> $start
+ * @param int $amount
+ *
+ * @return LinearSequence
+ *
  * @no-named-arguments
  */
 function sequence_linear($start, $amount)
diff --git a/src/Functional/Some.php b/src/Functional/Some.php
index df27e0a8..f55fb3ee 100644
--- a/src/Functional/Some.php
+++ b/src/Functional/Some.php
@@ -11,27 +11,27 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns true if some of the elements in the collection pass the callback truthy test. Short-circuits and stops
  * traversing the collection if a truthy element is found. Callback arguments will be value, index, collection
  *
- * @param Traversable|array $collection
- * @param callable|null $callback
+ * @template K
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):mixed $callback
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function some($collection, callable $callback = null)
 {
     InvalidArgumentException::assertCollection($collection, __FUNCTION__, 1);
 
-    if ($callback === null) {
-        $callback = '\Functional\id';
-    }
-
     foreach ($collection as $index => $element) {
-        if ($callback($element, $index, $collection)) {
+        if (null === $callback ? id($element) : $callback($element, $index, $collection)) {
             return true;
         }
     }
diff --git a/src/Functional/Sort.php b/src/Functional/Sort.php
index 8dcc32ea..4c85da48 100644
--- a/src/Functional/Sort.php
+++ b/src/Functional/Sort.php
@@ -16,10 +16,15 @@
 /**
  * Sorts a collection with a user-defined function, optionally preserving array keys
  *
- * @param Traversable|array $collection
- * @param callable $callback
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,V,iterable<K,V>):int $callback
  * @param bool $preserveKeys
- * @return array
+ *
+ * @return ($preserveKeys is true ? array<K,V> : list<V>)
+ *
  * @no-named-arguments
  */
 function sort($collection, callable $callback, $preserveKeys = false)
diff --git a/src/Functional/Sum.php b/src/Functional/Sum.php
index e0f478b9..7763d626 100644
--- a/src/Functional/Sum.php
+++ b/src/Functional/Sum.php
@@ -11,14 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Takes a collection and returns the sum of the elements
  *
- * @param Traversable|array $collection
- * @param integer|float $initial
- * @return integer|float
+ * @template K
+ * @template V of int|float
+ *
+ * @param iterable<K,V> $collection
+ * @param V $initial
+ *
+ * @return V
+ *
  * @no-named-arguments
  */
 function sum($collection, $initial = 0)
diff --git a/src/Functional/SuppressError.php b/src/Functional/SuppressError.php
index 49baed2f..b6e5acc7 100644
--- a/src/Functional/SuppressError.php
+++ b/src/Functional/SuppressError.php
@@ -17,9 +17,15 @@
 /**
  * Takes a function and returns a new function that wraps the callback and suppresses the PHP error
  *
- * @param callable $callback
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $callback
+ *
  * @throws ErrorException Throws exception if PHP error happened
- * @return mixed
+ *
+ * @return callable(V...):R
+ *
  * @no-named-arguments
  */
 function suppress_error(callable $callback)
diff --git a/src/Functional/Tail.php b/src/Functional/Tail.php
index 495131d2..c378204b 100644
--- a/src/Functional/Tail.php
+++ b/src/Functional/Tail.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns all items from $collection except first element (head). Preserves $collection keys.
  * Takes an optional callback for filtering the collection.
  *
- * @param Traversable|array $collection
- * @param callable $callback
- * @return array
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param callable(V,K,iterable<K,V>):mixed $callback
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function tail($collection, callable $callback = null)
@@ -35,7 +39,7 @@ function tail($collection, callable $callback = null)
             continue;
         }
 
-        if (!$callback || $callback($element, $index, $collection)) {
+        if (null === $callback || $callback($element, $index, $collection)) {
             $tail[$index] = $element;
         }
     }
diff --git a/src/Functional/TailRecursion.php b/src/Functional/TailRecursion.php
index 2fd548a0..4e526f91 100644
--- a/src/Functional/TailRecursion.php
+++ b/src/Functional/TailRecursion.php
@@ -16,8 +16,13 @@
  * I took the solution from here https://gist.github.com/beberlei/4145442
  * but reworked it and made without classes.
  *
- * @param callable $fn
- * @return callable
+ * @template V
+ * @template R
+ *
+ * @param callable(V...):R $fn
+ *
+ * @return callable(V...):(null|R)
+ *
  * @no-named-arguments
  */
 function tail_recursion(callable $fn): callable
diff --git a/src/Functional/TakeLeft.php b/src/Functional/TakeLeft.php
index 2520877e..970ddd31 100644
--- a/src/Functional/TakeLeft.php
+++ b/src/Functional/TakeLeft.php
@@ -11,16 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Creates a slice of $collection with $count elements taken from the beginning. If the collection has less than $count
  * elements, the whole collection will be returned as an array.
  *
- * @param Traversable|array $collection
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
  * @param int $count
  *
- * @return array
+ * @return array<K,V>
+ *
  * @no-named-arguments
  */
 function take_left($collection, $count)
diff --git a/src/Functional/TakeRight.php b/src/Functional/TakeRight.php
index c7af137b..55e146c3 100644
--- a/src/Functional/TakeRight.php
+++ b/src/Functional/TakeRight.php
@@ -11,7 +11,6 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Creates a slice of $collection with $count elements taken from the end. If the collection has less than $count
@@ -19,11 +18,16 @@
  * This function will reorder and reset the integer array indices by default. This behaviour can be changed by setting
  * preserveKeys to TRUE. String keys are always preserved, regardless of this parameter.
  *
- * @param Traversable|array $collection
+ *
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
  * @param int $count
  * @param bool $preserveKeys
  *
- * @return array
+ * @return array<K,V>
+ *
  * @no-named-arguments
  */
 function take_right($collection, $count, $preserveKeys = false)
diff --git a/src/Functional/Tap.php b/src/Functional/Tap.php
index a9322e84..33c643d7 100644
--- a/src/Functional/Tap.php
+++ b/src/Functional/Tap.php
@@ -13,9 +13,13 @@
 /**
  * Call the given Closure with the given value, then return the value.
  *
- * @param  mixed  $value
- * @param  callable $callback
- * @return mixed
+ * @template V
+ *
+ * @param V $value
+ * @param callable(V):mixed $callback
+ *
+ * @return V
+ *
  * @no-named-arguments
  */
 function tap($value, callable $callback)
diff --git a/src/Functional/True.php b/src/Functional/True.php
index 8013c8f4..027e1759 100644
--- a/src/Functional/True.php
+++ b/src/Functional/True.php
@@ -11,13 +11,14 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns true if all elements of the collection are strictly true
  *
- * @param Traversable|array $collection
+ * @param iterable<mixed> $collection
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function true($collection)
diff --git a/src/Functional/Truthy.php b/src/Functional/Truthy.php
index d38ef546..c1fa8e4a 100644
--- a/src/Functional/Truthy.php
+++ b/src/Functional/Truthy.php
@@ -11,13 +11,14 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns true if all elements of the collection evaluate to true
  *
- * @param Traversable|array $collection
+ * @param iterable<mixed> $collection
+ *
  * @return bool
+ *
  * @no-named-arguments
  */
 function truthy($collection)
diff --git a/src/Functional/Unique.php b/src/Functional/Unique.php
index 656ac2be..6f281d23 100644
--- a/src/Functional/Unique.php
+++ b/src/Functional/Unique.php
@@ -11,15 +11,19 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Returns an array of unique elements
  *
- * @param Traversable|array $collection
- * @param callable $callback
+ * @template K of array-key
+ * @template V
+ *
+ * @param iterable<K,V> $collection
+ * @param null|callable(V,K,iterable<K,V>):mixed $callback
  * @param bool $strict
- * @return array
+ *
+ * @return (K is numeric-string ? array<int,V> : array<K,V>)
+ *
  * @no-named-arguments
  */
 function unique($collection, callable $callback = null, $strict = true)
diff --git a/src/Functional/ValueToKey.php b/src/Functional/ValueToKey.php
index 345723f7..2d559472 100644
--- a/src/Functional/ValueToKey.php
+++ b/src/Functional/ValueToKey.php
@@ -14,8 +14,6 @@
 use Traversable;
 use WeakReference;
 
-use function serialize;
-
 use const PHP_VERSION_ID;
 
 /**
diff --git a/src/Functional/With.php b/src/Functional/With.php
index 0c00ddd3..374d033b 100644
--- a/src/Functional/With.php
+++ b/src/Functional/With.php
@@ -15,10 +15,16 @@
 /**
  * Invoke a callback on a value if the value is not null
  *
- * @param mixed $value
- * @param callable $callback
- * @param mixed $default The default value to return if $value is null
- * @return mixed
+ * @template V
+ * @template V2
+ * @template V3
+ *
+ * @param V|null $value
+ * @param callable(V):V2 $callback
+ * @param V3 $default The default value to return if $value is null
+ *
+ * @return ($value is null ? V3 : V2)
+ *
  * @no-named-arguments
  */
 function with($value, callable $callback, $default = null)
diff --git a/src/Functional/Zip.php b/src/Functional/Zip.php
index 23abf2e0..30cbf757 100644
--- a/src/Functional/Zip.php
+++ b/src/Functional/Zip.php
@@ -11,13 +11,18 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Recombines arrays by index and applies a callback optionally
  *
- * @param array|Traversable ...$args One or more callbacks
- * @return array
+ * @template K of array-key
+ * @template V
+ * @template Z
+ *
+ * @param iterable<K,V>|callable(V...):Z ...$args One or more callbacks
+ *
+ * @return (K is numeric-string ? array<int,Z> : array<K,Z>)
+ *
  * @no-named-arguments
  */
 function zip(...$args)
diff --git a/src/Functional/ZipAll.php b/src/Functional/ZipAll.php
index d8c95e20..4dda90b5 100644
--- a/src/Functional/ZipAll.php
+++ b/src/Functional/ZipAll.php
@@ -11,7 +11,6 @@
 namespace Functional;
 
 use Functional\Exceptions\InvalidArgumentException;
-use Traversable;
 
 /**
  * Recombines arrays by index (column) and applies a callback optionally
@@ -19,8 +18,10 @@
  * When the input collections are different lengths the resulting collections
  * will all have the length which is required to fit all the keys
  *
- * @param array|Traversable ...$args One or more callbacks
- * @return array
+ * @param iterable<mixed> ...$args One or more callbacks
+ *
+ * @return array<mixed>
+ *
  * @no-named-arguments
  */
 function zip_all(...$args)