diff --git a/src/DataStructures/StrictCollection.php b/src/DataStructures/StrictCollection.php
index 96726e5..d814faa 100644
--- a/src/DataStructures/StrictCollection.php
+++ b/src/DataStructures/StrictCollection.php
@@ -32,6 +32,34 @@ use OCC\Basics\Interfaces\CountableTrait;
 use OCC\Basics\Traits\Getter;
 use Serializable;
 
+use function array_is_list;
+use function array_map;
+use function array_sum;
+use function count;
+use function function_exists;
+use function get_debug_type;
+use function is_a;
+use function is_array;
+use function is_bool;
+use function is_callable;
+use function is_countable;
+use function is_double;
+use function is_float;
+use function is_int;
+use function is_integer;
+use function is_iterable;
+use function is_long;
+use function is_null;
+use function is_numeric;
+use function is_resource;
+use function is_scalar;
+use function is_string;
+use function is_object;
+use function ltrim;
+use function serialize;
+use function sprintf;
+use function unserialize;
+
 /**
  * A type-sensitive, unsorted collection.
  *
diff --git a/src/DataStructures/StrictList.php b/src/DataStructures/StrictList.php
index 5c3bd4c..db1ec77 100644
--- a/src/DataStructures/StrictList.php
+++ b/src/DataStructures/StrictList.php
@@ -34,6 +34,36 @@ use SplDoublyLinkedList;
 use OCC\Basics\Traits\Getter;
 use Serializable;
 
+use function array_map;
+use function array_sum;
+use function count;
+use function function_exists;
+use function get_debug_type;
+use function in_array;
+use function is_a;
+use function is_array;
+use function is_bool;
+use function is_callable;
+use function is_countable;
+use function is_double;
+use function is_float;
+use function is_int;
+use function is_integer;
+use function is_iterable;
+use function is_long;
+use function is_null;
+use function is_numeric;
+use function is_resource;
+use function is_scalar;
+use function is_string;
+use function is_object;
+use function iterator_to_array;
+use function ltrim;
+use function range;
+use function serialize;
+use function sprintf;
+use function unserialize;
+
 /**
  * A type-sensitive, taversable list.
  *
diff --git a/src/DataStructures/StrictQueue.php b/src/DataStructures/StrictQueue.php
index 90bbe00..f132fd7 100644
--- a/src/DataStructures/StrictQueue.php
+++ b/src/DataStructures/StrictQueue.php
@@ -31,6 +31,8 @@ use RangeException;
 use RuntimeException;
 use Serializable;
 
+use function sprintf;
+
 /**
  * A type-sensitive, taversable queue (FIFO).
  *
diff --git a/src/DataStructures/StrictStack.php b/src/DataStructures/StrictStack.php
index 00c355c..357897e 100644
--- a/src/DataStructures/StrictStack.php
+++ b/src/DataStructures/StrictStack.php
@@ -31,6 +31,8 @@ use RangeException;
 use RuntimeException;
 use Serializable;
 
+use function sprintf;
+
 /**
  * A type-sensitive, taversable stack (LIFO).
  *
diff --git a/src/ErrorHandlers/ThrowErrorException.php b/src/ErrorHandlers/ThrowErrorException.php
index f580b6b..f0ccd93 100644
--- a/src/ErrorHandlers/ThrowErrorException.php
+++ b/src/ErrorHandlers/ThrowErrorException.php
@@ -25,6 +25,8 @@ namespace OCC\Basics\ErrorHandlers;
 
 use ErrorException;
 
+use function error_reporting;
+
 /**
  * Throws internal errors as exceptions.
  *
diff --git a/src/ErrorHandlers/TriggerExceptionError.php b/src/ErrorHandlers/TriggerExceptionError.php
index 98d0f02..feddf1c 100644
--- a/src/ErrorHandlers/TriggerExceptionError.php
+++ b/src/ErrorHandlers/TriggerExceptionError.php
@@ -25,6 +25,9 @@ namespace OCC\Basics\ErrorHandlers;
 
 use Throwable;
 
+use function sprintf;
+use function trigger_error;
+
 /**
  * Triggers errors for uncaught exceptions.
  *
diff --git a/src/Interfaces/ArrayAccessTrait.php b/src/Interfaces/ArrayAccessTrait.php
index 2cc109d..974da74 100644
--- a/src/Interfaces/ArrayAccessTrait.php
+++ b/src/Interfaces/ArrayAccessTrait.php
@@ -25,6 +25,8 @@ namespace OCC\Basics\Interfaces;
 
 use ArrayAccess;
 
+use function is_null;
+
 /**
  * A generic implementation of the ArrayAccess interface.
  *
diff --git a/src/Interfaces/CountableTrait.php b/src/Interfaces/CountableTrait.php
index 039a725..7e40b10 100644
--- a/src/Interfaces/CountableTrait.php
+++ b/src/Interfaces/CountableTrait.php
@@ -25,6 +25,8 @@ namespace OCC\Basics\Interfaces;
 
 use Countable;
 
+use function count;
+
 /**
  * A generic implementation of the Countable interface.
  *
diff --git a/src/Interfaces/IteratorTrait.php b/src/Interfaces/IteratorTrait.php
index f29c5ae..f222078 100644
--- a/src/Interfaces/IteratorTrait.php
+++ b/src/Interfaces/IteratorTrait.php
@@ -25,6 +25,13 @@ namespace OCC\Basics\Interfaces;
 
 use Iterator;
 
+use function current;
+use function is_null;
+use function key;
+use function next;
+use function prev;
+use function reset;
+
 /**
  * A generic implementation of the Iterator interface.
  *
diff --git a/src/Traits/Getter.php b/src/Traits/Getter.php
index 68a5d21..5fb7559 100644
--- a/src/Traits/Getter.php
+++ b/src/Traits/Getter.php
@@ -25,6 +25,12 @@ namespace OCC\Basics\Traits;
 
 use InvalidArgumentException;
 
+use function boolval;
+use function method_exists;
+use function property_exists;
+use function sprintf;
+use function ucfirst;
+
 /**
  * Reads data from inaccessible properties by using magic methods.
  *
diff --git a/src/Traits/OverloadingGetter.php b/src/Traits/OverloadingGetter.php
index a1a858e..633df97 100644
--- a/src/Traits/OverloadingGetter.php
+++ b/src/Traits/OverloadingGetter.php
@@ -23,6 +23,8 @@ declare(strict_types=1);
 
 namespace OCC\Basics\Traits;
 
+use function boolval;
+
 /**
  * Overloads a class with readable magic properties.
  *
diff --git a/src/Traits/Setter.php b/src/Traits/Setter.php
index 77c8a99..6580164 100644
--- a/src/Traits/Setter.php
+++ b/src/Traits/Setter.php
@@ -25,6 +25,11 @@ namespace OCC\Basics\Traits;
 
 use InvalidArgumentException;
 
+use function method_exists;
+use function property_exists;
+use function sprintf;
+use function ucfirst;
+
 /**
  * Writes data to inaccessible properties by using magic methods.
  *