diff --git a/src/Tokenizer/Parser/Boundary.php b/src/Tokenizer/Parser/Boundary.php
index 99fc0ca..b4371a2 100644
--- a/src/Tokenizer/Parser/Boundary.php
+++ b/src/Tokenizer/Parser/Boundary.php
@@ -20,7 +20,7 @@ final class Boundary
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      * @param array     $matches
      */
     public static function isBoundary(Tokenizer $tokenizer, $string, array &$matches)
diff --git a/src/Tokenizer/Parser/Comment.php b/src/Tokenizer/Parser/Comment.php
index 78cef30..6697346 100644
--- a/src/Tokenizer/Parser/Comment.php
+++ b/src/Tokenizer/Parser/Comment.php
@@ -20,7 +20,7 @@ final class Comment
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      */
     public static function isComment(Tokenizer $tokenizer, $string)
     {
@@ -50,7 +50,7 @@ protected static function isTwoCharacterComment($string)
     }
 
     /**
-     * @param $string
+     * @param string $string
      *
      * @return bool
      */
@@ -60,7 +60,7 @@ protected static function startsWithDoubleDash($string)
     }
 
     /**
-     * @param $string
+     * @param string $string
      *
      * @return bool
      */
diff --git a/src/Tokenizer/Parser/Numeral.php b/src/Tokenizer/Parser/Numeral.php
index f7c7a71..93d5ab9 100644
--- a/src/Tokenizer/Parser/Numeral.php
+++ b/src/Tokenizer/Parser/Numeral.php
@@ -20,7 +20,7 @@ final class Numeral
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      * @param array     $matches
      *
      * @return array
diff --git a/src/Tokenizer/Parser/Quoted.php b/src/Tokenizer/Parser/Quoted.php
index 9ba66d2..fe778f9 100644
--- a/src/Tokenizer/Parser/Quoted.php
+++ b/src/Tokenizer/Parser/Quoted.php
@@ -20,7 +20,7 @@ final class Quoted
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      */
     public static function isQuoted(Tokenizer $tokenizer, $string)
     {
diff --git a/src/Tokenizer/Parser/String.php b/src/Tokenizer/Parser/String.php
index 6ad687d..d34a919 100644
--- a/src/Tokenizer/Parser/String.php
+++ b/src/Tokenizer/Parser/String.php
@@ -20,7 +20,7 @@ final class String
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      * @param array     $matches
      */
     public static function isFunction(Tokenizer $tokenizer, $string, array &$matches)
@@ -61,7 +61,7 @@ protected static function getFunctionString($string, array &$matches)
 
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      * @param array     $matches
      */
     public static function getNonReservedString(Tokenizer $tokenizer, $string, array &$matches)
diff --git a/src/Tokenizer/Parser/UserDefined.php b/src/Tokenizer/Parser/UserDefined.php
index 3d695f2..4c3ad9e 100644
--- a/src/Tokenizer/Parser/UserDefined.php
+++ b/src/Tokenizer/Parser/UserDefined.php
@@ -20,7 +20,7 @@ final class UserDefined
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      *
      * @return array
      */
diff --git a/src/Tokenizer/Parser/WhiteSpace.php b/src/Tokenizer/Parser/WhiteSpace.php
index 6e811c7..9332cb0 100644
--- a/src/Tokenizer/Parser/WhiteSpace.php
+++ b/src/Tokenizer/Parser/WhiteSpace.php
@@ -20,7 +20,7 @@ final class WhiteSpace
 {
     /**
      * @param Tokenizer $tokenizer
-     * @param           $string
+     * @param           string $string
      * @param array     $matches
      */
     public static function isWhiteSpace(Tokenizer $tokenizer, $string, array &$matches)