diff --git a/DateFormatter/DateFormat/HourTransformer.php b/DateFormatter/DateFormat/HourTransformer.php
index 54dcbfe2..a9734ac0 100644
--- a/DateFormatter/DateFormat/HourTransformer.php
+++ b/DateFormatter/DateFormat/HourTransformer.php
@@ -25,8 +25,8 @@ abstract class HourTransformer extends Transformer
     /**
      * Returns a normalized hour value suitable for the hour transformer type.
      *
-     * @param int    $hour   The hour value
-     * @param string $marker An optional AM/PM marker
+     * @param int         $hour   The hour value
+     * @param string|null $marker An optional AM/PM marker
      *
      * @return int The normalized hour value
      */
diff --git a/DateFormatter/IntlDateFormatter.php b/DateFormatter/IntlDateFormatter.php
index 5b683c4c..86257898 100644
--- a/DateFormatter/IntlDateFormatter.php
+++ b/DateFormatter/IntlDateFormatter.php
@@ -124,7 +124,7 @@ abstract class IntlDateFormatter
      * @param int|null                                $datetype Type of date formatting, one of the format type constants
      * @param int|null                                $timetype Type of time formatting, one of the format type constants
      * @param \IntlTimeZone|\DateTimeZone|string|null $timezone Timezone identifier
-     * @param int                                     $calendar Calendar to use for formatting or parsing. The only currently
+     * @param int|null                                $calendar Calendar to use for formatting or parsing. The only currently
      *                                                          supported value is IntlDateFormatter::GREGORIAN (or null using the default calendar, i.e. "GREGORIAN")
      * @param string|null                             $pattern  Optional pattern to use when formatting
      *
@@ -418,11 +418,11 @@ public function localtime(string $value, int &$position = 0)
     /**
      * Parse string to a timestamp value.
      *
-     * @param string $value    String to convert to a time value
-     * @param int    $position Not supported. Position at which to start the parsing in $value (zero-based)
-     *                         If no error occurs before $value is consumed, $parse_pos will
-     *                         contain -1 otherwise it will contain the position at which parsing
-     *                         ended. If $parse_pos > strlen($value), the parse fails immediately.
+     * @param string   $value    String to convert to a time value
+     * @param int|null $position Not supported. Position at which to start the parsing in $value (zero-based)
+     *                           If no error occurs before $value is consumed, $parse_pos will
+     *                           contain -1 otherwise it will contain the position at which parsing
+     *                           ended. If $parse_pos > strlen($value), the parse fails immediately.
      *
      * @return int|false Parsed value as a timestamp
      *
@@ -494,7 +494,7 @@ public function setLenient(bool $lenient)
     /**
      * Set the formatter's pattern.
      *
-     * @param string $pattern A pattern string in conformance with the ICU IntlDateFormatter documentation
+     * @param string|null $pattern A pattern string in conformance with the ICU IntlDateFormatter documentation
      *
      * @return bool true on success or false on failure
      *
diff --git a/Locale/Locale.php b/Locale/Locale.php
index 79d2f079..d8066714 100644
--- a/Locale/Locale.php
+++ b/Locale/Locale.php
@@ -152,8 +152,8 @@ public static function getDefault()
     /**
      * Not supported. Returns the localized display name for the locale language.
      *
-     * @param string $locale   The locale code to return the display language from
-     * @param string $inLocale Optional format locale code to use to display the language name
+     * @param string      $locale   The locale code to return the display language from
+     * @param string|null $inLocale Optional format locale code to use to display the language name
      *
      * @return string
      *
@@ -169,8 +169,8 @@ public static function getDisplayLanguage(string $locale, string $inLocale = nul
     /**
      * Not supported. Returns the localized display name for the locale.
      *
-     * @param string $locale   The locale code to return the display locale name from
-     * @param string $inLocale Optional format locale code to use to display the locale name
+     * @param string      $locale   The locale code to return the display locale name from
+     * @param string|null $inLocale Optional format locale code to use to display the locale name
      *
      * @return string
      *
@@ -186,8 +186,8 @@ public static function getDisplayName(string $locale, string $inLocale = null)
     /**
      * Not supported. Returns the localized display name for the locale region.
      *
-     * @param string $locale   The locale code to return the display region from
-     * @param string $inLocale Optional format locale code to use to display the region name
+     * @param string      $locale   The locale code to return the display region from
+     * @param string|null $inLocale Optional format locale code to use to display the region name
      *
      * @return string
      *
@@ -203,8 +203,8 @@ public static function getDisplayRegion(string $locale, string $inLocale = null)
     /**
      * Not supported. Returns the localized display name for the locale script.
      *
-     * @param string $locale   The locale code to return the display script from
-     * @param string $inLocale Optional format locale code to use to display the script name
+     * @param string      $locale   The locale code to return the display script from
+     * @param string|null $inLocale Optional format locale code to use to display the script name
      *
      * @return string
      *
@@ -220,8 +220,8 @@ public static function getDisplayScript(string $locale, string $inLocale = null)
     /**
      * Not supported. Returns the localized display name for the locale variant.
      *
-     * @param string $locale   The locale code to return the display variant from
-     * @param string $inLocale Optional format locale code to use to display the variant name
+     * @param string      $locale   The locale code to return the display variant from
+     * @param string|null $inLocale Optional format locale code to use to display the variant name
      *
      * @return string
      *
@@ -301,10 +301,10 @@ public static function getScript(string $locale)
     /**
      * Not supported. Returns the closest language tag for the locale.
      *
-     * @param array  $langtag      A list of the language tags to compare to locale
-     * @param string $locale       The locale to use as the language range when matching
-     * @param bool   $canonicalize If true, the arguments will be converted to canonical form before matching
-     * @param string $default      The locale to use if no match is found
+     * @param array       $langtag      A list of the language tags to compare to locale
+     * @param string      $locale       The locale to use as the language range when matching
+     * @param bool        $canonicalize If true, the arguments will be converted to canonical form before matching
+     * @param string|null $default      The locale to use if no match is found
      *
      * @see https://php.net/locale.lookup
      *
diff --git a/NumberFormatter/NumberFormatter.php b/NumberFormatter/NumberFormatter.php
index 2a369c27..b573f639 100644
--- a/NumberFormatter/NumberFormatter.php
+++ b/NumberFormatter/NumberFormatter.php
@@ -244,10 +244,10 @@ abstract class NumberFormatter
 
     /**
      * @param string|null $locale  The locale code. The only currently supported locale is "en" (or null using the default locale, i.e. "en")
-     * @param int         $style   Style of the formatting, one of the format style constants.
+     * @param int|null    $style   Style of the formatting, one of the format style constants.
      *                             The only supported styles are NumberFormatter::DECIMAL
      *                             and NumberFormatter::CURRENCY.
-     * @param string      $pattern Not supported. A pattern string in case $style is NumberFormat::PATTERN_DECIMAL or
+     * @param string|null $pattern Not supported. A pattern string in case $style is NumberFormat::PATTERN_DECIMAL or
      *                             NumberFormat::PATTERN_RULEBASED. It must conform to  the syntax
      *                             described in the ICU DecimalFormat or ICU RuleBasedNumberFormat documentation
      *
@@ -281,10 +281,10 @@ public function __construct(?string $locale = 'en', int $style = null, string $p
      * Static constructor.
      *
      * @param string|null $locale  The locale code. The only supported locale is "en" (or null using the default locale, i.e. "en")
-     * @param int         $style   Style of the formatting, one of the format style constants.
+     * @param int|null    $style   Style of the formatting, one of the format style constants.
      *                             The only currently supported styles are NumberFormatter::DECIMAL
      *                             and NumberFormatter::CURRENCY.
-     * @param string      $pattern Not supported. A pattern string in case $style is NumberFormat::PATTERN_DECIMAL or
+     * @param string|null $pattern Not supported. A pattern string in case $style is NumberFormat::PATTERN_DECIMAL or
      *                             NumberFormat::PATTERN_RULEBASED. It must conform to  the syntax
      *                             described in the ICU DecimalFormat or ICU RuleBasedNumberFormat documentation
      *
@@ -485,9 +485,9 @@ public function getTextAttribute(int $attr)
     /**
      * Not supported. Parse a currency number.
      *
-     * @param string $value    The value to parse
-     * @param string $currency Parameter to receive the currency name (reference)
-     * @param int    $position Offset to begin the parsing on return this value will hold the offset at which the parsing ended
+     * @param string   $value    The value to parse
+     * @param string   $currency Parameter to receive the currency name (reference)
+     * @param int|null $position Offset to begin the parsing on return this value will hold the offset at which the parsing ended
      *
      * @return float|false The parsed numeric value or false on error
      *
diff --git a/ResourceBundle.php b/ResourceBundle.php
index 4f2ee32d..c0ef5d1e 100644
--- a/ResourceBundle.php
+++ b/ResourceBundle.php
@@ -32,13 +32,13 @@ abstract protected static function getPath(): string;
      *
      * @see BundleEntryReaderInterface::readEntry()
      *
-     * @param string[] $indices  The indices to read from the bundle
-     * @param string   $locale   The locale to read
-     * @param bool     $fallback Whether to merge the value with the value from
-     *                           the fallback locale (e.g. "en" for "en_GB").
-     *                           Only applicable if the result is multivalued
-     *                           (i.e. array or \ArrayAccess) or cannot be found
-     *                           in the requested locale.
+     * @param string[]    $indices  The indices to read from the bundle
+     * @param string|null $locale   The locale to read
+     * @param bool        $fallback Whether to merge the value with the value from
+     *                              the fallback locale (e.g. "en" for "en_GB").
+     *                              Only applicable if the result is multivalued
+     *                              (i.e. array or \ArrayAccess) or cannot be found
+     *                              in the requested locale.
      *
      * @return mixed returns an array or {@link \ArrayAccess} instance for
      *               complex data and a scalar value for simple data