use psalm v5

composer.json

@@ -20,7 +20,7 @@
         "ext-intl": "*",
         "friendsofphp/php-cs-fixer": "^3.49",
         "phpunit/phpunit": "^9.6",
-        "vimeo/psalm": "^4.30"
+        "vimeo/psalm": "^5.21"
     },
 
     "suggest": {

psalm.xml.dist

@@ -4,6 +4,8 @@
     ensureArrayStringOffsetsExist="true"
     findUnusedVariablesAndParams="true"
     findUnusedPsalmSuppress="true"
+    findUnusedBaselineEntry="true"
+    findUnusedCode="false"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
     xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"

src/Duration.php

@@ -62,6 +62,7 @@ public static function fromString(string $duration): self
     /**
      * @psalm-pure
      * @psalm-suppress ImpurePropertyAssignment
+     * @psalm-suppress InaccessibleProperty
      */
     public static function fromParts(int $years = 0, int $months = 0, int $weeks = 0, int $days = 0, int $hours = 0, int $minutes = 0, int $seconds = 0, int $microseconds = 0, bool $inverted = false): self
     {
@@ -205,7 +206,6 @@ public function isZero(): bool
 
     public function format(string $format): string
     {
-        /** @psalm-suppress ImpureMethodCall */
         return $this->interval->format($format);
     }
 
@@ -303,6 +303,7 @@ public function __debugInfo(): array
     private static function fromSinglePart(string $part, int $count): self
     {
         if (1 !== $count) {
+            /** @psalm-suppress ImpureMethodCall */
             return new self(\DateInterval::createFromDateString($count.$part));
         }
 
@@ -313,6 +314,7 @@ private static function fromSinglePart(string $part, int $count): self
         static $durations = [];
 
         if (!isset($durations[$part])) {
+            /** @psalm-suppress ImpureMethodCall */
             $durations[$part] = new self(\DateInterval::createFromDateString('1'.$part));
         }
 

src/TimeZone.php

@@ -139,7 +139,7 @@ public function __serialize(): array
     }
 
     /**
-     * @param array{name: string} $data
+     * @param array{name: non-empty-string} $data
      */
     public function __unserialize(array $data): void
     {