fix psalm errors

Author: Baptouuuu

src/Accumulate.php

@@ -38,6 +38,7 @@ public function current(): mixed
         /** @psalm-suppress UnusedMethodCall */
         $this->pop();
 
+        /** @var S */
         return \current($this->values);
     }
 

src/Sequence/Aggregate.php

@@ -58,7 +58,10 @@ public function __invoke(callable $map): \Generator
 
         /** @psalm-suppress ImpureMethodCall */
         while ($this->values->valid()) {
-            /** @psalm-suppress ImpureFunctionCall */
+            /**
+             * @psalm-suppress PossiblyNullArgument
+             * @psalm-suppress ImpureFunctionCall
+             */
             $aggregate = $this->walk($map($n2, $n1), $void);
 
             foreach ($aggregate as $element) {

src/Sequence/Lazy.php

@@ -860,6 +860,7 @@ public function dropWhile(callable $condition): self
                 /**
                  * @psalm-suppress ImpureMethodCall
                  * @psalm-suppress ImpureFunctionCall
+                 * @psalm-suppress PossiblyNullArgument
                  */
                 if (!$condition($generator->current())) {
                     /** @psalm-suppress ImpureMethodCall */

src/Sequence/Primitive.php

@@ -609,6 +609,7 @@ public function dropWhile(callable $condition): self
             /**
              * @psalm-suppress ImpureMethodCall
              * @psalm-suppress ImpureFunctionCall
+             * @psalm-suppress PossiblyNullArgument
              */
             if (!$condition($iterator->current())) {
                 /** @psalm-suppress ImpureMethodCall */

src/Str.php

@@ -285,6 +285,12 @@ public function pregSplit(string|\Stringable $regex, int $limit = -1): Sequence
     {
         /** @psalm-suppress ArgumentTypeCoercion */
         $strings = \preg_split((string) $regex, $this->value, $limit);
+
+        if ($strings === false) {
+            /** @psalm-suppress ImpureFunctionCall */
+            throw new InvalidRegex('', \preg_last_error());
+        }
+
         /** @var Sequence<self> */
         $sequence = Sequence::of();