string component fixes

src/Symfony/Component/String/AbstractUnicodeString.php

@@ -13,6 +13,7 @@
 
 use Symfony\Component\String\Exception\ExceptionInterface;
 use Symfony\Component\String\Exception\InvalidArgumentException;
+use Symfony\Component\String\Exception\RuntimeException;
 
 /**
  * Represents a string of abstract Unicode characters.

src/Symfony/Component/String/BinaryString.php

@@ -13,6 +13,7 @@
 
 use Symfony\Component\String\Exception\ExceptionInterface;
 use Symfony\Component\String\Exception\InvalidArgumentException;
+use Symfony\Component\String\Exception\RuntimeException;
 
 /**
  * Represents a binary-safe string of bytes.
@@ -301,7 +302,7 @@ public function slice(int $start = 0, int $length = null): parent
     public function splice(string $replacement, int $start = 0, int $length = null): parent
     {
         $str = clone $this;
-        $str = substr_replace($this->string, $replacement, $start, $length ?? \PHP_INT_MAX);
+        $str->string = substr_replace($this->string, $replacement, $start, $length ?? \PHP_INT_MAX);
 
         return $str;
     }

src/Symfony/Component/String/GraphemeString.php

@@ -179,7 +179,7 @@ public function length(): int
     /**
      * @return static
      */
-    public function normalize(int $form = self::NFC): self
+    public function normalize(int $form = self::NFC): parent
     {
         if (\in_array($form, [self::NFD, self::NFKD])) {
             $this->ignoreCase = null;

src/Symfony/Component/String/Utf8String.php

@@ -85,7 +85,7 @@ public function endsWith($suffix): bool
         }
 
         if ($this->ignoreCase) {
-            return preg_match('{'.preg_quote($suffix).'$}iu');
+            return preg_match('{'.preg_quote($suffix).'$}iu', $this->string);
         }
 
         return \strlen($this->string) - \strlen($suffix) === strrpos($this->string, $suffix);