Simplifie le cast en string des unions.

src/php/Models/Types/Union.php

@@ -58,14 +58,17 @@ final class Union extends AbstractType
      */
     public function castToStringOrStringArray(string $expr): string
     {
-        $cast = $expr;
-        foreach ($this->types as $type) {
+        $alternatives = $this->types;
+        $first = array_shift($alternatives);
+        $cast = $first->castToStringOrStringArray($expr);
+        foreach ($alternatives as $type) {
+            $typeCast = $type->castToStringOrStringArray($expr);
+            if ($typeCast === $cast) {
+                continue;
+            }
             $check = $type->checkType($expr);
             if ($check) {
-                $typeCast = $type->castToStringOrStringArray($expr);
-                if ($typeCast !== $cast) {
-                    $cast = sprintf('(%s ? %s : %s)', $check, $type->castToStringOrStringArray($expr), $cast);
-                }
+                $cast = sprintf('(%s ? %s : %s)', $check, $typeCast, $cast);
             }
         }