StateBearer must be constructable from State

src/State.php

@@ -107,6 +107,12 @@ final class State implements StateBearer
         return $this;
     }
 
+    /** @return self */
+    public static function fromState(State $State)
+    {
+        return $State;
+    }
+
     public function isolatedCopy(): self
     {
         return new self(\array_map(

src/StateBearer.php

@@ -5,4 +5,6 @@ namespace Erusev\Parsedown;
 interface StateBearer
 {
     public function state(): State;
+    /** @return static */
+    public static function fromState(State $State);
 }

tests/src/StateTest.php

@@ -39,4 +39,16 @@ final class StateTest extends TestCase
     {
         $this->assertInstanceOf(State::class, clone(new State));
     }
+
+    /**
+     * @return void
+     * @throws \PHPUnit\Framework\Exception
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
+     */
+    public function testStateFromStateIdentical()
+    {
+        $State = new State;
+
+        $this->assertSame($State, State::fromState($State));
+    }
 }