Describe the position argument without contrasting it, cover the past-the-end reset

src/AbstractLexer.php

@@ -114,7 +114,7 @@ abstract class AbstractLexer
      * Resets the lexer position on the input to the given position.
      *
      * @param int $position Character offset into the input, as found in
-     *                      Token::$position; not an index in the token list.
+     *                      Token::$position.
      *
      * @return void
      */

tests/AbstractLexerTest.php

@@ -119,6 +119,24 @@ class AbstractLexerTest extends TestCase
         $this->assertEquals($target, $this->concreteLexer->lookahead);
     }
 
+    public function testResetPositionPastTheLastToken(): void
+    {
+        $this->concreteLexer->setInput('price=10');
+
+        $tokenCount = 0;
+        while ($this->concreteLexer->moveNext()) {
+            $tokenCount++;
+        }
+
+        $this->assertSame(3, $tokenCount);
+
+        // No token starts at or after this offset, so the lexer lands at the end.
+        $this->concreteLexer->resetPosition(99);
+
+        $this->assertFalse($this->concreteLexer->moveNext());
+        $this->assertNull($this->concreteLexer->lookahead);
+    }
+
     /** @phpstan-param list<Token<string, string|int>>  $expectedTokens */
     #[DataProvider('dataProvider')]
     public function testMoveNext(string $input, array $expectedTokens): void