@ is now part of the name of an attribute or a macro. Macros without '@' must be function-like.

resources/examples/raylib/raylib_snake.c3

@@ -153,7 +153,7 @@ fn void update_game()
 			snake[0].position.x += -SQUARE_SIZE;
             snake[0].position.y += 0;
 		default:
-			@unreachable();
+			unreachable();
 	}
     for (int i = 1; i < counter_tail; i++)
     {

resources/examples/raylib/raylib_tetris.c3

@@ -462,7 +462,7 @@ fn void get_random_piece()
             incoming_piece[2][1] = MOVING;
             incoming_piece[3][1] = MOVING; //S inversa
         default:
-            @unreachable();
+            unreachable();
     }
 }