When I going to Disable Twig template cache , Fatal error When I going to Disable Twig template cache , Fatal error . i.e 


  The website encountered an unexpected error. Please try again later.
  Error: Unsupported operand types in
  Drupal\Core\Template\TwigEnvironment->__construct() (line 69 of
  core\lib\Drupal\Core\Template\TwigEnvironment.php).


I followed below steps :

1.Copy and rename the file from sites/example.settings.local.php to  sites/default/settings.local.php
2.Open settings.php file in sites/default and uncomment these lines:

if (file_exists($app_root . '/' . $site_path . '/settings.local.php')) {
include $app_root . '/' . $site_path . '/settings.local.php';
}


3.Uncomment these lines in settings.local.php

$settings['cache']['bins']['render'] = 'cache.backend.null';
$settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';



Open development.services.yml in the sites folder and add the following code

 parameters:
twig.config:
debug: true
auto_reload: true
cache: false
Rebuild the cache and your good to go


My development.services.yml code : 

parameters:
  http.response.debug_cacheability_headers: true
  twig.config:
  debug: true
  auto_reload: true
  cache: false
services:
  cache.backend.null:
    class: Drupal\Core\Cache\NullBackendFactory
The least hassle way is to install Drupal Console

Then run the command drupal site:mode dev (turns off caching and turns on twig debug)

Once you're done, run drupal site:mode prod (turns off twig debug, turns caching back on).