Revert "Issue #2752961 by dawehner, Wim Leers, Jo Fitzgerald, bradjones1, chr.fritsch, greg.1.anderson, anavarre, Berdir, moshe weitzman, bkosborne, alexpott, Crell, catch, msonnabaum, lauriii, joelpittet, deviantintegral, cilefen, effulgentsia, xjm: No reliable method exists for clearing the Twig cache"

This reverts commit ada497ac.

Issue #2752961 by dawehner, Wim Leers, Jo Fitzgerald, bradjones1, chr.fritsch, greg.1.anderson, anavarre, Berdir, moshe weitzman, bkosborne, alexpott, Crell, catch, msonnabaum, lauriii, joelpittet, deviantintegral, cilefen, effulgentsia, xjm: No reliable method exists for clearing the Twig cache

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2569119 by pwolanin, marvin_B8, jhedstrom, csheltonlcm, alexpott, dawehner, Fabianx, catch:  Use Crypt::hashBase64(), not hash('crc32b') or sha1 for placeholder tokens

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2513266 by mikeker, joelpittet, lauriii, Cottser, pwolanin, larowlan, Fabianx, stevector, catch, alexpott, dawehner: Twig templates can call delete() on entities and other objects

Issue #2576533 by alexpott, stefan.r, Wim Leers, dawehner, xjm, effulgentsia, catch: Rename SafeStringInterface to MarkupInterface and move related classes

Issue #2571817 by Cottser, hussainweb: Remove race condition handling in TwigEnvironment::loadTemplate(), it's fixed upstream now

Issue #2568171 by Cottser, dawehner, hussainweb, Wim Leers, cilefen, znerol: Upgrade to Twig 1.22 and implement our own cache class

Issue #2567139 by Cottser, stefan.r, joelpittet: Twig autoescape default strategy deprecation error triggered on every page load

Issue #2544932 by dawehner, Fabianx, Wim Leers, Gábor Hojtsy, alexpott, catch, chx, msonnabaum: Twig should not rely on loading php from shared file system

Issue #2429659 by chx, Berdir, mpdonadio, geerlingguy, Cottser, rteijeiro, Fabianx, catch, dawehner: Race conditions in the twig template cache

Issue #2506581 by alexpott, Wim Leers, Fabianx, xjm, joelpittet, Cottser, dawehner: Remove SafeMarkup::set() from Renderer::doRender

Issue #2464045 by fgm: Move twig_render_var/twig_drupal_escape_filter to TwigExtension, inject the renderer in Twig extension and inline render() / show() function instead of calling it

Issue #2369981 by Cottser: Not found templates are displayed literally instead of throwing an Exception due to string loader

Issue #2291449 by Cottser: Add Twig template inheritance based on the theme registry, enable adding Twig loaders

Issue #2328111 by dawehner, martin107, neclimdul: Replace most instances of the DRUPAL_ROOT constant with the app.root container parameter.

Issue #2317557 by dawehner, Cottser, joelpittet, jhodgdon: Fixed renderInline not compatible with twig_auto_reload.

Issue #2330503 by pfrenssen, dawehner: Fixed [sechole] Inline templates pass through unsafe strings.

Issue #2251113 by alexpott, damiankloip, Crell, Wim Leers, dawehner, sun: Use container parameters instead of settings.

Issue #2289999 by dawehner, Cottser | Fabianx: Add an easy way to create HTML on the fly without having to create a theme function / template.

Issue #2212309 by joelpittet: Drupal\Core\Template and twig.engine docs, coding standards, and unused code cleanup.

Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, alexpott, tstoeckler, Xano, tim.plunkett, BassistJimmyJam | beejeebus: Make modules and installation profiles only require .info.yml files.

Revert "Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, tstoeckler, Xano, tim.plunkett, BassistJimmyJam: Make modules and installation profiles only require .info.yml files."

This reverts commit b4c561d0.

Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, tstoeckler, Xano, tim.plunkett, BassistJimmyJam: Make modules and installation profiles only require .info.yml files.

Issue #2210197 by sun, longwave, Sutharsan: Remove public access to Extension::$type, ::$name, ::$filename.

Revert "Issue #2210197 by sun, longwave: Remove public access to Extension::$type, ::$name, ::$filename." Broke 'drush en simpletest' on testbots

This reverts commit 2c51074d.

Issue #2198343 by damiankloip, longwave: Convert all usages of cache() and cache_invalidate_tags() procedural functions.

Issue #1696786 by Fabianx, jenlampton, stevector, steveoliver, jwilson3, amateescu, chx: Integrate Twig into core: Implementation issue.