Issue #3427177 by longwave, quietone, dineshkumarbollu, samit.310@gmail.com, mondrake, alexpott: Replace calls to ::expectError*() from Drupal\Tests\Core\Render\ElementTest

Issue #3352256 by e0ipso, plopesc, bbrala, longwave, dww, catch, larowlan: Move code from the experimental SDC module to core

Issue #3083690 by gxleano, mparker17, jungle, joachim, Kris77: '"@key" is an invalid render array key' error in \Drupal\Core\Render\Element is misleading

Issue #3117291 by NitinLama, smustgrave, silverham, Chi: Element::isEmpty() should check for #weight property

Issue #3172166 by Pooja Ganjage, ekes, Megha_kundar, xjm, alexpott, tstoeckler, mbovan, Spokje: Element::properties() produces notices if given an array with integer keys

Revert "Issue #3172166 by Pooja Ganjage, ekes, Megha_kundar, tstoeckler, mbovan, Spokje, alexpott: Element::properties() produces notices if given an array with integer keys"

This reverts commit 60a42060.

Issue #3172166 by Pooja Ganjage, ekes, Megha_kundar, tstoeckler, mbovan, Spokje, alexpott: Element::properties() produces notices if given an array with integer keys

Issue #2938969 by msankhala, dhirendra.mishra, paulocs, TR, MerryHamster, alexpott, jofitz, longwave, Manuel Garcia, tameeshb, boaloysius, Yasiru Nilan, xjm, wturrell, ritzz, ZeiP, darrenwh: Replace drupal_render() in docblock and comments outside of @param, @return, @Link, @see and outside of @code - @endcode

Issue #2851394 by GoZ, hgunicamp, oknate, jungle, wolffereast, tameeshb, mmatsoo, ridhimaabrol24, jofitz, swarad07, tanc, shaktik, dimaro, shashikant_chauhan, MerryHamster, quietone, nitesh624, martin_q, boaloysius, gaurav.kapoor, nitvirus, ankithashetty, Munavijayalakshmi, kostyashupenko, leolando.tan, amit.drupal, ravi.shankar, akashkrishnan01, Swapnil_Kotwal, Saviktor, mrinalini9, anmolgoyal74, Venkatesh Rajan.J, shimpy, lomasr, Dinesh18, shubham.prakash, mahtab_alam, markdorison, cilefen, longwave, bleen, xjm, alexpott, gmaltoni: Fix grammar 'a' to 'an' when necessary

Issue #3086374 by mondrake, alexpott, joseph.olstad, Spokje, ravi.shankar, Gábor Hojtsy, heddn, Charlie ChX Negyesi, amateescu: Make Drupal 9 compatible with PHP 7.4

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

Issue #2487600 by dawehner, Wim Leers, fgm: #access should support AccessResultInterface objects or better has to always use it

Issue #1493324 by tim.plunkett, dmsmidt, mgifford, bleen18, davidhernandez, crasx, mparker17, stefan.r, YesCT, joelpittet, tstoeckler, larowlan, vijaycs85, swentel, rpayanm, Bojhan, LewisNyman, emma.maria, BarisW, njbarrett, rteijeiro, nod_, sun, joshtaylor, mrjmd, webchick, marcvangend, kattekrab, SKAUGHT, bowersox, andrewmacpherson, Manjit.Singh, RavindraSingh, Wim Leers, BLadwin, aspilicious, mortendk, mausolos, jessebeach, Gábor Hojtsy, anandps, falcon03, franz, andypost, rooby, rootwork, Cottser, Xano: Inline form errors for accessibility and UX

Issue #1805054 by Wim Leers, Gábor Hojtsy, effulgentsia, jibran, jessebeach, catch, dawehner, Fabianx, sun, larowlan: Cache localized, access filtered, URL resolved, and rendered menu trees

Issue #2491155 by mikeburrelljr, Mac_Weber, opdavies: Update drupal.org and kernel.org URLs in core modules (Follow-up to 2489912)

Issue #2448765 by nlisgo, Damien Tournoud, vlad.n, rteijeiro, Berdir, Fabianx, dawehner: Element::children sort order undefined and slower than it could be - This makes tests fail in PHP7

Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Issue #2109793 by damiankloip, dawehner, tim.plunkett: Convert element_* methods in common.inc to a class.