feat(Core): Enable C++20 support (#10440)

* feat(Core): Enable C++20 support

* Update Duration.h

* Revert "Update Duration.h"

This reverts commit 177093e992c5d47d8c3b978c84857f5ecba12889.

* maybe fix GCC

* cherry-pick https://gcc.gnu.org/pipermail/gcc-cvs/2020-June/299715.html

* Update Duration.h

* Update Duration.h

* Update Duration.h

* Update Duration.h

* Update Duration.h

* Update Duration.h

* Update Duration.h

* Revert "Update Duration.h"

This reverts commit dc4e2ce281dd1a33cfac5be56488a3b96131bfd5.

* Update Duration.h

* Update Duration.h

* Update Duration.h

* cleanup

* more cleanup

* maybe fix build

* restore advstd::type_identity because GCC8 is garbage

* Update advstd.h

* fix gcc8 :zzz:

* Update CMakeLists.txt

* Update CMakeLists.txt

* Update src/common/Utilities/advstd.h

Co-authored-by: Francesco Borzì <borzifrancesco@gmail.com>

9 files changed, 23 insertions, 80 deletions

diff --git a/.github/workflows/cpp20.yml b/.github/workflows/cpp20.yml
deleted file mode 100644
index 3fcd885b77..0000000000
--- a/.github/workflows/cpp20.yml
+++ /dev/null
@@ -1,46 +0,0 @@
-name: C++20
-on:
-  push:
-    branches:
-      - 'master'
-  pull_request:
-    types: ['labeled', 'labeled', 'opened', 'synchronize', 'reopened']
-
-concurrency:
-  group: ${{ github.head_ref }} || concat(${{ github.ref }}, ${{ github.workflow }})
-  cancel-in-progress: true
-
-jobs:
-  build:
-    runs-on: ubuntu-20.04
-    name: C++20
-    env:
-      COMPILER: clang
-      ENABLE_CPP_20: 1
-    if: github.repository == 'azerothcore/azerothcore-wotlk' && (github.ref == 'refs/heads/master' || contains(github.event.pull_request.labels.*.name, 'file-cpp') || github.event.label.name == 'file-cpp' || contains(github.event.pull_request.labels.*.name, 'run-build') || github.event.label.name == 'run-build')
-    steps:
-      - uses: actions/checkout@v2
-      - name: Cache
-        uses: actions/cache@v2
-        with:
-          path: var/ccache
-          key: ccache:C++20:${{ github.ref }}:${{ github.sha }}
-          restore-keys: |
-            ccache:C++20:${{ github.ref }}
-            ccache:C++20
-      - name: Configure OS
-        run: source ./acore.sh install-deps
-        env:
-          CONTINUOUS_INTEGRATION: true
-      - name: Create conf/config.sh
-        run: source ./apps/ci/ci-conf.sh
-      - name: Import db
-        run: source ./apps/ci/ci-import-db.sh
-      - name: Build
-        run: source ./apps/ci/ci-compile.sh
-      - name: Dry run
-        run: source ./apps/ci/ci-worldserver-dry-run.sh
-      - name: Check startup errors
-        run: source ./apps/ci/ci-error-check.sh
-      - name: Run unit tests
-        run: source ./apps/ci/ci-run-unit-tests.sh
diff --git a/conf/dist/config.cmake b/conf/dist/config.cmake
index 329f2656eb..43bc3dd5ee 100644
--- a/conf/dist/config.cmake
+++ b/conf/dist/config.cmake
@@ -87,8 +87,5 @@ endif()
 set(WITH_SOURCE_TREE       "hierarchical" CACHE STRING "Build the source tree for IDE's.")
 set_property(CACHE WITH_SOURCE_TREE PROPERTY STRINGS no flat hierarchical)
 
-# If disable - use c++17
-option(USE_CPP_20 "Enable c++20 standard" 0)
-
 # Config abort
 option(CONFIG_ABORT_INCORRECT_OPTIONS "Enable abort if core found incorrect option in config files" 0)
diff --git a/deps/boost/CMakeLists.txt b/deps/boost/CMakeLists.txt
index afe44ba4a3..db4ef4ef5d 100644
--- a/deps/boost/CMakeLists.txt
+++ b/deps/boost/CMakeLists.txt
@@ -27,7 +27,7 @@ include (CheckCXXSourceCompiles)
 
 if (WIN32)
   # On windows the requirements are higher according to the wiki.
-  set(BOOST_REQUIRED_VERSION 1.70)
+  set(BOOST_REQUIRED_VERSION 1.74)
 else()
   set(BOOST_REQUIRED_VERSION 1.67)
 endif()
diff --git a/src/cmake/macros/ConfigureBaseTargets.cmake b/src/cmake/macros/ConfigureBaseTargets.cmake
index 046b8728f1..830a634ba6 100644
--- a/src/cmake/macros/ConfigureBaseTargets.cmake
+++ b/src/cmake/macros/ConfigureBaseTargets.cmake
@@ -16,15 +16,9 @@ add_library(acore-compile-option-interface INTERFACE)
 # Use -std=c++11 instead of -std=gnu++11
 set(CXX_EXTENSIONS OFF)
 
-if (USE_CPP_20)
-  # Enable support С++20
-  set(CMAKE_CXX_STANDARD 20)
-  message(STATUS "Enabled С++20 standard")
-else()
-  # Enable support С++17
-  set(CMAKE_CXX_STANDARD 17)
-  message(STATUS "Enabled С++17 standard")
-endif()
+# Enable C++20 support
+set(CMAKE_CXX_STANDARD 20)
+message(STATUS "Enabled С++20 standard")
 
 # An interface library to make the warnings level available to other targets
 # This interface taget is set-up through the platform specific script
diff --git a/src/cmake/showoptions.cmake b/src/cmake/showoptions.cmake
index 906692e106..1d2366a281 100644
--- a/src/cmake/showoptions.cmake
+++ b/src/cmake/showoptions.cmake
@@ -182,12 +182,6 @@ if(BUILD_SHARED_LIBS)
   WarnAboutSpacesInBuildPath()
 endif()
 
-if (USE_CPP_20)
-  message("")
-  message(" *** Enabled C++20 standart")
-  message(" *** Please note that this is an experimental feature!")
-endif()
-
 if (CONFIG_ABORT_INCORRECT_OPTIONS)
   message("")
   message(" WARNING !")
diff --git a/src/common/Utilities/Duration.h b/src/common/Utilities/Duration.h
index 9ddb1a68a1..ed6bbf8817 100644
--- a/src/common/Utilities/Duration.h
+++ b/src/common/Utilities/Duration.h
@@ -35,7 +35,22 @@ using Minutes = std::chrono::minutes;
 /// Hours shorthand typedef.
 using Hours = std::chrono::hours;
 
-#if __cplusplus > 201703L
+// Workaround for GCC and Clang 10 in C++20
+#if defined(__GNUC__) && (!defined(__clang__) || (__clang_major__ == 10))
+/// Days shorthand typedef.
+using Days = std::chrono::duration<__INT64_TYPE__, std::ratio<86400>>;
+
+/// Weeks shorthand typedef.
+using Weeks = std::chrono::duration<__INT64_TYPE__, std::ratio<604800>>;
+
+/// Years shorthand typedef.
+using Years = std::chrono::duration<__INT64_TYPE__, std::ratio<31556952>>;
+
+/// Months shorthand typedef.
+using Months = std::chrono::duration<__INT64_TYPE__, std::ratio<2629746>>;
+
+#else
+
 /// Days shorthand typedef.
 using Days = std::chrono::days;
 
@@ -47,19 +62,8 @@ using Years = std::chrono::years;
 
 /// Months shorthand typedef.
 using Months = std::chrono::months;
-#else
-/// Days shorthand typedef. (delete after start support c++20)
-using Days = std::chrono::duration<int, std::ratio_multiply<std::ratio<24>, Hours::period>>;
 
-/// Weeks shorthand typedef. (delete after start support c++20)
-using Weeks = std::chrono::duration<int, std::ratio_multiply<std::ratio<7>, Days::period>>;
-
-/// Years shorthand typedef. (delete after start support c++20)
-using Years = std::chrono::duration<int, std::ratio_multiply<std::ratio<146097, 400>, Days::period>>;
-
-/// Months shorthand typedef. (delete after start support c++20)
-using Months = std::chrono::duration<int, std::ratio_divide<Years::period, std::ratio<12>>>;
-#endif
+#endif // GCC_VERSION
 
 /// time_point shorthand typedefs
 using TimePoint = std::chrono::steady_clock::time_point;
diff --git a/src/common/Utilities/EventProcessor.h b/src/common/Utilities/EventProcessor.h
index 81b3bf79c3..aaf6481a76 100644
--- a/src/common/Utilities/EventProcessor.h
+++ b/src/common/Utilities/EventProcessor.h
@@ -21,7 +21,6 @@
 #include "Define.h"
 #include "Duration.h"
 #include "Random.h"
-
 #include "advstd.h"
 #include <map>
 #include <type_traits>
diff --git a/src/common/Utilities/advstd.h b/src/common/Utilities/advstd.h
index 3e58973058..3b33dbaec6 100644
--- a/src/common/Utilities/advstd.h
+++ b/src/common/Utilities/advstd.h
@@ -24,6 +24,8 @@
 // this namespace holds implementations of upcoming stdlib features that our c++ version doesn't have yet
 namespace advstd
 {
+    // This workaround for std::remove_cvref_t, std::type_identify is needed for GCC 8...
+    // TODO: remove when we drop GCC 8 support. https://en.cppreference.com/w/cpp/compiler_support/20
     // C++20 advstd::remove_cvref_t
     template <class T>
     using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
diff --git a/src/server/game/Chat/Hyperlinks.cpp b/src/server/game/Chat/Hyperlinks.cpp
index e817ac461f..cc9e43cafc 100644
--- a/src/server/game/Chat/Hyperlinks.cpp
+++ b/src/server/game/Chat/Hyperlinks.cpp
@@ -24,7 +24,6 @@
 #include "SharedDefines.h"
 #include "SpellInfo.h"
 #include "SpellMgr.h"
-#include "advstd.h"
 
 using namespace Acore::Hyperlinks;