c++20!

CMakeLists.txt

@@ -176,7 +176,9 @@ if (ARCH_NATIVE)
     set (COMPILER_FLAGS "${COMPILER_FLAGS} -march=native")
 endif ()
 
-set (CMAKE_CXX_STANDARD 17)
+# cmake < 3.12 doesn't supoprt 20. We'll set CMAKE_CXX_FLAGS for now
+# set (CMAKE_CXX_STANDARD 20)
+set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++2a")
 set (CMAKE_CXX_EXTENSIONS 0) # https://cmake.org/cmake/help/latest/prop_tgt/CXX_EXTENSIONS.html#prop_tgt:CXX_EXTENSIONS
 set (CMAKE_CXX_STANDARD_REQUIRED ON)
 

contrib/CMakeLists.txt

@@ -2,10 +2,10 @@
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w -std=c++1z")
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w")
 elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w -std=c++1z")
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w")
 endif ()
 
 set_property(DIRECTORY PROPERTY EXCLUDE_FROM_ALL 1)

contrib/arrow-cmake/CMakeLists.txt

 include(ExternalProject)
 
+set (CMAKE_CXX_STANDARD 17)
+
 # === thrift
 
 set(LIBRARY_DIR ${ClickHouse_SOURCE_DIR}/contrib/thrift/lib/cpp)

contrib/capnproto-cmake/CMakeLists.txt

 set (CAPNPROTO_SOURCE_DIR ${ClickHouse_SOURCE_DIR}/contrib/capnproto/c++/src)
 
+set (CMAKE_CXX_STANDARD 17)
+
 set (KJ_SRCS
     ${CAPNPROTO_SOURCE_DIR}/kj/array.c++
     ${CAPNPROTO_SOURCE_DIR}/kj/common.c++

contrib/icu-cmake/CMakeLists.txt

 set(ICU_SOURCE_DIR ${ClickHouse_SOURCE_DIR}/contrib/icu/icu4c/source)
 set(ICUDATA_SOURCE_DIR ${ClickHouse_SOURCE_DIR}/contrib/icudata/)
 
+set (CMAKE_CXX_STANDARD 17)
+
 # These lists of sources were generated from build log of the original ICU build system (configure + make).
 
 set(ICUUC_SOURCES

dbms/src/DataStreams/PushingToViewsBlockOutputStream.cpp

@@ -129,7 +129,7 @@ void PushingToViewsBlockOutputStream::write(const Block & block)
         for (size_t view_num = 0; view_num < views.size(); ++view_num)
         {
             auto thread_group = CurrentThread::getGroup();
-            pool.scheduleOrThrowOnError([=]
+            pool.scheduleOrThrowOnError([=, this]
             {
                 setThreadName("PushingToViews");
                 if (thread_group)

dbms/src/Interpreters/EmbeddedDictionaries.cpp

@@ -72,7 +72,7 @@ bool EmbeddedDictionaries::reloadImpl(const bool throw_on_error, const bool forc
 
     bool was_exception = false;
 
-    DictionaryReloader<RegionsHierarchies> reload_regions_hierarchies = [=] (const Poco::Util::AbstractConfiguration & config)
+    DictionaryReloader<RegionsHierarchies> reload_regions_hierarchies = [=, this] (const Poco::Util::AbstractConfiguration & config)
     {
         return geo_dictionaries_loader->reloadRegionsHierarchies(config);
     };
@@ -80,7 +80,7 @@ bool EmbeddedDictionaries::reloadImpl(const bool throw_on_error, const bool forc
     if (!reloadDictionary<RegionsHierarchies>(regions_hierarchies, std::move(reload_regions_hierarchies), throw_on_error, force_reload))
         was_exception = true;
 
-    DictionaryReloader<RegionsNames> reload_regions_names = [=] (const Poco::Util::AbstractConfiguration & config)
+    DictionaryReloader<RegionsNames> reload_regions_names = [=, this] (const Poco::Util::AbstractConfiguration & config)
     {
         return geo_dictionaries_loader->reloadRegionsNames(config);
     };

dbms/src/Storages/StorageMerge.cpp

@@ -252,7 +252,7 @@ BlockInputStreams StorageMerge::read(
         else
         {
             source_streams.emplace_back(std::make_shared<LazyBlockInputStream>(
-                header, [=]() mutable -> BlockInputStreamPtr
+                header, [=, this]() mutable -> BlockInputStreamPtr
                 {
                     BlockInputStreams streams = createSourceStreams(query_info, processed_stage, max_block_size,
                                                                     header, storage, struct_lock, real_column_names,

libs/libdaemon/src/BaseDaemon.cpp

@@ -209,7 +209,7 @@ public:
 
                 /// This allows to receive more signals if failure happens inside onFault function.
                 /// Example: segfault while symbolizing stack trace.
-                std::thread([=] { onFault(sig, info, context, stack_trace, thread_num, query_id); }).detach();
+                std::thread([=, this] { onFault(sig, info, context, stack_trace, thread_num, query_id); }).detach();
             }
         }
     }