Remove C++11 requirements from test/Jamfile

Update .drone.jsonnet
Update ci.yml
2024-05-18 03:18:56 +03:00 · 2024-05-18 02:43:52 +03:00 · 2024-05-17 22:04:55 +03:00 · 2024-05-17 21:44:21 +03:00 · 2024-03-25 02:22:20 +02:00 · 2024-03-24 19:16:09 +02:00
24 changed files with 1470 additions and 91 deletions
--- a/.drone.jsonnet
+++ b/.drone.jsonnet
@ -0,0 +1,438 @@
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+local library = "variant2";
+
+local triggers =
+{
+    branch: [ "master", "develop", "feature/*" ]
+};
+
+local ubsan = { UBSAN: '1', UBSAN_OPTIONS: 'print_stacktrace=1' };
+local asan = { ASAN: '1' };
+
+local linux_pipeline(name, image, environment, packages = "", sources = [], arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "linux",
+        arch: arch
+    },
+    steps:
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'set -e',
+                'wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -',
+            ] +
+            (if sources != [] then [ ('apt-add-repository "' + source + '"') for source in sources ] else []) +
+            (if packages != "" then [ 'apt-get update', 'apt-get -y install ' + packages ] else []) +
+            [
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local macos_pipeline(name, environment, xcode_version = "12.2", osx_version = "catalina", arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "exec",
+    trigger: triggers,
+    platform: {
+        "os": "darwin",
+        "arch": arch
+    },
+    node: {
+        "os": osx_version
+    },
+    steps: [
+        {
+            name: "everything",
+            environment: environment + { "DEVELOPER_DIR": "/Applications/Xcode-" + xcode_version + ".app/Contents/Developer" },
+            commands:
+            [
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local windows_pipeline(name, image, environment, arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "windows",
+        arch: arch
+    },
+    "steps":
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'cmd /C .drone\\\\drone.bat ' + library,
+            ]
+        }
+    ]
+};
+
+[
+    linux_pipeline(
+        "Linux 16.04 GCC 4.8 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11', ADDRMD: '32,64' },
+        "g++-4.8-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 GCC 4.9 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '11', ADDRMD: '32,64' },
+        "g++-4.9-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 GCC 5* 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 6 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-6', CXXSTD: '11,14', ADDRMD: '32,64' },
+        "g++-6-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 7* 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 8 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-8', CXXSTD: '11,14,17', ADDRMD: '32,64' },
+        "g++-8-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* 32/64",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* ARM64",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' },
+        arch="arm64",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* S390x",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' },
+        arch="s390x",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 10 32/64",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-10', CXXSTD: '11,14,17,20', ADDRMD: '32,64' },
+        "g++-10-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 11* 32/64",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 32/64",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '11,14,17,20,2b', ADDRMD: '32,64' },
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 GCC 13 32 ASAN",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14,17,20,2b', ADDRMD: '32' } + asan,
+        "g++-13-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 GCC 13 64 ASAN",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14,17,20,2b', ADDRMD: '64' } + asan,
+        "g++-13-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 GCC 13 32 UBSAN",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14,17,20,2b', ADDRMD: '32' } + ubsan,
+        "g++-13-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 GCC 13 64 UBSAN",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14,17,20,2b', ADDRMD: '64' } + ubsan,
+        "g++-13-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 32",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '32' },
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 64",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '64' },
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.5",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.5', CXXSTD: '11' },
+        "clang-3.5",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.6",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.6', CXXSTD: '11,14' },
+        "clang-3.6",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.7",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.7', CXXSTD: '11,14' },
+        "clang-3.7",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.8",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.8', CXXSTD: '11,14' },
+        "clang-3.8",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 3.9",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '11,14' },
+        "clang-3.9",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 4.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '11,14' },
+        "clang-4.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 5.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '11,14,1z' },
+        "clang-5.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 6.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '11,14,17' },
+        "clang-6.0",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 7",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '11,14,17' },
+        "clang-7",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 8",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '11,14,17' },
+        "clang-8",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 9",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '11,14,17,2a' },
+        "clang-9",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 10",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '11,14,17,2a' },
+        "clang-10",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 11",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '11,14,17,2a' },
+        "clang-11",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 12",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '11,14,17,2a' },
+        "clang-12",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 13",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-13', CXXSTD: '11,14,17,20,2b' },
+        "clang-13",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 14",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '11,14,17,20,2b' },
+        "clang-14",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 15",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-15', CXXSTD: '11,14,17,20,2b' },
+        "clang-15",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 Clang 16",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-16', CXXSTD: '11,14,17,20,2b' },
+        "clang-16",
+    ),
+
+    linux_pipeline(
+        "Linux 23.10 Clang 17 UBSAN",
+        "cppalliance/droneubuntu2310:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-17', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        "clang-17",
+    ),
+
+    linux_pipeline(
+        "Linux 23.10 Clang 17 ASAN",
+        "cppalliance/droneubuntu2310:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-17', CXXSTD: '11,14,17,20,2b' } + asan,
+        "clang-17",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 18 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        "clang-18",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 18 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '11,14,17,20,2b' } + asan,
+        "clang-18",
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,1z' } + ubsan,
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,1z' } + asan,
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,17,20,2b' } + asan,
+        xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    windows_pipeline(
+        "Windows VS2015 msvc-14.0",
+        "cppalliance/dronevs2015",
+        { TOOLSET: 'msvc-14.0', CXXSTD: '14,latest', B2_DONT_EMBED_MANIFEST: '1' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1 permissive-",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2 permissive-",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2022 msvc-14.3",
+        "cppalliance/dronevs2022:1",
+        { TOOLSET: 'msvc-14.3', CXXSTD: '14,17,20,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2022 msvc-14.3 permissive-",
+        "cppalliance/dronevs2022:1",
+        { TOOLSET: 'msvc-14.3', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
+]
--- a/.drone/drone.bat
+++ b/.drone/drone.bat
@ -0,0 +1,24 @@
+@REM Copyright 2022 Peter Dimov
+@REM Distributed under the Boost Software License, Version 1.0.
+@REM https://www.boost.org/LICENSE_1_0.txt
+
+@ECHO ON
+
+set LIBRARY=%1
+set DRONE_BUILD_DIR=%CD%
+
+set BOOST_BRANCH=develop
+if "%DRONE_BRANCH%" == "master" set BOOST_BRANCH=master
+cd ..
+git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+xcopy /s /e /q %DRONE_BUILD_DIR% libs\%LIBRARY%\
+python tools/boostdep/depinst/depinst.py %LIBRARY%
+cmd /c bootstrap
+b2 -d0 headers
+
+if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
+if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
+if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker
--- a/.drone/drone.sh
+++ b/.drone/drone.sh
@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+set -ex
+export PATH=~/.local/bin:/usr/local/bin:$PATH
+
+DRONE_BUILD_DIR=$(pwd)
+
+BOOST_BRANCH=develop
+if [ "$DRONE_BRANCH" = "master" ]; then BOOST_BRANCH=master; fi
+
+cd ..
+git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+cp -r $DRONE_BUILD_DIR/* libs/$LIBRARY
+python tools/boostdep/depinst/depinst.py $LIBRARY
+./bootstrap.sh
+./b2 -d0 headers
+
+echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
+./b2 -j3 libs/$LIBRARY/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release ${ADDRMD:+address-model=$ADDRMD} ${UBSAN:+undefined-sanitizer=norecover debug-symbols=on} ${ASAN:+address-sanitizer=norecover debug-symbols=on} ${LINKFLAGS:+linkflags=$LINKFLAGS}
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -18,97 +18,181 @@ jobs:
      matrix:
        include:
          - toolset: gcc-4.8
-            cxxstd: "03,11"
-            os: ubuntu-18.04
+            cxxstd: "11"
+            container: ubuntu:16.04
+            os: ubuntu-latest
            install: g++-4.8
+          - toolset: gcc-4.9
+            cxxstd: "11"
+            container: ubuntu:16.04
+            os: ubuntu-latest
+            install: g++-4.9
          - toolset: gcc-5
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
+            cxxstd: "11,14,1z"
+            container: ubuntu:18.04
+            os: ubuntu-latest
            install: g++-5
          - toolset: gcc-6
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
+            cxxstd: "11,14,1z"
+            container: ubuntu:18.04
+            os: ubuntu-latest
            install: g++-6
          - toolset: gcc-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            cxxstd: "11,14,17"
+            container: ubuntu:18.04
+            os: ubuntu-latest
          - toolset: gcc-8
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
+            cxxstd: "11,14,17,2a"
+            os: ubuntu-20.04
            install: g++-8
          - toolset: gcc-9
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            os: ubuntu-20.04
          - toolset: gcc-10
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            cxxstd: "11,14,17,2a"
+            os: ubuntu-22.04
            install: g++-10
          - toolset: gcc-11
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
+            cxxstd: "11,14,17,2a"
+            os: ubuntu-22.04
            install: g++-11
+          - toolset: gcc-12
+            cxxstd: "11,14,17,20,2b"
+            os: ubuntu-22.04
+            install: g++-12
+          - toolset: gcc-13
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:23.04
+            os: ubuntu-latest
+            install: g++-13
+          - toolset: gcc-14
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: g++-14
          - toolset: clang
            compiler: clang++-3.9
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
+            cxxstd: "11,14"
+            container: ubuntu:18.04
+            os: ubuntu-latest
            install: clang-3.9
          - toolset: clang
            compiler: clang++-4.0
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
+            cxxstd: "11,14"
+            container: ubuntu:18.04
+            os: ubuntu-latest
            install: clang-4.0
          - toolset: clang
            compiler: clang++-5.0
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
+            cxxstd: "11,14,1z"
+            container: ubuntu:18.04
+            os: ubuntu-latest
            install: clang-5.0
          - toolset: clang
            compiler: clang++-6.0
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            cxxstd: "11,14,17"
+            os: ubuntu-20.04
            install: clang-6.0
          - toolset: clang
            compiler: clang++-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
+            cxxstd: "11,14,17"
+            os: ubuntu-20.04
            install: clang-7
          - toolset: clang
            compiler: clang++-8
-            cxxstd: "03,11,14,17"
+            cxxstd: "11,14,17"
            os: ubuntu-20.04
            install: clang-8
          - toolset: clang
            compiler: clang++-9
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            os: ubuntu-20.04
            install: clang-9
          - toolset: clang
            compiler: clang++-10
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            os: ubuntu-20.04
            install: clang-10
          - toolset: clang
            compiler: clang++-11
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            os: ubuntu-20.04
            install: clang-11
          - toolset: clang
            compiler: clang++-12
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            os: ubuntu-20.04
            install: clang-12
          - toolset: clang
-            cxxstd: "03,11,14,17,2a"
-            os: macos-10.15
+            compiler: clang++-13
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:22.04
+            os: ubuntu-latest
+            install: clang-13
+          - toolset: clang
+            compiler: clang++-14
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:22.04
+            os: ubuntu-latest
+            install: clang-14
+          - toolset: clang
+            compiler: clang++-15
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:22.04
+            os: ubuntu-latest
+            install: clang-15
+          - toolset: clang
+            compiler: clang++-16
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:23.04
+            os: ubuntu-latest
+            install: clang-16
+          - toolset: clang
+            compiler: clang++-17
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:23.10
+            os: ubuntu-latest
+            install: clang-17
+          - toolset: clang
+            compiler: clang++-18
+            cxxstd: "11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: clang-18
+          - toolset: clang
+            cxxstd: "11,14,17,2a"
+            os: macos-11
+          - toolset: clang
+            cxxstd: "11,14,17,20,2b"
+            os: macos-12
+          - toolset: clang
+            cxxstd: "11,14,17,20,2b"
+            os: macos-13
+          - toolset: clang
+            cxxstd: "11,14,17,20,2b"
+            os: macos-14

    runs-on: ${{matrix.os}}
+    container: ${{matrix.container}}
+
+    defaults:
+      run:
+        shell: bash

    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
+
+      - name: Setup container environment
+        if: matrix.container
+        run: |
+          apt-get update
+          apt-get -y install sudo python3 git g++

      - name: Install packages
        if: matrix.install
-        run: sudo apt install ${{matrix.install}}
+        run: |
+          sudo apt-get update
+          sudo apt-get -y install ${{matrix.install}}

      - name: Setup Boost
        run: |
@ -128,7 +212,7 @@ jobs:
          cd boost-root
          cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
          git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          python3 tools/boostdep/depinst/depinst.py $LIBRARY
          ./bootstrap.sh
          ./b2 -d0 headers

@ -148,30 +232,30 @@ jobs:
      matrix:
        include:
          - toolset: msvc-14.0
-            cxxstd: "14"
+            cxxstd: "14,latest"
            addrmd: 32,64
            os: windows-2019
-          - toolset: msvc-14.1
-            cxxstd: "14,17,latest"
-            addrmd: 32,64
-            os: windows-2016
          - toolset: msvc-14.2
-            cxxstd: "14,17,latest"
+            cxxstd: "14,17,20,latest"
            addrmd: 32,64
            os: windows-2019
          - toolset: msvc-14.3
+            cxxstd: "14,17,20,latest"
+            addrmd: 32,64
+            os: windows-2022
+          - toolset: clang-win
            cxxstd: "14,17,latest"
            addrmd: 32,64
            os: windows-2022
          - toolset: gcc
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "11,14,17,2a"
            addrmd: 64
            os: windows-2019

    runs-on: ${{matrix.os}}

    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4

      - name: Setup Boost
        shell: cmd
@ -199,25 +283,27 @@ jobs:
        shell: cmd
        run: |
          cd ../boost-root
-          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release
+          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release embed-manifest-via=linker

  posix-cmake-subdir:
    strategy:
      fail-fast: false
      matrix:
        include:
-          - os: ubuntu-18.04
          - os: ubuntu-20.04
-          - os: macos-10.15
+          - os: ubuntu-22.04
+          - os: macos-11
+          - os: macos-12
+          - os: macos-13

    runs-on: ${{matrix.os}}

    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4

      - name: Install packages
        if: matrix.install
-        run: sudo apt install ${{matrix.install}}
+        run: sudo apt-get -y install ${{matrix.install}}

      - name: Setup Boost
        run: |
@ -252,18 +338,20 @@ jobs:
      fail-fast: false
      matrix:
        include:
-          - os: ubuntu-18.04
          - os: ubuntu-20.04
-          - os: macos-10.15
+          - os: ubuntu-22.04
+          - os: macos-11
+          - os: macos-12
+          - os: macos-13

    runs-on: ${{matrix.os}}

    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4

      - name: Install packages
        if: matrix.install
-        run: sudo apt install ${{matrix.install}}
+        run: sudo apt-get -y install ${{matrix.install}}

      - name: Setup Boost
        run: |
@ -308,18 +396,20 @@ jobs:
      fail-fast: false
      matrix:
        include:
-          - os: ubuntu-18.04
          - os: ubuntu-20.04
-          - os: macos-10.15
+          - os: ubuntu-22.04
+          - os: macos-11
+          - os: macos-12
+          - os: macos-13

    runs-on: ${{matrix.os}}

    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4

      - name: Install packages
        if: matrix.install
-        run: sudo apt install ${{matrix.install}}
+        run: sudo apt-get -y install ${{matrix.install}}

      - name: Setup Boost
        run: |
@ -356,3 +446,183 @@ jobs:
        run: |
          cd ../boost-root/__build__
          ctest --output-on-failure --no-tests=error
+
+  windows-cmake-subdir:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: windows-2019
+          - os: windows-2022
+
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Boost
+        shell: cmd
+        run: |
+          echo GITHUB_REPOSITORY: %GITHUB_REPOSITORY%
+          for /f %%i in ("%GITHUB_REPOSITORY%") do set LIBRARY=%%~nxi
+          echo LIBRARY: %LIBRARY%
+          echo LIBRARY=%LIBRARY%>>%GITHUB_ENV%
+          echo GITHUB_BASE_REF: %GITHUB_BASE_REF%
+          echo GITHUB_REF: %GITHUB_REF%
+          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
+          set BOOST_BRANCH=develop
+          for /f %%i in ("%GITHUB_BASE_REF%") do if "%%~nxi" == "master" set BOOST_BRANCH=master
+          echo BOOST_BRANCH: %BOOST_BRANCH%
+          cd ..
+          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+          cd boost-root
+          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" %LIBRARY%
+
+      - name: Use library with add_subdirectory (Debug)
+        shell: cmd
+        run: |
+          cd ../boost-root/libs/%LIBRARY%/test/cmake_subdir_test
+          mkdir __build__ && cd __build__
+          cmake ..
+          cmake --build . --config Debug
+          ctest --output-on-failure --no-tests=error -C Debug
+
+      - name: Use library with add_subdirectory (Release)
+        shell: cmd
+        run: |
+          cd ../boost-root/libs/%LIBRARY%/test/cmake_subdir_test/__build__
+          cmake --build . --config Release
+          ctest --output-on-failure --no-tests=error -C Release
+
+  windows-cmake-install:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: windows-2019
+          - os: windows-2022
+
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Boost
+        shell: cmd
+        run: |
+          echo GITHUB_REPOSITORY: %GITHUB_REPOSITORY%
+          for /f %%i in ("%GITHUB_REPOSITORY%") do set LIBRARY=%%~nxi
+          echo LIBRARY: %LIBRARY%
+          echo LIBRARY=%LIBRARY%>>%GITHUB_ENV%
+          echo GITHUB_BASE_REF: %GITHUB_BASE_REF%
+          echo GITHUB_REF: %GITHUB_REF%
+          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
+          set BOOST_BRANCH=develop
+          for /f %%i in ("%GITHUB_BASE_REF%") do if "%%~nxi" == "master" set BOOST_BRANCH=master
+          echo BOOST_BRANCH: %BOOST_BRANCH%
+          cd ..
+          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+          cd boost-root
+          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" %LIBRARY%
+
+      - name: Configure
+        shell: cmd
+        run: |
+          cd ../boost-root
+          mkdir __build__ && cd __build__
+          cmake -DBOOST_INCLUDE_LIBRARIES=%LIBRARY% -DCMAKE_INSTALL_PREFIX=C:/cmake-prefix ..
+
+      - name: Install (Debug)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          cmake --build . --target install --config Debug
+
+      - name: Install (Release)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          cmake --build . --target install --config Release
+
+      - name: Use the installed library (Debug)
+        shell: cmd
+        run: |
+          cd ../boost-root/libs/%LIBRARY%/test/cmake_install_test && mkdir __build__ && cd __build__
+          cmake -DCMAKE_INSTALL_PREFIX=C:/cmake-prefix ..
+          cmake --build . --config Debug
+          ctest --output-on-failure --no-tests=error -C Debug
+
+      - name: Use the installed library (Release)
+        shell: cmd
+        run: |
+          cd ../boost-root/libs/%LIBRARY%/test/cmake_install_test/__build__
+          cmake --build . --config Release
+          ctest --output-on-failure --no-tests=error -C Release
+
+  windows-cmake-test:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: windows-2019
+          - os: windows-2022
+
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Boost
+        shell: cmd
+        run: |
+          echo GITHUB_REPOSITORY: %GITHUB_REPOSITORY%
+          for /f %%i in ("%GITHUB_REPOSITORY%") do set LIBRARY=%%~nxi
+          echo LIBRARY: %LIBRARY%
+          echo LIBRARY=%LIBRARY%>>%GITHUB_ENV%
+          echo GITHUB_BASE_REF: %GITHUB_BASE_REF%
+          echo GITHUB_REF: %GITHUB_REF%
+          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
+          set BOOST_BRANCH=develop
+          for /f %%i in ("%GITHUB_BASE_REF%") do if "%%~nxi" == "master" set BOOST_BRANCH=master
+          echo BOOST_BRANCH: %BOOST_BRANCH%
+          cd ..
+          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+          cd boost-root
+          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" %LIBRARY%
+
+      - name: Configure
+        shell: cmd
+        run: |
+          cd ../boost-root
+          mkdir __build__ && cd __build__
+          cmake -DBOOST_INCLUDE_LIBRARIES=%LIBRARY% -DBUILD_TESTING=ON ..
+
+      - name: Build tests (Debug)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          cmake --build . --target tests --config Debug
+
+      - name: Run tests (Debug)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          ctest --output-on-failure --no-tests=error -C Debug
+
+      - name: Build tests (Release)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          cmake --build . --target tests --config Release
+
+      - name: Run tests (Release)
+        shell: cmd
+        run: |
+          cd ../boost-root/__build__
+          ctest --output-on-failure --no-tests=error -C Release
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -19,6 +19,15 @@ target_link_libraries(boost_variant2
    Boost::mp11
 )

+if(CMAKE_VERSION VERSION_GREATER 3.18 AND CMAKE_GENERATOR MATCHES "Visual Studio")
+
+  file(GLOB_RECURSE boost_variant2_IDEFILES CONFIGURE_DEPENDS include/*.hpp)
+  source_group(TREE ${PROJECT_SOURCE_DIR}/include FILES ${boost_variant2_IDEFILES} PREFIX "Header Files")
+  list(APPEND boost_variant2_IDEFILES extra/boost_variant2.natvis)
+  target_sources(boost_variant2 PRIVATE ${boost_variant2_IDEFILES})
+
+endif()
+
 target_compile_features(boost_variant2 INTERFACE cxx_std_11)

 if(BUILD_TESTING AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt")
--- a/README.md
+++ b/README.md
@ -12,7 +12,7 @@ Supported compilers:

 * g++ 4.8 or later with `-std=c++11` or above
 * clang++ 3.9 or later with `-std=c++11` or above
-* Visual Studio 2015, 2017, 2019
+* Visual Studio 2015 or later

 Tested on [Github Actions](https://github.com/boostorg/variant2/actions) and
 [Appveyor](https://ci.appveyor.com/project/pdimov/variant2-fkab9).
--- a/appveyor.yml
+++ b/appveyor.yml
@ -22,17 +22,24 @@ environment:
      ADDRMD: 32,64
      CXXSTD: 14,17,latest
    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      TOOLSET: clang-win
-      ADDRMD: 64
-      CXXSTD: 14,17,latest
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      TOOLSET: msvc-14.2
+      TOOLSET: msvc-14.1
      ADDRMD: 32,64
      CXXSTD: 14,17,latest
+      CXXFLAGS: /permissive-
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      TOOLSET: clang-win
+      ADDRMD: 64
+      CXXSTD: 14,17,latest
    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
      TOOLSET: clang-win
      ADDRMD: 64
      CXXSTD: 14,17,latest
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      CMAKE: 1
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      CMAKE_SUBDIR: 1
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      CMAKE_INSTALL: 1

 install:
  - set BOOST_BRANCH=develop
@ -51,4 +58,28 @@ build: off
 test_script:
  - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
  - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-  - b2 -j3 libs/variant2/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+  - if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+  - if "%CMAKE%%CMAKE_SUBDIR%%CMAKE_INSTALL%" == ""  b2 -j3 libs/variant2/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker
+
+  - if not "%CMAKE%" == ""  mkdir __build__ && cd __build__
+  - if not "%CMAKE%" == ""  cmake -DBUILD_TESTING=ON -DBOOST_INCLUDE_LIBRARIES=variant2 -DBoost_VERBOSE=ON ..
+  - if not "%CMAKE%" == ""  cmake --build . --target tests -j 3 --config Debug & ctest --output-on-failure --no-tests=error -j 3 -C Debug
+  - if not "%CMAKE%" == ""  cmake --build . --target tests -j 3 --config Release & ctest --output-on-failure --no-tests=error -j 3 -C Release
+  - if not "%CMAKE%" == ""  cmake --build . --target tests -j 3 --config MinSizeRel & ctest --output-on-failure --no-tests=error -j 3 -C MinSizeRel
+  - if not "%CMAKE%" == ""  cmake --build . --target tests -j 3 --config RelWithDebInfo & ctest --output-on-failure --no-tests=error -j 3 -C RelWithDebInfo
+
+  - if not "%CMAKE_SUBDIR%" == ""  cd libs/variant2/test/cmake_subdir_test && mkdir __build__ && cd __build__
+  - if not "%CMAKE_SUBDIR%" == ""  cmake ..
+  - if not "%CMAKE_SUBDIR%" == ""  cmake --build . --config Debug && cmake --build . --target check --config Debug
+  - if not "%CMAKE_SUBDIR%" == ""  cmake --build . --config Release && cmake --build . --target check --config Release
+  - if not "%CMAKE_SUBDIR%" == ""  cmake --build . --config MinSizeRel && cmake --build . --target check --config MinSizeRel
+  - if not "%CMAKE_SUBDIR%" == ""  cmake --build . --config RelWithDebInfo && cmake --build . --target check --config RelWithDebInfo
+
+  - if not "%CMAKE_INSTALL%" == ""  mkdir __build__ && cd __build__
+  - if not "%CMAKE_INSTALL%" == ""  cmake -DBOOST_INCLUDE_LIBRARIES=variant2 -DCMAKE_INSTALL_PREFIX=C:/cmake-prefix ..
+  - if not "%CMAKE_INSTALL%" == ""  cmake --build . --target install --config Debug
+  - if not "%CMAKE_INSTALL%" == ""  cmake --build . --target install --config Release
+  - if not "%CMAKE_INSTALL%" == ""  cd ../libs/variant2/test/cmake_install_test && mkdir __build__ && cd __build__
+  - if not "%CMAKE_INSTALL%" == ""  cmake -DCMAKE_INSTALL_PREFIX=C:/cmake-prefix ..
+  - if not "%CMAKE_INSTALL%" == ""  cmake --build . --config Debug && cmake --build . --target check --config Debug
+  - if not "%CMAKE_INSTALL%" == ""  cmake --build . --config Release && cmake --build . --target check --config Release
--- a/doc/variant2/changelog.adoc
+++ b/doc/variant2/changelog.adoc
@ -1,5 +1,5 @@
 ////
-Copyright 2019-2021 Peter Dimov
+Copyright 2019-2022 Peter Dimov
 Distributed under the Boost Software License, Version 1.0.
 https://www.boost.org/LICENSE_1_0.txt
 ////
@ -8,6 +8,14 @@ https://www.boost.org/LICENSE_1_0.txt
 # Revision History
 :idprefix: changelog_

+## Changes in 1.83.0
+
+* Added `uses_double_storage()`.
+
+## Changes in 1.81.0
+
+* Added support for `boost::json::value_from` and `boost::json::value_to`.
+
 ## Changes in 1.79.0

 * Added `operator<<` for `monostate`.
--- a/doc/variant2/implementation.adoc
+++ b/doc/variant2/implementation.adoc
@ -16,7 +16,7 @@ This implementation only depends on Boost.Config, Boost.Assert, and Boost.Mp11.

 * GCC 4.8 or later with `-std=c++11` or above
 * Clang 3.9 or later with `-std=c++11` or above
-* Visual Studio 2015, 2017, 2019
+* Visual Studio 2015 or later

 Tested on https://github.com/boostorg/variant2/actions[Github Actions] and
 https://ci.appveyor.com/project/pdimov/variant2-fkab9[Appveyor].
--- a/doc/variant2/reference.adoc
+++ b/doc/variant2/reference.adoc
@ -157,7 +157,7 @@ template<class R = /*unspecified*/, class F, class... V>
 // visit_by_index (extension)

 template<class R = /*unspecified*/, class V, class... F>
-  constexpr /*see below*/ visit_by_index(V&& v, F&&.. f);
+  constexpr /*see below*/ visit_by_index(V&& v, F&&... f);

 // monostate

@ -250,6 +250,8 @@ public:
  constexpr bool valueless_by_exception() const noexcept;
  constexpr size_t index() const noexcept;

+  static constexpr bool uses_double_storage() noexcept;
+
  // swap

  void swap( variant& r ) noexcept( /*see below*/ );
@ -570,6 +572,18 @@ constexpr size_t index() const noexcept;
 Returns:  ::
  The zero-based index of the active alternative.

+```
+static constexpr bool uses_double_storage() noexcept;
+```
+[none]
+* {blank}
+
+Returns:  ::
+  `true` if the variant uses double storage to meet the never valueless
+  guarantee because one of the alternatives is not nothrow move constructible,
+  and `false` otherwise.
+
+
 #### Swap

 ```
@ -922,7 +936,7 @@ Remarks: :: If `R` is given explicitly, as in `visit<int>`, the return

 ```
 template<class R = /*unspecified*/, class V, class... F>
-  constexpr /*see below*/ visit_by_index(V&& v, F&&.. f);
+  constexpr /*see below*/ visit_by_index(V&& v, F&&... f);
 ```
 [none]
 * {blank}
--- a/extra/boost_variant2.natvis
+++ b/extra/boost_variant2.natvis
@ -0,0 +1,178 @@
+<?xml version="1.0" encoding="utf-8"?>
+<AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">
+
+  <Type Name="boost::variant2::detail::variant_base_impl&lt;*,1,*&gt;">
+    <Intrinsic Name="index" Expression="(int)ix_ - 1"/>
+    <DisplayString Condition="index() ==  0" Optional="true">{{ index=0, value={*($T2*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  1" Optional="true">{{ index=1, value={*($T3*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  2" Optional="true">{{ index=2, value={*($T4*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  3" Optional="true">{{ index=3, value={*($T5*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  4" Optional="true">{{ index=4, value={*($T6*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  5" Optional="true">{{ index=5, value={*($T7*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  6" Optional="true">{{ index=6, value={*($T8*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  7" Optional="true">{{ index=7, value={*($T9*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  8" Optional="true">{{ index=8, value={*($T10*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() ==  9" Optional="true">{{ index=9, value={*($T11*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 10" Optional="true">{{ index=10, value={*($T12*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 11" Optional="true">{{ index=11, value={*($T13*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 12" Optional="true">{{ index=12, value={*($T14*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 13" Optional="true">{{ index=13, value={*($T15*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 14" Optional="true">{{ index=14, value={*($T16*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 15" Optional="true">{{ index=15, value={*($T17*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 16" Optional="true">{{ index=16, value={*($T18*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 17" Optional="true">{{ index=17, value={*($T19*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 18" Optional="true">{{ index=18, value={*($T20*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 19" Optional="true">{{ index=19, value={*($T21*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 20" Optional="true">{{ index=10, value={*($T22*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 21" Optional="true">{{ index=21, value={*($T23*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 22" Optional="true">{{ index=22, value={*($T24*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 23" Optional="true">{{ index=23, value={*($T25*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 24" Optional="true">{{ index=24, value={*($T26*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 25" Optional="true">{{ index=25, value={*($T27*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 26" Optional="true">{{ index=26, value={*($T28*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 27" Optional="true">{{ index=27, value={*($T29*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 28" Optional="true">{{ index=28, value={*($T30*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 29" Optional="true">{{ index=29, value={*($T31*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 30" Optional="true">{{ index=30, value={*($T32*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 31" Optional="true">{{ index=31, value={*($T33*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 32" Optional="true">{{ index=32, value={*($T34*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 33" Optional="true">{{ index=33, value={*($T35*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 34" Optional="true">{{ index=34, value={*($T36*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 35" Optional="true">{{ index=35, value={*($T37*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 36" Optional="true">{{ index=36, value={*($T38*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 37" Optional="true">{{ index=37, value={*($T39*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 38" Optional="true">{{ index=38, value={*($T40*)&amp;st_} }}</DisplayString>
+    <DisplayString Condition="index() == 39" Optional="true">{{ index=39, value={*($T41*)&amp;st_} }}</DisplayString>
+    <Expand>
+      <Item Name="index">index()</Item>
+      <Item Name="[value]" Condition="index() ==  0" Optional="true">*($T2*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  1" Optional="true">*($T3*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  2" Optional="true">*($T4*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  3" Optional="true">*($T5*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  4" Optional="true">*($T6*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  5" Optional="true">*($T7*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  6" Optional="true">*($T8*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  7" Optional="true">*($T9*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  8" Optional="true">*($T10*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() ==  9" Optional="true">*($T11*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 10" Optional="true">*($T12*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 11" Optional="true">*($T13*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 12" Optional="true">*($T14*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 13" Optional="true">*($T15*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 14" Optional="true">*($T16*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 15" Optional="true">*($T17*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 16" Optional="true">*($T18*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 17" Optional="true">*($T19*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 18" Optional="true">*($T20*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 19" Optional="true">*($T21*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 20" Optional="true">*($T22*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 21" Optional="true">*($T23*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 22" Optional="true">*($T24*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 23" Optional="true">*($T25*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 24" Optional="true">*($T26*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 25" Optional="true">*($T27*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 26" Optional="true">*($T28*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 27" Optional="true">*($T29*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 28" Optional="true">*($T30*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 29" Optional="true">*($T31*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 30" Optional="true">*($T32*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 31" Optional="true">*($T33*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 32" Optional="true">*($T34*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 33" Optional="true">*($T35*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 34" Optional="true">*($T36*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 35" Optional="true">*($T37*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 36" Optional="true">*($T38*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 37" Optional="true">*($T39*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 38" Optional="true">*($T40*)&amp;st_</Item>
+      <Item Name="[value]" Condition="index() == 39" Optional="true">*($T41*)&amp;st_</Item>
+    </Expand>
+  </Type>
+
+  <Type Name="boost::variant2::detail::variant_base_impl&lt;*,0,*&gt;">
+    <Intrinsic Name="index" Expression="(int)((ix_-2)/2)"/>
+    <DisplayString Condition="index() ==  0" Optional="true">{{ index=0, value={*($T2*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  1" Optional="true">{{ index=1, value={*($T3*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  2" Optional="true">{{ index=2, value={*($T4*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  3" Optional="true">{{ index=3, value={*($T5*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  4" Optional="true">{{ index=4, value={*($T6*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  5" Optional="true">{{ index=5, value={*($T7*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  6" Optional="true">{{ index=6, value={*($T8*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  7" Optional="true">{{ index=7, value={*($T9*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  8" Optional="true">{{ index=8, value={*($T10*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() ==  9" Optional="true">{{ index=9, value={*($T11*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 10" Optional="true">{{ index=10, value={*($T12*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 11" Optional="true">{{ index=11, value={*($T13*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 12" Optional="true">{{ index=12, value={*($T14*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 13" Optional="true">{{ index=13, value={*($T15*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 14" Optional="true">{{ index=14, value={*($T16*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 15" Optional="true">{{ index=15, value={*($T17*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 16" Optional="true">{{ index=16, value={*($T18*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 17" Optional="true">{{ index=17, value={*($T19*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 18" Optional="true">{{ index=18, value={*($T20*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 19" Optional="true">{{ index=19, value={*($T21*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 20" Optional="true">{{ index=20, value={*($T22*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 21" Optional="true">{{ index=21, value={*($T23*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 22" Optional="true">{{ index=22, value={*($T24*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 23" Optional="true">{{ index=23, value={*($T25*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 24" Optional="true">{{ index=24, value={*($T26*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 25" Optional="true">{{ index=25, value={*($T27*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 26" Optional="true">{{ index=26, value={*($T28*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 27" Optional="true">{{ index=27, value={*($T29*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 28" Optional="true">{{ index=28, value={*($T30*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 29" Optional="true">{{ index=29, value={*($T31*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 30" Optional="true">{{ index=30, value={*($T32*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 31" Optional="true">{{ index=31, value={*($T33*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 32" Optional="true">{{ index=32, value={*($T34*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 33" Optional="true">{{ index=33, value={*($T35*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 34" Optional="true">{{ index=34, value={*($T36*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 35" Optional="true">{{ index=35, value={*($T37*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 36" Optional="true">{{ index=36, value={*($T38*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 37" Optional="true">{{ index=37, value={*($T39*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 38" Optional="true">{{ index=38, value={*($T40*)&amp;st_[ix_%2]} }}</DisplayString>
+    <DisplayString Condition="index() == 39" Optional="true">{{ index=39, value={*($T41*)&amp;st_[ix_%2]} }}</DisplayString>
+    <Expand>
+      <Item Name="index">index()</Item>
+      <Item Name="[value]" Condition="index() ==  0" Optional="true">*($T2*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  1" Optional="true">*($T3*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  2" Optional="true">*($T4*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  3" Optional="true">*($T5*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  4" Optional="true">*($T6*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  5" Optional="true">*($T7*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  6" Optional="true">*($T8*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  7" Optional="true">*($T9*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  8" Optional="true">*($T10*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() ==  9" Optional="true">*($T11*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 10" Optional="true">*($T12*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 11" Optional="true">*($T13*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 12" Optional="true">*($T14*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 13" Optional="true">*($T15*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 14" Optional="true">*($T16*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 15" Optional="true">*($T17*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 16" Optional="true">*($T18*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 17" Optional="true">*($T19*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 18" Optional="true">*($T20*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 19" Optional="true">*($T21*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 20" Optional="true">*($T22*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 21" Optional="true">*($T23*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 22" Optional="true">*($T24*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 23" Optional="true">*($T25*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 24" Optional="true">*($T26*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 25" Optional="true">*($T27*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 26" Optional="true">*($T28*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 27" Optional="true">*($T29*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 28" Optional="true">*($T30*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 29" Optional="true">*($T31*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 30" Optional="true">*($T32*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 31" Optional="true">*($T33*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 32" Optional="true">*($T34*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 33" Optional="true">*($T35*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 34" Optional="true">*($T36*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 35" Optional="true">*($T37*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 36" Optional="true">*($T38*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 37" Optional="true">*($T39*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 38" Optional="true">*($T40*)&amp;st_[ix_%2]</Item>
+      <Item Name="[value]" Condition="index() == 39" Optional="true">*($T41*)&amp;st_[ix_%2]</Item>
+    </Expand>
+  </Type>
+
+</AutoVisualizer>
--- a/include/boost/variant2/variant.hpp
+++ b/include/boost/variant2/variant.hpp
@ -15,17 +15,17 @@

 #include <boost/mp11.hpp>
 #include <boost/assert.hpp>
+#include <boost/assert/source_location.hpp>
 #include <boost/config.hpp>
-#include <boost/detail/workaround.hpp>
-#include <boost/cstdint.hpp>
+#include <boost/config/workaround.hpp>
 #include <cstddef>
 #include <type_traits>
 #include <exception>
-#include <initializer_list>
 #include <utility>
-#include <functional> // std::hash
-#include <cstdint>
+#include <typeindex> // std::hash
 #include <iosfwd>
+#include <cstdint>
+#include <cerrno>

 //

@ -685,7 +685,20 @@ template<class T1, class... T> union variant_storage_impl<mp11::mp_true, T1, T..

    template<std::size_t I, class... A> BOOST_CXX14_CONSTEXPR void emplace_impl( mp11::mp_true, mp11::mp_size_t<I>, A&&... a )
    {
+#if defined(BOOST_GCC) && (__GNUC__ >= 7)
+# pragma GCC diagnostic push
+// False positive in at least GCC 7 and GCC 10 ASAN triggered by monostate (via result<void>)
+# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#if __GNUC__ >= 12
+// False positive in at least GCC 12 and GCC 13 ASAN and -Og triggered by monostate (via result<void>)
+# pragma GCC diagnostic ignored "-Wuninitialized"
+#endif
+#endif
        *this = variant_storage_impl( mp11::mp_size_t<I>(), std::forward<A>(a)... );
+
+#if defined(BOOST_GCC) && (__GNUC__ >= 7)
+# pragma GCC diagnostic pop
+#endif
    }

    template<std::size_t I, class... A> BOOST_CXX14_CONSTEXPR void emplace( mp11::mp_size_t<I>, A&&... a )
@ -908,6 +921,11 @@ template<class... T> struct variant_base_impl<true, true, T...>

        this->emplace_impl<J, U>( std::is_nothrow_constructible<U, A&&...>(), std::forward<A>(a)... );
    }
+
+    static constexpr bool uses_double_storage() noexcept
+    {
+        return false;
+    }
 };

 // trivially destructible, double buffered
@ -966,6 +984,11 @@ template<class... T> struct variant_base_impl<true, false, T...>

        ix_ = J * 2 + i2;
    }
+
+    static constexpr bool uses_double_storage() noexcept
+    {
+        return true;
+    }
 };

 // not trivially destructible, single buffered
@ -1056,6 +1079,11 @@ template<class... T> struct variant_base_impl<false, true, T...>
        st_.emplace( mp11::mp_size_t<J>(), std::move(tmp) );
        ix_ = J;
    }
+
+    static constexpr bool uses_double_storage() noexcept
+    {
+        return false;
+    }
 };

 // not trivially destructible, double buffered
@ -1181,6 +1209,11 @@ template<class... T> struct variant_base_impl<false, false, T...>

        ix_ = J * 2 + i2;
    }
+
+    static constexpr bool uses_double_storage() noexcept
+    {
+        return true;
+    }
 };

 } // namespace detail
@ -1601,7 +1634,17 @@ public:
    template<class U,
        class Ud = typename std::decay<U>::type,
        class E1 = typename std::enable_if< !std::is_same<Ud, variant>::value && !std::is_base_of<variant, Ud>::value && !detail::is_in_place_index<Ud>::value && !detail::is_in_place_type<Ud>::value >::type,
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1950)
+
+        class V = mp11::mp_apply_q< mp11::mp_bind_front<detail::resolve_overload_type, U&&>, variant >,
+
+#else
+
        class V = detail::resolve_overload_type<U&&, T...>,
+
+#endif
+
        class E2 = typename std::enable_if<std::is_constructible<V, U&&>::value>::type
        >
    constexpr variant( U&& u )
@ -1691,6 +1734,8 @@ public:

    using variant_base::index;

+    using variant_base::uses_double_storage;
+
    // swap

 private:
@ -2285,8 +2330,8 @@ namespace detail

 inline std::size_t hash_value_impl_( mp11::mp_true, std::size_t index, std::size_t value )
 {
-    boost::ulong_long_type hv = ( boost::ulong_long_type( 0xCBF29CE4 ) << 32 ) + 0x84222325;
-    boost::ulong_long_type const prime = ( boost::ulong_long_type( 0x00000100 ) << 32 ) + 0x000001B3;
+    unsigned long long hv = 0xCBF29CE484222325ull;
+    unsigned long long const prime = 0x100000001B3ull;

    hv ^= index;
    hv *= prime;
@ -2392,6 +2437,109 @@ template<> struct hash< ::boost::variant2::monostate >

 } // namespace std

+// JSON support
+
+namespace boost
+{
+namespace json
+{
+
+class value;
+
+struct value_from_tag;
+
+template<class T>
+void value_from( T&& t, value& jv );
+
+template<class T>
+struct try_value_to_tag;
+
+template<class T1, class T2>
+struct result_for;
+
+template<class T>
+typename result_for<T, value>::type
+try_value_to( value const & jv );
+
+template<class T>
+typename result_for<T, value>::type
+result_from_errno( int e, boost::source_location const* loc ) noexcept;
+
+template<class T> struct is_null_like;
+
+template<> struct is_null_like<variant2::monostate>: std::true_type {};
+
+} // namespace json
+
+namespace variant2
+{
+
+namespace detail
+{
+
+struct tag_invoke_L1
+{
+    boost::json::value& v;
+
+#if defined(BOOST_MSVC) && BOOST_MSVC / 10 == 191
+    // msvc-14.1 with /permissive- needs this
+    explicit tag_invoke_L1( boost::json::value& v_ ): v( v_ ) {}
+#endif
+
+    template<class T> void operator()( T const& t ) const
+    {
+        boost::json::value_from( t, v );
+    }
+};
+
+} // namespace detail
+
+template<class... T>
+    void tag_invoke( boost::json::value_from_tag const&, boost::json::value& v, variant<T...> const & w )
+{
+    visit( detail::tag_invoke_L1{ v }, w );
+}
+
+namespace detail
+{
+
+template<class V> struct tag_invoke_L2
+{
+    boost::json::value const& v;
+    typename boost::json::result_for<V, boost::json::value>::type& r;
+
+    template<class I> void operator()( I /*i*/ ) const
+    {
+        if( !r )
+        {
+            using Ti = mp11::mp_at_c<V, I::value>;
+            auto r2 = boost::json::try_value_to<Ti>( v );
+
+            if( r2 )
+            {
+                r.emplace( in_place_index_t<I::value>{}, std::move( *r2 ) );
+            }
+        }
+    }
+};
+
+} // namespace detail
+
+template<class... T>
+    typename boost::json::result_for<variant<T...>, boost::json::value>::type
+    tag_invoke( boost::json::try_value_to_tag<variant<T...>> const&, boost::json::value const& v )
+{
+    static constexpr boost::source_location loc = BOOST_CURRENT_LOCATION;
+    auto r = boost::json::result_from_errno< variant<T...> >( EINVAL, &loc );
+
+    mp11::mp_for_each<mp11::mp_iota_c<sizeof...(T)>>( detail::tag_invoke_L2< variant<T...> >{ v, r } );
+
+    return r;
+}
+
+} // namespace variant2
+} // namespace boost
+
 #undef BOOST_VARIANT2_CX14_ASSERT

 #if defined(_MSC_VER) && _MSC_VER < 1910
--- a/test/Jamfile
+++ b/test/Jamfile
@ -16,8 +16,6 @@ project

  : requirements

-    [ requires cxx11_variadic_templates cxx11_template_aliases cxx11_decltype cxx11_constexpr ]
-
    <toolset>msvc:<warnings-as-errors>on
    <toolset>gcc:<warnings-as-errors>on
    <toolset>clang:<warnings-as-errors>on
@ -126,3 +124,12 @@ run variant_visit_by_index.cpp ;

 run variant_ostream_insert.cpp ;
 run is_output_streamable.cpp ;
+
+local JSON = <library>/boost//json/<warnings>off "<toolset>msvc-14.0:<build>no" "<toolset>msvc-14.2:<cxxflags>-wd5104" "<undefined-sanitizer>norecover:<link>static" ;
+
+run variant_json_value_from.cpp : : : $(JSON) ;
+run variant_json_value_to.cpp : : : $(JSON) ;
+
+compile variant_uses_double_storage.cpp ;
+
+run variant_derived_construct2.cpp ;
--- a/test/variant_derived_construct2.cpp
+++ b/test/variant_derived_construct2.cpp
@ -0,0 +1,60 @@
+// Copyright 2024 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct expr: boost::variant2::variant<bool, int, double>
+{
+    using variant::variant;
+};
+
+int main()
+{
+    using boost::variant2::get;
+
+    {
+        expr v{ true };
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), true );
+    }
+
+    {
+        expr v{ 2 };
+
+        BOOST_TEST_EQ( v.index(), 1 );
+        BOOST_TEST_EQ( get<1>(v), 2 );
+    }
+
+    {
+        expr v{ 3.0 };
+
+        BOOST_TEST_EQ( v.index(), 2 );
+        BOOST_TEST_EQ( get<2>(v), 3.0 );
+    }
+
+    {
+        expr v( true );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), true );
+    }
+
+    {
+        expr v( 2 );
+
+        BOOST_TEST_EQ( v.index(), 1 );
+        BOOST_TEST_EQ( get<1>(v), 2 );
+    }
+
+    {
+        expr v( 3.0 );
+
+        BOOST_TEST_EQ( v.index(), 2 );
+        BOOST_TEST_EQ( get<2>(v), 3.0 );
+    }
+
+    return boost::report_errors();
+}
--- a/test/variant_emplace_index.cpp
+++ b/test/variant_emplace_index.cpp
@ -288,5 +288,39 @@ int main()
    BOOST_TEST_EQ( Z1::instances, 0 );
    BOOST_TEST_EQ( Z2::instances, 0 );

+    {
+        variant<monostate, monostate> v;
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+    }
+
+    {
+        variant<monostate, int> v;
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+    }
+
    return boost::report_errors();
 }
--- a/test/variant_get_by_index_cx.cpp
+++ b/test/variant_get_by_index_cx.cpp
@ -58,7 +58,7 @@ int main()
    {
        constexpr variant<int, float> v( 3.14f );

-        STATIC_ASSERT( get<1>(v) == 3.14f );
+        STATIC_ASSERT( get<1>(v) == (float)3.14f ); // see FLT_EVAL_METHOD

        STATIC_ASSERT_IF( get_if<0>(&v) == nullptr );
        STATIC_ASSERT_IF( get_if<1>(&v) == &get<1>(v) );
@ -87,7 +87,7 @@ int main()
    {
        constexpr variant<int, int, float> v( 3.14f );

-        STATIC_ASSERT( get<2>(v) == 3.14f );
+        STATIC_ASSERT( get<2>(v) == (float)3.14f );

        STATIC_ASSERT_IF( get_if<0>(&v) == nullptr );
        STATIC_ASSERT_IF( get_if<1>(&v) == nullptr );
--- a/test/variant_get_by_type_cx.cpp
+++ b/test/variant_get_by_type_cx.cpp
@ -58,7 +58,7 @@ int main()
    {
        constexpr variant<int, float> v( 3.14f );

-        STATIC_ASSERT( get<float>(v) == 3.14f );
+        STATIC_ASSERT( get<float>(v) == (float)3.14f ); // see FLT_EVAL_METHOD

        STATIC_ASSERT_IF( get_if<int>(&v) == nullptr );
        STATIC_ASSERT_IF( get_if<float>(&v) == &get<float>(v) );
@ -83,7 +83,7 @@ int main()
    {
        constexpr variant<int, int, float> v( 3.14f );

-        STATIC_ASSERT( get<float>(v) == 3.14f );
+        STATIC_ASSERT( get<float>(v) == (float)3.14f );

        STATIC_ASSERT_IF( get_if<float>(&v) == &get<float>(v) );
    }
--- a/test/variant_in_place_index_construct_cx.cpp
+++ b/test/variant_in_place_index_construct_cx.cpp
@ -68,7 +68,7 @@ int main()
        constexpr variant<int, float> v( in_place_index_t<1>{}, 3.14f );

        STATIC_ASSERT( v.index() == 1 );
-        STATIC_ASSERT( get<1>(v) == 3.14f );
+        STATIC_ASSERT( get<1>(v) == (float)3.14f ); // see FLT_EVAL_METHOD
    }

    {
@ -89,14 +89,14 @@ int main()
        constexpr variant<int, int, float, float, X, X> v( in_place_index_t<2>{}, 3.14f );

        STATIC_ASSERT( v.index() == 2 );
-        STATIC_ASSERT( get<2>(v) == 3.14f );
+        STATIC_ASSERT( get<2>(v) == (float)3.14f );
    }

    {
        constexpr variant<int, int, float, float, X, X> v( in_place_index_t<3>{}, 3.14f );

        STATIC_ASSERT( v.index() == 3 );
-        STATIC_ASSERT( get<3>(v) == 3.14f );
+        STATIC_ASSERT( get<3>(v) == (float)3.14f );
    }

    {
--- a/test/variant_in_place_type_construct_cx.cpp
+++ b/test/variant_in_place_type_construct_cx.cpp
@ -80,7 +80,7 @@ int main()
        constexpr variant<int, float> v( in_place_type_t<float>{}, 3.14f );

        STATIC_ASSERT( v.index() == 1 );
-        STATIC_ASSERT( get<1>(v) == 3.14f );
+        STATIC_ASSERT( get<1>(v) == (float)3.14f ); // see FLT_EVAL_METHOD

        STATIC_ASSERT( holds_alternative<float>(v) );
    }
@ -89,7 +89,7 @@ int main()
        constexpr variant<int, int, float, X> v( in_place_type_t<float>{}, 3.14f );

        STATIC_ASSERT( v.index() == 2 );
-        STATIC_ASSERT( get<2>(v) == 3.14f );
+        STATIC_ASSERT( get<2>(v) == (float)3.14f );

        STATIC_ASSERT( holds_alternative<float>(v) );
    }
--- a/test/variant_json_value_from.cpp
+++ b/test/variant_json_value_from.cpp
@ -0,0 +1,41 @@
+// Copyright 2022 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/json/value_from.hpp>
+#include <boost/json/serialize.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <string>
+
+using namespace boost::variant2;
+namespace json = boost::json;
+
+int main()
+{
+    {
+        monostate m;
+        json::value w = json::value_from( m );
+        BOOST_TEST_EQ( w, json::value( nullptr ) );
+    }
+
+    {
+        variant<monostate, int, std::string> v;
+        json::value w = json::value_from( v );
+        BOOST_TEST_EQ( w, json::value( nullptr ) );
+    }
+
+    {
+        variant<monostate, int, std::string> v( 17 );
+        json::value w = json::value_from( v );
+        BOOST_TEST_EQ( w, json::value( 17 ) );
+    }
+
+    {
+        variant<monostate, int, std::string> v( "test" );
+        json::value w = json::value_from( v );
+        BOOST_TEST_EQ( w, json::value( "test" ) );
+    }
+
+    return boost::report_errors();
+}
--- a/test/variant_json_value_to.cpp
+++ b/test/variant_json_value_to.cpp
@ -0,0 +1,42 @@
+// Copyright 2022 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/json/value_to.hpp>
+#include <boost/json/serialize.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+using namespace boost::variant2;
+namespace json = boost::json;
+
+int main()
+{
+    {
+        json::value v;
+        auto r = json::try_value_to<monostate>( v );
+        BOOST_TEST( r.has_value() );
+    }
+
+    using V = variant<monostate, int, std::string>;
+
+    {
+        json::value v;
+        auto r = json::try_value_to<V>( v );
+        BOOST_TEST( r.has_value() ) && BOOST_TEST_EQ( *r, V() );
+    }
+
+    {
+        json::value v( 12 );
+        auto r = json::try_value_to<V>( v );
+        BOOST_TEST( r.has_value() ) && BOOST_TEST_EQ( *r, V(12) );
+    }
+
+    {
+        json::value v( "test" );
+        auto r = json::try_value_to<V>( v );
+        BOOST_TEST( r.has_value() ) && BOOST_TEST_EQ( *r, V("test") );
+    }
+
+    return boost::report_errors();
+}
--- a/test/variant_uses_double_storage.cpp
+++ b/test/variant_uses_double_storage.cpp
@ -0,0 +1,50 @@
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <type_traits>
+
+using namespace boost::variant2;
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+struct X1
+{
+};
+
+STATIC_ASSERT( std::is_nothrow_move_constructible<X1>::value );
+STATIC_ASSERT( std::is_trivially_destructible<X1>::value );
+
+struct X2
+{
+    ~X2() {}
+};
+
+STATIC_ASSERT( std::is_nothrow_move_constructible<X2>::value );
+STATIC_ASSERT( !std::is_trivially_destructible<X2>::value );
+
+struct X3
+{
+    X3( X3&& ) {}
+};
+
+STATIC_ASSERT( !std::is_nothrow_move_constructible<X3>::value );
+STATIC_ASSERT( std::is_trivially_destructible<X3>::value );
+
+struct X4
+{
+    ~X4() {}
+    X4( X4&& ) {}
+};
+
+STATIC_ASSERT( !std::is_nothrow_move_constructible<X4>::value );
+STATIC_ASSERT( !std::is_trivially_destructible<X4>::value );
+
+//
+
+STATIC_ASSERT( !variant<int, float>::uses_double_storage() );
+STATIC_ASSERT( !variant<int, float, X1>::uses_double_storage() );
+STATIC_ASSERT( !variant<int, float, X2>::uses_double_storage() );
+STATIC_ASSERT( variant<int, float, X3>::uses_double_storage() );
+STATIC_ASSERT( variant<int, float, X4>::uses_double_storage() );
--- a/test/variant_value_construct_cx.cpp
+++ b/test/variant_value_construct_cx.cpp
@ -82,7 +82,7 @@ int main()

        STATIC_ASSERT( v.index() == 1 );
        STATIC_ASSERT( holds_alternative<float>(v) );
-        STATIC_ASSERT( get<1>(v) == 3.14f );
+        STATIC_ASSERT( get<1>(v) == (float)3.14f ); // see FLT_EVAL_METHOD
    }

    {
@ -97,7 +97,7 @@ int main()

        STATIC_ASSERT( v.index() == 2 );
        STATIC_ASSERT( holds_alternative<float>(v) );
-        STATIC_ASSERT( get<2>(v) == 3.14f );
+        STATIC_ASSERT( get<2>(v) == (float)3.14f );
    }

    {
--- a/test/variant_visit_r.cpp
+++ b/test/variant_visit_r.cpp
@ -61,18 +61,18 @@ int main()
    }

    {
-        variant<int, float> const v( 3.14f );
+        variant<int, float> const v( 3.125f );

        BOOST_TEST_EQ( visit<int>( F1(), v ), 3 );
-        BOOST_TEST_EQ( visit<float>( F1(), v ), 3.14f );
+        BOOST_TEST_EQ( visit<float>( F1(), v ), 3.125f );
    }

    {
        variant<int, float> v1( 1 );
-        variant<int, float> const v2( 3.14f );
+        variant<int, float> const v2( 3.125f );

        BOOST_TEST_EQ( visit<int>( F2(), v1, v2 ), 4 );
-        BOOST_TEST_EQ( visit<float>( F2(), v1, v2 ), 1 + 3.14f );
+        BOOST_TEST_EQ( visit<float>( F2(), v1, v2 ), 1 + 3.125f );
    }

    {
Author	SHA1	Message	Date
Peter Dimov	f9bdafd3ca	Remove C++11 requirements from test/Jamfile	2024-05-18 03:18:56 +03:00
Peter Dimov	38293da18e	Update .drone.jsonnet	2024-05-18 02:43:52 +03:00
Peter Dimov	65ab0f8cef	Update ci.yml	2024-05-17 22:04:55 +03:00
Peter Dimov	78796d0e7d	Increase workaround to < 1950, because VS2022 has reached _MSC_VER=1940. Refs #43 .	2024-05-17 21:44:21 +03:00
Peter Dimov	ff36c3aa1f	Merge pull request #42 from K-ballo/more-natvis Improve natvis	2024-03-25 02:22:20 +02:00
Peter Dimov	f0acc9326e	Work around MSVC failures in variant_derived_construct2. Refs #43 .	2024-03-24 19:16:09 +02:00
Peter Dimov	a936eae01b	Add test/variant_derived_construct2. Refs #43 .	2024-03-24 18:41:49 +02:00
Agustin Berge	77234b514c	Improve natvis: - extend support from 10 to 40 alternatives, - split single-buffer vs double-buffer definitions, - adjust display string to follow MS definition for std::variant	2024-03-23 16:04:54 -03:00
Peter Dimov	c125b32938	Add msvc-14.3 /permissive- to Drone	2024-02-08 20:58:45 +02:00
Peter Dimov	3298078c8b	Update .drone.jsonnet	2024-01-11 22:05:28 +02:00
Peter Dimov	a38839febc	Update ci.yml	2024-01-11 21:20:40 +02:00
Peter Dimov	c3071b7d0b	Merge pull request #40 from Lastique/patch-1 Add missing dots in visit_by_index docs	2024-01-11 21:03:37 +02:00
Andrey Semashev	9cf32980a9	Add missing dots in visit_by_index docs	2024-01-11 20:18:06 +03:00
Peter Dimov	9e4234bfd5	Merge pull request #39 from 13steinj/develop Suppress -Wuninitialized in emplace_impl	2023-10-24 12:42:10 +03:00
Jonathan Stein	55f1332ce0	Suppress -Wuninitialized in emplace_impl Closes #38	2023-10-23 15:46:15 -05:00
Peter Dimov	db12c36b89	Remove unnecessary includes	2023-10-11 18:28:11 +03:00
Peter Dimov	a5cb0582d5	Make tag_invoke_L2 more msvc-14.0-friendly	2023-09-03 18:28:49 +03:00
Peter Dimov	e2546b70ca	Document uses_double_storage(). Refs #37 .	2023-06-29 18:32:58 +03:00
Peter Dimov	362224a009	Update ci.yml	2023-06-29 16:44:47 +03:00
Peter Dimov	2c590716ab	Use the exact 3.125f in variant_visit_r.cpp	2023-06-29 12:05:55 +03:00
Peter Dimov	82b98fb757	Cast 3.14f to float because FLT_EVAL_METHOD (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108742 ) for discussion	2023-06-29 10:46:54 +03:00
Peter Dimov	30afb9e183	Update test/Jamfile to fix Drone issues	2023-06-29 09:54:49 +03:00
Peter Dimov	129e27ce09	Update Drone files	2023-06-29 09:33:44 +03:00
Peter Dimov	26595285d3	Add variant<>::uses_double_storage(). Refs #37 .	2023-06-28 22:14:56 +03:00
Peter Dimov	95a8c5ffec	Update .drone.jsonnet	2023-01-23 03:53:25 +02:00
Peter Dimov	ec2819a05e	Update CMakeLists.txt	2023-01-13 00:56:45 +02:00
Peter Dimov	fcf9746a2d	Merge branch 'develop' of https://github.com/vinniefalco/boost-variant2 into feature/pr-36	2023-01-13 00:55:17 +02:00
Peter Dimov	a74ebd34dc	Update appveyor.yml	2023-01-12 21:12:17 +02:00
Peter Dimov	1b34c20685	Update appveyor.yml	2023-01-12 18:38:10 +02:00
Peter Dimov	604d3700ad	Add CMake tests to Appveyor	2023-01-12 10:49:41 +02:00
Peter Dimov	4d1fd43d72	Update supported compilers in documentation and README	2022-10-27 21:25:57 +03:00
Peter Dimov	376925a209	Work around msvc-14.1 /permissive- failure	2022-10-24 15:47:09 +03:00
Peter Dimov	bcb8796225	Add /permissive- jobs to Drone and Appveyor	2022-10-24 15:27:05 +03:00
Peter Dimov	a948b85c74	Update revision history	2022-10-18 17:38:59 +03:00
Peter Dimov	32862d6db7	Add missing std::move	2022-10-18 16:02:33 +03:00
Peter Dimov	423d350ff1	Remove unneeded forward declarations	2022-10-18 16:01:31 +03:00
Peter Dimov	aad1f86fae	Reflect the change in is_null_like	2022-10-18 16:00:14 +03:00
Peter Dimov	1f8c4a1900	Replace polymorphic lambdas with function objects for C++11	2022-10-18 06:29:57 +03:00
Peter Dimov	67a12199e6	Add JSON support (refs #28 )	2022-10-18 06:08:18 +03:00
Peter Dimov	457147d1b0	Suppress -Wmaybe-uninitialized in emplace_impl	2022-10-18 03:20:36 +03:00
Peter Dimov	4a5f3dc498	Add variant<monostate, T>::emplace tests to fish out -Wmaybe-uninitialized warnings	2022-10-18 02:56:15 +03:00
Peter Dimov	6fe1c69bc8	Add Drone support	2022-10-18 02:16:59 +03:00
Peter Dimov	78a974429a	Update ci.yml	2022-10-15 19:39:32 +03:00
Vinnie Falco	4c5f254b9c	add boost_variant2.natvis and interface source files	2022-08-19 12:13:08 -07:00
Peter Dimov	c633a953de	Change macos-10.15 to macos-11 in ci.yml	2022-08-15 19:26:35 +03:00
Peter Dimov	8ee7c5aad0	Update ci.yml	2022-07-14 14:47:06 +03:00