Fix NDK version in Android CI

GCC 4.8.0 - 7.0 has a bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480) involving specialization in a namespace enclosing the specialized template. This PR fixes an appearance of this bug in the span header.

.github/workflows/android.yml

@@ -0,0 +1,50 @@
+name: CI_Android
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  Android:
+    runs-on: macos-latest
+    defaults:
+      run:
+        working-directory: build
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Create build directory
+        run: mkdir -p build
+        working-directory: .
+
+      - name: Start emulator
+        run: |
+          echo "y" | $ANDROID_HOME/tools/bin/sdkmanager --install 'system-images;android-24;default;x86_64'
+          echo "no" | $ANDROID_HOME/tools/bin/avdmanager create avd -n xamarin_android_emulator -k 'system-images;android-24;default;x86_64' --force
+          $ANDROID_HOME/emulator/emulator -list-avds
+          echo "Starting emulator"
+          # Start emulator in background
+          nohup $ANDROID_HOME/emulator/emulator -avd xamarin_android_emulator -no-snapshot > /dev/null 2>&1 &
+          echo "Emulator starting"
+
+      - name: Configure
+        run: cmake -Werror=dev -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK_LATEST_HOME/build/cmake/android.toolchain.cmake -DANDROID_PLATFORM=16 -DANDROID_ABI=x86_64 -DCMAKE_BUILD_TYPE=Debug ..
+
+      - name: Build
+        run: cmake --build . --parallel
+
+      - name: Wait for emulator ready
+        run: |
+          $ANDROID_HOME/platform-tools/adb wait-for-device shell 'while [[ -z $(getprop sys.boot_completed | tr -d '\r') ]]; do sleep 10; done; input keyevent 82'
+          $ANDROID_HOME/platform-tools/adb devices
+          $ANDROID_HOME/platform-tools/adb shell getprop ro.product.cpu.abi
+          echo "Emulator started"
+
+      - name: Deploy tests
+        run: |
+          adb push tests /data/local/tmp
+          adb shell find /data/local/tmp/tests -maxdepth 1 -exec chmod +x {} \\\;
+
+      - name: Test
+        run: adb shell find /data/local/tmp/tests -name "*_tests" -maxdepth 1 -exec {} \\\;

.github/workflows/ios.yml

@@ -0,0 +1,52 @@
+name: CI_iOS
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  iOS:
+    runs-on: macos-latest
+    defaults:
+      run:
+        working-directory: build
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Create build directory
+        run: mkdir -p build
+        working-directory: .
+
+      - name: Configure
+        run: |
+          cmake \
+            -Werror=dev \
+            -GXcode \
+            -DCMAKE_SYSTEM_NAME=iOS \
+            "-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64" \
+            -DCMAKE_OSX_DEPLOYMENT_TARGET=9 \
+            -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
+            "-DMACOSX_BUNDLE_GUI_IDENTIFIER=GSL.\$(EXECUTABLE_NAME)" \
+            -DMACOSX_BUNDLE_BUNDLE_VERSION=3.1.0 \
+            -DMACOSX_BUNDLE_SHORT_VERSION_STRING=3.1.0 \
+            ..
+
+      - name: Build
+        run: cmake --build . --parallel `sysctl -n hw.ncpu` --config Release -- -sdk iphonesimulator
+
+      - name: Start simulator
+        run: |
+          RUNTIME=`xcrun simctl list runtimes iOS -j|jq '.runtimes|last.identifier'`
+          UDID=`xcrun simctl list devices iPhone available -j|jq -r ".devices[$RUNTIME]|last.udid"`
+          xcrun simctl bootstatus $UDID -b
+
+      - name: Test
+        run: |
+          for TEST in `find tests/Release-iphonesimulator -depth 1 -name "*.app"`
+          do
+            xcrun simctl install booted $TEST
+            TEST_ID=`plutil -convert json -o - $TEST/Info.plist|jq -r ".CFBundleIdentifier"`
+            xcrun simctl launch --console booted $TEST_ID
+            xcrun simctl uninstall booted $TEST_ID
+          done

.travis.yml

@@ -1,295 +0,0 @@
-# Based on https://github.com/ldionne/hana/blob/master/.travis.yml
-
-language: cpp
-sudo: false
-notifications:
-  email: false
-
-# Use Linux unless specified otherwise
-os: linux
-dist: trusty
-
-cache:
-  directories:
-    - ${TRAVIS_BUILD_DIR}/deps
-
-matrix:
-  include:
-
-    ##########################################################################
-    # Clang on OSX
-    # Travis seems to take longer to start OSX instances,
-    # so leave this first for the overall build to be faster
-    ##########################################################################
-
-    # XCode 8.3
-    - env: COMPILER=clang++ BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      os: osx
-      osx_image: xcode8.3
-      compiler: clang
-
-    - env: COMPILER=clang++ BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      os: osx
-      osx_image: xcode8.3
-      compiler: clang
-
-    # XCode 9.1
-    - env: COMPILER=clang++ BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      os: osx
-      osx_image: xcode9.1
-      compiler: clang
-
-    - env: COMPILER=clang++ BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      os: osx
-      osx_image: xcode9.1
-      compiler: clang
-
-    ##########################################################################
-    # Clang on Linux
-    ##########################################################################
-
-    # Clang 3.6
-    - env: COMPILER=clang++-3.6 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang36
-        apt:
-          packages:
-            - clang-3.6
-            - g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.6
-
-    - env: COMPILER=clang++-3.6 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang36
-
-    # Clang 3.7
-    - env: COMPILER=clang++-3.7 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang37
-        apt:
-          packages:
-            - clang-3.7
-            - g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.7
-
-    - env: COMPILER=clang++-3.7 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang37
-
-    # Clang 3.8
-    - env: COMPILER=clang++-3.8 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang38
-        apt:
-          packages:
-            - clang-3.8
-            - g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.8
-
-    - env: COMPILER=clang++-3.8 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang38
-
-    # Clang 3.9
-    - env: COMPILER=clang++-3.9 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang39
-        apt:
-          packages:
-            - clang-3.9
-            - g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.9
-
-    - env: COMPILER=clang++-3.9 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang39
-
-    # Clang 4.0
-    - env: COMPILER=clang++-4.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang40
-        apt:
-          packages:
-            - clang-4.0
-            - g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-4.0
-
-    - env: COMPILER=clang++-4.0 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang40
-
-    # Clang 5.0
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang50
-        apt:
-          packages:
-            - clang-5.0
-            - g++-7
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-5.0
-            - sourceline: 'deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-5.0 main'
-              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
-
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang50
-
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
-      addons: *clang50
-
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Release GSL_CXX_STANDARD=17
-      addons: *clang50
-
-    # Clang 6.0
-    - env: COMPILER=clang++-6.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang60
-        apt:
-          packages:
-            - clang-6.0
-            - g++-7
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-6.0
-            - sourceline: 'deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-6.0 main'
-              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
-
-    - env: COMPILER=clang++-6.0 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang60
-
-    # Clang 6.0 c++17
-    - env: COMPILER=clang++-6.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
-      addons: *clang60
-
-    - env: COMPILER=clang++-6.0 BUILD_TYPE=Release GSL_CXX_STANDARD=17
-      addons: *clang60
-
-    # Clang 7.0
-    - env: COMPILER=clang++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &clang70
-        apt:
-          packages:
-            - clang-7
-            - g++-7
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-7
-
-
-    - env: COMPILER=clang++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *clang70
-
-    # Clang 7.0 c++17
-    - env: COMPILER=clang++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
-      addons: *clang70
-
-    - env: COMPILER=clang++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=17
-      addons: *clang70
-
-    ##########################################################################
-    # GCC on Linux
-    ##########################################################################
-
-    # GCC 5
-    - env: COMPILER=g++-5 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &gcc5
-        apt:
-          packages: g++-5
-          sources:
-            - ubuntu-toolchain-r-test
-
-    - env: COMPILER=g++-5 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *gcc5
-
-    # GCC 6
-    - env: COMPILER=g++-6 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &gcc6
-        apt:
-          packages: g++-6
-          sources:
-            - ubuntu-toolchain-r-test
-
-    - env: COMPILER=g++-6 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *gcc6
-
-    # GCC 7
-    - env: COMPILER=g++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
-      addons: &gcc7
-        apt:
-          packages: g++-7
-          sources:
-            - ubuntu-toolchain-r-test
-
-    - env: COMPILER=g++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=14
-      addons: *gcc7
-
-    # GCC 7 c++17 
-    - env: COMPILER=g++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
-      addons: *gcc7
-
-    - env: COMPILER=g++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=17
-      addons: *gcc7
-
-install:
-  # Set the ${CXX} variable properly
-  - export CXX=${COMPILER}
-  - ${CXX} --version
-
-  # Dependencies required by the CI are installed in ${TRAVIS_BUILD_DIR}/deps/
-  - DEPS_DIR="${TRAVIS_BUILD_DIR}/deps"
-  - mkdir -p "${DEPS_DIR}"
-  - cd "${DEPS_DIR}"
-
-  # Travis machines have 2 cores
-  - JOBS=2
-
-  ############################################################################
-  # Install a recent CMake (unless already installed on OS X)
-  ############################################################################
-  - CMAKE_VERSION=3.7.2
-  - |
-    if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then
-      CMAKE_URL="https://cmake.org/files/v${CMAKE_VERSION%.[0-9]}/cmake-${CMAKE_VERSION}-Linux-x86_64.tar.gz"
-      mkdir cmake && travis_retry wget --no-check-certificate -O - ${CMAKE_URL} | tar --strip-components=1 -xz -C cmake
-      export PATH=${DEPS_DIR}/cmake/bin:${PATH}
-    else
-      brew install cmake || brew upgrade cmake
-    fi
-  - cmake --version
-
-  ############################################################################
-  # [linux]: Install the right version of libc++
-  ############################################################################
-  - |
-    LLVM_INSTALL=${DEPS_DIR}/llvm/install
-    # if in linux and compiler clang and llvm not installed
-    if [[ "${TRAVIS_OS_NAME}" == "linux" && "${CXX%%+*}" == "clang" && -n "$(ls -A ${LLVM_INSTALL})" ]]; then
-      if   [[ "${CXX}" == "clang++-3.6" ]]; then LLVM_VERSION="3.6.2";
-      elif [[ "${CXX}" == "clang++-3.7" ]]; then LLVM_VERSION="3.7.1";
-      elif [[ "${CXX}" == "clang++-3.8" ]]; then LLVM_VERSION="3.8.1";
-      elif [[ "${CXX}" == "clang++-3.9" ]]; then LLVM_VERSION="3.9.1";
-      fi
-      LLVM_URL="http://llvm.org/releases/${LLVM_VERSION}/llvm-${LLVM_VERSION}.src.tar.xz"
-      LIBCXX_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxx-${LLVM_VERSION}.src.tar.xz"
-      LIBCXXABI_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxxabi-${LLVM_VERSION}.src.tar.xz"
-      mkdir -p llvm llvm/build llvm/projects/libcxx llvm/projects/libcxxabi
-      travis_retry wget -O - ${LLVM_URL} | tar --strip-components=1 -xJ -C llvm
-      travis_retry wget -O - ${LIBCXX_URL} | tar --strip-components=1 -xJ -C llvm/projects/libcxx
-      travis_retry wget -O - ${LIBCXXABI_URL} | tar --strip-components=1 -xJ -C llvm/projects/libcxxabi
-      (cd llvm/build && cmake .. -DCMAKE_INSTALL_PREFIX=${LLVM_INSTALL})
-      (cd llvm/build/projects/libcxx && make install -j2)
-      (cd llvm/build/projects/libcxxabi && make install -j2)
-      export CXXFLAGS="-isystem ${LLVM_INSTALL}/include/c++/v1"
-      export LDFLAGS="-L ${LLVM_INSTALL}/lib -l c++ -l c++abi"
-      export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${LLVM_INSTALL}/lib"
-    fi
-
-before_script:
-  # have CMake to generate build files
-  - cd "${TRAVIS_BUILD_DIR}"
-  - mkdir build && cd build
-  - cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DGSL_CXX_STANDARD=$GSL_CXX_STANDARD
-  
-script:
-  # build and run tests
-  - cmake --build . -- -j${JOBS}
-  - ctest --output-on-failure -j${JOBS}

CMakeLists.txt

@@ -1,94 +1,61 @@
-cmake_minimum_required(VERSION 3.1.3)
+cmake_minimum_required(VERSION 3.1.3...3.16)
 
-project(GSL CXX)
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/")
+include(guidelineSupportLibrary)
 
-include(ExternalProject)
-find_package(Git)
+project(GSL
+    VERSION 4.0.0
+    LANGUAGES CXX
+)
 
-# creates a library GSL which is an interface (header files only)
+# Must include after the project call due to GNUInstallDirs requiring a language be enabled (IE. CXX)
+include(GNUInstallDirs)
+
+# Creates a library GSL which is an interface (header files only)
 add_library(GSL INTERFACE)
 
-# determine whether this is a standalone project or included by other projects
+# NOTE: If you want to use GSL prefer to link against GSL using this alias target
+# EX:
+#   target_link_libraries(foobar PRIVATE Microsoft.GSL::GSL)
+#
+# Add Microsoft.GSL::GSL alias for GSL so that dependents can be agnostic about
+# whether GSL was added via `add_subdirectory` or `find_package`
+add_library(Microsoft.GSL::GSL ALIAS GSL)
+
+# Determine whether this is a standalone project or included by other projects
 set(GSL_STANDALONE_PROJECT OFF)
 if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
-  set(GSL_STANDALONE_PROJECT ON)
-endif ()
+    set(GSL_STANDALONE_PROJECT ON)
+endif()
 
-set(GSL_CXX_STANDARD "14" CACHE STRING "Use c++ standard")
-set(GSL_CXX_STD "cxx_std_${GSL_CXX_STANDARD}")
+### Project options
+option(GSL_INSTALL "Generate and install GSL target" ${GSL_STANDALONE_PROJECT})
+option(GSL_TEST "Build and perform GSL tests" ${GSL_STANDALONE_PROJECT})
 
-if (MSVC)
-    set(GSL_CXX_STD_OPT "-std:c++${GSL_CXX_STANDARD}")
+# This GSL implementation generally assumes a platform that implements C++14 support.
+set(gsl_min_cxx_standard "14")
+
+if (GSL_STANDALONE_PROJECT)
+    gsl_set_default_cxx_standard(${gsl_min_cxx_standard})
 else()
-    set(GSL_CXX_STD_OPT "-std=c++${GSL_CXX_STANDARD}")
+    gsl_client_set_cxx_standard(${gsl_min_cxx_standard})
 endif()
 
-# when minimum version required is 3.8.0 remove if below
-# both branches do exactly the same thing
-if (CMAKE_VERSION VERSION_LESS 3.7.9)
-    include(CheckCXXCompilerFlag)
-    CHECK_CXX_COMPILER_FLAG("${GSL_CXX_STD_OPT}" COMPILER_SUPPORTS_CXX_STANDARD)
+# Setup include directory
+add_subdirectory(include)
 
-    if(COMPILER_SUPPORTS_CXX_STANDARD)
-        target_compile_options(GSL INTERFACE "${GSL_CXX_STD_OPT}")
-    else()
-        message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no c++${GSL_CXX_STANDARD} support. Please use a different C++ compiler.")
-    endif()
-else ()
-    target_compile_features(GSL INTERFACE "${GSL_CXX_STD}")
-    # on *nix systems force the use of -std=c++XX instead of -std=gnu++XX (default)
-    set(CMAKE_CXX_EXTENSIONS OFF)
+# Add natvis file
+gsl_add_native_visualizer_support()
+
+# Add packaging support
+gsl_create_packaging_file()
+
+if (GSL_INSTALL)
+    # Setup install/export logic
+    gsl_install_logic()
 endif()
 
-# add definitions to the library and targets that consume it
-target_compile_definitions(GSL INTERFACE
-    $<$<CXX_COMPILER_ID:MSVC>:
-        # remove unnecessary warnings about unchecked iterators
-        _SCL_SECURE_NO_WARNINGS
-        # remove deprecation warnings about std::uncaught_exception() (from catch)
-        _SILENCE_CXX17_UNCAUGHT_EXCEPTION_DEPRECATION_WARNING
-    >
-)
-
-# add include folders to the library and targets that consume it
-# the SYSTEM keyword suppresses warnings for users of the library
-if(GSL_STANDALONE_PROJECT)
-    target_include_directories(GSL INTERFACE
-        $<BUILD_INTERFACE:
-            ${CMAKE_CURRENT_SOURCE_DIR}/include
-        >
-    )
-else()
-    target_include_directories(GSL SYSTEM INTERFACE
-        $<BUILD_INTERFACE:
-            ${CMAKE_CURRENT_SOURCE_DIR}/include
-        >
-    )
-endif()
-
-
-if (CMAKE_VERSION VERSION_GREATER 3.7.8)
-    if (MSVC_IDE)
-        option(VS_ADD_NATIVE_VISUALIZERS "Configure project to use Visual Studio native visualizers" TRUE)
-    else()
-        set(VS_ADD_NATIVE_VISUALIZERS FALSE CACHE INTERNAL "Native visualizers are Visual Studio extension" FORCE)
-    endif()
-
-    # add natvis file to the library so it will automatically be loaded into Visual Studio
-    if(VS_ADD_NATIVE_VISUALIZERS)
-        target_sources(GSL INTERFACE
-            ${CMAKE_CURRENT_SOURCE_DIR}/GSL.natvis
-        )
-    endif()
-endif()
-
-install(
-    DIRECTORY include/gsl
-    DESTINATION include
-)
-
-option(GSL_TEST "Generate tests." ${GSL_STANDALONE_PROJECT})
 if (GSL_TEST)
-	enable_testing()
-	add_subdirectory(tests)
-endif ()
+    enable_testing()
+    add_subdirectory(tests)
+endif()

CONTRIBUTING.md

@@ -17,7 +17,7 @@ Please submit a Contributor License Agreement (CLA) before submitting a pull req
 Your pull request should: 
 
 * Include a description of what your change intends to do
-* Be a child commit of a reasonably recent commit in the **master** branch 
+* Be a child commit of a reasonably recent commit in the **main** branch 
     * Requests need not be a single commit, but should be a linear sequence of commits (i.e. no merge commits in your PR)
 * It is desirable, but not necessary, for the tests to pass at each commit. Please see [README.md](./README.md) for instructions to build the test suite. 
 * Have clear commit messages 

GSL.natvis

@@ -19,9 +19,7 @@
         </Expand>
     </Type>
 
-    <!-- These types are from the span header. -->
-    <!-- This is for dynamic_extent spans. -->
-    <Type Name="gsl::span&lt;*, -1&gt;">
+    <Type Name="gsl::span&lt;*, *&gt;">
         <DisplayString>{{ extent = {storage_.size_} }}</DisplayString>
         <Expand>
             <ArrayItems>
@@ -31,43 +29,7 @@
         </Expand>
     </Type>
 
-    <!-- This works for constexpr size spans. -->
-    <Type Name="gsl::span&lt;*, *&gt;">
-        <DisplayString>{{ extent = {extent} }}</DisplayString>
-        <Expand>
-            <ArrayItems>
-                <Size>extent</Size>
-                <ValuePointer>storage_.data_</ValuePointer>
-            </ArrayItems>
-        </Expand>
-    </Type>
-
-    <!-- This is for dynamic_extent string_spans. -->
-    <Type Name="gsl::basic_string_span&lt;*, -1&gt;">
-        <DisplayString>{span_.storage_.data_,[span_.storage_.size_]na}</DisplayString>
-        <Expand>
-            <Item Name="[size]">span_.storage_.size_</Item>
-            <ArrayItems>
-                <Size>span_.storage_.size_</Size>
-                <ValuePointer>span_.storage_.data_</ValuePointer>
-            </ArrayItems>
-        </Expand>
-    </Type>
-
-    <!-- This works for constexpr size string_spans. -->
     <Type Name="gsl::basic_string_span&lt;*, *&gt;">
-        <DisplayString>{span_.storage_.data_,[span_.extent]na}</DisplayString>
-        <Expand>
-            <Item Name="[size]">span_.extent</Item>
-            <ArrayItems>
-                <Size>span_.extent</Size>
-                <ValuePointer>span_.storage_.data_</ValuePointer>
-            </ArrayItems>
-        </Expand>
-    </Type>
-
-    <!-- This is for dynamic_extent zstring_spans. -->
-    <Type Name="gsl::basic_zstring_span&lt;*, -1&gt;">
         <DisplayString>{span_.storage_.data_,[span_.storage_.size_]na}</DisplayString>
         <Expand>
             <Item Name="[size]">span_.storage_.size_</Item>
@@ -77,19 +39,18 @@
             </ArrayItems>
         </Expand>
     </Type>
-    
-    <!-- This works for constexpr size string_spans. -->
+
     <Type Name="gsl::basic_zstring_span&lt;*, *&gt;">
-        <DisplayString>{span_.storage_.data_,[span_.extent]na}</DisplayString>
+        <DisplayString>{span_.storage_.data_,[span_.storage_.size_]na}</DisplayString>
         <Expand>
-            <Item Name="[size]">span_.extent</Item>
+            <Item Name="[size]">span_.storage_.size_</Item>
             <ArrayItems>
-                <Size>span_.extent</Size>
+                <Size>span_.storage_.size_</Size>
                 <ValuePointer>span_.storage_.data_</ValuePointer>
             </ArrayItems>
         </Expand>
     </Type>
-    
+
     <!-- These types are from the gsl header. -->
     <Type Name="gsl::not_null&lt;*&gt;">
         <!-- We can always dereference this since it's an invariant. -->

README.md

@@ -1,12 +1,11 @@
-# GSL: Guidelines Support Library [![Build Status](https://travis-ci.org/Microsoft/GSL.svg?branch=master)](https://travis-ci.org/Microsoft/GSL) [![Build status](https://ci.appveyor.com/api/projects/status/github/Microsoft/GSL?svg=true)](https://ci.appveyor.com/project/neilmacintosh/GSL)
+# GSL: Guidelines Support Library
+[![Build Status](https://dev.azure.com/cppstat/GSL/_apis/build/status/microsoft.GSL?branchName=main)](https://dev.azure.com/cppstat/GSL/_build/latest?definitionId=1&branchName=main)
 
 The Guidelines Support Library (GSL) contains functions and types that are suggested for use by the
 [C++ Core Guidelines](https://github.com/isocpp/CppCoreGuidelines) maintained by the [Standard C++ Foundation](https://isocpp.org).
 This repo contains Microsoft's implementation of GSL.
 
-The library includes types like `span<T>`, `string_span`, `owner<>` and others.
-
-The entire implementation is provided inline in the headers under the [gsl](./include/gsl) directory. The implementation generally assumes a platform that implements C++14 support. There are specific workarounds to support MSVC 2015.
+The entire implementation is provided inline in the headers under the [gsl](./include/gsl) directory. The implementation generally assumes a platform that implements C++14 support.
 
 While some types have been broken out into their own headers (e.g. [gsl/span](./include/gsl/span)),
 it is simplest to just include [gsl/gsl](./include/gsl/gsl) and gain access to the entire library.
@@ -18,42 +17,111 @@ other platforms. Please see [CONTRIBUTING.md](./CONTRIBUTING.md) for more inform
 This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
 
 # Usage of Third Party Libraries
-This project makes use of the [Catch](https://github.com/philsquared/catch) testing library. Please see the [ThirdPartyNotices.txt](./ThirdPartyNotices.txt) file for details regarding the licensing of Catch.
+This project makes use of the [Google Test](https://github.com/google/googletest) testing library. Please see the [ThirdPartyNotices.txt](./ThirdPartyNotices.txt) file for details regarding the licensing of Google Test.
+
+# Supported features
+## Microsoft GSL implements the following from the C++ Core Guidelines:
+
+Feature                            | Supported? | Description
+-----------------------------------|:----------:|-------------
+[**1. Views**][cg-views]           |            |
+owner                              | &#x2611;   | an alias for a raw pointer
+not_null                           | &#x2611;   | restricts a pointer / smart pointer to hold non-null values
+span                               | &#x2611;   | a view over a contiguous sequence of memory. Based on the standardized verison of `std::span`, however `gsl::span` enforces bounds checking. See the [wiki](https://github.com/microsoft/GSL/wiki/gsl::span-and-std::span) for additional information.
+span_p                             | &#x2610;   | spans a range starting from a pointer to the first place for which the predicate is true
+basic_zstring                      | &#x2611;   | A pointer to a C-string (zero-terminated array) with a templated char type
+zstring                            | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of char
+czstring                           | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of const char
+wzstring                           | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of wchar_t
+cwzstring                          | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of const wchar_t
+u16zstring                         | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of char16_t
+cu16zstring                        | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of const char16_t
+u32zstring                         | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of char32_t
+cu32zstring                        | &#x2611;   | An alias to `basic_zstring` with dynamic extent and a char type of const char32_t
+[**2. Owners**][cg-owners]         |            |
+unique_ptr                         | &#x2611;   | an alias to `std::unique_ptr`
+shared_ptr                         | &#x2611;   | an alias to `std::shared_ptr`
+stack_array                        | &#x2610;   | a stack-allocated array
+dyn_array                          | &#x2610;   | a heap-allocated array
+[**3. Assertions**][cg-assertions] |            |
+Expects                            | &#x2611;   | a precondition assertion; on failure it terminates
+Ensures                            | &#x2611;   | a postcondition assertion; on failure it terminates
+[**4. Utilities**][cg-utilities]   |            |
+move_owner                         | &#x2610;   | a helper function that moves one `owner` to the other
+byte                               | &#x2611;   | either an alias to std::byte or a byte type
+final_action                       | &#x2611;   | a RAII style class that invokes a functor on its destruction
+finally                            | &#x2611;   | a helper function instantiating `final_action`
+GSL_SUPPRESS                       | &#x2611;   | a macro that takes an argument and turns it into `[[gsl::suppress(x)]]` or `[[gsl::suppress("x")]]`
+[[implicit]]                       | &#x2610;   | a "marker" to put on single-argument constructors to explicitly make them non-explicit
+index                              | &#x2611;   | a type to use for all container and array indexing (currently an alias for std::ptrdiff_t)
+joining_thread                     | &#x2610;   | a RAII style version of `std::thread` that joins
+narrow                             | &#x2611;   | a checked version of narrow_cast; it can throw `narrowing_error`
+narrow_cast                        | &#x2611;   | a narrowing cast for values and a synonym for static_cast
+narrowing_error                    | &#x2611;   | a custom exception type thrown by `narrow()`
+[**5. Concepts**][cg-concepts]     | &#x2610;   |
+
+## The following features do not exist in or have been removed from the C++ Core Guidelines:
+Feature                            | Supported? | Description
+-----------------------------------|:----------:|-------------
+strict_not_null                    | &#x2611;   | A stricter version of `not_null` with explicit constructors
+multi_span                         | &#x2610;   | Deprecated. Multi-dimensional span.
+strided_span                       | &#x2610;   | Deprecated. Support for this type has been discontinued.
+basic_string_span                  | &#x2610;   | Deprecated. Like `span` but for strings with a templated char type
+string_span                        | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of char
+cstring_span                       | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of const char
+wstring_span                       | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of wchar_t
+cwstring_span                      | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of const wchar_t
+u16string_span                     | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of char16_t
+cu16string_span                    | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of const char16_t
+u32string_span                     | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of char32_t
+cu32string_span                    | &#x2610;   | Deprecated. An alias to `basic_string_span` with a char type of const char32_t
+
+This is based on [CppCoreGuidelines semi-specification](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gsl-guidelines-support-library).
+
+[cg-views]: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gslview-views
+[cg-owners]: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gslowner-ownership-pointers
+[cg-assertions]: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gslassert-assertions
+[cg-utilities]: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gslutil-utilities
+[cg-concepts]: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#gslconcept-concepts
 
 # Quick Start
-## Supported Platforms
-The test suite that exercises GSL has been built and passes successfully on the following platforms:<sup>1)</sup>
+## Supported Compilers / Toolsets
+The GSL officially supports the latest and previous major versions of VS with MSVC & LLVM, GCC, Clang, and XCode with Apple-Clang.
+Within these two major versions, we try to target the latest minor updates / revisions (although this may be affected by
+delays between a toolchain's release and when it becomes widely available for use).
+Below is a table showing the versions currently being tested.
 
-* Windows using Visual Studio 2015
-* Windows using Visual Studio 2017
-* Windows using Clang/LLVM 3.6
-* Windows using Clang/LLVM 7.0.0
-* Windows using GCC 5.1
-* Windows using Intel C++ Compiler 18.0
-* GNU/Linux using Clang/LLVM 3.6-3.9
-* GNU/Linux using Clang/LLVM 4.0
-* GNU/Linux using Clang/LLVM 5.0
-* GNU/Linux using Clang/LLVM 6.0
-* GNU/Linux using Clang/LLVM 7.0
-* GNU/Linux using GCC 5.1
-* OS X Mojave 10.14.4 using Apple LLVM version 10.0.0 (10.0.1.10010046)
-* OS X Mojave 10.14.3 using Apple LLVM version 10.0.0 (clang-1000.11.45.5)
-* OS X Yosemite using Xcode with Apple Clang 7.0.0.7000072
-* OS X Yosemite using GCC-5.2.0
-* OS X Sierra 10.12.4 using Apple LLVM version 8.1.0 (Clang-802.0.42)
-* OS X El Capitan (10.11) using Xcode with AppleClang 8.0.0.8000042
-* OS X High Sierra 10.13.2 (17C88) using Apple LLVM version 9.0.0 (clang-900.0.39.2)
-* FreeBSD 10.x with Clang/LLVM 3.6
+Compiler |Toolset Versions Currently Tested
+:------- |--:
+ XCode | 13.2.1 & 12.5.1
+ GCC | 11[^1] & 10[^2]
+ Clang | 12[^2] & 11[^2]
+ Visual Studio with MSVC | VS2022[^3] & VS2019[^4]
+ Visual Studio with LLVM | VS2022[^3] & VS2019[^4]
 
-> If you successfully port GSL to another platform, we would love to hear from you. Please submit an issue to let us know. Also please consider
-contributing any changes that were necessary back to this project to benefit the wider community.
 
-<sup>1)</sup> For `gsl::byte` to work correctly with Clang and GCC you might have to use the ` -fno-strict-aliasing` compiler option.
+[^1]: Precise version may be found in the [latest CI results](https://dev.azure.com/cppstat/GSL/_build?definitionId=1&branchFilter=26).
+[^2]: Precise version may be found in the [latest CI results](https://dev.azure.com/cppstat/GSL/_build?definitionId=1&branchFilter=26). Should be the version specified [here](https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#language-and-runtime).
+[^3]: Precise version may be found in the [latest CI results](https://dev.azure.com/cppstat/GSL/_build?definitionId=1&branchFilter=26). Should be the version specified [here](https://github.com/actions/virtual-environments/blob/main/images/win/Windows2022-Readme.md#visual-studio-enterprise-2022).
+[^4]: Precise version may be found in the [latest CI results](https://dev.azure.com/cppstat/GSL/_build?definitionId=1&branchFilter=26). Should be the version specified [here](https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md#visual-studio-enterprise-2019).
+
+---
+If you successfully port GSL to another platform, we would love to hear from you!
+- Submit an issue specifying the platform and target.
+- Consider contributing your changes by filing a pull request with any necessary changes.
+- If at all possible, add a CI/CD step and add the button to the table below!
+
+Target | CI/CD Status
+:------- | -----------:
+iOS | ![CI_iOS](https://github.com/microsoft/GSL/workflows/CI_iOS/badge.svg)
+Android | ![CI_Android](https://github.com/microsoft/GSL/workflows/CI_Android/badge.svg)
+
+Note: These CI/CD steps are run with each pull request, however failures in them are non-blocking.
 
 ## Building the tests
 To build the tests, you will require the following:
 
-* [CMake](http://cmake.org), version 3.1.3 or later to be installed and in your PATH.
+* [CMake](http://cmake.org), version 3.1.3 (3.2.3 for AppleClang) or later to be installed and in your PATH.
 
 These steps assume the source code of this repository has been cloned into a directory named `c:\GSL`.
 
@@ -65,7 +133,7 @@ These steps assume the source code of this repository has been cloned into a dir
 
 2. Configure CMake to use the compiler of your choice (you can see a list by running `cmake --help`).
 
-        cmake -G "Visual Studio 14 2015" c:\GSL
+        cmake -G "Visual Studio 15 2017" c:\GSL
 
 3. Build the test suite (in this case, in the Debug configuration, Release is another good choice).
 
@@ -77,6 +145,18 @@ These steps assume the source code of this repository has been cloned into a dir
 
 All tests should pass - indicating your platform is fully supported and you are ready to use the GSL types!
 
+## Building GSL - Using vcpkg
+
+You can download and install GSL using the [vcpkg](https://github.com/Microsoft/vcpkg) dependency manager:
+
+    git clone https://github.com/Microsoft/vcpkg.git
+    cd vcpkg
+    ./bootstrap-vcpkg.sh
+    ./vcpkg integrate install
+    vcpkg install ms-gsl
+
+The GSL port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
+
 ## Using the libraries
 As the types are entirely implemented inline in headers, there are no linking requirements.
 
@@ -97,5 +177,45 @@ Include the library using:
 
     #include <gsl/gsl>
 
+## Usage in CMake
+
+The library provides a Config file for CMake, once installed it can be found via
+
+    find_package(Microsoft.GSL CONFIG)
+
+Which, when successful, will add library target called `Microsoft.GSL::GSL` which you can use via the usual
+`target_link_libraries` mechanism.
+
+### FetchContent
+
+If you are using cmake version 3.11+ you can use the offical FetchContent module.
+This allows you to easily incorporate GSL into your project.
+
+```cmake
+# NOTE: This example uses cmake version 3.14 (FetchContent_MakeAvailable).
+# Since it streamlines the FetchContent process
+cmake_minimum_required(VERSION 3.14)
+
+include(FetchContent)
+
+# In this example we are picking a specific tag.
+# You can also pick a specific commit, if you need to.
+FetchContent_Declare(GSL
+    GIT_REPOSITORY "https://github.com/microsoft/GSL"
+    GIT_TAG "v3.1.0"
+)
+
+FetchContent_MakeAvailable(GSL)
+
+# Now you can link against the GSL interface library
+add_executable(foobar)
+
+# Link against the interface library (IE header only library)
+target_link_libraries(foobar PRIVATE GSL)
+```
+
 ## Debugging visualization support
 For Visual Studio users, the file [GSL.natvis](./GSL.natvis) in the root directory of the repository can be added to your project if you would like more helpful visualization of GSL types in the Visual Studio debugger than would be offered by default.
+
+If you are using cmake this will be done automatically for you.
+See 'GSL_VS_ADD_NATIVE_VISUALIZERS'

SECURITY.md

@@ -0,0 +1,41 @@
+<!-- BEGIN MICROSOFT SECURITY.MD V0.0.7 BLOCK -->
+
+## Security
+
+Microsoft takes the security of our software products and services seriously, which includes all source code repositories managed through our GitHub organizations, which include [Microsoft](https://github.com/Microsoft), [Azure](https://github.com/Azure), [DotNet](https://github.com/dotnet), [AspNet](https://github.com/aspnet), [Xamarin](https://github.com/xamarin), and [our GitHub organizations](https://opensource.microsoft.com/).
+
+If you believe you have found a security vulnerability in any Microsoft-owned repository that meets [Microsoft's definition of a security vulnerability](https://aka.ms/opensource/security/definition), please report it to us as described below.
+
+## Reporting Security Issues
+
+**Please do not report security vulnerabilities through public GitHub issues.**
+
+Instead, please report them to the Microsoft Security Response Center (MSRC) at [https://msrc.microsoft.com/create-report](https://aka.ms/opensource/security/create-report).
+
+If you prefer to submit without logging in, send email to [secure@microsoft.com](mailto:secure@microsoft.com).  If possible, encrypt your message with our PGP key; please download it from the [Microsoft Security Response Center PGP Key page](https://aka.ms/opensource/security/pgpkey).
+
+You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Additional information can be found at [microsoft.com/msrc](https://aka.ms/opensource/security/msrc). 
+
+Please include the requested information listed below (as much as you can provide) to help us better understand the nature and scope of the possible issue:
+
+  * Type of issue (e.g. buffer overflow, SQL injection, cross-site scripting, etc.)
+  * Full paths of source file(s) related to the manifestation of the issue
+  * The location of the affected source code (tag/branch/commit or direct URL)
+  * Any special configuration required to reproduce the issue
+  * Step-by-step instructions to reproduce the issue
+  * Proof-of-concept or exploit code (if possible)
+  * Impact of the issue, including how an attacker might exploit the issue
+
+This information will help us triage your report more quickly.
+
+If you are reporting for a bug bounty, more complete reports can contribute to a higher bounty award. Please visit our [Microsoft Bug Bounty Program](https://aka.ms/opensource/security/bounty) page for more details about our active programs.
+
+## Preferred Languages
+
+We prefer all communications to be in English.
+
+## Policy
+
+Microsoft follows the principle of [Coordinated Vulnerability Disclosure](https://aka.ms/opensource/security/cvd).
+
+<!-- END MICROSOFT SECURITY.MD BLOCK -->

ThirdPartyNotices.txt

@@ -2,38 +2,40 @@
 THIRD-PARTY SOFTWARE NOTICES AND INFORMATION
 Do Not Translate or Localize
 
-GSL: Guidelines Support Library incorporates third party material from the projects listed below. The original copyright notice and the license under which Microsoft received such third party material are set forth below. Microsoft reserves all other rights not expressly granted, whether by implication, estoppel or otherwise.  
+GSL: Guidelines Support Library incorporates third party material from the projects listed below.
 
+-------------------------------------------------------------------------------
+Software: Google Test
+Owner: Google Inc.
+Source URL: github.com/google/googletest
+License: BSD 3 - Clause
+Text:
+    Copyright 2008, Google Inc.
+    All rights reserved.
 
-1.	Catch (https://github.com/philsquared/Catch)
-
-
-%% Catch NOTICES, INFORMATION, AND LICENSE BEGIN HERE
-=========================================
-Boost Software License - Version 1.0 - August 17th, 2003
-
-Permission is hereby granted, free of charge, to any person or organization
-obtaining a copy of the software and accompanying documentation covered by
-this license (the "Software") to use, reproduce, display, distribute,
-execute, and transmit the Software, and to prepare derivative works of the
-Software, and to permit third-parties to whom the Software is furnished to
-do so, all subject to the following:
-
-The copyright notices in the Software and this entire statement, including
-the above license grant, this restriction and the following disclaimer,
-must be included in all copies of the Software, in whole or in part, and
-all derivative works of the Software, unless such copies or derivative
-works are solely in the form of machine-executable object code generated by
-a source language processor.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
-SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
-FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
-ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
-=========================================
-END OF Catch NOTICES, INFORMATION, AND LICENSE
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
 
+        * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+        * Redistributions in binary form must reproduce the above
+    copyright notice, this list of conditions and the following disclaimer
+    in the documentation and/or other materials provided with the
+    distribution.
+        * Neither the name of Google Inc. nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
 
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+-------------------------------------------------------------------------------

appveyor.yml

@@ -1,128 +0,0 @@
-shallow_clone: true
-
-platform:
-  - x86
-  - x64
-
-configuration:
-  - Debug
-  - Release
-
-image:
-  - Visual Studio 2015
-  - Visual Studio 2017
-  - Visual Studio 2019
-
-environment:
-  NINJA_TAG: v1.8.2
-  NINJA_SHA512: 9B9CE248240665FCD6404B989F3B3C27ED9682838225E6DC9B67B551774F251E4FF8A207504F941E7C811E7A8BE1945E7BCB94472A335EF15E23A0200A32E6D5
-  NINJA_PATH: C:\Tools\ninja\ninja-%NINJA_TAG%
-  VCVAR2015: 'C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat'
-  VCVAR2017: 'C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvarsall.bat'
-  VCVAR2019: 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat'
-  matrix:
-    - GSL_CXX_STANDARD: 14
-      USE_TOOLSET: MSVC
-      USE_GENERATOR: MSBuild
-    - GSL_CXX_STANDARD: 17
-      USE_TOOLSET: MSVC
-      USE_GENERATOR: MSBuild
-    - GSL_CXX_STANDARD: 14
-      USE_TOOLSET: LLVM
-      USE_GENERATOR: Ninja
-    - GSL_CXX_STANDARD: 17
-      USE_TOOLSET: LLVM
-      USE_GENERATOR: Ninja
-
-matrix:
-    exclude:
-    - image: Visual Studio 2015
-      GSL_CXX_STANDARD: 17
-    - image: Visual Studio 2015
-      USE_TOOLSET: LLVM
-      USE_GENERATOR: MSBuild
-
-cache:
-  - C:\cmake-3.14.4-win32-x86
-  - C:\Tools\ninja
-
-install:
-  - ps: |
-      if (![IO.File]::Exists("$env:NINJA_PATH\ninja.exe")) {
-        Start-FileDownload `
-          "https://github.com/ninja-build/ninja/releases/download/$env:NINJA_TAG/ninja-win.zip"
-        $hash = (Get-FileHash ninja-win.zip -Algorithm SHA512).Hash
-        if ($env:NINJA_SHA512 -eq $hash) {
-          7z e -y -bso0 ninja-win.zip -o"$env:NINJA_PATH"
-        } else { Write-Warning "Ninja download hash changed!"; Write-Output "$hash" }
-      }
-      if ([IO.File]::Exists("$env:NINJA_PATH\ninja.exe")) {
-        $env:PATH = "$env:NINJA_PATH;$env:PATH"
-      } else { Write-Warning "Failed to find ninja.exe in expected location." }
-      if ($env:USE_TOOLSET -ne "LLVM") {
-        if (![IO.File]::Exists("C:\cmake-3.14.0-win32-x86\bin\cmake.exe")) {
-          Start-FileDownload 'https://cmake.org/files/v3.14/cmake-3.14.4-win32-x86.zip'
-          7z x -y -bso0 cmake-3.14.4-win32-x86.zip -oC:\
-        }
-        $env:PATH="C:\cmake-3.14.4-win32-x86\bin;$env:PATH"
-      }
-
-before_build:
-  - ps: |
-      if ("$env:USE_GENERATOR" -eq "Ninja") {
-        $GeneratorFlags = '-k 10'
-        $Architecture = $env:PLATFORM
-        if ("$env:APPVEYOR_BUILD_WORKER_IMAGE" -eq "Visual Studio 2015") {
-          $env:VCVARSALL = "`"$env:VCVAR2015`" $Architecture"
-        } elseif ("$env:APPVEYOR_BUILD_WORKER_IMAGE" -eq "Visual Studio 2017") {
-          $env:VCVARSALL = "`"$env:VCVAR2017`" $Architecture"
-        } else {
-          $env:VCVARSALL = "`"$env:VCVAR2019`" $Architecture"
-        }
-        $env:CMakeGenFlags = "-G Ninja -DGSL_CXX_STANDARD=$env:GSL_CXX_STANDARD"
-      } else {
-        $GeneratorFlags = '/m /v:minimal'
-        if ("$env:APPVEYOR_BUILD_WORKER_IMAGE" -eq "Visual Studio 2015") {
-          $Generator = 'Visual Studio 14 2015'
-        } elseif ("$env:APPVEYOR_BUILD_WORKER_IMAGE" -eq "Visual Studio 2017") {
-          $Generator = 'Visual Studio 15 2017'
-        } else {
-          $Generator = 'Visual Studio 16 2019'
-        }
-        if ("$env:PLATFORM" -eq "x86") { 
-            $Architecture = "Win32"
-        } else { 
-            $Architecture = "x64" 
-        }
-        if ("$env:USE_TOOLSET" -eq "LLVM") {
-          $env:CMakeGenFlags = "-G `"$Generator`" -A $Architecture -T llvm -DGSL_CXX_STANDARD=$env:GSL_CXX_STANDARD"
-        } else {
-          $env:CMakeGenFlags = "-G `"$Generator`" -A $Architecture -DGSL_CXX_STANDARD=$env:GSL_CXX_STANDARD"
-        }
-      }
-      if ("$env:USE_TOOLSET" -eq "LLVM") {
-        $env:CC  = "clang-cl"
-        $env:CXX = "clang-cl"
-        if ("$env:PLATFORM" -eq "x86") {
-          $env:CFLAGS   = "-m32";
-          $env:CXXFLAGS = "-m32";
-        } else {
-          $env:CFLAGS   = "-m64";
-          $env:CXXFLAGS = "-m64";
-        }
-      }
-      $env:CMakeBuildFlags = "--config $env:CONFIGURATION -- $GeneratorFlags"
-  - mkdir build
-  - cd build
-  - if %USE_GENERATOR%==Ninja (call %VCVARSALL%)
-  - echo %CMakeGenFlags%
-  - cmake .. %CMakeGenFlags%
-
-build_script:
-  - echo %CMakeBuildFlags%
-  - cmake --build . %CMakeBuildFlags%
-
-test_script:
-  - ctest -j2
-
-deploy: off

azure-pipelines.yml

@@ -0,0 +1,66 @@
+trigger:
+  - main
+
+pr:
+  autoCancel: true
+
+stages:
+- stage: GCC
+  dependsOn: []
+  jobs:
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: gcc
+      image: ubuntu-20.04
+      compilerVersions: [ 11, 10 ]
+      setupfile: 'setup_gcc.yml'
+
+- stage: Clang
+  dependsOn: []
+  jobs:
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: clang
+      image: ubuntu-20.04
+      compilerVersions: [ 12, 11 ]
+      setupfile: 'setup_clang.yml'
+
+- stage: Xcode
+  dependsOn: []
+  jobs:
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: 'Xcode'
+      image: macOS-11
+      compilerVersions: [ '12.5.1', '13.2.1' ]
+      setupfile: 'setup_apple.yml'
+
+- stage: VS_MSVC
+  dependsOn: []
+  jobs:
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: 'VS2019 (MSVC)'
+      compilerVersions: [ 'default' ]
+      image: windows-2019
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: 'VS2022 (MSVC)'
+      compilerVersions: [ 'default' ]
+      image: windows-2022
+
+- stage: VS_LLVM
+  dependsOn: []
+  jobs:
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: 'VS2019 (LLVM)'
+      compilerVersions: [ 'default' ]
+      image: windows-2019
+      extraCmakeArgs: '-T ClangCL'
+  - template: ./pipelines/jobs.yml
+    parameters:
+      compiler: 'VS2022 (LLVM)'
+      compilerVersions: [ 'default' ]
+      image: windows-2022
+      extraCmakeArgs: '-T ClangCL'

cmake/guidelineSupportLibrary.cmake

@@ -0,0 +1,116 @@
+# This cmake module is meant to hold helper functions/macros
+# that make maintaining the cmake build system much easier.
+# This is especially helpful since gsl needs to provide coverage
+# for multiple versions of cmake.
+#
+# Any functions/macros should have a gsl_* prefix to avoid problems
+if (CMAKE_VERSION VERSION_GREATER 3.10 OR CMAKE_VERSION VERSION_EQUAL 3.10)
+    include_guard()
+else()
+    if (DEFINED guideline_support_library_include_guard)
+        return()
+    endif()
+    set(guideline_support_library_include_guard ON)
+endif()
+
+# Necessary for 'write_basic_package_version_file'
+include(CMakePackageConfigHelpers)
+
+function(gsl_set_default_cxx_standard min_cxx_standard)
+    set(GSL_CXX_STANDARD "${min_cxx_standard}" CACHE STRING "Use c++ standard")
+
+    set(GSL_CXX_STD "cxx_std_${GSL_CXX_STANDARD}")
+
+    if (MSVC)
+        set(GSL_CXX_STD_OPT "-std:c++${GSL_CXX_STANDARD}")
+    else()
+        set(GSL_CXX_STD_OPT "-std=c++${GSL_CXX_STANDARD}")
+    endif()
+
+    # when minimum version required is 3.8.0 remove if below
+    # both branches do exactly the same thing
+    if (CMAKE_VERSION VERSION_LESS 3.7.9)
+        include(CheckCXXCompilerFlag)
+        CHECK_CXX_COMPILER_FLAG("${GSL_CXX_STD_OPT}" COMPILER_SUPPORTS_CXX_STANDARD)
+
+        if(COMPILER_SUPPORTS_CXX_STANDARD)
+            target_compile_options(GSL INTERFACE "${GSL_CXX_STD_OPT}")
+        else()
+            message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no c++${GSL_CXX_STANDARD} support. Please use a different C++ compiler.")
+        endif()
+    else()
+        target_compile_features(GSL INTERFACE "${GSL_CXX_STD}")
+        # on *nix systems force the use of -std=c++XX instead of -std=gnu++XX (default)
+        set(CMAKE_CXX_EXTENSIONS OFF)
+    endif()
+endfunction()
+
+# The best way for a project to specify the GSL's C++ standard is by the client specifying
+# the CMAKE_CXX_STANDARD. However, this isn't always ideal. Since the CMAKE_CXX_STANDARD is
+# tied to the cmake version. And many projects have low cmake minimums.
+#
+# So provide an alternative approach in case that doesn't work.
+function(gsl_client_set_cxx_standard min_cxx_standard)
+    if (DEFINED CMAKE_CXX_STANDARD)
+        if (${CMAKE_CXX_STANDARD} VERSION_LESS ${min_cxx_standard})
+            message(FATAL_ERROR "GSL: Requires at least CXX standard ${min_cxx_standard}, user provided ${CMAKE_CXX_STANDARD}")
+        endif()
+
+        # Set the GSL standard to what the client desires
+        set(GSL_CXX_STANDARD "${CMAKE_CXX_STANDARD}" PARENT_SCOPE)
+
+        # Exit out early to avoid extra unneccessary work
+        return()
+    endif()
+
+    # Otherwise pick a reasonable default
+    gsl_set_default_cxx_standard(${min_cxx_standard})
+endfunction()
+
+# Adding the GSL.natvis files improves the debugging experience for users of this library.
+function(gsl_add_native_visualizer_support)
+    if (CMAKE_VERSION VERSION_GREATER 3.7.8)
+        if (MSVC_IDE)
+            option(GSL_VS_ADD_NATIVE_VISUALIZERS "Configure project to use Visual Studio native visualizers" TRUE)
+        else()
+            set(GSL_VS_ADD_NATIVE_VISUALIZERS FALSE CACHE INTERNAL "Native visualizers are Visual Studio extension" FORCE)
+        endif()
+
+        # add natvis file to the library so it will automatically be loaded into Visual Studio
+        if(GSL_VS_ADD_NATIVE_VISUALIZERS)
+            target_sources(GSL INTERFACE $<BUILD_INTERFACE:${GSL_SOURCE_DIR}/GSL.natvis>)
+        endif()
+    endif()
+endfunction()
+
+function(gsl_install_logic)
+    install(TARGETS GSL EXPORT Microsoft.GSLConfig)
+    install(
+        DIRECTORY include/gsl
+        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+    )
+    # Make library importable by other projects
+    install(EXPORT Microsoft.GSLConfig NAMESPACE Microsoft.GSL:: DESTINATION ${CMAKE_INSTALL_DATADIR}/cmake/Microsoft.GSL)
+    export(TARGETS GSL NAMESPACE Microsoft.GSL:: FILE Microsoft.GSLConfig.cmake)
+
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/Microsoft.GSLConfigVersion.cmake DESTINATION ${CMAKE_INSTALL_DATADIR}/cmake/Microsoft.GSL)
+endfunction()
+
+# Add find_package() versioning support. The version for
+# generated Microsoft.GSLConfigVersion.cmake will be used from
+# last project() command. The version's compatibility is set between all
+# minor versions (as it was in prev. GSL releases).
+function(gsl_create_packaging_file)
+    if(${CMAKE_VERSION} VERSION_LESS "3.14.0")
+        write_basic_package_version_file(
+            ${CMAKE_CURRENT_BINARY_DIR}/Microsoft.GSLConfigVersion.cmake
+            COMPATIBILITY SameMajorVersion
+        )
+    else()
+        write_basic_package_version_file(
+            ${CMAKE_CURRENT_BINARY_DIR}/Microsoft.GSLConfigVersion.cmake
+            COMPATIBILITY SameMajorVersion
+            ARCH_INDEPENDENT
+        )
+    endif()
+endfunction()

include/CMakeLists.txt

@@ -0,0 +1,20 @@
+
+# Add include folders to the library and targets that consume it
+# the SYSTEM keyword suppresses warnings for users of the library
+#
+# By adding this directory as an include directory the user gets a
+# namespace effect.
+#
+# IE:
+#   #include <gsl/gsl>
+if(GSL_STANDALONE_PROJECT)
+    target_include_directories(GSL INTERFACE
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
+    )
+else()
+    target_include_directories(GSL SYSTEM INTERFACE
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
+    )
+endif()

include/gsl/algorithm

@@ -0,0 +1,63 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_ALGORITHM_H
+#define GSL_ALGORITHM_H
+
+#include "assert" // for Expects
+#include "span"   // for dynamic_extent, span
+
+#include <algorithm>   // for copy_n
+#include <cstddef>     // for ptrdiff_t
+#include <type_traits> // for is_assignable
+
+#ifdef _MSC_VER
+#pragma warning(push)
+
+// turn off some warnings that are noisy about our Expects statements
+#pragma warning(disable : 4127) // conditional expression is constant
+#pragma warning(disable : 4996) // unsafe use of std::copy_n
+
+#endif // _MSC_VER
+
+namespace gsl
+{
+// Note: this will generate faster code than std::copy using span iterator in older msvc+stl
+// not necessary for msvc since VS2017 15.8 (_MSC_VER >= 1915)
+template <class SrcElementType, std::size_t SrcExtent, class DestElementType,
+          std::size_t DestExtent>
+void copy(span<SrcElementType, SrcExtent> src, span<DestElementType, DestExtent> dest)
+{
+    static_assert(std::is_assignable<decltype(*dest.data()), decltype(*src.data())>::value,
+                  "Elements of source span can not be assigned to elements of destination span");
+    static_assert(SrcExtent == dynamic_extent || DestExtent == dynamic_extent ||
+                      (SrcExtent <= DestExtent),
+                  "Source range is longer than target range");
+
+    Expects(dest.size() >= src.size());
+    // clang-format off
+    GSL_SUPPRESS(stl.1) // NO-FORMAT: attribute
+    // clang-format on
+    std::copy_n(src.data(), src.size(), dest.data());
+}
+
+} // namespace gsl
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif // _MSC_VER
+
+#endif // GSL_ALGORITHM_H

include/gsl/assert

@@ -0,0 +1,136 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_CONTRACTS_H
+#define GSL_CONTRACTS_H
+
+//
+// Temporary until MSVC STL supports no-exceptions mode.
+// Currently terminate is a no-op in this mode, so we add termination behavior back
+//
+#if defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS))
+#define GSL_KERNEL_MODE
+
+#define GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND
+#include <intrin.h>
+#define RANGE_CHECKS_FAILURE 0
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Winvalid-noreturn"
+#endif // defined(__clang__)
+
+#else // defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) &&
+      // !_HAS_EXCEPTIONS))
+
+#include <exception>
+
+#endif // defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) &&
+       // !_HAS_EXCEPTIONS))
+
+//
+// make suppress attributes parse for some compilers
+// Hopefully temporary until suppression standardization occurs
+//
+#if defined(__clang__)
+#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
+#else
+#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
+#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
+#else
+#define GSL_SUPPRESS(x)
+#endif // _MSC_VER
+#endif // __clang__
+
+#define GSL_STRINGIFY_DETAIL(x) #x
+#define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x)
+
+#if defined(__clang__) || defined(__GNUC__)
+#define GSL_LIKELY(x) __builtin_expect(!!(x), 1)
+#define GSL_UNLIKELY(x) __builtin_expect(!!(x), 0)
+
+#else
+
+#define GSL_LIKELY(x) (!!(x))
+#define GSL_UNLIKELY(x) (!!(x))
+#endif // defined(__clang__) || defined(__GNUC__)
+
+//
+// GSL_ASSUME(cond)
+//
+// Tell the optimizer that the predicate cond must hold. It is unspecified
+// whether or not cond is actually evaluated.
+//
+#ifdef _MSC_VER
+#define GSL_ASSUME(cond) __assume(cond)
+#elif defined(__GNUC__)
+#define GSL_ASSUME(cond) ((cond) ? static_cast<void>(0) : __builtin_unreachable())
+#else
+#define GSL_ASSUME(cond) static_cast<void>((cond) ? 0 : 0)
+#endif
+
+//
+// GSL.assert: assertions
+//
+
+namespace gsl
+{
+
+namespace details
+{
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+
+    typedef void(__cdecl* terminate_handler)();
+
+    // clang-format off
+    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute
+    // clang-format on
+    [[noreturn]] inline void __cdecl default_terminate_handler()
+    {
+        __fastfail(RANGE_CHECKS_FAILURE);
+    }
+
+    inline gsl::details::terminate_handler& get_terminate_handler() noexcept
+    {
+        static terminate_handler handler = &default_terminate_handler;
+        return handler;
+    }
+
+#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+
+    [[noreturn]] inline void terminate() noexcept
+    {
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+        (*gsl::details::get_terminate_handler())();
+#else
+        std::terminate();
+#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+    }
+
+} // namespace details
+} // namespace gsl
+
+#define GSL_CONTRACT_CHECK(type, cond)                                                             \
+    (GSL_LIKELY(cond) ? static_cast<void>(0) : gsl::details::terminate())
+
+#define Expects(cond) GSL_CONTRACT_CHECK("Precondition", cond)
+#define Ensures(cond) GSL_CONTRACT_CHECK("Postcondition", cond)
+
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND) && defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
+#endif // GSL_CONTRACTS_H

include/gsl/byte

@@ -0,0 +1,213 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_BYTE_H
+#define GSL_BYTE_H
+
+//
+// make suppress attributes work for some compilers
+// Hopefully temporary until suppression standardization occurs
+//
+#if defined(__clang__)
+#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
+#else
+#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
+#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
+#else
+#define GSL_SUPPRESS(x)
+#endif // _MSC_VER
+#endif // __clang__
+
+#include <type_traits>
+
+// VS2017 15.8 added support for the __cpp_lib_byte definition
+// To do: drop _HAS_STD_BYTE when support for pre 15.8 expires
+#ifdef _MSC_VER
+
+#pragma warning(push)
+
+// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
+#pragma warning(disable : 26493) // don't use c-style casts // TODO: MSVC suppression in templates
+                                 // does not always work
+
+#ifndef GSL_USE_STD_BYTE
+// this tests if we are under MSVC and the standard lib has std::byte and it is enabled
+#if (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) ||                                                   \
+    (defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603)
+
+#define GSL_USE_STD_BYTE 1
+
+#else // (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) || (defined(__cpp_lib_byte) && __cpp_lib_byte >=
+      // 201603)
+
+#define GSL_USE_STD_BYTE 0
+
+#endif // (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) || (defined(__cpp_lib_byte) && __cpp_lib_byte >=
+       // 201603)
+#endif // GSL_USE_STD_BYTE
+
+#else // _MSC_VER
+
+#ifndef GSL_USE_STD_BYTE
+#include <cstddef> /* __cpp_lib_byte */
+// this tests if we are under GCC or Clang with enough -std=c++1z power to get us std::byte
+// also check if libc++ version is sufficient (> 5.0) or libstdc++ actually contains std::byte
+#if defined(__cplusplus) && (__cplusplus >= 201703L) &&                                            \
+    (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603) ||                                      \
+     defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+
+#define GSL_USE_STD_BYTE 1
+
+#else // defined(__cplusplus) && (__cplusplus >= 201703L) &&
+      //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
+      //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+
+#define GSL_USE_STD_BYTE 0
+
+#endif // defined(__cplusplus) && (__cplusplus >= 201703L) &&
+       //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
+       //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+#endif // GSL_USE_STD_BYTE
+
+#endif // _MSC_VER
+
+// Use __may_alias__ attribute on gcc and clang
+#if defined __clang__ || (defined(__GNUC__) && __GNUC__ > 5)
+#define byte_may_alias __attribute__((__may_alias__))
+#else // defined __clang__ || defined __GNUC__
+#define byte_may_alias
+#endif // defined __clang__ || defined __GNUC__
+
+#if GSL_USE_STD_BYTE
+#include <cstddef>
+#endif
+
+namespace gsl
+{
+#if GSL_USE_STD_BYTE
+
+using std::byte;
+using std::to_integer;
+
+#else // GSL_USE_STD_BYTE
+
+// This is a simple definition for now that allows
+// use of byte within span<> to be standards-compliant
+enum class byte_may_alias byte : unsigned char
+{
+};
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte& operator<<=(byte& b, IntegerType shift) noexcept
+{
+    return b = byte(static_cast<unsigned char>(b) << shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte operator<<(byte b, IntegerType shift) noexcept
+{
+    return byte(static_cast<unsigned char>(b) << shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte& operator>>=(byte& b, IntegerType shift) noexcept
+{
+    return b = byte(static_cast<unsigned char>(b) >> shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte operator>>(byte b, IntegerType shift) noexcept
+{
+    return byte(static_cast<unsigned char>(b) >> shift);
+}
+
+constexpr byte& operator|=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
+}
+
+constexpr byte operator|(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
+}
+
+constexpr byte& operator&=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
+}
+
+constexpr byte operator&(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
+}
+
+constexpr byte& operator^=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
+}
+
+constexpr byte operator^(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
+}
+
+constexpr byte operator~(byte b) noexcept { return byte(~static_cast<unsigned char>(b)); }
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr IntegerType to_integer(byte b) noexcept
+{
+    return static_cast<IntegerType>(b);
+}
+
+#endif // GSL_USE_STD_BYTE
+
+template <bool E, typename T>
+constexpr byte to_byte_impl(T t) noexcept
+{
+    static_assert(
+        E, "gsl::to_byte(t) must be provided an unsigned char, otherwise data loss may occur. "
+           "If you are calling to_byte with an integer contant use: gsl::to_byte<t>() version.");
+    return static_cast<byte>(t);
+}
+template <>
+// NOTE: need suppression since c++14 does not allow "return {t}"
+// GSL_SUPPRESS(type.4) // NO-FORMAT: attribute // TODO: suppression does not work
+constexpr byte to_byte_impl<true, unsigned char>(unsigned char t) noexcept
+{
+    return byte(t);
+}
+
+template <typename T>
+constexpr byte to_byte(T t) noexcept
+{
+    return to_byte_impl<std::is_same<T, unsigned char>::value, T>(t);
+}
+
+template <int I>
+constexpr byte to_byte() noexcept
+{
+    static_assert(I >= 0 && I <= 255,
+                  "gsl::byte only has 8 bits of storage, values must be in range 0-255");
+    return static_cast<byte>(I);
+}
+
+} // namespace gsl
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif // _MSC_VER
+
+#endif // GSL_BYTE_H

include/gsl/gsl

@@ -17,13 +17,16 @@
 #ifndef GSL_GSL_H
 #define GSL_GSL_H
 
-#include <gsl/gsl_algorithm> // copy
-#include <gsl/gsl_assert>    // Ensures/Expects
-#include <gsl/gsl_byte>      // byte
-#include <gsl/gsl_util>      // finally()/narrow()/narrow_cast()...
-#include <gsl/multi_span>    // multi_span, strided_span...
-#include <gsl/pointers>      // owner, not_null
-#include <gsl/span>          // span
-#include <gsl/string_span>   // zstring, string_span, zstring_builder...
+#include "algorithm"   // copy
+#include "assert"      // Ensures/Expects
+#include "byte"        // byte
+#include "pointers"    // owner, not_null
+#include "span"        // span
+#include "string_span" // zstring, string_span, zstring_builder...
+#include "util"        // finally()/narrow_cast()...
+
+#ifdef __cpp_exceptions
+#include "narrow" // narrow()
+#endif
 
 #endif // GSL_GSL_H

include/gsl/gsl_algorithm

@@ -1,61 +1,4 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef GSL_ALGORITHM_H
-#define GSL_ALGORITHM_H
-
-#include <gsl/gsl_assert> // for Expects
-#include <gsl/span>       // for dynamic_extent, span
-
-#include <algorithm>   // for copy_n
-#include <cstddef>     // for ptrdiff_t
-#include <type_traits> // for is_assignable
-
-#ifdef _MSC_VER
-#pragma warning(push)
-
-// turn off some warnings that are noisy about our Expects statements
-#pragma warning(disable : 4127) // conditional expression is constant
-#pragma warning(disable : 4996) // unsafe use of std::copy_n
-
-#endif // _MSC_VER
-
-namespace gsl
-{
-// Note: this will generate faster code than std::copy using span iterator in older msvc+stl
-// not necessary for msvc since VS2017 15.8 (_MSC_VER >= 1915)
-template <class SrcElementType, std::ptrdiff_t SrcExtent, class DestElementType,
-          std::ptrdiff_t DestExtent>
-void copy(span<SrcElementType, SrcExtent> src, span<DestElementType, DestExtent> dest)
-{
-    static_assert(std::is_assignable<decltype(*dest.data()), decltype(*src.data())>::value,
-                  "Elements of source span can not be assigned to elements of destination span");
-    static_assert(SrcExtent == dynamic_extent || DestExtent == dynamic_extent ||
-                      (SrcExtent <= DestExtent),
-                  "Source range is longer than target range");
-
-    Expects(dest.size() >= src.size());
-    GSL_SUPPRESS(stl.1) // NO-FORMAT: attribute
-    std::copy_n(src.data(), src.size(), dest.data());
-}
-
-} // namespace gsl
-
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif // _MSC_VER
-
-#endif // GSL_ALGORITHM_H
+#pragma once
+#pragma message(                                                                                   \
+    "This header will soon be removed. Use <gsl/algorithm> instead of <gsl/gsl_algorithm>")
+#include "algorithm"

include/gsl/gsl_assert

@@ -1,177 +1,3 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef GSL_CONTRACTS_H
-#define GSL_CONTRACTS_H
-
-#include <exception>
-#include <stdexcept> // for logic_error
-
-//
-// make suppress attributes parse for some compilers
-// Hopefully temporary until suppression standardization occurs
-//
-#if defined(__clang__)
-#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
-#else
-#if defined(_MSC_VER)
-#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
-#else
-#define GSL_SUPPRESS(x)
-#endif // _MSC_VER
-#endif // __clang__
-
-//
-// Temporary until MSVC STL supports no-exceptions mode.
-// Currently terminate is a no-op in this mode, so we add termination behavior back
-//
-#if defined(_MSC_VER) && defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS
-#define GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND
-#include <intrin.h>
-#define RANGE_CHECKS_FAILURE 0
-
-#if defined(__clang__)
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Winvalid-noreturn"
-#endif
-
-#endif
-
-//
-// There are three configuration options for this GSL implementation's behavior
-// when pre/post conditions on the GSL types are violated:
-//
-// 1. GSL_TERMINATE_ON_CONTRACT_VIOLATION: std::terminate will be called (default)
-// 2. GSL_THROW_ON_CONTRACT_VIOLATION: a gsl::fail_fast exception will be thrown
-// 3. GSL_UNENFORCED_ON_CONTRACT_VIOLATION: nothing happens
-//
-#if !(defined(GSL_THROW_ON_CONTRACT_VIOLATION) || defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) ||  \
-      defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION))
-#define GSL_TERMINATE_ON_CONTRACT_VIOLATION
-#endif
-
-#define GSL_STRINGIFY_DETAIL(x) #x
-#define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x)
-
-#if defined(__clang__) || defined(__GNUC__)
-#define GSL_LIKELY(x) __builtin_expect(!!(x), 1)
-#define GSL_UNLIKELY(x) __builtin_expect(!!(x), 0)
-#else
-#define GSL_LIKELY(x) (!!(x))
-#define GSL_UNLIKELY(x) (!!(x))
-#endif
-
-//
-// GSL_ASSUME(cond)
-//
-// Tell the optimizer that the predicate cond must hold. It is unspecified
-// whether or not cond is actually evaluated.
-//
-#ifdef _MSC_VER
-#define GSL_ASSUME(cond) __assume(cond)
-#elif defined(__GNUC__)
-#define GSL_ASSUME(cond) ((cond) ? static_cast<void>(0) : __builtin_unreachable())
-#else
-#define GSL_ASSUME(cond) static_cast<void>((cond) ? 0 : 0)
-#endif
-
-//
-// GSL.assert: assertions
-//
-
-namespace gsl
-{
-struct fail_fast : public std::logic_error
-{
-    explicit fail_fast(char const* const message) : std::logic_error(message) {}
-};
-
-namespace details
-{
-#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
-
-    typedef void  (__cdecl *terminate_handler)();
-
-    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute
-    [[noreturn]] inline void __cdecl default_terminate_handler()
-    {
-        __fastfail(RANGE_CHECKS_FAILURE);
-    }
-
-    inline gsl::details::terminate_handler& get_terminate_handler() noexcept
-    {
-        static terminate_handler handler = &default_terminate_handler;
-        return handler;
-    }
-
-#endif
-
-    [[noreturn]] inline void terminate() noexcept
-    {
-#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
-        (*gsl::details::get_terminate_handler())();
-#else
-        std::terminate();
-#endif
-    }
-
-#if defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
-
-    template <typename Exception>
-    [[noreturn]] void throw_exception(Exception&&) noexcept
-    {
-        gsl::details::terminate();
-    }
-
-#else
-
-    template <typename Exception>
-    [[noreturn]] void throw_exception(Exception&& exception)
-    {
-        throw std::forward<Exception>(exception);
-    }
-
-#endif // GSL_TERMINATE_ON_CONTRACT_VIOLATION
-
-} // namespace details
-} // namespace gsl
-
-#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
-
-#define GSL_CONTRACT_CHECK(type, cond)                                                             \
-    (GSL_LIKELY(cond) ? static_cast<void>(0)                                                       \
-                      : gsl::details::throw_exception(gsl::fail_fast(                              \
-                            "GSL: " type " failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__))))
-
-#elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
-
-#define GSL_CONTRACT_CHECK(type, cond)                                                             \
-    (GSL_LIKELY(cond) ? static_cast<void>(0) : gsl::details::terminate())
-
-#elif defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION)
-
-#define GSL_CONTRACT_CHECK(type, cond) GSL_ASSUME(cond)
-
-#endif // GSL_THROW_ON_CONTRACT_VIOLATION
-
-#define Expects(cond) GSL_CONTRACT_CHECK("Precondition", cond)
-#define Ensures(cond) GSL_CONTRACT_CHECK("Postcondition", cond)
-
-#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND) && defined(__clang__)
-#pragma clang diagnostic pop
-#endif
-
-#endif // GSL_CONTRACTS_H
+#pragma once
+#pragma message("This header will soon be removed. Use <gsl/assert> instead of <gsl/gsl_assert>")
+#include "assert"

include/gsl/gsl_byte

@@ -1,205 +1,3 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef GSL_BYTE_H
-#define GSL_BYTE_H
-
-//
-// make suppress attributes work for some compilers
-// Hopefully temporary until suppression standardization occurs
-//
-#if defined(__clang__)
-#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
-#else
-#if defined(_MSC_VER)
-#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
-#else
-#define GSL_SUPPRESS(x)
-#endif // _MSC_VER
-#endif // __clang__
-
-#include <type_traits>
-
-// VS2017 15.8 added support for the __cpp_lib_byte definition
-// To do: drop _HAS_STD_BYTE when support for pre 15.8 expires
-#ifdef _MSC_VER
-
-#pragma warning(push)
-
-// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
-#pragma warning(disable : 26493) // don't use c-style casts // TODO: MSVC suppression in templates does not always work
-
-#ifndef GSL_USE_STD_BYTE
-// this tests if we are under MSVC and the standard lib has std::byte and it is enabled
-#if (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) || (defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603)
-
-#define GSL_USE_STD_BYTE 1
-
-#else // (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) || (defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603)
-
-#define GSL_USE_STD_BYTE 0
-
-#endif // (defined(_HAS_STD_BYTE) && _HAS_STD_BYTE) || (defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603)
-#endif // GSL_USE_STD_BYTE
-
-#else // _MSC_VER
-
-#ifndef GSL_USE_STD_BYTE
-#include <cstddef> /* __cpp_lib_byte */
-// this tests if we are under GCC or Clang with enough -std:c++1z power to get us std::byte
-// also check if libc++ version is sufficient (> 5.0) or libstc++ actually contains std::byte
-#if defined(__cplusplus) && (__cplusplus >= 201703L) && \
-  (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  || \
-   defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
-
-#define GSL_USE_STD_BYTE 1
-
-#else // defined(__cplusplus) && (__cplusplus >= 201703L) &&
-      //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
-      //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
-
-#define GSL_USE_STD_BYTE 0
-
-#endif //defined(__cplusplus) && (__cplusplus >= 201703L) &&
-       //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
-       //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
-#endif // GSL_USE_STD_BYTE
-
-#endif // _MSC_VER
-
-// Use __may_alias__ attribute on gcc and clang
-#if defined __clang__ || (defined(__GNUC__) && __GNUC__ > 5)
-#define byte_may_alias __attribute__((__may_alias__))
-#else // defined __clang__ || defined __GNUC__
-#define byte_may_alias
-#endif // defined __clang__ || defined __GNUC__
-
-namespace gsl
-{
-#if GSL_USE_STD_BYTE
-
-using std::byte;
-using std::to_integer;
-
-#else // GSL_USE_STD_BYTE
-
-// This is a simple definition for now that allows
-// use of byte within span<> to be standards-compliant
-enum class byte_may_alias byte : unsigned char
-{
-};
-
-template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
-constexpr byte& operator<<=(byte& b, IntegerType shift) noexcept
-{
-    return b = byte(static_cast<unsigned char>(b) << shift);
-}
-
-template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
-constexpr byte operator<<(byte b, IntegerType shift) noexcept
-{
-    return byte(static_cast<unsigned char>(b) << shift);
-}
-
-template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
-constexpr byte& operator>>=(byte& b, IntegerType shift) noexcept
-{
-    return b = byte(static_cast<unsigned char>(b) >> shift);
-}
-
-template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
-constexpr byte operator>>(byte b, IntegerType shift) noexcept
-{
-    return byte(static_cast<unsigned char>(b) >> shift);
-}
-
-constexpr byte& operator|=(byte& l, byte r) noexcept
-{
-    return l = byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
-}
-
-constexpr byte operator|(byte l, byte r) noexcept
-{
-    return byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
-}
-
-constexpr byte& operator&=(byte& l, byte r) noexcept
-{
-    return l = byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
-}
-
-constexpr byte operator&(byte l, byte r) noexcept
-{
-    return byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
-}
-
-constexpr byte& operator^=(byte& l, byte r) noexcept
-{
-    return l = byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
-}
-
-constexpr byte operator^(byte l, byte r) noexcept
-{
-    return byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
-}
-
-constexpr byte operator~(byte b) noexcept { return byte(~static_cast<unsigned char>(b)); }
-
-template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
-constexpr IntegerType to_integer(byte b) noexcept
-{
-    return static_cast<IntegerType>(b);
-}
-
-#endif // GSL_USE_STD_BYTE
-
-template <bool E, typename T>
-constexpr byte to_byte_impl(T t) noexcept
-{
-    static_assert(
-        E, "gsl::to_byte(t) must be provided an unsigned char, otherwise data loss may occur. "
-           "If you are calling to_byte with an integer contant use: gsl::to_byte<t>() version.");
-    return static_cast<byte>(t);
-}
-template <>
-// NOTE: need suppression since c++14 does not allow "return {t}"
-// GSL_SUPPRESS(type.4) // NO-FORMAT: attribute // TODO: suppression does not work
-constexpr byte to_byte_impl<true, unsigned char>(unsigned char t) noexcept
-{
-    return byte(t);
-}
-
-template <typename T>
-constexpr byte to_byte(T t) noexcept
-{
-    return to_byte_impl<std::is_same<T, unsigned char>::value, T>(t);
-}
-
-template <int I>
-constexpr byte to_byte() noexcept
-{
-    static_assert(I >= 0 && I <= 255,
-                  "gsl::byte only has 8 bits of storage, values must be in range 0-255");
-    return static_cast<byte>(I);
-}
-
-} // namespace gsl
-
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif // _MSC_VER
-
-#endif // GSL_BYTE_H
+#pragma once
+#pragma message("This header will soon be removed. Use <gsl/byte> instead of <gsl/gsl_byte>")
+#include "byte"

include/gsl/gsl_narrow

@@ -0,0 +1,3 @@
+#pragma once
+#pragma message("This header will soon be removed. Use <gsl/narrow> instead of <gsl/gsl_narrow>")
+#include "narrow"

include/gsl/gsl_util

@@ -1,172 +1,3 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef GSL_UTIL_H
-#define GSL_UTIL_H
-
-#include <gsl/gsl_assert> // for Expects
-
-#include <array>
-#include <cstddef>          // for ptrdiff_t, size_t
-#include <exception>        // for exception
-#include <initializer_list> // for initializer_list
-#include <type_traits>      // for is_signed, integral_constant
-#include <utility>          // for exchange, forward
-
-#if defined(_MSC_VER) && !defined(__clang__)
-
-#pragma warning(push)
-#pragma warning(disable : 4127) // conditional expression is constant
-
-#if _MSC_VER < 1910
-#pragma push_macro("constexpr")
-#define constexpr /*constexpr*/
-#endif            // _MSC_VER < 1910
-#endif            // _MSC_VER
-
-#if (defined(_MSC_VER) && _MSC_VER < 1910) || (!defined(__clang__) && defined(__GNUC__) && __GNUC__ < 6)
-#define GSL_CONSTEXPR_NARROW 0
-#else
-#define GSL_CONSTEXPR_NARROW 1
-#endif
-
-namespace gsl
-{
-//
-// GSL.util: utilities
-//
-
-// index type for all container indexes/subscripts/sizes
-using index = std::ptrdiff_t;
-
-// final_action allows you to ensure something gets run at the end of a scope
-template <class F>
-class final_action
-{
-public:
-    explicit final_action(F f) noexcept : f_(std::move(f)) {}
-
-    final_action(final_action&& other) noexcept : f_(std::move(other.f_)), invoke_(std::exchange(other.invoke_, false)) {}
-
-    final_action(const final_action&) = delete;
-    final_action& operator=(const final_action&) = delete;
-    final_action& operator=(final_action&&) = delete;
-
-    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // terminate if throws
-    ~final_action() noexcept
-    {
-        if (invoke_) f_();
-    }
-
-private:
-    F f_;
-    bool invoke_{true};
-};
-
-// finally() - convenience function to generate a final_action
-template <class F>
-final_action<F> finally(const F& f) noexcept
-{
-    return final_action<F>(f);
-}
-
-template <class F>
-final_action<F> finally(F&& f) noexcept
-{
-    return final_action<F>(std::forward<F>(f));
-}
-
-// narrow_cast(): a searchable way to do narrowing casts of values
-template <class T, class U>
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-constexpr T narrow_cast(U&& u) noexcept
-{
-    return static_cast<T>(std::forward<U>(u));
-}
-
-struct narrowing_error : public std::exception
-{
-};
-
-namespace details
-{
-    template <class T, class U>
-    struct is_same_signedness
-        : public std::integral_constant<bool, std::is_signed<T>::value == std::is_signed<U>::value>
-    {
-    };
-} // namespace details
-
-// narrow() : a checked version of narrow_cast() that throws if the cast changed the value
-template <class T, class U>
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // TODO: MSVC /analyze does not recognise noexcept(false)
-#if GSL_CONSTEXPR_NARROW
-constexpr
-#endif
-T narrow(U u) noexcept(false)
-{
-    T t = narrow_cast<T>(u);
-    if (static_cast<U>(t) != u) gsl::details::throw_exception(narrowing_error());
-    if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
-        gsl::details::throw_exception(narrowing_error());
-    return t;
-}
-
-//
-// at() - Bounds-checked way of accessing builtin arrays, std::array, std::vector
-//
-template <class T, std::size_t N>
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-constexpr T& at(T (&arr)[N], const index i)
-{
-    Expects(i >= 0 && i < narrow_cast<index>(N));
-    return arr[narrow_cast<std::size_t>(i)];
-}
-
-template <class Cont>
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-constexpr auto at(Cont& cont, const index i) -> decltype(cont[cont.size()])
-{
-    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
-    using size_type = decltype(cont.size());
-    return cont[narrow_cast<size_type>(i)];
-}
-
-template <class T>
-GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-constexpr T at(const std::initializer_list<T> cont, const index i)
-{
-    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
-    return *(cont.begin() + i);
-}
-
-} // namespace gsl
-
-#if defined(_MSC_VER) && !defined(__clang__)
-#if _MSC_VER < 1910
-#undef constexpr
-#pragma pop_macro("constexpr")
-
-#endif // _MSC_VER < 1910
-
-#pragma warning(pop)
-
-#endif // _MSC_VER
-
-#endif // GSL_UTIL_H
+#pragma once
+#pragma message("This header will soon be removed. Use <gsl/util> instead of <gsl/gsl_util>")
+#include "util"

include/gsl/narrow

@@ -0,0 +1,83 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_NARROW_H
+#define GSL_NARROW_H
+#include "assert"    // for GSL_SUPPRESS
+#include "util"      // for narrow_cast
+#include <exception> // for std::exception
+namespace gsl
+{
+struct narrowing_error : public std::exception
+{
+    const char* what() const noexcept override { return "narrowing_error"; }
+};
+
+// narrow() : a checked version of narrow_cast() that throws if the cast changed the value
+template <class T, class U, typename std::enable_if<std::is_arithmetic<T>::value>::type* = nullptr>
+// clang-format off
+GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // TODO: MSVC /analyze does not recognise noexcept(false)
+GSL_SUPPRESS(es.46) // NO-FORMAT: attribute // The warning suggests that a floating->unsigned conversion can occur
+                                            // in the static_cast below, and that gsl::narrow should be used instead.
+                                            // Suppress this warning, since gsl::narrow is defined in terms of
+                                            // static_cast
+    // clang-format on
+    constexpr T narrow(U u) noexcept(false)
+{
+    constexpr const bool is_different_signedness =
+        (std::is_signed<T>::value != std::is_signed<U>::value);
+
+GSL_SUPPRESS(es.103) // NO-FORMAT: attribute // don't overflow
+GSL_SUPPRESS(es.104) // NO-FORMAT: attribute // don't underflow
+GSL_SUPPRESS(p.2) // NO-FORMAT: attribute // don't rely on undefined behavior
+    const T t = narrow_cast<T>(u); // While this is technically undefined behavior in some cases (i.e., if the source value is of floating-point type
+                                   // and cannot fit into the destination integral type), the resultant behavior is benign on the platforms
+                                   // that we target (i.e., no hardware trap representations are hit).
+
+#if defined(__clang__) || defined(__GNUC__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+    if (static_cast<U>(t) != u || (is_different_signedness && ((t < T{}) != (u < U{}))))
+    {
+        throw narrowing_error{};
+    }
+#if defined(__clang__) || defined(__GNUC__)
+    #pragma GCC diagnostic pop
+#endif
+
+    return t;
+}
+
+template <class T, class U, typename std::enable_if<!std::is_arithmetic<T>::value>::type* = nullptr>
+// clang-format off
+GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // TODO: MSVC /analyze does not recognise noexcept(false)
+    // clang-format on
+    constexpr T narrow(U u) noexcept(false)
+{
+    const T t = narrow_cast<T>(u);
+
+    if (static_cast<U>(t) != u)
+    {
+        throw narrowing_error{};
+    }
+
+    return t;
+}
+} // namespace gsl
+#endif // GSL_NARROW_H

include/gsl/pointers

@@ -17,33 +17,48 @@
 #ifndef GSL_POINTERS_H
 #define GSL_POINTERS_H
 
-#include <gsl/gsl_assert>  // for Ensures, Expects
+#include "assert" // for Ensures, Expects
 
 #include <algorithm>    // for forward
-#include <iosfwd>       // for ptrdiff_t, nullptr_t, ostream, size_t
+#include <cstddef>      // for ptrdiff_t, nullptr_t, size_t
 #include <memory>       // for shared_ptr, unique_ptr
 #include <system_error> // for hash
 #include <type_traits>  // for enable_if_t, is_convertible, is_assignable
 
-#if defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
-#pragma push_macro("constexpr")
-#define constexpr /*constexpr*/
-
-#endif                          // defined(_MSC_VER) && _MSC_VER < 1910
+#if !defined(GSL_NO_IOSTREAMS)
+#include <iosfwd> // for ostream
+#endif            // !defined(GSL_NO_IOSTREAMS)
 
 namespace gsl
 {
 
+namespace details
+{
+    template <typename T, typename = void>
+    struct is_comparable_to_nullptr : std::false_type
+    {
+    };
+
+    template <typename T>
+    struct is_comparable_to_nullptr<
+        T,
+        std::enable_if_t<std::is_convertible<decltype(std::declval<T>() != nullptr), bool>::value>>
+        : std::true_type
+    {
+    };
+} // namespace details
+
 //
 // GSL.owner: ownership pointers
 //
-using std::unique_ptr;
 using std::shared_ptr;
+using std::unique_ptr;
 
 //
 // owner
 //
-// owner<T> is designed as a bridge for code that must deal directly with owning pointers for some reason
+// owner<T> is designed as a bridge for code that must deal directly with owning pointers for some
+// reason
 //
 // T must be a pointer type
 // - disallow construction from any type other than pointer type
@@ -69,7 +84,7 @@ template <class T>
 class not_null
 {
 public:
-    static_assert(std::is_assignable<T&, std::nullptr_t>::value, "T cannot be assigned nullptr.");
+    static_assert(details::is_comparable_to_nullptr<T>::value, "T cannot be compared to nullptr.");
 
     template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
     constexpr not_null(U&& u) : ptr_(std::forward<U>(u))
@@ -78,28 +93,25 @@ public:
     }
 
     template <typename = std::enable_if_t<!std::is_same<std::nullptr_t, T>::value>>
-    constexpr not_null(T u) : ptr_(u)
+    constexpr not_null(T u) : ptr_(std::move(u))
     {
         Expects(ptr_ != nullptr);
     }
 
     template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
     constexpr not_null(const not_null<U>& other) : not_null(other.get())
-    {
-    }
+    {}
 
-    not_null(not_null&& other) = default;
     not_null(const not_null& other) = default;
     not_null& operator=(const not_null& other) = default;
-
-    constexpr T get() const
+    constexpr std::conditional_t<std::is_copy_constructible<T>::value, T, const T&> get() const
     {
         Ensures(ptr_ != nullptr);
         return ptr_;
     }
 
     constexpr operator T() const { return get(); }
-    constexpr T operator->() const { return get(); }
+    constexpr decltype(auto) operator->() const { return get(); }
     constexpr decltype(auto) operator*() const { return *get(); }
 
     // prevents compilation when someone attempts to assign a null pointer constant
@@ -120,49 +132,64 @@ private:
 };
 
 template <class T>
-auto make_not_null(T&& t) {
+auto make_not_null(T&& t) noexcept
+{
     return not_null<std::remove_cv_t<std::remove_reference_t<T>>>{std::forward<T>(t)};
 }
 
+#if !defined(GSL_NO_IOSTREAMS)
 template <class T>
 std::ostream& operator<<(std::ostream& os, const not_null<T>& val)
 {
     os << val.get();
     return os;
 }
+#endif // !defined(GSL_NO_IOSTREAMS)
 
 template <class T, class U>
-auto operator==(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() == rhs.get())
+auto operator==(const not_null<T>& lhs,
+                const not_null<U>& rhs) noexcept(noexcept(lhs.get() == rhs.get()))
+    -> decltype(lhs.get() == rhs.get())
 {
     return lhs.get() == rhs.get();
 }
 
 template <class T, class U>
-auto operator!=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() != rhs.get())
+auto operator!=(const not_null<T>& lhs,
+                const not_null<U>& rhs) noexcept(noexcept(lhs.get() != rhs.get()))
+    -> decltype(lhs.get() != rhs.get())
 {
     return lhs.get() != rhs.get();
 }
 
 template <class T, class U>
-auto operator<(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() < rhs.get())
+auto operator<(const not_null<T>& lhs,
+               const not_null<U>& rhs) noexcept(noexcept(lhs.get() < rhs.get()))
+    -> decltype(lhs.get() < rhs.get())
 {
     return lhs.get() < rhs.get();
 }
 
 template <class T, class U>
-auto operator<=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() <= rhs.get())
+auto operator<=(const not_null<T>& lhs,
+                const not_null<U>& rhs) noexcept(noexcept(lhs.get() <= rhs.get()))
+    -> decltype(lhs.get() <= rhs.get())
 {
     return lhs.get() <= rhs.get();
 }
 
 template <class T, class U>
-auto operator>(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() > rhs.get())
+auto operator>(const not_null<T>& lhs,
+               const not_null<U>& rhs) noexcept(noexcept(lhs.get() > rhs.get()))
+    -> decltype(lhs.get() > rhs.get())
 {
     return lhs.get() > rhs.get();
 }
 
 template <class T, class U>
-auto operator>=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() >= rhs.get())
+auto operator>=(const not_null<T>& lhs,
+                const not_null<U>& rhs) noexcept(noexcept(lhs.get() >= rhs.get()))
+    -> decltype(lhs.get() >= rhs.get())
 {
     return lhs.get() >= rhs.get();
 }
@@ -184,7 +211,7 @@ namespace std
 template <class T>
 struct hash<gsl::not_null<T>>
 {
-    std::size_t operator()(const gsl::not_null<T>& value) const { return hash<T>{}(value); }
+    std::size_t operator()(const gsl::not_null<T>& value) const { return hash<T>{}(value.get()); }
 };
 
 } // namespace std
@@ -210,28 +237,23 @@ namespace gsl
 //   - remove unnecessary asserts
 //
 template <class T>
-class strict_not_null: public not_null<T>
+class strict_not_null : public not_null<T>
 {
 public:
-
     template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
-    constexpr explicit strict_not_null(U&& u) :
-        not_null<T>(std::forward<U>(u))
+    constexpr explicit strict_not_null(U&& u) : not_null<T>(std::forward<U>(u))
     {}
 
     template <typename = std::enable_if_t<!std::is_same<std::nullptr_t, T>::value>>
-    constexpr explicit strict_not_null(T u) :
-        not_null<T>(u)
+    constexpr explicit strict_not_null(T u) : not_null<T>(u)
     {}
 
     template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
-    constexpr strict_not_null(const not_null<U>& other) :
-        not_null<T>(other)
+    constexpr strict_not_null(const not_null<U>& other) : not_null<T>(other)
     {}
 
     template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
-    constexpr strict_not_null(const strict_not_null<U>& other) :
-        not_null<T>(other)
+    constexpr strict_not_null(const strict_not_null<U>& other) : not_null<T>(other)
     {}
 
     strict_not_null(strict_not_null&& other) = default;
@@ -268,15 +290,18 @@ template <class T>
 strict_not_null<T> operator+(std::ptrdiff_t, const strict_not_null<T>&) = delete;
 
 template <class T>
-auto make_strict_not_null(T&& t) {
+auto make_strict_not_null(T&& t) noexcept
+{
     return strict_not_null<std::remove_cv_t<std::remove_reference_t<T>>>{std::forward<T>(t)};
 }
 
-#if ( defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L) )
+#if (defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L))
 
 // deduction guides to prevent the ctad-maybe-unsupported warning
-template <class T> not_null(T) -> not_null<T>;
-template <class T> strict_not_null(T) -> strict_not_null<T>;
+template <class T>
+not_null(T) -> not_null<T>;
+template <class T>
+strict_not_null(T) -> strict_not_null<T>;
 
 #endif // ( defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L) )
 
@@ -287,16 +312,12 @@ namespace std
 template <class T>
 struct hash<gsl::strict_not_null<T>>
 {
-    std::size_t operator()(const gsl::strict_not_null<T>& value) const { return hash<T>{}(value); }
+    std::size_t operator()(const gsl::strict_not_null<T>& value) const
+    {
+        return hash<T>{}(value.get());
+    }
 };
 
 } // namespace std
 
-#if defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
-
-#undef constexpr
-#pragma pop_macro("constexpr")
-
-#endif // defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
-
 #endif // GSL_POINTERS_H

include/gsl/span_ext

@@ -0,0 +1,212 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_SPAN_EXT_H
+#define GSL_SPAN_EXT_H
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// File: span_ext
+// Purpose: continue offering features that have been cut from the official
+//   implementation of span.
+//   While modernizing gsl::span a number of features needed to be removed to
+//   be compliant with the design of std::span
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "assert" // GSL_KERNEL_MODE
+#include "util"   // for narrow_cast, narrow
+
+#include <cstddef> // for ptrdiff_t, size_t
+#include <utility>
+
+#ifndef GSL_KERNEL_MODE
+#include <algorithm> // for lexicographical_compare
+#endif               // GSL_KERNEL_MODE
+
+namespace gsl
+{
+
+// [span.views.constants], constants
+GSL_INLINE constexpr const std::size_t dynamic_extent = narrow_cast<std::size_t>(-1);
+
+template <class ElementType, std::size_t Extent = dynamic_extent>
+class span;
+
+// std::equal and std::lexicographical_compare are not /kernel compatible
+// so all comparison operators must be removed for kernel mode.
+#ifndef GSL_KERNEL_MODE
+
+// [span.comparison], span comparison operators
+template <class ElementType, std::size_t FirstExtent, std::size_t SecondExtent>
+constexpr bool operator==(span<ElementType, FirstExtent> l, span<ElementType, SecondExtent> r)
+{
+    return std::equal(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator!=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l == r);
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator<(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return std::lexicographical_compare(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator<=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l > r);
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator>(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return r < l;
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator>=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l < r);
+}
+
+#endif // GSL_KERNEL_MODE
+
+//
+// make_span() - Utility functions for creating spans
+//
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* ptr, typename span<ElementType>::size_type count)
+{
+    return span<ElementType>(ptr, count);
+}
+
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* firstElem, ElementType* lastElem)
+{
+    return span<ElementType>(firstElem, lastElem);
+}
+
+template <class ElementType, std::size_t N>
+constexpr span<ElementType, N> make_span(ElementType (&arr)[N]) noexcept
+{
+    return span<ElementType, N>(arr);
+}
+
+template <class Container>
+constexpr span<typename Container::value_type> make_span(Container& cont)
+{
+    return span<typename Container::value_type>(cont);
+}
+
+template <class Container>
+constexpr span<const typename Container::value_type> make_span(const Container& cont)
+{
+    return span<const typename Container::value_type>(cont);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont, std::size_t count)
+{
+    return span<typename Ptr::element_type>(cont, count);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont)
+{
+    return span<typename Ptr::element_type>(cont);
+}
+
+// Specialization of gsl::at for span
+template <class ElementType, std::size_t Extent>
+constexpr ElementType& at(span<ElementType, Extent> s, index i)
+{
+    // No bounds checking here because it is done in span::operator[] called below
+    Ensures(i >= 0);
+    return s[narrow_cast<std::size_t>(i)];
+}
+
+// [span.obs] Free observer functions
+template <class ElementType, std::size_t Extent>
+constexpr std::ptrdiff_t ssize(const span<ElementType, Extent>& s) noexcept
+{
+    return static_cast<std::ptrdiff_t>(s.size());
+}
+
+// [span.iter] Free functions for begin/end functions
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::iterator
+begin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.begin();
+}
+
+template <class ElementType, std::size_t Extent = dynamic_extent>
+constexpr typename span<ElementType, Extent>::iterator
+end(const span<ElementType, Extent>& s) noexcept
+{
+    return s.end();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+rbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rbegin();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+rend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rend();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::iterator
+cbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.begin();
+}
+
+template <class ElementType, std::size_t Extent = dynamic_extent>
+constexpr typename span<ElementType, Extent>::iterator
+cend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.end();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+crbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rbegin();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+crend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rend();
+}
+
+} // namespace gsl
+
+#endif // GSL_SPAN_EXT_H

include/gsl/util

@@ -0,0 +1,166 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_UTIL_H
+#define GSL_UTIL_H
+
+#include "assert" // for Expects
+
+#include <array>
+#include <cstddef>          // for ptrdiff_t, size_t
+#include <initializer_list> // for initializer_list
+#include <type_traits>      // for is_signed, integral_constant
+#include <utility>          // for exchange, forward
+
+#if defined(__has_include) && __has_include(<version>)
+#include <version>
+#if defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
+#include <span>
+#endif // __cpp_lib_span >= 202002L
+#endif //__has_include(<version>)
+
+#if defined(_MSC_VER) && !defined(__clang__)
+
+#pragma warning(push)
+#pragma warning(disable : 4127) // conditional expression is constant
+
+#endif // _MSC_VER
+
+#if defined(__cplusplus) && (__cplusplus >= 201703L)
+#define GSL_NODISCARD [[nodiscard]]
+#else
+#define GSL_NODISCARD
+#endif // defined(__cplusplus) && (__cplusplus >= 201703L)
+
+#if defined(__cpp_inline_variables)
+#define GSL_INLINE inline
+#else
+#define GSL_INLINE
+#endif
+
+namespace gsl
+{
+//
+// GSL.util: utilities
+//
+
+// index type for all container indexes/subscripts/sizes
+using index = std::ptrdiff_t;
+
+// final_action allows you to ensure something gets run at the end of a scope
+template <class F>
+class final_action
+{
+public:
+    static_assert(!std::is_reference<F>::value && !std::is_const<F>::value &&
+                      !std::is_volatile<F>::value,
+                  "Final_action should store its callable by value");
+
+    explicit final_action(F f) noexcept : f_(std::move(f)) {}
+
+    final_action(final_action&& other) noexcept
+        : f_(std::move(other.f_)), invoke_(std::exchange(other.invoke_, false))
+    {}
+
+    final_action(const final_action&) = delete;
+    final_action& operator=(const final_action&) = delete;
+    final_action& operator=(final_action&&) = delete;
+
+    // clang-format off
+    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // terminate if throws
+    // clang-format on
+    ~final_action() noexcept
+    {
+        if (invoke_) f_();
+    }
+
+private:
+    F f_;
+    bool invoke_{true};
+};
+
+// finally() - convenience function to generate a final_action
+template <class F>
+GSL_NODISCARD final_action<typename std::remove_cv<typename std::remove_reference<F>::type>::type>
+finally(F&& f) noexcept
+{
+    return final_action<typename std::remove_cv<typename std::remove_reference<F>::type>::type>(
+        std::forward<F>(f));
+}
+
+// narrow_cast(): a searchable way to do narrowing casts of values
+template <class T, class U>
+// clang-format off
+GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
+    constexpr T narrow_cast(U&& u) noexcept
+{
+    return static_cast<T>(std::forward<U>(u));
+}
+
+//
+// at() - Bounds-checked way of accessing builtin arrays, std::array, std::vector
+//
+template <class T, std::size_t N>
+// clang-format off
+GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
+    // clang-format on
+    constexpr T& at(T (&arr)[N], const index i)
+{
+    Expects(i >= 0 && i < narrow_cast<index>(N));
+    return arr[narrow_cast<std::size_t>(i)];
+}
+
+template <class Cont>
+// clang-format off
+GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
+    // clang-format on
+    constexpr auto at(Cont& cont, const index i) -> decltype(cont[cont.size()])
+{
+    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
+    using size_type = decltype(cont.size());
+    return cont[narrow_cast<size_type>(i)];
+}
+
+template <class T>
+// clang-format off
+GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+    // clang-format on
+    constexpr T at(const std::initializer_list<T> cont, const index i)
+{
+    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
+    return *(cont.begin() + i);
+}
+
+#if defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
+template <class T, size_t extent = std::dynamic_extent>
+constexpr auto at(std::span<T, extent> sp, const index i) -> decltype(sp[sp.size()])
+{
+    Expects(i >= 0 && i < narrow_cast<index>(sp.size()));
+    return sp[gsl::narrow_cast<size_t>(i)];
+}
+#endif // __cpp_lib_span >= 202002L
+} // namespace gsl
+
+#if defined(_MSC_VER) && !defined(__clang__)
+
+#pragma warning(pop)
+
+#endif // _MSC_VER
+
+#endif // GSL_UTIL_H

pipelines/jobs.yml

@@ -0,0 +1,43 @@
+parameters:
+  CXXVersions: [ 14, 17, 20 ]
+  buildTypes: [ 'Debug', 'Release' ]
+  image: ''
+
+  compiler: ''
+  compilerVersions: ["default"] # if default value, simply uses whatever version is on the machine.
+                                # the text of this default value doesn't actually matter.
+  setupfile: ''
+  extraCmakeArgs: ''
+
+jobs:
+- ${{ each compilerVersion in parameters.compilerVersions }}:
+  - ${{ each CXXVersion in parameters.CXXVersions }}:
+    - ${{ each buildType in parameters.buildTypes }}:
+      - job:
+        displayName: ${{ format('{0} {1} C++{2} {3}', parameters.compiler, compilerVersion, CXXVersion, buildType) }}
+        pool:
+            vmImage: ${{ parameters.image }}
+        continueOnError: false
+
+        steps:
+          - ${{ if not(eq(parameters.setupfile, '')) }}:
+            - template: ${{ parameters.setupfile }}
+              parameters:
+                version: ${{ compilerVersion }}
+
+          - task: CMake@1
+            name: Configure
+            inputs:
+              workingDirectory: build
+              cmakeArgs: '-DGSL_CXX_STANDARD=${{ CXXVersion }} -DCMAKE_BUILD_TYPE=${{ buildType }} -DCI_TESTING:BOOL=ON -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON -Werror=dev ${{ parameters.extraCmakeArgs }} .. '
+
+          - task: CMake@1
+            name: Build
+            inputs:
+              workingDirectory: build
+              cmakeArgs: '--build . '
+
+          - script: ctest . --output-on-failure --no-compress-output
+            name: CTest
+            workingDirectory: build
+            failOnStderr: true

pipelines/setup_apple.yml

@@ -0,0 +1,9 @@
+parameters:
+    version: 0
+
+steps:
+  - script: |
+      if [ "${{ parameters.version }}" != "default" ]; then sudo xcode-select -switch /Applications/Xcode_${{ parameters.version }}.app; fi
+
+    displayName: "Setup Xcode Version"
+    failOnStderr: true

pipelines/setup_clang.yml

@@ -0,0 +1,13 @@
+parameters:
+    version: 0
+
+steps:
+  - script: |
+      echo "##vso[task.setvariable variable=CXX;]${CXX}"
+      echo "##vso[task.setvariable variable=CC;]${CC}"
+
+    displayName: "Setup Clang Version"
+    failOnStderr: true
+    env:
+      CC: clang-${{ parameters.version }}
+      CXX: clang++-${{ parameters.version }}

pipelines/setup_gcc.yml

@@ -0,0 +1,14 @@
+parameters:
+    version: 0
+
+steps:
+  - script: |
+      echo "##vso[task.setvariable variable=CXX;]${CXX}"
+      echo "##vso[task.setvariable variable=CC;]${CC}"
+      if [ "${{ parameters.version }}" = "11" ]; then sudo apt-get install $CXX; fi
+
+    displayName: "Setup GCC Version"
+    failOnStderr: true
+    env:
+      CC: gcc-${{ parameters.version }}
+      CXX: g++-${{ parameters.version }}

tests/CMakeLists.txt

@@ -1,35 +1,68 @@
 cmake_minimum_required(VERSION 3.0.2)
 
 project(GSLTests CXX)
+enable_testing()  # again, for support standalone testing
+
+include(FindPkgConfig)
+include(ExternalProject)
 
 # will make visual studio generated project group files
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
-list(APPEND CATCH_CMAKE_ARGS
-    "-DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/external"
-    "-DNO_SELFTEST=true"
-)
-
-if(GIT_FOUND)
-    # add catch
-    ExternalProject_Add(
-        catch
-        PREFIX ${CMAKE_BINARY_DIR}/catch
-        GIT_REPOSITORY https://github.com/catchorg/Catch2.git
-        GIT_TAG v2.0.1
-        CMAKE_ARGS ${CATCH_CMAKE_ARGS}
-        LOG_DOWNLOAD 1
-        UPDATE_DISCONNECTED 1
-    )
-else()
-    # assume catch is installed in a system directory
-    add_custom_target(catch)
+if(CI_TESTING AND GSL_CXX_STANDARD EQUAL 20)
+    add_compile_definitions(FORCE_STD_SPAN_TESTS=1)
 endif()
 
-if (MSVC AND (GSL_CXX_STANDARD EQUAL 17))
+if(IOS)
+    add_compile_definitions(GTEST_HAS_DEATH_TEST=1 IOS_PROCESS_DELAY_WORKAROUND=1)
+endif()
+
+pkg_search_module(GTestMain gtest_main)
+if (NOT GTestMain_FOUND)
+    # No pre-installed GTest is available, try to download it using Git.
+    find_package(Git REQUIRED QUIET)
+
+    configure_file(CMakeLists.txt.in googletest-download/CMakeLists.txt)
+    execute_process(
+        COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
+        RESULT_VARIABLE result
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
+    )
+    if(result)
+        message(FATAL_ERROR "CMake step for googletest failed: ${result}")
+    endif()
+
+    execute_process(
+        COMMAND ${CMAKE_COMMAND} --build .
+        RESULT_VARIABLE result
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download
+    )
+    if(result)
+        message(FATAL_ERROR "CMake step for googletest failed: ${result}")
+    endif()
+
+    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+    set(GTestMain_LIBRARIES gtest_main)
+
+    add_subdirectory(
+        ${CMAKE_CURRENT_BINARY_DIR}/googletest-src
+        ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
+        EXCLUDE_FROM_ALL
+    )
+endif()
+
+if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+    # CMake has been started independently in this directory with tests. Do
+    # import the globally installed Guidelines Support Library and test it
+    # instead of the current version from the include/ folder.
+    find_package(Microsoft.GSL REQUIRED)
+endif()
+
+if (MSVC AND (GSL_CXX_STANDARD GREATER_EQUAL 17))
     set(GSL_CPLUSPLUS_OPT -Zc:__cplusplus -permissive-)
 endif()
 
+include(CheckCXXCompilerFlag)
 # this interface adds compile options to how the tests are run
 # please try to keep entries ordered =)
 add_library(gsl_tests_config INTERFACE)
@@ -39,16 +72,45 @@ if(MSVC) # MSVC or simulating MSVC
         /EHsc
         /W4
         /WX
+        $<$<CXX_COMPILER_ID:MSVC>:
+          /wd4996  # Use of function or classes marked [[deprecated]]
+          /wd26409 # CppCoreCheck - GTest
+          /wd26426 # CppCoreCheck - GTest
+          /wd26440 # CppCoreCheck - GTest
+          /wd26446 # CppCoreCheck - prefer gsl::at()
+          /wd26472 # CppCoreCheck - use gsl::narrow(_cast)
+          /wd26481 # CppCoreCheck - use span instead of pointer arithmetic
+          $<$<VERSION_LESS:$<CXX_COMPILER_VERSION>,1920>: # VS2015
+            /wd4189 # variable is initialized but not referenced
+            $<$<NOT:$<CONFIG:Debug>>: # Release, RelWithDebInfo
+              /wd4702 # Unreachable code
+            >
+          >
+        >
         $<$<CXX_COMPILER_ID:Clang>:
           -Weverything
+          -Wfloat-equal
           -Wno-c++98-compat
           -Wno-c++98-compat-pedantic
+          -Wno-covered-switch-default # GTest
+          -Wno-deprecated-declarations # Allow tests for [[deprecated]] elements
+          -Wno-global-constructors # GTest
+          -Wno-language-extension-token # GTest gtest-port.h
           -Wno-missing-braces
           -Wno-missing-prototypes
-          -Wno-unknown-attributes
-          $<$<EQUAL:${GSL_CXX_STANDARD},14>:-Wno-unused-member-function>
+          -Wno-shift-sign-overflow # GTest gtest-port.h
+          -Wno-undef # GTest
+          -Wno-used-but-marked-unused # GTest EXPECT_DEATH
+          $<$<EQUAL:${GSL_CXX_STANDARD},14>: # no support for [[maybe_unused]]
+            -Wno-unused-member-function
+            -Wno-unused-variable
+          >
         >
     )
+    check_cxx_compiler_flag("-Wno-reserved-identifier" WARN_RESERVED_ID)
+    if (WARN_RESERVED_ID)
+        target_compile_options(gsl_tests_config INTERFACE "-Wno-reserved-identifier")
+    endif()
 else()
     target_compile_options(gsl_tests_config INTERFACE
         -fno-strict-aliasing
@@ -61,73 +123,84 @@ else()
         -Wpedantic
         -Wshadow
         -Wsign-conversion
+        -Wfloat-equal
+        -Wno-deprecated-declarations # Allow tests for [[deprecated]] elements
         $<$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:
           -Weverything
           -Wno-c++98-compat
           -Wno-c++98-compat-pedantic
           -Wno-missing-braces
+          -Wno-covered-switch-default # GTest
+          -Wno-global-constructors # GTest
           -Wno-missing-prototypes
           -Wno-padded
           -Wno-unknown-attributes
-          $<$<EQUAL:${GSL_CXX_STANDARD},14>:-Wno-unused-member-function>
+          -Wno-used-but-marked-unused # GTest EXPECT_DEATH
           -Wno-weak-vtables
+          $<$<EQUAL:${GSL_CXX_STANDARD},14>: # no support for [[maybe_unused]]
+            -Wno-unused-member-function
+            -Wno-unused-variable
+          >
         >
         $<$<CXX_COMPILER_ID:Clang>:
-          $<$<CXX_COMPILER_VERSION:5.0.2>:-Wno-undefined-func-template>
+          $<$<AND:$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,4.99>,$<VERSION_LESS:$<CXX_COMPILER_VERSION>,6>>:
+            $<$<EQUAL:${GSL_CXX_STANDARD},17>:-Wno-undefined-func-template>
+          >
+          $<$<AND:$<EQUAL:${GSL_CXX_STANDARD},20>,$<OR:$<CXX_COMPILER_VERSION:11.0.0>,$<CXX_COMPILER_VERSION:10.0.0>>>:
+              -Wno-zero-as-null-pointer-constant  # failing Clang Ubuntu 20.04 tests, seems to be a bug with clang 10.0.0
+                                                  # and clang 11.0.0. (operator< is being re-written by the compiler
+                                                  # as operator<=> and raising the warning)
+          >
+        >
+        $<$<CXX_COMPILER_ID:AppleClang>:
+          $<$<AND:$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,9.1>,$<VERSION_LESS:$<CXX_COMPILER_VERSION>,10>>:
+            $<$<EQUAL:${GSL_CXX_STANDARD},17>:-Wno-undefined-func-template>
+          >
+        >
+        $<$<CXX_COMPILER_ID:GNU>:
+          -Wdouble-promotion # float implicit to double
+          -Wlogical-op # suspicious uses of logical operators
+          $<$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,6>>:
+            -Wduplicated-cond # duplicated if-else conditions
+            -Wmisleading-indentation
+            -Wnull-dereference
+            $<$<EQUAL:${GSL_CXX_STANDARD},14>: # no support for [[maybe_unused]]
+              -Wno-unused-variable
+            >
+          >
+          $<$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,7>>:
+            -Wduplicated-branches # identical if-else branches
+          >
         >
     )
 endif(MSVC)
 
-# for tests to find the catch header
-target_include_directories(gsl_tests_config INTERFACE
-    ${CMAKE_BINARY_DIR}/external/include
+# for tests to find the gtest header
+target_include_directories(gsl_tests_config SYSTEM INTERFACE
+    googletest/googletest/include
 )
 
-# set definitions for tests
-target_compile_definitions(gsl_tests_config INTERFACE
-    GSL_THROW_ON_CONTRACT_VIOLATION
+add_executable(gsl_tests
+    algorithm_tests.cpp
+    assertion_tests.cpp
+    at_tests.cpp
+    byte_tests.cpp
+    notnull_tests.cpp
+    owner_tests.cpp
+    span_compatibility_tests.cpp
+    span_ext_tests.cpp
+    span_tests.cpp
+    strict_notnull_tests.cpp
+    string_span_tests.cpp
+    utils_tests.cpp
 )
 
-# create the main executable for each test. this reduces the compile time
-# of each test by pre-compiling catch.
-add_library(test_catch STATIC test.cpp)
-target_link_libraries(test_catch
-    GSL
+target_link_libraries(gsl_tests
+    Microsoft.GSL::GSL
     gsl_tests_config
+    ${GTestMain_LIBRARIES}
 )
-add_dependencies(test_catch catch)
-set_property(TARGET test_catch PROPERTY FOLDER "GSL_tests")
-
-function(add_gsl_test name)
-    add_executable(${name} ${name}.cpp)
-    target_link_libraries(${name}
-        GSL
-        test_catch
-        gsl_tests_config
-    )
-    add_dependencies(${name} catch)
-    add_test(
-      ${name}
-      ${name}
-    )
-    # group all tests under GSL_tests
-    set_property(TARGET ${name} PROPERTY FOLDER "GSL_tests")
-endfunction()
-
-add_gsl_test(span_tests)
-add_gsl_test(multi_span_tests)
-add_gsl_test(strided_span_tests)
-add_gsl_test(string_span_tests)
-add_gsl_test(at_tests)
-add_gsl_test(bounds_tests)
-add_gsl_test(notnull_tests)
-add_gsl_test(assertion_tests)
-add_gsl_test(utils_tests)
-add_gsl_test(owner_tests)
-add_gsl_test(byte_tests)
-add_gsl_test(algorithm_tests)
-add_gsl_test(strict_notnull_tests)
-
+add_test(gsl_tests gsl_tests)
 
 # No exception tests
 
@@ -142,7 +215,7 @@ endforeach(flag_var)
 add_library(gsl_tests_config_noexcept INTERFACE)
 if(MSVC) # MSVC or simulating MSVC
     target_compile_definitions(gsl_tests_config_noexcept INTERFACE
-        _HAS_EXCEPTIONS=0
+        _HAS_EXCEPTIONS=0 # disable exceptions in the Microsoft STL
     )
     target_compile_options(gsl_tests_config_noexcept INTERFACE
         ${GSL_CPLUSPLUS_OPT}
@@ -151,15 +224,22 @@ if(MSVC) # MSVC or simulating MSVC
         $<$<CXX_COMPILER_ID:MSVC>:
           /wd4577
           /wd4702
+          /wd26440 # CppCoreCheck - GTest
+          /wd26446 # CppCoreCheck - prefer gsl::at()
         >
         $<$<CXX_COMPILER_ID:Clang>:
           -Weverything
+          -Wfloat-equal
           -Wno-c++98-compat
           -Wno-c++98-compat-pedantic
           -Wno-missing-prototypes
           -Wno-unknown-attributes
         >
     )
+    check_cxx_compiler_flag("-Wno-reserved-identifier" WARN_RESERVED_ID)
+    if (WARN_RESERVED_ID)
+        target_compile_options(gsl_tests_config_noexcept INTERFACE "-Wno-reserved-identifier")
+    endif()
 else()
     target_compile_options(gsl_tests_config_noexcept INTERFACE
         -fno-exceptions
@@ -173,6 +253,7 @@ else()
         -Wpedantic
         -Wshadow
         -Wsign-conversion
+        -Wfloat-equal
         $<$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:
           -Weverything
           -Wno-c++98-compat
@@ -181,27 +262,28 @@ else()
           -Wno-unknown-attributes
           -Wno-weak-vtables
         >
+        $<$<CXX_COMPILER_ID:GNU>:
+          -Wdouble-promotion # float implicit to double
+          -Wlogical-op # suspicious uses of logical operators
+          -Wuseless-cast # casting to its own type
+          $<$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,6>>:
+            -Wduplicated-cond # duplicated if-else conditions
+            -Wmisleading-indentation
+            -Wnull-dereference
+          >
+          $<$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,7>>:
+            -Wduplicated-branches # identical if-else branches
+          >
+          $<$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,8>>:
+            -Wcast-align=strict # increase alignment (i.e. char* to int*)
+          >
+        >
     )
 endif(MSVC)
 
-# set definitions for tests
-target_compile_definitions(gsl_tests_config_noexcept INTERFACE
-    GSL_TERMINATE_ON_CONTRACT_VIOLATION
+add_executable(gsl_noexcept_tests no_exception_ensure_tests.cpp)
+target_link_libraries(gsl_noexcept_tests
+    Microsoft.GSL::GSL
+    gsl_tests_config_noexcept
 )
-
-function(add_gsl_test_noexcept name)
-    add_executable(${name} ${name}.cpp)
-    target_link_libraries(${name}
-        GSL
-        gsl_tests_config_noexcept
-    )
-    add_test(
-      ${name}
-      ${name}
-    )
-    # group all tests under GSL_tests_noexcept
-    set_property(TARGET ${name} PROPERTY FOLDER "GSL_tests_noexcept")
-endfunction()
-
-add_gsl_test_noexcept(no_exception_throw_tests)
-add_gsl_test_noexcept(no_exception_ensure_tests)
+add_test(gsl_noexcept_tests gsl_noexcept_tests)

tests/CMakeLists.txt.in

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.0.2)
+project(googletest-download NONE)
+
+include(ExternalProject)
+ExternalProject_Add(googletest
+  GIT_REPOSITORY    https://github.com/google/googletest.git
+  GIT_TAG           1b18723e874b256c1e39378c6774a90701d70f7a
+  SOURCE_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-src"
+  BINARY_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-build"
+  CONFIGURE_COMMAND ""
+  BUILD_COMMAND     ""
+  INSTALL_COMMAND   ""
+  TEST_COMMAND      ""
+)

tests/algorithm_tests.cpp

@@ -14,30 +14,22 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-#endif
+#include <array>         // for array
+#include <cstddef>       // for size_t
+#include <gsl/algorithm> // for copy
+#include <gsl/span>      // for span
+#include <gtest/gtest.h>
 
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, CHE...
+#include "deathTestCommon.h"
 
-#include <gsl/gsl_algorithm> // for copy
-#include <gsl/span>          // for span
-
-#include <array>   // for array
-#include <cstddef> // for size_t
-
-namespace gsl {
+namespace gsl
+{
 struct fail_fast;
-}  // namespace gsl
+} // namespace gsl
 
-using namespace std;
 using namespace gsl;
 
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("same_type")
+TEST(algorithm_tests, same_type)
 {
     // dynamic source and destination span
     {
@@ -50,9 +42,10 @@ TEST_CASE("same_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -67,9 +60,10 @@ TEST_CASE("same_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -78,15 +72,16 @@ TEST_CASE("same_type")
         std::array<int, 5> src{1, 2, 3, 4, 5};
         std::array<int, 10> dst{};
 
-        const span<int> src_span(src);
-        const span<int, 10> dst_span(dst);
+        const gsl::span<int> src_span(src);
+        const gsl::span<int, 10> dst_span(dst);
 
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -101,17 +96,15 @@ TEST_CASE("same_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 }
 
-
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("compatible_type")
+TEST(algorithm_tests, compatible_type)
 {
     // dynamic source and destination span
     {
@@ -124,9 +117,10 @@ TEST_CASE("compatible_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -141,9 +135,10 @@ TEST_CASE("compatible_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -158,9 +153,10 @@ TEST_CASE("compatible_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 
@@ -175,15 +171,16 @@ TEST_CASE("compatible_type")
         copy(src_span, dst_span);
         copy(src_span, dst_span.subspan(src_span.size()));
 
-        for (std::size_t i = 0; i < src.size(); ++i) {
-            CHECK(dst[i] == src[i]);
-            CHECK(dst[i + src.size()] == src[i]);
+        for (std::size_t i = 0; i < src.size(); ++i)
+        {
+            EXPECT_TRUE(dst[i] == src[i]);
+            EXPECT_TRUE(dst[i + src.size()] == src[i]);
         }
     }
 }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-TEST_CASE("incompatible_type")
+TEST(algorithm_tests, incompatible_type)
 {
     std::array<int, 4> src{1, 2, 3, 4};
     std::array<int*, 12> dst{};
@@ -201,8 +198,14 @@ TEST_CASE("incompatible_type")
 }
 #endif
 
-TEST_CASE("small_destination_span")
+TEST(algorithm_tests, small_destination_span)
 {
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. small_destination_span";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     std::array<int, 12> src{1, 2, 3, 4};
     std::array<int, 4> dst{};
 
@@ -211,9 +214,9 @@ TEST_CASE("small_destination_span")
     const span<int> dst_span_dyn(dst);
     const span<int, 4> dst_span_static(dst);
 
-    CHECK_THROWS_AS(copy(src_span_dyn, dst_span_dyn), fail_fast);
-    CHECK_THROWS_AS(copy(src_span_dyn, dst_span_static), fail_fast);
-    CHECK_THROWS_AS(copy(src_span_static, dst_span_dyn), fail_fast);
+    EXPECT_DEATH(copy(src_span_dyn, dst_span_dyn), expected);
+    EXPECT_DEATH(copy(src_span_dyn, dst_span_static), expected);
+    EXPECT_DEATH(copy(src_span_static, dst_span_dyn), expected);
 
 #ifdef CONFIRM_COMPILATION_ERRORS
     copy(src_span_static, dst_span_static);

tests/assertion_tests.cpp

@@ -14,39 +14,47 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, CHECK...
-
-#include <gsl/gsl_assert> // for fail_fast (ptr only), Ensures, Expects
+#include "deathTestCommon.h"
+#include <gsl/assert> // for fail_fast (ptr only), Ensures, Expects
+#include <gtest/gtest.h>
 
 using namespace gsl;
 
+namespace
+{
+
 int f(int i)
 {
     Expects(i > 0 && i < 10);
     return i;
 }
 
-TEST_CASE("expects")
-{
-    CHECK(f(2) == 2);
-    CHECK_THROWS_AS(f(10), fail_fast);
-}
-
 int g(int i)
 {
     i++;
     Ensures(i > 0 && i < 10);
     return i;
 }
+} // namespace
 
-TEST_CASE("ensures")
+TEST(assertion_tests, expects)
 {
-    CHECK(g(2) == 3);
-    CHECK_THROWS_AS(g(9), fail_fast);
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. expects";
+        std::abort();
+    });
+
+    EXPECT_TRUE(f(2) == 2);
+    EXPECT_DEATH(f(10), GetExpectedDeathString(terminateHandler));
+}
+
+TEST(assertion_tests, ensures)
+{
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. ensures";
+        std::abort();
+    });
+
+    EXPECT_TRUE(g(2) == 3);
+    EXPECT_DEATH(g(9), GetExpectedDeathString(terminateHandler));
 }

tests/at_tests.cpp

@@ -14,103 +14,140 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-#endif
+#include <gtest/gtest.h>
 
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK_THROW...
-
-#include <gsl/gsl_util> // for at
+#include <gsl/util> // for at
 
 #include <array>            // for array
 #include <cstddef>          // for size_t
 #include <initializer_list> // for initializer_list
 #include <vector>           // for vector
+#if defined(__cplusplus) && __cplusplus >= 202002L
+#include <span>
+#endif // __cplusplus >= 202002L
 
+#include "deathTestCommon.h"
 
-namespace gsl {
-struct fail_fast;
-}  // namespace gsl
-
-using gsl::fail_fast;
-
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("static_array")
+TEST(at_tests, static_array)
 {
     int a[4] = {1, 2, 3, 4};
     const int(&c_a)[4] = a;
 
-    for (int i = 0; i < 4; ++i) {
-        CHECK(&gsl::at(a, i) == &a[i]);
-        CHECK(&gsl::at(c_a, i) == &a[i]);
+    for (int i = 0; i < 4; ++i)
+    {
+        EXPECT_TRUE(&gsl::at(a, i) == &a[i]);
+        EXPECT_TRUE(&gsl::at(c_a, i) == &a[i]);
     }
 
-    CHECK_THROWS_AS(gsl::at(a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(a, 4), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, 4), fail_fast);
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. static_array";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    EXPECT_DEATH(gsl::at(a, -1), expected);
+    EXPECT_DEATH(gsl::at(a, 4), expected);
+    EXPECT_DEATH(gsl::at(c_a, -1), expected);
+    EXPECT_DEATH(gsl::at(c_a, 4), expected);
 }
 
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("std_array")
+TEST(at_tests, std_array)
 {
     std::array<int, 4> a = {1, 2, 3, 4};
     const std::array<int, 4>& c_a = a;
 
-    for (int i = 0; i < 4; ++i) {
-        CHECK(&gsl::at(a, i) == &a[static_cast<std::size_t>(i)]);
-        CHECK(&gsl::at(c_a, i) == &a[static_cast<std::size_t>(i)]);
+    for (int i = 0; i < 4; ++i)
+    {
+        EXPECT_TRUE(&gsl::at(a, i) == &a[static_cast<std::size_t>(i)]);
+        EXPECT_TRUE(&gsl::at(c_a, i) == &a[static_cast<std::size_t>(i)]);
     }
 
-    CHECK_THROWS_AS(gsl::at(a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(a, 4), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, 4), fail_fast);
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. std_array";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    EXPECT_DEATH(gsl::at(a, -1), expected);
+    EXPECT_DEATH(gsl::at(a, 4), expected);
+    EXPECT_DEATH(gsl::at(c_a, -1), expected);
+    EXPECT_DEATH(gsl::at(c_a, 4), expected);
 }
 
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("StdVector")
+TEST(at_tests, std_vector)
 {
     std::vector<int> a = {1, 2, 3, 4};
     const std::vector<int>& c_a = a;
 
-    for (int i = 0; i < 4; ++i) {
-        CHECK(&gsl::at(a, i) == &a[static_cast<std::size_t>(i)]);
-        CHECK(&gsl::at(c_a, i) == &a[static_cast<std::size_t>(i)]);
+    for (int i = 0; i < 4; ++i)
+    {
+        EXPECT_TRUE(&gsl::at(a, i) == &a[static_cast<std::size_t>(i)]);
+        EXPECT_TRUE(&gsl::at(c_a, i) == &a[static_cast<std::size_t>(i)]);
     }
 
-    CHECK_THROWS_AS(gsl::at(a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(a, 4), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(c_a, 4), fail_fast);
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. std_vector";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    EXPECT_DEATH(gsl::at(a, -1), expected);
+    EXPECT_DEATH(gsl::at(a, 4), expected);
+    EXPECT_DEATH(gsl::at(c_a, -1), expected);
+    EXPECT_DEATH(gsl::at(c_a, 4), expected);
 }
 
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("InitializerList")
+TEST(at_tests, InitializerList)
 {
     const std::initializer_list<int> a = {1, 2, 3, 4};
 
-    for (int i = 0; i < 4; ++i) {
-        CHECK(gsl::at(a, i) == i + 1);
-        CHECK(gsl::at({1, 2, 3, 4}, i) == i + 1);
+    for (int i = 0; i < 4; ++i)
+    {
+        EXPECT_TRUE(gsl::at(a, i) == i + 1);
+        EXPECT_TRUE(gsl::at({1, 2, 3, 4}, i) == i + 1);
     }
 
-    CHECK_THROWS_AS(gsl::at(a, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at(a, 4), fail_fast);
-    CHECK_THROWS_AS(gsl::at({1, 2, 3, 4}, -1), fail_fast);
-    CHECK_THROWS_AS(gsl::at({1, 2, 3, 4}, 4), fail_fast);
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. InitializerList";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    EXPECT_DEATH(gsl::at(a, -1), expected);
+    EXPECT_DEATH(gsl::at(a, 4), expected);
+    EXPECT_DEATH(gsl::at({1, 2, 3, 4}, -1), expected);
+    EXPECT_DEATH(gsl::at({1, 2, 3, 4}, 4), expected);
 }
 
+#if defined(FORCE_STD_SPAN_TESTS) || defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
+TEST(at_tests, std_span)
+{
+    std::vector<int> vec{1, 2, 3, 4, 5};
+    std::span sp{vec};
+
+    std::vector<int> cvec{1, 2, 3, 4, 5};
+    std::span csp{cvec};
+
+    for (gsl::index i = 0; i < gsl::narrow_cast<gsl::index>(vec.size()); ++i)
+    {
+        EXPECT_TRUE(&gsl::at(sp, i) == &vec[gsl::narrow_cast<size_t>(i)]);
+        EXPECT_TRUE(&gsl::at(csp, i) == &cvec[gsl::narrow_cast<size_t>(i)]);
+    }
+
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. std_span";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    EXPECT_DEATH(gsl::at(sp, -1), expected);
+    EXPECT_DEATH(gsl::at(sp, gsl::narrow_cast<gsl::index>(sp.size())), expected);
+    EXPECT_DEATH(gsl::at(csp, -1), expected);
+    EXPECT_DEATH(gsl::at(csp, gsl::narrow_cast<gsl::index>(sp.size())), expected);
+}
+#endif // defined(FORCE_STD_SPAN_TESTS) || defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
+
 #if !defined(_MSC_VER) || defined(__clang__) || _MSC_VER >= 1910
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
 static constexpr bool test_constexpr()
 {
     int a1[4] = {1, 2, 3, 4};
@@ -118,7 +155,8 @@ static constexpr bool test_constexpr()
     std::array<int, 4> a2 = {1, 2, 3, 4};
     const std::array<int, 4>& c_a2 = a2;
 
-    for (int i = 0; i < 4; ++i) {
+    for (int i = 0; i < 4; ++i)
+    {
         if (&gsl::at(a1, i) != &a1[i]) return false;
         if (&gsl::at(c_a1, i) != &a1[i]) return false;
         // requires C++17:
@@ -132,4 +170,3 @@ static constexpr bool test_constexpr()
 
 static_assert(test_constexpr(), "FAIL");
 #endif
-

tests/bounds_tests.cpp

@@ -1,125 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-#pragma warning(disable : 4996)  // use of function or classes marked [[deprecated]]
-#endif
-
-#if __clang__ || __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, TEST_CASE
-
-#include <gsl/multi_span> // for static_bounds, static_bounds_dynamic_range_t
-
-#include <cstddef> // for ptrdiff_t, size_t
-
-namespace gsl {
-struct fail_fast;
-}  // namespace gsl
-
-using namespace std;
-using namespace gsl;
-
-namespace
-{
-void use(std::ptrdiff_t&) {}
-}
-
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-TEST_CASE("basic_bounds")
-{
-    for (auto point : static_bounds<dynamic_range, 3, 4>{2}) {
-        for (decltype(point)::size_type j = 0;
-             j < static_cast<decltype(point)::size_type>(decltype(point)::rank); j++)
-        {
-            use(j);
-            use(point[static_cast<std::size_t>(j)]);
-        }
-    }
-}
-
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("bounds_basic")
-{
-    static_bounds<3, 4, 5> b;
-    const auto a = b.slice();
-    (void) a;
-    static_bounds<4, dynamic_range, 2> x{4};
-    x.slice().slice();
-}
-
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("arrayview_iterator")
-{
-    static_bounds<4, dynamic_range, 2> bounds{3};
-
-    const auto itr = bounds.begin();
-    (void) itr;
-#ifdef CONFIRM_COMPILATION_ERRORS
-    multi_span<int, 4, dynamic_range, 2> av(nullptr, bounds);
-
-    auto itr2 = av.cbegin();
-
-    for (auto& v : av) {
-        v = 4;
-    }
-    fill(av.begin(), av.end(), 0);
-#endif
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("bounds_convertible")
-{
-    static_bounds<7, 4, 2> b1;
-    static_bounds<7, dynamic_range, 2> b2 = b1;
-    (void) b2;
-#ifdef CONFIRM_COMPILATION_ERRORS
-    static_bounds<7, dynamic_range, 1> b4 = b2;
-#endif
-
-    static_bounds<dynamic_range, dynamic_range, dynamic_range> b3 = b1;
-    static_bounds<7, 4, 2> b4 = b3;
-    (void) b4;
-
-    static_bounds<dynamic_range> b11;
-
-    static_bounds<dynamic_range> b5;
-    static_bounds<34> b6;
-
-    b5 = static_bounds<20>();
-    CHECK_THROWS_AS(b6 = b5, fail_fast);
-    b5 = static_bounds<34>();
-    b6 = b5;
-
-    CHECK(b5 == b6);
-    CHECK(b5.size() == b6.size());
-}
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-copy(src_span_static, dst_span_static);
-#endif
-
-#if __clang__ || __GNUC__
-#pragma GCC diagnostic pop
-#endif

tests/byte_tests.cpp

@@ -14,122 +14,117 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-#endif
+#include <gtest/gtest.h>
 
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
-
-#include <gsl/gsl_byte> // for to_byte, to_integer, byte, operator&, ope...
+#include <gsl/byte> // for to_byte, to_integer, byte, operator&, ope...
 
 using namespace std;
 using namespace gsl;
 
 namespace
 {
-TEST_CASE("construction")
-{
-    {
-        const byte b = static_cast<byte>(4);
-        CHECK(static_cast<unsigned char>(b) == 4);
-    }
-
-    GSL_SUPPRESS(es.49)
-    {
-        const byte b = byte(12);
-        CHECK(static_cast<unsigned char>(b) == 12);
-    }
-
-    {
-        const byte b = to_byte<12>();
-        CHECK(static_cast<unsigned char>(b) == 12);
-    }
-    {
-        const unsigned char uc = 12;
-        const byte b = to_byte(uc);
-        CHECK(static_cast<unsigned char>(b) == 12);
-    }
-
-#if defined(__cplusplus) && (__cplusplus >= 201703L)
-    {
-        const byte b { 14 };
-        CHECK(static_cast<unsigned char>(b) == 14);
-    }
-#endif
-}
-
-TEST_CASE("bitwise_operations")
-{
-    const byte b = to_byte<0xFF>();
-
-    byte a = to_byte<0x00>();
-    CHECK((b | a) == to_byte<0xFF>());
-    CHECK(a == to_byte<0x00>());
-
-    a |= b;
-    CHECK(a == to_byte<0xFF>());
-
-    a = to_byte<0x01>();
-    CHECK((b & a) == to_byte<0x01>());
-
-    a &= b;
-    CHECK(a == to_byte<0x01>());
-
-    CHECK((b ^ a) == to_byte<0xFE>());
-
-    CHECK(a == to_byte<0x01>());
-    a ^= b;
-    CHECK(a == to_byte<0xFE>());
-
-    a = to_byte<0x01>();
-    CHECK(~a == to_byte<0xFE>());
-
-    a = to_byte<0xFF>();
-    CHECK((a << 4) == to_byte<0xF0>());
-    CHECK((a >> 4) == to_byte<0x0F>());
-
-    a <<= 4;
-    CHECK(a == to_byte<0xF0>());
-    a >>= 4;
-    CHECK(a == to_byte<0x0F>());
-}
-
-TEST_CASE("to_integer")
-{
-    const byte b = to_byte<0x12>();
-
-    CHECK(0x12 == gsl::to_integer<char>(b));
-    CHECK(0x12 == gsl::to_integer<short>(b));
-    CHECK(0x12 == gsl::to_integer<long>(b));
-    CHECK(0x12 == gsl::to_integer<long long>(b));
-
-    CHECK(0x12 == gsl::to_integer<unsigned char>(b));
-    CHECK(0x12 == gsl::to_integer<unsigned short>(b));
-    CHECK(0x12 == gsl::to_integer<unsigned long>(b));
-    CHECK(0x12 == gsl::to_integer<unsigned long long>(b));
-
-    //      CHECK(0x12 == gsl::to_integer<float>(b));   // expect compile-time error
-    //      CHECK(0x12 == gsl::to_integer<double>(b));  // expect compile-time error
-}
-
-int modify_both(gsl::byte & b, int& i)
+int modify_both(gsl::byte& b, int& i)
 {
     i = 10;
     b = to_byte<5>();
     return i;
 }
 
-GSL_SUPPRESS(type.1)
-TEST_CASE("aliasing")
+TEST(byte_tests, construction)
+{
+    {
+        const byte b = static_cast<byte>(4);
+        EXPECT_TRUE(static_cast<unsigned char>(b) == 4);
+    }
+
+    // clang-format off
+    GSL_SUPPRESS(es.49)
+    // clang-format on
+    {
+        const byte b = byte(12);
+        EXPECT_TRUE(static_cast<unsigned char>(b) == 12);
+    }
+
+    {
+        const byte b = to_byte<12>();
+        EXPECT_TRUE(static_cast<unsigned char>(b) == 12);
+    }
+    {
+        const unsigned char uc = 12;
+        const byte b = to_byte(uc);
+        EXPECT_TRUE(static_cast<unsigned char>(b) == 12);
+    }
+
+#if defined(__cplusplus) && (__cplusplus >= 201703L)
+    {
+        const byte b{14};
+        EXPECT_TRUE(static_cast<unsigned char>(b) == 14);
+    }
+#endif
+}
+
+TEST(byte_tests, bitwise_operations)
+{
+    const byte b = to_byte<0xFF>();
+
+    byte a = to_byte<0x00>();
+    EXPECT_TRUE((b | a) == to_byte<0xFF>());
+    EXPECT_TRUE(a == to_byte<0x00>());
+
+    a |= b;
+    EXPECT_TRUE(a == to_byte<0xFF>());
+
+    a = to_byte<0x01>();
+    EXPECT_TRUE((b & a) == to_byte<0x01>());
+
+    a &= b;
+    EXPECT_TRUE(a == to_byte<0x01>());
+
+    EXPECT_TRUE((b ^ a) == to_byte<0xFE>());
+
+    EXPECT_TRUE(a == to_byte<0x01>());
+    a ^= b;
+    EXPECT_TRUE(a == to_byte<0xFE>());
+
+    a = to_byte<0x01>();
+    EXPECT_TRUE(~a == to_byte<0xFE>());
+
+    a = to_byte<0xFF>();
+    EXPECT_TRUE((a << 4) == to_byte<0xF0>());
+    EXPECT_TRUE((a >> 4) == to_byte<0x0F>());
+
+    a <<= 4;
+    EXPECT_TRUE(a == to_byte<0xF0>());
+    a >>= 4;
+    EXPECT_TRUE(a == to_byte<0x0F>());
+}
+
+TEST(byte_tests, to_integer)
+{
+    const byte b = to_byte<0x12>();
+
+    EXPECT_TRUE(0x12 == gsl::to_integer<char>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<short>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<long>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<long long>(b));
+
+    EXPECT_TRUE(0x12 == gsl::to_integer<unsigned char>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<unsigned short>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<unsigned long>(b));
+    EXPECT_TRUE(0x12 == gsl::to_integer<unsigned long long>(b));
+
+    //      EXPECT_TRUE(0x12 == gsl::to_integer<float>(b));   // expect compile-time error
+    //      EXPECT_TRUE(0x12 == gsl::to_integer<double>(b));  // expect compile-time error
+}
+
+TEST(byte_tests, aliasing)
 {
     int i{0};
     const int res = modify_both(reinterpret_cast<byte&>(i), i);
-    CHECK(res == i);
+    EXPECT_TRUE(res == i);
 }
 
-}
+} // namespace
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 copy(src_span_static, dst_span_static);

tests/deathTestCommon.h

@@ -0,0 +1,11 @@
+#pragma once
+#include <gsl/assert>
+
+constexpr char deathstring[] = "Expected Death";
+constexpr char failed_set_terminate_deathstring[] = ".*";
+
+// This prevents a failed call to set_terminate from failing the test suite.
+constexpr const char* GetExpectedDeathString(std::terminate_handler handle)
+{
+    return handle ? deathstring : failed_set_terminate_deathstring;
+}

tests/no_exception_ensure_tests.cpp

@@ -14,8 +14,11 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
+#include <chrono>
 #include <cstdlib>  // for std::exit
 #include <gsl/span> // for span
+#include <iostream>
+#include <thread>
 
 int operator_subscript_no_throw() noexcept
 {
@@ -42,6 +45,10 @@ void setup_termination_handler() noexcept
 
 int main() noexcept
 {
+    std::cout << "Running main() from " __FILE__ "\n";
+#if defined(IOS_PROCESS_DELAY_WORKAROUND)
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+#endif
     setup_termination_handler();
     operator_subscript_no_throw();
     return -1;

tests/no_exception_throw_tests.cpp

@@ -1,48 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include <cstdlib>        // for std::exit
-#include <gsl/gsl_assert> // for get_terminate
-#include <gsl/gsl_util>   // for narrow
-
-int narrow_no_throw()
-{
-    const long long bigNumber = 0x0fffffffffffffff;
-    return gsl::narrow<int>(bigNumber);
-}
-
-[[noreturn]] void test_terminate() { std::exit(0); }
-
-void setup_termination_handler() noexcept
-{
-#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
-
-    auto& handler = gsl::details::get_terminate_handler();
-    handler = &test_terminate;
-
-#else
-
-    std::set_terminate(test_terminate);
-
-#endif
-}
-
-int main()
-{
-    setup_termination_handler();
-    narrow_no_throw();
-    return -1;
-}

tests/notnull_tests.cpp

@@ -14,16 +14,7 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-
-// Fix VS2015 build breaks in Release
-#pragma warning(disable : 4702) // unreachable code
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+#include <gtest/gtest.h>
 
 #include <gsl/pointers> // for not_null, operator<, operator<=, operator>
 
@@ -34,11 +25,7 @@
 #include <string>    // for basic_string, operator==, string, operator<<
 #include <typeinfo>  // for type_info
 
-namespace gsl
-{
-struct fail_fast;
-} // namespace gsl
-
+#include "deathTestCommon.h"
 using namespace gsl;
 
 struct MyBase
@@ -73,7 +60,9 @@ struct CustomPtr
 template <typename T, typename U>
 std::string operator==(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) == reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                           : "false";
 }
@@ -81,7 +70,9 @@ std::string operator==(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 template <typename T, typename U>
 std::string operator!=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) != reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                           : "false";
 }
@@ -89,7 +80,9 @@ std::string operator!=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 template <typename T, typename U>
 std::string operator<(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) < reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
 }
@@ -97,7 +90,9 @@ std::string operator<(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 template <typename T, typename U>
 std::string operator>(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) > reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
 }
@@ -105,7 +100,9 @@ std::string operator>(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 template <typename T, typename U>
 std::string operator<=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) <= reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                           : "false";
 }
@@ -113,7 +110,9 @@ std::string operator<=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 template <typename T, typename U>
 std::string operator>=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return reinterpret_cast<const void*>(lhs.p_) >= reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                           : "false";
 }
@@ -127,16 +126,21 @@ struct NonCopyableNonMovable
     NonCopyableNonMovable& operator=(NonCopyableNonMovable&&) = delete;
 };
 
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+namespace
+{
+// clang-format off
+GSL_SUPPRESS(f .4) // NO-FORMAT: attribute
+// clang-format on
 bool helper(not_null<int*> p) { return *p == 12; }
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+// clang-format off
+GSL_SUPPRESS(f .4) // NO-FORMAT: attribute
+// clang-format on
 bool helper_const(not_null<const int*> p) { return *p == 12; }
 
 int* return_pointer() { return nullptr; }
-const int* return_pointer_const() { return nullptr; }
+} // namespace
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullConstructors")
+TEST(notnull_tests, TestNotNullConstructors)
 {
     {
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -153,18 +157,24 @@ TEST_CASE("TestNotNullConstructors")
 #endif
     }
 
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullConstructors";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     {
         // from shared pointer
         int i = 12;
         auto rp = RefCounted<int>(&i);
         not_null<int*> p(rp);
-        CHECK(p.get() == &i);
+        EXPECT_TRUE(p.get() == &i);
 
         not_null<std::shared_ptr<int>> x(
             std::make_shared<int>(10)); // shared_ptr<int> is nullptr assignable
 
         int* pi = nullptr;
-        CHECK_THROWS_AS(not_null<decltype(pi)>(pi), fail_fast);
+        EXPECT_DEATH((not_null<decltype(pi)>(pi)), expected);
     }
 
     {
@@ -175,7 +185,7 @@ TEST_CASE("TestNotNullConstructors")
         helper(&t);
         helper_const(&t);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -191,7 +201,7 @@ TEST_CASE("TestNotNullConstructors")
         helper(x);
         helper_const(x);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -205,7 +215,7 @@ TEST_CASE("TestNotNullConstructors")
         helper_const(cp);
         helper_const(x);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -215,19 +225,18 @@ TEST_CASE("TestNotNullConstructors")
 
         auto x = not_null<const int*>{cp};
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
         // from returned pointer
 
-        CHECK_THROWS_AS(helper(return_pointer()), fail_fast);
-        CHECK_THROWS_AS(helper_const(return_pointer()), fail_fast);
+        EXPECT_DEATH(helper(return_pointer()), expected);
+        EXPECT_DEATH(helper_const(return_pointer()), expected);
     }
 }
 
 template <typename T>
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
 void ostream_helper(T v)
 {
     not_null<T*> p(&v);
@@ -236,18 +245,18 @@ void ostream_helper(T v)
         std::ostringstream ref;
         os << static_cast<void*>(p);
         ref << static_cast<void*>(&v);
-        CHECK(os.str() == ref.str());
+        EXPECT_TRUE(os.str() == ref.str());
     }
     {
         std::ostringstream os;
         std::ostringstream ref;
         os << *p;
         ref << v;
-        CHECK(os.str() == ref.str());
+        EXPECT_TRUE(os.str() == ref.str());
     }
 }
 
-TEST_CASE("TestNotNullostream")
+TEST(notnull_tests, TestNotNullostream)
 {
     ostream_helper<int>(17);
     ostream_helper<float>(21.5f);
@@ -258,9 +267,7 @@ TEST_CASE("TestNotNullostream")
     ostream_helper<std::string>("string");
 }
 
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullCasting")
+TEST(notnull_tests, TestNotNullCasting)
 {
     MyBase base;
     MyDerived derived;
@@ -270,7 +277,7 @@ TEST_CASE("TestNotNullCasting")
     not_null<MyDerived*> p{&derived};
     not_null<MyBase*> q(&base);
     q = p; // allowed with heterogeneous copy ctor
-    CHECK(q == p);
+    EXPECT_TRUE(q == p);
 
 #ifdef CONFIRM_COMPILATION_ERRORS
     q = u; // no viable conversion possible between MyBase* and Unrelated*
@@ -280,20 +287,26 @@ TEST_CASE("TestNotNullCasting")
     not_null<Unrelated*> s = reinterpret_cast<Unrelated*>(p);
 #endif
     not_null<Unrelated*> t(reinterpret_cast<Unrelated*>(p.get()));
-    CHECK(reinterpret_cast<void*>(p.get()) == reinterpret_cast<void*>(t.get()));
+    EXPECT_TRUE(reinterpret_cast<void*>(p.get()) == reinterpret_cast<void*>(t.get()));
 }
 
-TEST_CASE("TestNotNullAssignment")
+TEST(notnull_tests, TestNotNullAssignment)
 {
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullAssignmentd";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     int i = 12;
     not_null<int*> p(&i);
-    CHECK(helper(p));
+    EXPECT_TRUE(helper(p));
 
     int* q = nullptr;
-    CHECK_THROWS_AS(p = not_null<int*>(q), fail_fast);
+    EXPECT_DEATH(p = not_null<int*>(q), expected);
 }
 
-TEST_CASE("TestNotNullRawPointerComparison")
+TEST(notnull_tests, TestNotNullRawPointerComparison)
 {
     int ints[2] = {42, 43};
     int* p1 = &ints[0];
@@ -302,34 +315,33 @@ TEST_CASE("TestNotNullRawPointerComparison")
     using NotNull1 = not_null<decltype(p1)>;
     using NotNull2 = not_null<decltype(p2)>;
 
-    CHECK((NotNull1(p1) == NotNull1(p1)) == true);
-    CHECK((NotNull1(p1) == NotNull2(p2)) == false);
+    EXPECT_TRUE((NotNull1(p1) == NotNull1(p1)) == true);
+    EXPECT_TRUE((NotNull1(p1) == NotNull2(p2)) == false);
 
-    CHECK((NotNull1(p1) != NotNull1(p1)) == false);
-    CHECK((NotNull1(p1) != NotNull2(p2)) == true);
+    EXPECT_TRUE((NotNull1(p1) != NotNull1(p1)) == false);
+    EXPECT_TRUE((NotNull1(p1) != NotNull2(p2)) == true);
 
-    CHECK((NotNull1(p1) < NotNull1(p1)) == false);
-    CHECK((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
-    CHECK((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));
+    EXPECT_TRUE((NotNull1(p1) < NotNull1(p1)) == false);
+    EXPECT_TRUE((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
+    EXPECT_TRUE((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));
 
-    CHECK((NotNull1(p1) > NotNull1(p1)) == false);
-    CHECK((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
-    CHECK((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));
+    EXPECT_TRUE((NotNull1(p1) > NotNull1(p1)) == false);
+    EXPECT_TRUE((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
+    EXPECT_TRUE((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));
 
-    CHECK((NotNull1(p1) <= NotNull1(p1)) == true);
-    CHECK((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
-    CHECK((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));
+    EXPECT_TRUE((NotNull1(p1) <= NotNull1(p1)) == true);
+    EXPECT_TRUE((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
+    EXPECT_TRUE((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullDereferenceOperator")
+TEST(notnull_tests, TestNotNullDereferenceOperator)
 {
     {
         auto sp1 = std::make_shared<NonCopyableNonMovable>();
 
         using NotNullSp1 = not_null<decltype(sp1)>;
-        CHECK(typeid(*sp1) == typeid(*NotNullSp1(sp1)));
-        CHECK(std::addressof(*NotNullSp1(sp1)) == std::addressof(*sp1));
+        EXPECT_TRUE(typeid(*sp1) == typeid(*NotNullSp1(sp1)));
+        EXPECT_TRUE(std::addressof(*NotNullSp1(sp1)) == std::addressof(*sp1));
     }
 
     {
@@ -337,22 +349,22 @@ TEST_CASE("TestNotNullDereferenceOperator")
         CustomPtr<int> p1(&ints[0]);
 
         using NotNull1 = not_null<decltype(p1)>;
-        CHECK(typeid(*NotNull1(p1)) == typeid(*p1));
-        CHECK(*NotNull1(p1) == 42);
+        EXPECT_TRUE(typeid(*NotNull1(p1)) == typeid(*p1));
+        EXPECT_TRUE(*NotNull1(p1) == 42);
         *NotNull1(p1) = 43;
-        CHECK(ints[0] == 43);
+        EXPECT_TRUE(ints[0] == 43);
     }
 
     {
         int v = 42;
         gsl::not_null<int*> p(&v);
-        CHECK(typeid(*p) == typeid(*(&v)));
+        EXPECT_TRUE(typeid(*p) == typeid(*(&v)));
         *p = 43;
-        CHECK(v == 43);
+        EXPECT_TRUE(v == 43);
     }
 }
 
-TEST_CASE("TestNotNullSharedPtrComparison")
+TEST(notnull_tests, TestNotNullSharedPtrComparison)
 {
     auto sp1 = std::make_shared<int>(42);
     auto sp2 = std::make_shared<const int>(43);
@@ -360,31 +372,30 @@ TEST_CASE("TestNotNullSharedPtrComparison")
     using NotNullSp1 = not_null<decltype(sp1)>;
     using NotNullSp2 = not_null<decltype(sp2)>;
 
-    CHECK((NotNullSp1(sp1) == NotNullSp1(sp1)) == true);
-    CHECK((NotNullSp1(sp1) == NotNullSp2(sp2)) == false);
+    EXPECT_TRUE((NotNullSp1(sp1) == NotNullSp1(sp1)) == true);
+    EXPECT_TRUE((NotNullSp1(sp1) == NotNullSp2(sp2)) == false);
 
-    CHECK((NotNullSp1(sp1) != NotNullSp1(sp1)) == false);
-    CHECK((NotNullSp1(sp1) != NotNullSp2(sp2)) == true);
+    EXPECT_TRUE((NotNullSp1(sp1) != NotNullSp1(sp1)) == false);
+    EXPECT_TRUE((NotNullSp1(sp1) != NotNullSp2(sp2)) == true);
 
-    CHECK((NotNullSp1(sp1) < NotNullSp1(sp1)) == false);
-    CHECK((NotNullSp1(sp1) < NotNullSp2(sp2)) == (sp1 < sp2));
-    CHECK((NotNullSp2(sp2) < NotNullSp1(sp1)) == (sp2 < sp1));
+    EXPECT_TRUE((NotNullSp1(sp1) < NotNullSp1(sp1)) == false);
+    EXPECT_TRUE((NotNullSp1(sp1) < NotNullSp2(sp2)) == (sp1 < sp2));
+    EXPECT_TRUE((NotNullSp2(sp2) < NotNullSp1(sp1)) == (sp2 < sp1));
 
-    CHECK((NotNullSp1(sp1) > NotNullSp1(sp1)) == false);
-    CHECK((NotNullSp1(sp1) > NotNullSp2(sp2)) == (sp1 > sp2));
-    CHECK((NotNullSp2(sp2) > NotNullSp1(sp1)) == (sp2 > sp1));
+    EXPECT_TRUE((NotNullSp1(sp1) > NotNullSp1(sp1)) == false);
+    EXPECT_TRUE((NotNullSp1(sp1) > NotNullSp2(sp2)) == (sp1 > sp2));
+    EXPECT_TRUE((NotNullSp2(sp2) > NotNullSp1(sp1)) == (sp2 > sp1));
 
-    CHECK((NotNullSp1(sp1) <= NotNullSp1(sp1)) == true);
-    CHECK((NotNullSp1(sp1) <= NotNullSp2(sp2)) == (sp1 <= sp2));
-    CHECK((NotNullSp2(sp2) <= NotNullSp1(sp1)) == (sp2 <= sp1));
+    EXPECT_TRUE((NotNullSp1(sp1) <= NotNullSp1(sp1)) == true);
+    EXPECT_TRUE((NotNullSp1(sp1) <= NotNullSp2(sp2)) == (sp1 <= sp2));
+    EXPECT_TRUE((NotNullSp2(sp2) <= NotNullSp1(sp1)) == (sp2 <= sp1));
 
-    CHECK((NotNullSp1(sp1) >= NotNullSp1(sp1)) == true);
-    CHECK((NotNullSp1(sp1) >= NotNullSp2(sp2)) == (sp1 >= sp2));
-    CHECK((NotNullSp2(sp2) >= NotNullSp1(sp1)) == (sp2 >= sp1));
+    EXPECT_TRUE((NotNullSp1(sp1) >= NotNullSp1(sp1)) == true);
+    EXPECT_TRUE((NotNullSp1(sp1) >= NotNullSp2(sp2)) == (sp1 >= sp2));
+    EXPECT_TRUE((NotNullSp2(sp2) >= NotNullSp1(sp1)) == (sp2 >= sp1));
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullCustomPtrComparison")
+TEST(notnull_tests, TestNotNullCustomPtrComparison)
 {
     int ints[2] = {42, 43};
     CustomPtr<int> p1(&ints[0]);
@@ -393,33 +404,32 @@ TEST_CASE("TestNotNullCustomPtrComparison")
     using NotNull1 = not_null<decltype(p1)>;
     using NotNull2 = not_null<decltype(p2)>;
 
-    CHECK((NotNull1(p1) == NotNull1(p1)) == "true");
-    CHECK((NotNull1(p1) == NotNull2(p2)) == "false");
+    EXPECT_TRUE((NotNull1(p1) == NotNull1(p1)) == "true");
+    EXPECT_TRUE((NotNull1(p1) == NotNull2(p2)) == "false");
 
-    CHECK((NotNull1(p1) != NotNull1(p1)) == "false");
-    CHECK((NotNull1(p1) != NotNull2(p2)) == "true");
+    EXPECT_TRUE((NotNull1(p1) != NotNull1(p1)) == "false");
+    EXPECT_TRUE((NotNull1(p1) != NotNull2(p2)) == "true");
 
-    CHECK((NotNull1(p1) < NotNull1(p1)) == "false");
-    CHECK((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
-    CHECK((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));
+    EXPECT_TRUE((NotNull1(p1) < NotNull1(p1)) == "false");
+    EXPECT_TRUE((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
+    EXPECT_TRUE((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));
 
-    CHECK((NotNull1(p1) > NotNull1(p1)) == "false");
-    CHECK((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
-    CHECK((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));
+    EXPECT_TRUE((NotNull1(p1) > NotNull1(p1)) == "false");
+    EXPECT_TRUE((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
+    EXPECT_TRUE((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));
 
-    CHECK((NotNull1(p1) <= NotNull1(p1)) == "true");
-    CHECK((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
-    CHECK((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));
+    EXPECT_TRUE((NotNull1(p1) <= NotNull1(p1)) == "true");
+    EXPECT_TRUE((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
+    EXPECT_TRUE((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));
 
-    CHECK((NotNull1(p1) >= NotNull1(p1)) == "true");
-    CHECK((NotNull1(p1) >= NotNull2(p2)) == (p1 >= p2));
-    CHECK((NotNull2(p2) >= NotNull1(p1)) == (p2 >= p1));
+    EXPECT_TRUE((NotNull1(p1) >= NotNull1(p1)) == "true");
+    EXPECT_TRUE((NotNull1(p1) >= NotNull2(p2)) == (p1 >= p2));
+    EXPECT_TRUE((NotNull2(p2) >= NotNull1(p1)) == (p2 >= p1));
 }
 
 #if defined(__cplusplus) && (__cplusplus >= 201703L)
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullConstructorTypeDeduction")
+TEST(notnull_tests, TestNotNullConstructorTypeDeduction)
 {
     {
         int i = 42;
@@ -428,7 +438,7 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
         helper(not_null{&i});
         helper_const(not_null{&i});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -439,15 +449,21 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
         helper(not_null{p});
         helper_const(not_null{p});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullConstructorTypeDeduction";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     {
         auto workaround_macro = []() {
             int* p1 = nullptr;
             const not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
@@ -455,14 +471,14 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
             const int* p1 = nullptr;
             const not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
         int* p = nullptr;
 
-        CHECK_THROWS_AS(helper(not_null{p}), fail_fast);
-        CHECK_THROWS_AS(helper_const(not_null{p}), fail_fast);
+        EXPECT_DEATH(helper(not_null{p}), expected);
+        EXPECT_DEATH(helper_const(not_null{p}), expected);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -475,7 +491,7 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
 }
 #endif // #if defined(__cplusplus) && (__cplusplus >= 201703L)
 
-TEST_CASE("TestMakeNotNull")
+TEST(notnull_tests, TestMakeNotNull)
 {
     {
         int i = 42;
@@ -484,7 +500,7 @@ TEST_CASE("TestMakeNotNull")
         helper(make_not_null(&i));
         helper_const(make_not_null(&i));
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -495,42 +511,60 @@ TEST_CASE("TestMakeNotNull")
         helper(make_not_null(p));
         helper_const(make_not_null(p));
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. TestMakeNotNull";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     {
         const auto workaround_macro = []() {
             int* p1 = nullptr;
             const auto x = make_not_null(p1);
-            CHECK(*x == 42);
+            EXPECT_TRUE(*x == 42);
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
         const auto workaround_macro = []() {
             const int* p1 = nullptr;
             const auto x = make_not_null(p1);
-            CHECK(*x == 42);
+            EXPECT_TRUE(*x == 42);
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
         int* p = nullptr;
 
-        CHECK_THROWS_AS(helper(make_not_null(p)), fail_fast);
-        CHECK_THROWS_AS(helper_const(make_not_null(p)), fail_fast);
+        EXPECT_DEATH(helper(make_not_null(p)), expected);
+        EXPECT_DEATH(helper_const(make_not_null(p)), expected);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
     {
-        CHECK_THROWS_AS(make_not_null(nullptr), fail_fast);
-        CHECK_THROWS_AS(helper(make_not_null(nullptr)), fail_fast);
-        CHECK_THROWS_AS(helper_const(make_not_null(nullptr)), fail_fast);
+        EXPECT_DEATH(make_not_null(nullptr), expected);
+        EXPECT_DEATH(helper(make_not_null(nullptr)), expected);
+        EXPECT_DEATH(helper_const(make_not_null(nullptr)), expected);
     }
 #endif
 }
 
-static_assert(std::is_nothrow_move_constructible<not_null<void*>>::value,
-              "not_null must be no-throw move constructible");
+TEST(notnull_tests, TestStdHash)
+{
+    int x = 42;
+    int y = 99;
+    not_null<int*> nn{&x};
+    const not_null<int*> cnn{&x};
+
+    std::hash<not_null<int*>> hash_nn;
+    std::hash<int*> hash_intptr;
+
+    EXPECT_TRUE(hash_nn(nn) == hash_intptr(&x));
+    EXPECT_FALSE(hash_nn(nn) == hash_intptr(&y));
+    EXPECT_FALSE(hash_nn(nn) == hash_intptr(nullptr));
+}

tests/owner_tests.cpp

@@ -14,40 +14,30 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+#include <gtest/gtest.h>
 
 #include <gsl/pointers> // for owner
 
 using namespace gsl;
 
-GSL_SUPPRESS(f.23) // NO-FORMAT: attribute
+GSL_SUPPRESS(f .23) // NO-FORMAT: attribute
 void f(int* i) { *i += 1; }
 
-GSL_SUPPRESS(r.11) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.3) // NO-FORMAT: attribute // TODO: false positive
-GSL_SUPPRESS(r.5) // NO-FORMAT: attribute
-TEST_CASE("basic_test")
+TEST(owner_tests, basic_test)
 {
     owner<int*> p = new int(120);
-    CHECK(*p == 120);
+    EXPECT_TRUE(*p == 120);
     f(p);
-    CHECK(*p == 121);
+    EXPECT_TRUE(*p == 121);
     delete p;
 }
 
-TEST_CASE("check_pointer_constraint")
+TEST(owner_tests, check_pointer_constraint)
 {
-    #ifdef CONFIRM_COMPILATION_ERRORS
+#ifdef CONFIRM_COMPILATION_ERRORS
     {
         owner<int> integerTest = 10;
         owner<std::shared_ptr<int>> sharedPtrTest(new int(10));
     }
-    #endif
+#endif
 }

tests/span_ext_tests.cpp

@@ -0,0 +1,361 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include <gtest/gtest.h>
+
+#include <gsl/span> // for span and span_ext
+#include <gsl/util> // for narrow_cast, at
+
+#include <array>    // for array
+#include <iostream> // for cerr
+#include <vector>   // for vector
+
+using namespace std;
+using namespace gsl;
+
+#include "deathTestCommon.h"
+
+TEST(span_ext_test, make_span_from_pointer_length_constructor)
+{
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. from_pointer_length_constructor";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
+    int arr[4] = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(&arr[0], 2);
+        EXPECT_TRUE(s.size() == 2);
+        EXPECT_TRUE(s.data() == &arr[0]);
+        EXPECT_TRUE(s[0] == 1);
+        EXPECT_TRUE(s[1] == 2);
+    }
+
+    {
+        int* p = nullptr;
+        auto s = make_span(p, narrow_cast<gsl::span<int>::size_type>(0));
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == nullptr);
+    }
+
+    {
+        int* p = nullptr;
+        auto workaround_macro = [=]() { make_span(p, 2); };
+        EXPECT_DEATH(workaround_macro(), expected);
+    }
+}
+
+TEST(span_ext_test, make_span_from_pointer_pointer_construction)
+{
+    int arr[4] = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(&arr[0], &arr[2]);
+        EXPECT_TRUE(s.size() == 2);
+        EXPECT_TRUE(s.data() == &arr[0]);
+        EXPECT_TRUE(s[0] == 1);
+        EXPECT_TRUE(s[1] == 2);
+    }
+
+    {
+        auto s = make_span(&arr[0], &arr[0]);
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == &arr[0]);
+    }
+
+    {
+        int* p = nullptr;
+        auto s = make_span(p, p);
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == nullptr);
+    }
+}
+
+TEST(span_ext_test, make_span_from_array_constructor)
+{
+    int arr[5] = {1, 2, 3, 4, 5};
+    int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
+    int arr3d[2][3][2] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
+
+    {
+        const auto s = make_span(arr);
+        EXPECT_TRUE(s.size() == 5);
+        EXPECT_TRUE(s.data() == std::addressof(arr[0]));
+    }
+
+    {
+        const auto s = make_span(std::addressof(arr2d[0]), 1);
+        EXPECT_TRUE(s.size() == 1);
+        EXPECT_TRUE(s.data() == std::addressof(arr2d[0]));
+    }
+
+    {
+        const auto s = make_span(std::addressof(arr3d[0]), 1);
+        EXPECT_TRUE(s.size() == 1);
+        EXPECT_TRUE(s.data() == std::addressof(arr3d[0]));
+    }
+}
+
+TEST(span_ext_test, make_span_from_dynamic_array_constructor)
+{
+    double(*arr)[3][4] = new double[100][3][4];
+
+    {
+        auto s = make_span(&arr[0][0][0], 10);
+        EXPECT_TRUE(s.size() == 10);
+        EXPECT_TRUE(s.data() == &arr[0][0][0]);
+    }
+
+    delete[] arr;
+}
+
+TEST(span_ext_test, make_span_from_std_array_constructor)
+{
+    std::array<int, 4> arr = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(arr);
+        EXPECT_TRUE(s.size() == arr.size());
+        EXPECT_TRUE(s.data() == arr.data());
+    }
+
+    // This test checks for the bug found in gcc 6.1, 6.2, 6.3, 6.4, 6.5 7.1, 7.2, 7.3 - issue #590
+    {
+        gsl::span<int> s1 = make_span(arr);
+
+        static gsl::span<int> s2;
+        s2 = s1;
+
+#if defined(__GNUC__) && __GNUC__ == 6 && (__GNUC_MINOR__ == 4 || __GNUC_MINOR__ == 5) &&          \
+    __GNUC_PATCHLEVEL__ == 0 && defined(__OPTIMIZE__)
+        // Known to be broken in gcc 6.4 and 6.5 with optimizations
+        // Issue in gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83116
+        EXPECT_TRUE(s1.size() == 4);
+        EXPECT_TRUE(s2.size() == 0);
+#else
+        EXPECT_TRUE(s1.size() == s2.size());
+#endif
+    }
+}
+
+TEST(span_ext_test, make_span_from_const_std_array_constructor)
+{
+    const std::array<int, 4> arr = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(arr);
+        EXPECT_TRUE(s.size() == arr.size());
+        EXPECT_TRUE(s.data() == arr.data());
+    }
+}
+
+TEST(span_ext_test, make_span_from_std_array_const_constructor)
+{
+    std::array<const int, 4> arr = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(arr);
+        EXPECT_TRUE(s.size() == arr.size());
+        EXPECT_TRUE(s.data() == arr.data());
+    }
+}
+
+TEST(span_ext_test, make_span_from_container_constructor)
+{
+    std::vector<int> v = {1, 2, 3};
+    const std::vector<int> cv = v;
+
+    {
+        auto s = make_span(v);
+        EXPECT_TRUE(s.size() == v.size());
+        EXPECT_TRUE(s.data() == v.data());
+
+        auto cs = make_span(cv);
+        EXPECT_TRUE(cs.size() == cv.size());
+        EXPECT_TRUE(cs.data() == cv.data());
+    }
+}
+
+TEST(span_test, interop_with_gsl_at)
+{
+    int arr[5] = {1, 2, 3, 4, 5};
+    gsl::span<int> s{arr};
+    EXPECT_TRUE(at(s, 0) == 1);
+    EXPECT_TRUE(at(s, 1) == 2);
+}
+
+TEST(span_ext_test, iterator_free_functions)
+{
+    int a[] = {1, 2, 3, 4};
+    gsl::span<int> s{a};
+
+    EXPECT_TRUE((std::is_same<decltype(s.begin()), decltype(begin(s))>::value));
+    EXPECT_TRUE((std::is_same<decltype(s.end()), decltype(end(s))>::value));
+
+    EXPECT_TRUE((std::is_same<decltype(std::cbegin(s)), decltype(cbegin(s))>::value));
+    EXPECT_TRUE((std::is_same<decltype(std::cend(s)), decltype(cend(s))>::value));
+
+    EXPECT_TRUE((std::is_same<decltype(s.rbegin()), decltype(rbegin(s))>::value));
+    EXPECT_TRUE((std::is_same<decltype(s.rend()), decltype(rend(s))>::value));
+
+    EXPECT_TRUE((std::is_same<decltype(std::crbegin(s)), decltype(crbegin(s))>::value));
+    EXPECT_TRUE((std::is_same<decltype(std::crend(s)), decltype(crend(s))>::value));
+
+    EXPECT_TRUE(s.begin() == begin(s));
+    EXPECT_TRUE(s.end() == end(s));
+
+    EXPECT_TRUE(s.rbegin() == rbegin(s));
+    EXPECT_TRUE(s.rend() == rend(s));
+
+    EXPECT_TRUE(s.begin() == cbegin(s));
+    EXPECT_TRUE(s.end() == cend(s));
+
+    EXPECT_TRUE(s.rbegin() == crbegin(s));
+    EXPECT_TRUE(s.rend() == crend(s));
+}
+
+TEST(span_ext_test, ssize_free_function)
+{
+    int a[] = {1, 2, 3, 4};
+    gsl::span<int> s{a};
+
+    EXPECT_FALSE((std::is_same<decltype(s.size()), decltype(ssize(s))>::value));
+    EXPECT_TRUE(s.size() == static_cast<std::size_t>(ssize(s)));
+}
+
+#ifndef GSL_KERNEL_MODE
+TEST(span_ext_test, comparison_operators)
+{
+    {
+        gsl::span<int> s1;
+        gsl::span<int> s2;
+        EXPECT_TRUE(s1 == s2);
+        EXPECT_FALSE(s1 != s2);
+        EXPECT_FALSE(s1 < s2);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s1 >= s2);
+        EXPECT_TRUE(s2 == s1);
+        EXPECT_FALSE(s2 != s1);
+        EXPECT_FALSE(s2 != s1);
+        EXPECT_TRUE(s2 <= s1);
+        EXPECT_FALSE(s2 > s1);
+        EXPECT_TRUE(s2 >= s1);
+    }
+
+    {
+        int arr[] = {2, 1};
+        gsl::span<int> s1 = arr;
+        gsl::span<int> s2 = arr;
+
+        EXPECT_TRUE(s1 == s2);
+        EXPECT_FALSE(s1 != s2);
+        EXPECT_FALSE(s1 < s2);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s1 >= s2);
+        EXPECT_TRUE(s2 == s1);
+        EXPECT_FALSE(s2 != s1);
+        EXPECT_FALSE(s2 < s1);
+        EXPECT_TRUE(s2 <= s1);
+        EXPECT_FALSE(s2 > s1);
+        EXPECT_TRUE(s2 >= s1);
+    }
+
+    {
+        int arr[] = {2, 1}; // bigger
+
+        gsl::span<int> s1;
+        gsl::span<int> s2 = arr;
+
+        EXPECT_TRUE(s1 != s2);
+        EXPECT_TRUE(s2 != s1);
+        EXPECT_FALSE(s1 == s2);
+        EXPECT_FALSE(s2 == s1);
+        EXPECT_TRUE(s1 < s2);
+        EXPECT_FALSE(s2 < s1);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s2 <= s1);
+        EXPECT_TRUE(s2 > s1);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s2 >= s1);
+        EXPECT_FALSE(s1 >= s2);
+    }
+
+    {
+        int arr1[] = {1, 2};
+        int arr2[] = {1, 2};
+        gsl::span<int> s1 = arr1;
+        gsl::span<int> s2 = arr2;
+
+        EXPECT_TRUE(s1 == s2);
+        EXPECT_FALSE(s1 != s2);
+        EXPECT_FALSE(s1 < s2);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s1 >= s2);
+        EXPECT_TRUE(s2 == s1);
+        EXPECT_FALSE(s2 != s1);
+        EXPECT_FALSE(s2 < s1);
+        EXPECT_TRUE(s2 <= s1);
+        EXPECT_FALSE(s2 > s1);
+        EXPECT_TRUE(s2 >= s1);
+    }
+
+    {
+        int arr[] = {1, 2, 3};
+
+        gsl::span<int> s1 = {&arr[0], 2}; // shorter
+        gsl::span<int> s2 = arr;          // longer
+
+        EXPECT_TRUE(s1 != s2);
+        EXPECT_TRUE(s2 != s1);
+        EXPECT_FALSE(s1 == s2);
+        EXPECT_FALSE(s2 == s1);
+        EXPECT_TRUE(s1 < s2);
+        EXPECT_FALSE(s2 < s1);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s2 <= s1);
+        EXPECT_TRUE(s2 > s1);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s2 >= s1);
+        EXPECT_FALSE(s1 >= s2);
+    }
+
+    {
+        int arr1[] = {1, 2}; // smaller
+        int arr2[] = {2, 1}; // bigger
+
+        gsl::span<int> s1 = arr1;
+        gsl::span<int> s2 = arr2;
+
+        EXPECT_TRUE(s1 != s2);
+        EXPECT_TRUE(s2 != s1);
+        EXPECT_FALSE(s1 == s2);
+        EXPECT_FALSE(s2 == s1);
+        EXPECT_TRUE(s1 < s2);
+        EXPECT_FALSE(s2 < s1);
+        EXPECT_TRUE(s1 <= s2);
+        EXPECT_FALSE(s2 <= s1);
+        EXPECT_TRUE(s2 > s1);
+        EXPECT_FALSE(s1 > s2);
+        EXPECT_TRUE(s2 >= s1);
+        EXPECT_FALSE(s1 >= s2);
+    }
+}
+#endif // GSL_KERNEL_MODE

tests/strict_notnull_tests.cpp

@@ -14,40 +14,42 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
+#include <gsl/pointers> // for not_null, operator<, operator<=, operator>
+#include <gtest/gtest.h>
 
-// Fix VS2015 build breaks in Release
-#pragma warning(disable : 4702) // unreachable code
-#endif
-
-#include <catch/catch.hpp>    // for AssertionHandler, StringRef, CHECK, TEST_...
-#include <gsl/pointers>           // for not_null, operator<, operator<=, operator>
-
-namespace gsl
-{
-struct fail_fast;
-} // namespace gsl
+#include "deathTestCommon.h"
 
 using namespace gsl;
 
-GSL_SUPPRESS(f.4)  // NO-FORMAT: attribute
-bool helper(not_null<int*> p) { return *p == 12; }
+namespace
+{
+// clang-format off
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+// clang-format on
+bool helper(not_null<int*> p) { return *p == 12; }
+
+// clang-format off
+GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+// clang-format on
 bool helper_const(not_null<const int*> p) { return *p == 12; }
 
+// clang-format off
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+// clang-format on
 bool strict_helper(strict_not_null<int*> p) { return *p == 12; }
+
+// clang-format off
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
+// clang-format on
 bool strict_helper_const(strict_not_null<const int*> p) { return *p == 12; }
 
+#ifdef CONFIRM_COMPILATION_ERRORS
 int* return_pointer() { return nullptr; }
 const int* return_pointer_const() { return nullptr; }
+#endif
+} // namespace
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestStrictNotNull")
+TEST(strict_notnull_tests, TestStrictNotNull)
 {
     {
         // raw ptr <-> strict_not_null
@@ -66,7 +68,7 @@ TEST_CASE("TestStrictNotNull")
         helper(snn1);
         helper_const(snn1);
 
-        CHECK(*snn1 == 42);
+        EXPECT_TRUE(*snn1 == 42);
     }
 
     {
@@ -80,7 +82,7 @@ TEST_CASE("TestStrictNotNull")
         strict_helper_const(snn1);
         strict_helper_const(snn2);
 
-        CHECK(snn1 == snn2);
+        EXPECT_TRUE(snn1 == snn2);
     }
 
     {
@@ -95,8 +97,8 @@ TEST_CASE("TestStrictNotNull")
         helper(snn);
         helper_const(snn);
 
-        CHECK(snn == nn1);
-        CHECK(snn == nn2);
+        EXPECT_TRUE(snn == nn1);
+        EXPECT_TRUE(snn == nn2);
     }
 
     {
@@ -111,16 +113,16 @@ TEST_CASE("TestStrictNotNull")
         strict_helper(nn);
         strict_helper_const(nn);
 
-        CHECK(snn1 == nn);
-        CHECK(snn2 == nn);
+        EXPECT_TRUE(snn1 == nn);
+        EXPECT_TRUE(snn2 == nn);
 
         std::hash<strict_not_null<int*>> hash_snn;
         std::hash<not_null<int*>> hash_nn;
 
-        CHECK(hash_nn(snn1) == hash_nn(nn));
-        CHECK(hash_snn(snn1) == hash_nn(nn));
-        CHECK(hash_nn(snn1) == hash_nn(snn2));
-        CHECK(hash_snn(snn1) == hash_snn(nn));
+        EXPECT_TRUE(hash_nn(snn1) == hash_nn(nn));
+        EXPECT_TRUE(hash_snn(snn1) == hash_nn(nn));
+        EXPECT_TRUE(hash_nn(snn1) == hash_nn(snn2));
+        EXPECT_TRUE(hash_snn(snn1) == hash_snn(nn));
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -132,9 +134,14 @@ TEST_CASE("TestStrictNotNull")
 
 #if defined(__cplusplus) && (__cplusplus >= 201703L)
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
+TEST(strict_notnull_tests, TestStrictNotNullConstructorTypeDeduction)
 {
+    const auto terminateHandler = std::set_terminate([] {
+        std::cerr << "Expected Death. TestStrictNotNullConstructorTypeDeduction";
+        std::abort();
+    });
+    const auto expected = GetExpectedDeathString(terminateHandler);
+
     {
         int i = 42;
 
@@ -142,7 +149,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
         helper(strict_not_null{&i});
         helper_const(strict_not_null{&i});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -153,7 +160,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
         helper(strict_not_null{p});
         helper_const(strict_not_null{p});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -161,7 +168,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
             int* p1 = nullptr;
             const strict_not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
@@ -169,14 +176,14 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
             const int* p1 = nullptr;
             const strict_not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), expected);
     }
 
     {
         int* p = nullptr;
 
-        CHECK_THROWS_AS(helper(strict_not_null{p}), fail_fast);
-        CHECK_THROWS_AS(helper_const(strict_not_null{p}), fail_fast);
+        EXPECT_DEATH(helper(strict_not_null{p}), expected);
+        EXPECT_DEATH(helper_const(strict_not_null{p}), expected);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -188,6 +195,3 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
 #endif
 }
 #endif // #if defined(__cplusplus) && (__cplusplus >= 201703L)
-
-static_assert(std::is_nothrow_move_constructible<strict_not_null<void*>>::value,
-              "strict_not_null must be no-throw move constructible");

tests/strided_span_tests.cpp

@@ -1,806 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch deprecated
-#pragma warning(disable : 4996) // strided_span is in the process of being deprecated. 
-                                // Suppressing warnings until it is completely removed
-#endif
-
-#if __clang__ || __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, CHECK...
-
-#include <gsl/gsl_byte>   // for byte
-#include <gsl/gsl_util>   // for narrow_cast
-#include <gsl/multi_span> // for strided_span, index, multi_span, strided_...
-
-#include <iostream>    // for size_t
-#include <iterator>    // for begin, end
-#include <numeric>     // for iota
-#include <type_traits> // for integral_constant<>::value, is_convertible
-#include <vector>      // for vector
-
-namespace gsl {
-struct fail_fast;
-}  // namespace gsl
-
-using namespace std;
-using namespace gsl;
-
-namespace
-{
-struct BaseClass
-{
-};
-struct DerivedClass : BaseClass
-{
-};
-}
-
-TEST_CASE("span_section_test")
-{
-    int a[30][4][5];
-
-    const auto av = as_multi_span(a);
-    const auto sub = av.section({15, 0, 0}, gsl::multi_span_index<3>{2, 2, 2});
-    const auto subsub = sub.section({1, 0, 0}, gsl::multi_span_index<3>{1, 1, 1});
-    (void) subsub;
-}
-
-TEST_CASE("span_section")
-{
-    std::vector<int> data(5 * 10);
-    std::iota(begin(data), end(data), 0);
-    const multi_span<int, 5, 10> av = as_multi_span(multi_span<int>{data}, dim<5>(), dim<10>());
-
-    const strided_span<int, 2> av_section_1 = av.section({1, 2}, {3, 4});
-    CHECK(!av_section_1.empty());
-    CHECK((av_section_1[{0, 0}] == 12));
-    CHECK((av_section_1[{0, 1}] == 13));
-    CHECK((av_section_1[{1, 0}] == 22));
-    CHECK((av_section_1[{2, 3}] == 35));
-
-    const strided_span<int, 2> av_section_2 = av_section_1.section({1, 2}, {2, 2});
-    CHECK(!av_section_2.empty());
-    CHECK((av_section_2[{0, 0}] == 24));
-    CHECK((av_section_2[{0, 1}] == 25));
-    CHECK((av_section_2[{1, 0}] == 34));
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_constructors")
-{
-    // Check stride constructor
-    {
-        int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
-        const int carr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
-
-        strided_span<int, 1> sav1{arr, {{9}, {1}}}; // T -> T
-        CHECK(sav1.bounds().index_bounds() == multi_span_index<1>{9});
-        CHECK(sav1.bounds().stride() == 1);
-        CHECK((sav1[0] == 1 && sav1[8] == 9));
-
-        strided_span<const int, 1> sav2{carr, {{4}, {2}}}; // const T -> const T
-        CHECK(sav2.bounds().index_bounds() == multi_span_index<1>{4});
-        CHECK(sav2.bounds().strides() == multi_span_index<1>{2});
-        CHECK((sav2[0] == 1 && sav2[3] == 7));
-
-        strided_span<int, 2> sav3{arr, {{2, 2}, {6, 2}}}; // T -> const T
-        CHECK((sav3.bounds().index_bounds() == multi_span_index<2>{2, 2}));
-        CHECK((sav3.bounds().strides() == multi_span_index<2>{6, 2}));
-        CHECK((sav3[{0, 0}] == 1 && sav3[{0, 1}] == 3 && sav3[{1, 0}] == 7));
-    }
-
-    // Check multi_span constructor
-    {
-        int arr[] = {1, 2};
-
-        // From non-cv-qualified source
-        {
-            const multi_span<int> src = arr;
-
-            strided_span<int, 1> sav{src, {2, 1}};
-            CHECK(sav.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav[1] == 2);
-
-#if defined(_MSC_VER) && _MSC_VER > 1800
-            // strided_span<const int, 1> sav_c{ {src}, {2, 1} };
-            strided_span<const int, 1> sav_c{multi_span<const int>{src},
-                                             strided_bounds<1>{2, 1}};
-#else
-            strided_span<const int, 1> sav_c{multi_span<const int>{src},
-                                             strided_bounds<1>{2, 1}};
-#endif
-            CHECK(sav_c.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_c.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_c[1] == 2);
-
-#if defined(_MSC_VER) && _MSC_VER > 1800
-            strided_span<volatile int, 1> sav_v{src, {2, 1}};
-#else
-            strided_span<volatile int, 1> sav_v{multi_span<volatile int>{src},
-                                                strided_bounds<1>{2, 1}};
-#endif
-            CHECK(sav_v.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_v.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_v[1] == 2);
-
-#if defined(_MSC_VER) && _MSC_VER > 1800
-            strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
-#else
-            strided_span<const volatile int, 1> sav_cv{multi_span<const volatile int>{src},
-                                                       strided_bounds<1>{2, 1}};
-#endif
-            CHECK(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_cv.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_cv[1] == 2);
-        }
-
-        // From const-qualified source
-        {
-            const multi_span<const int> src{arr};
-
-            strided_span<const int, 1> sav_c{src, {2, 1}};
-            CHECK(sav_c.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_c.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_c[1] == 2);
-
-#if defined(_MSC_VER) && _MSC_VER > 1800
-            strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
-#else
-            strided_span<const volatile int, 1> sav_cv{multi_span<const volatile int>{src},
-                                                       strided_bounds<1>{2, 1}};
-#endif
-
-            CHECK(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_cv.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_cv[1] == 2);
-        }
-
-        // From volatile-qualified source
-        {
-            const multi_span<volatile int> src{arr};
-
-            strided_span<volatile int, 1> sav_v{src, {2, 1}};
-            CHECK(sav_v.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_v.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_v[1] == 2);
-
-#if defined(_MSC_VER) && _MSC_VER > 1800
-            strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
-#else
-            strided_span<const volatile int, 1> sav_cv{multi_span<const volatile int>{src},
-                                                       strided_bounds<1>{2, 1}};
-#endif
-            CHECK(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_cv.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_cv[1] == 2);
-        }
-
-        // From cv-qualified source
-        {
-            const multi_span<const volatile int> src{arr};
-
-            strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
-            CHECK(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
-            CHECK(sav_cv.bounds().strides() == multi_span_index<1>{1});
-            CHECK(sav_cv[1] == 2);
-        }
-    }
-
-    // Check const-casting constructor
-    {
-        int arr[2] = {4, 5};
-
-        const multi_span<int, 2> av(arr, 2);
-        multi_span<const int, 2> av2{av};
-        CHECK(av2[1] == 5);
-
-        static_assert(
-            std::is_convertible<const multi_span<int, 2>, multi_span<const int, 2>>::value,
-            "ctor is not implicit!");
-
-        const strided_span<int, 1> src{arr, {2, 1}};
-        strided_span<const int, 1> sav{src};
-        CHECK(sav.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav.bounds().stride() == 1);
-        CHECK(sav[1] == 5);
-
-        static_assert(
-            std::is_convertible<const strided_span<int, 1>, strided_span<const int, 1>>::value,
-            "ctor is not implicit!");
-    }
-
-    // Check copy constructor
-    {
-        int arr1[2] = {3, 4};
-        const strided_span<int, 1> src1{arr1, {2, 1}};
-        strided_span<int, 1> sav1{src1};
-
-        CHECK(sav1.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav1.bounds().stride() == 1);
-        CHECK(sav1[0] == 3);
-
-        int arr2[6] = {1, 2, 3, 4, 5, 6};
-        const strided_span<const int, 2> src2{arr2, {{3, 2}, {2, 1}}};
-        strided_span<const int, 2> sav2{src2};
-        CHECK((sav2.bounds().index_bounds() == multi_span_index<2>{3, 2}));
-        CHECK((sav2.bounds().strides() == multi_span_index<2>{2, 1}));
-        CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-    }
-
-    // Check const-casting assignment operator
-    {
-        int arr1[2] = {1, 2};
-        int arr2[6] = {3, 4, 5, 6, 7, 8};
-
-        const strided_span<int, 1> src{arr1, {{2}, {1}}};
-        strided_span<const int, 1> sav{arr2, {{3}, {2}}};
-        strided_span<const int, 1>& sav_ref = (sav = src);
-        CHECK(sav.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav.bounds().strides() == multi_span_index<1>{1});
-        CHECK(sav[0] == 1);
-        CHECK(&sav_ref == &sav);
-    }
-
-    // Check copy assignment operator
-    {
-        int arr1[2] = {3, 4};
-        int arr1b[1] = {0};
-        const strided_span<int, 1> src1{arr1, {2, 1}};
-        strided_span<int, 1> sav1{arr1b, {1, 1}};
-        strided_span<int, 1>& sav1_ref = (sav1 = src1);
-        CHECK(sav1.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav1.bounds().strides() == multi_span_index<1>{1});
-        CHECK(sav1[0] == 3);
-        CHECK(&sav1_ref == &sav1);
-
-        const int arr2[6] = {1, 2, 3, 4, 5, 6};
-        const int arr2b[1] = {0};
-        const strided_span<const int, 2> src2{arr2, {{3, 2}, {2, 1}}};
-        strided_span<const int, 2> sav2{arr2b, {{1, 1}, {1, 1}}};
-        strided_span<const int, 2>& sav2_ref = (sav2 = src2);
-        CHECK((sav2.bounds().index_bounds() == multi_span_index<2>{3, 2}));
-        CHECK((sav2.bounds().strides() == multi_span_index<2>{2, 1}));
-        CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-        CHECK(&sav2_ref == &sav2);
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_slice")
-{
-    std::vector<int> data(5 * 10);
-    std::iota(begin(data), end(data), 0);
-    const multi_span<int, 5, 10> src =
-        as_multi_span(multi_span<int>{data}, dim<5>(), dim<10>());
-
-    const strided_span<int, 2> sav{src, {{5, 10}, {10, 1}}};
-#ifdef CONFIRM_COMPILATION_ERRORS
-    const strided_span<const int, 2> csav{{src}, {{5, 10}, {10, 1}}};
-#endif
-    const strided_span<const int, 2> csav{multi_span<const int, 5, 10>{src},
-                                          {{5, 10}, {10, 1}}};
-
-    strided_span<int, 1> sav_sl = sav[2];
-    CHECK(sav_sl[0] == 20);
-    CHECK(sav_sl[9] == 29);
-
-    strided_span<const int, 1> csav_sl = sav[3];
-    CHECK(csav_sl[0] == 30);
-    CHECK(csav_sl[9] == 39);
-
-    CHECK(sav[4][0] == 40);
-    CHECK(sav[4][9] == 49);
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_column_major")
-{
-    // strided_span may be used to accommodate more peculiar
-    // use cases, such as column-major multidimensional array
-    // (aka. "FORTRAN" layout).
-
-    int cm_array[3 * 5] = {1, 4, 7, 10, 13, 2, 5, 8, 11, 14, 3, 6, 9, 12, 15};
-    strided_span<int, 2> cm_sav{cm_array, {{5, 3}, {1, 5}}};
-
-    // Accessing elements
-    CHECK((cm_sav[{0, 0}] == 1));
-    CHECK((cm_sav[{0, 1}] == 2));
-    CHECK((cm_sav[{1, 0}] == 4));
-    CHECK((cm_sav[{4, 2}] == 15));
-
-    // Slice
-    strided_span<int, 1> cm_sl = cm_sav[3];
-
-    CHECK(cm_sl[0] == 10);
-    CHECK(cm_sl[1] == 11);
-    CHECK(cm_sl[2] == 12);
-
-    // Section
-    strided_span<int, 2> cm_sec = cm_sav.section({2, 1}, {3, 2});
-
-    CHECK((cm_sec.bounds().index_bounds() == multi_span_index<2>{3, 2}));
-    CHECK((cm_sec[{0, 0}] == 8));
-    CHECK((cm_sec[{0, 1}] == 9));
-    CHECK((cm_sec[{1, 0}] == 11));
-    CHECK((cm_sec[{2, 1}] == 15));
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_bounds")
-{
-    int arr[] = {0, 1, 2, 3};
-    multi_span<int> av(arr);
-
-    {
-        // incorrect sections
-
-        CHECK_THROWS_AS(av.section(0, 0)[0], fail_fast);
-        CHECK_THROWS_AS(av.section(1, 0)[0], fail_fast);
-        CHECK_THROWS_AS(av.section(1, 1)[1], fail_fast);
-
-        CHECK_THROWS_AS(av.section(2, 5), fail_fast);
-        CHECK_THROWS_AS(av.section(5, 2), fail_fast);
-        CHECK_THROWS_AS(av.section(5, 0), fail_fast);
-        CHECK_THROWS_AS(av.section(0, 5), fail_fast);
-        CHECK_THROWS_AS(av.section(5, 5), fail_fast);
-    }
-
-    {
-        // zero stride
-        strided_span<int, 1> sav{av, {{4}, {}}};
-        CHECK(sav[0] == 0);
-        CHECK(sav[3] == 0);
-        CHECK_THROWS_AS(sav[4], fail_fast);
-    }
-
-    {
-        // zero extent
-        strided_span<int, 1> sav{av, {{}, {1}}};
-        CHECK_THROWS_AS(sav[0], fail_fast);
-    }
-
-    {
-        // zero extent and stride
-        strided_span<int, 1> sav{av, {{}, {}}};
-        CHECK_THROWS_AS(sav[0], fail_fast);
-    }
-
-    {
-        // strided array ctor with matching strided bounds
-        strided_span<int, 1> sav{arr, {4, 1}};
-        CHECK(sav.bounds().index_bounds() == multi_span_index<1>{4});
-        CHECK(sav[3] == 3);
-        CHECK_THROWS_AS(sav[4], fail_fast);
-    }
-
-    {
-        // strided array ctor with smaller strided bounds
-        strided_span<int, 1> sav{arr, {2, 1}};
-        CHECK(sav.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav[1] == 1);
-        CHECK_THROWS_AS(sav[2], fail_fast);
-    }
-
-    {
-        // strided array ctor with fitting irregular bounds
-        strided_span<int, 1> sav{arr, {2, 3}};
-        CHECK(sav.bounds().index_bounds() == multi_span_index<1>{2});
-        CHECK(sav[0] == 0);
-        CHECK(sav[1] == 3);
-        CHECK_THROWS_AS(sav[2], fail_fast);
-    }
-
-    {
-        // bounds cross data boundaries - from static arrays
-        CHECK_THROWS_AS((strided_span<int, 1>{arr, {3, 2}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{arr, {3, 3}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{arr, {4, 5}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{arr, {5, 1}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{arr, {5, 5}}), fail_fast);
-    }
-
-    {
-        // bounds cross data boundaries - from array view
-        CHECK_THROWS_AS((strided_span<int, 1>{av, {3, 2}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av, {3, 3}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av, {4, 5}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av, {5, 1}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av, {5, 5}}), fail_fast);
-    }
-
-    {
-        // bounds cross data boundaries - from dynamic arrays
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 4, {3, 2}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 4, {3, 3}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 4, {4, 5}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 4, {5, 1}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 4, {5, 5}}), fail_fast);
-        CHECK_THROWS_AS((strided_span<int, 1>{av.data(), 2, {2, 2}}), fail_fast);
-    }
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-    {
-        strided_span<int, 1> sav0{av.data(), {3, 2}};
-        strided_span<int, 1> sav1{arr, {1}};
-        strided_span<int, 1> sav2{arr, {1, 1, 1}};
-        strided_span<int, 1> sav3{av, {1}};
-        strided_span<int, 1> sav4{av, {1, 1, 1}};
-        strided_span<int, 2> sav5{av.as_multi_span(dim<2>(), dim<2>()), {1}};
-        strided_span<int, 2> sav6{av.as_multi_span(dim<2>(), dim<2>()), {1, 1, 1}};
-        strided_span<int, 2> sav7{av.as_multi_span(dim<2>(), dim<2>()),
-                                  {{1, 1}, {1, 1}, {1, 1}}};
-
-        multi_span_index<1> index{0, 1};
-        strided_span<int, 1> sav8{arr, {1, {1, 1}}};
-        strided_span<int, 1> sav9{arr, {{1, 1}, {1, 1}}};
-        strided_span<int, 1> sav10{av, {1, {1, 1}}};
-        strided_span<int, 1> sav11{av, {{1, 1}, {1, 1}}};
-        strided_span<int, 2> sav12{av.as_multi_span(dim<2>(), dim<2>()), {{1}, {1}}};
-        strided_span<int, 2> sav13{av.as_multi_span(dim<2>(), dim<2>()), {{1}, {1, 1, 1}}};
-        strided_span<int, 2> sav14{av.as_multi_span(dim<2>(), dim<2>()), {{1, 1, 1}, {1}}};
-    }
-#endif
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_type_conversion")
-{
-    int arr[] = {0, 1, 2, 3};
-    multi_span<int> av(arr);
-
-    {
-        strided_span<int, 1> sav{av.data(), av.size(), {av.size() / 2, 2}};
-#ifdef CONFIRM_COMPILATION_ERRORS
-        strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
-#endif
-    }
-    {
-        strided_span<int, 1> sav{av, {av.size() / 2, 2}};
-#ifdef CONFIRM_COMPILATION_ERRORS
-        strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
-#endif
-    }
-
-    multi_span<const byte, dynamic_range> bytes = as_bytes(av);
-
-    // retype strided array with regular strides - from raw data
-    {
-        strided_bounds<2> bounds{{2, bytes.size() / 4}, {bytes.size() / 2, 1}};
-        strided_span<const byte, 2> sav2{bytes.data(), bytes.size(), bounds};
-        strided_span<const int, 2> sav3 = sav2.as_strided_span<const int>();
-        CHECK(sav3[0][0] == 0);
-        CHECK(sav3[1][0] == 2);
-        CHECK_THROWS_AS(sav3[1][1], fail_fast);
-        CHECK_THROWS_AS(sav3[0][1], fail_fast);
-    }
-
-    // retype strided array with regular strides - from multi_span
-    {
-        strided_bounds<2> bounds{{2, bytes.size() / 4}, {bytes.size() / 2, 1}};
-        multi_span<const byte, 2, dynamic_range> bytes2 =
-            as_multi_span(bytes, dim<2>(), dim(bytes.size() / 2));
-        strided_span<const byte, 2> sav2{bytes2, bounds};
-        strided_span<int, 2> sav3 = sav2.as_strided_span<int>();
-        CHECK(sav3[0][0] == 0);
-        CHECK(sav3[1][0] == 2);
-        CHECK_THROWS_AS(sav3[1][1], fail_fast);
-        CHECK_THROWS_AS(sav3[0][1], fail_fast);
-    }
-
-    // retype strided array with not enough elements - last dimension of the array is too small
-    {
-        strided_bounds<2> bounds{{4, 2}, {4, 1}};
-        multi_span<const byte, 2, dynamic_range> bytes2 =
-            as_multi_span(bytes, dim<2>(), dim(bytes.size() / 2));
-        strided_span<const byte, 2> sav2{bytes2, bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-
-    // retype strided array with not enough elements - strides are too small
-    {
-        strided_bounds<2> bounds{{4, 2}, {2, 1}};
-        multi_span<const byte, 2, dynamic_range> bytes2 =
-            as_multi_span(bytes, dim<2>(), dim(bytes.size() / 2));
-        strided_span<const byte, 2> sav2{bytes2, bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-
-    // retype strided array with not enough elements - last dimension does not divide by the new
-    // typesize
-    {
-        strided_bounds<2> bounds{{2, 6}, {4, 1}};
-        multi_span<const byte, 2, dynamic_range> bytes2 =
-            as_multi_span(bytes, dim<2>(), dim(bytes.size() / 2));
-        strided_span<const byte, 2> sav2{bytes2, bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-
-    // retype strided array with not enough elements - strides does not divide by the new
-    // typesize
-    {
-        strided_bounds<2> bounds{{2, 1}, {6, 1}};
-        multi_span<const byte, 2, dynamic_range> bytes2 =
-            as_multi_span(bytes, dim<2>(), dim(bytes.size() / 2));
-        strided_span<const byte, 2> sav2{bytes2, bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-
-    // retype strided array with irregular strides - from raw data
-    {
-        strided_bounds<1> bounds{bytes.size() / 2, 2};
-        strided_span<const byte, 1> sav2{bytes.data(), bytes.size(), bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-
-    // retype strided array with irregular strides - from multi_span
-    {
-        strided_bounds<1> bounds{bytes.size() / 2, 2};
-        strided_span<const byte, 1> sav2{bytes, bounds};
-        CHECK_THROWS_AS(sav2.as_strided_span<int>(), fail_fast);
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-TEST_CASE("empty_strided_spans")
-{
-    {
-        multi_span<int, 0> empty_av(nullptr);
-        strided_span<int, 1> empty_sav{empty_av, {0, 1}};
-
-        CHECK(empty_sav.bounds().index_bounds() == multi_span_index<1>{0});
-        CHECK(empty_sav.empty());
-        CHECK_THROWS_AS(empty_sav[0], fail_fast);
-        CHECK_THROWS_AS(empty_sav.begin()[0], fail_fast);
-        CHECK_THROWS_AS(empty_sav.cbegin()[0], fail_fast);
-
-        for (const auto& v : empty_sav) {
-            (void) v;
-            CHECK(false);
-        }
-    }
-
-    {
-        strided_span<int, 1> empty_sav{nullptr, 0, {0, 1}};
-
-        CHECK(empty_sav.bounds().index_bounds() == multi_span_index<1>{0});
-        CHECK_THROWS_AS(empty_sav[0], fail_fast);
-        CHECK_THROWS_AS(empty_sav.begin()[0], fail_fast);
-        CHECK_THROWS_AS(empty_sav.cbegin()[0], fail_fast);
-
-        for (const auto& v : empty_sav) {
-            (void) v;
-            CHECK(false);
-        }
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-void iterate_every_other_element(multi_span<int, dynamic_range> av)
-{
-    // pick every other element
-
-    auto length = av.size() / 2;
-#if defined(_MSC_VER) && _MSC_VER > 1800
-    auto bounds = strided_bounds<1>({length}, {2});
-#else
-    auto bounds = strided_bounds<1>(multi_span_index<1>{length}, multi_span_index<1>{2});
-#endif
-    strided_span<int, 1> strided(&av.data()[1], av.size() - 1, bounds);
-
-    CHECK(strided.size() == length);
-    CHECK(strided.bounds().index_bounds()[0] == length);
-    for (auto i = 0; i < strided.size(); ++i) {
-        CHECK(strided[i] == av[2 * i + 1]);
-    }
-
-    int idx = 0;
-    for (auto num : strided) {
-        CHECK(num == av[2 * idx + 1]);
-        idx++;
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_section_iteration")
-{
-    int arr[8] = {4, 0, 5, 1, 6, 2, 7, 3};
-
-    // static bounds
-    {
-        multi_span<int, 8> av(arr, 8);
-        iterate_every_other_element(av);
-    }
-
-    // dynamic bounds
-    {
-        multi_span<int, dynamic_range> av(arr, 8);
-        iterate_every_other_element(av);
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.11) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.3) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.5) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-TEST_CASE("dynamic_strided_span_section_iteration")
-{
-    auto arr = new int[8];
-    for (int i = 0; i < 4; ++i) {
-        arr[2 * i] = 4 + i;
-        arr[2 * i + 1] = i;
-    }
-
-    auto av = as_multi_span(arr, 8);
-    iterate_every_other_element(av);
-
-    delete[] arr;
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute // TODO: does not work
-void iterate_second_slice(multi_span<int, dynamic_range, dynamic_range, dynamic_range> av)
-{
-    const int expected[6] = {2, 3, 10, 11, 18, 19};
-    auto section = av.section({0, 1, 0}, {3, 1, 2});
-
-    for (auto i = 0; i < section.extent<0>(); ++i) {
-        for (auto j = 0; j < section.extent<1>(); ++j)
-            for (auto k = 0; k < section.extent<2>(); ++k) {
-                auto idx = multi_span_index<3>{i, j, k}; // avoid braces in the CHECK macro
-                CHECK(section[idx] == expected[2 * i + 2 * j + k]);
-            }
-    }
-
-    for (auto i = 0; i < section.extent<0>(); ++i) {
-        for (auto j = 0; j < section.extent<1>(); ++j)
-            for (auto k = 0; k < section.extent<2>(); ++k)
-                CHECK(section[i][j][k] == expected[2 * i + 2 * j + k]);
-    }
-
-    int i = 0;
-    for (const auto num : section) {
-        CHECK(num == expected[i]);
-        i++;
-    }
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("strided_span_section_iteration_3d")
-{
-    int arr[3][4][2]{};
-    for (auto i = 0; i < 3; ++i) {
-        for (auto j = 0; j < 4; ++j)
-            for (auto k = 0; k < 2; ++k) arr[i][j][k] = 8 * i + 2 * j + k;
-    }
-
-    {
-        multi_span<int, 3, 4, 2> av = arr;
-        iterate_second_slice(av);
-    }
-}
-
-GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.3) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.5) // NO-FORMAT: attribute
-GSL_SUPPRESS(r.11) // NO-FORMAT: attribute
-TEST_CASE("dynamic_strided_span_section_iteration_3d")
-{
-    const auto height = 12, width = 2;
-    const auto size = height * width;
-
-    auto arr = new int[static_cast<std::size_t>(size)];
-    for (auto i = 0; i < size; ++i) {
-        arr[i] = i;
-    }
-
-    {
-        auto av = as_multi_span(as_multi_span(arr, 24), dim<3>(), dim<4>(), dim<2>());
-        iterate_second_slice(av);
-    }
-
-    {
-        auto av = as_multi_span(as_multi_span(arr, 24), dim(3), dim<4>(), dim<2>());
-        iterate_second_slice(av);
-    }
-
-    {
-        auto av = as_multi_span(as_multi_span(arr, 24), dim<3>(), dim(4), dim<2>());
-        iterate_second_slice(av);
-    }
-
-    {
-        auto av = as_multi_span(as_multi_span(arr, 24), dim<3>(), dim<4>(), dim(2));
-        iterate_second_slice(av);
-    }
-    delete[] arr;
-}
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
-TEST_CASE("strided_span_conversion")
-{
-    // get an multi_span of 'c' values from the list of X's
-
-    struct X
-    {
-        int a;
-        int b;
-        int c;
-    };
-
-    X arr[4] = {{0, 1, 2}, {3, 4, 5}, {6, 7, 8}, {9, 10, 11}};
-
-    int s = sizeof(int) / sizeof(byte);
-    auto d2 = 3 * s;
-    auto d1 = narrow_cast<int>(sizeof(int)) * 12 / d2;
-
-    // convert to 4x12 array of bytes
-    auto av = as_multi_span(as_bytes(as_multi_span(&arr[0], 4)), dim(d1), dim(d2));
-
-    CHECK(av.bounds().index_bounds()[0] == 4);
-    CHECK(av.bounds().index_bounds()[1] == 12);
-
-    // get the last 4 columns
-    auto section = av.section({0, 2 * s}, {4, s}); // { { arr[0].c[0], arr[0].c[1], arr[0].c[2],
-                                                   // arr[0].c[3] } , { arr[1].c[0], ... } , ...
-                                                   // }
-
-    // convert to array 4x1 array of integers
-    auto cs = section.as_strided_span<int>(); // { { arr[0].c }, {arr[1].c } , ... }
-
-    CHECK(cs.bounds().index_bounds()[0] == 4);
-    CHECK(cs.bounds().index_bounds()[1] == 1);
-
-    // transpose to 1x4 array
-    strided_bounds<2> reverse_bounds{
-        {cs.bounds().index_bounds()[1], cs.bounds().index_bounds()[0]},
-        {cs.bounds().strides()[1], cs.bounds().strides()[0]}};
-
-    strided_span<int, 2> transposed{cs.data(), cs.bounds().total_size(), reverse_bounds};
-
-    // slice to get a one-dimensional array of c's
-    strided_span<int, 1> result = transposed[0];
-
-    CHECK(result.bounds().index_bounds()[0] == 4);
-    CHECK_THROWS_AS(result.bounds().index_bounds()[1], fail_fast);
-
-    int i = 0;
-    for (auto& num : result) {
-        CHECK(num == arr[i].c);
-        i++;
-    }
-}
-
-#if __clang__ || __GNUC__
-#pragma GCC diagnostic pop
-#endif

tests/test.cpp

@@ -1,27 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#define CATCH_CONFIG_MAIN
-
-#ifdef _MSC_VER
-
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#include <CodeAnalysis/Warnings.h>
-#pragma warning(disable : ALL_CODE_ANALYSIS_WARNINGS) // from catch
-#endif // _MSC_VER
-
-#include <catch/catch.hpp>

tests/utils_tests.cpp

@@ -14,120 +14,142 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef _MSC_VER
-// blanket turn off warnings from CppCoreCheck from catch
-// so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
-
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
-
-#include <gsl/gsl_util> // for narrow, finally, narrow_cast, narrowing_e...
+#include <gtest/gtest.h>
 
 #include <algorithm>   // for move
+#include <complex>
+#include <cstddef>     // for std::ptrdiff_t
 #include <functional>  // for reference_wrapper, _Bind_helper<>::type
+#include <gsl/narrow>  // for narrow, narrowing_error
+#include <gsl/util>    // finally, narrow_cast
 #include <limits>      // for numeric_limits
 #include <stdint.h>    // for uint32_t, int32_t
 #include <type_traits> // for is_same
 
 using namespace gsl;
 
-TEST_CASE("sanity check for gsl::index typedef")
+namespace
+{
+void f(int& i) { i += 1; }
+static int j = 0;
+void g() { j += 1; }
+} // namespace
+
+TEST(utils_tests, sanity_check_for_gsl_index_typedef)
 {
     static_assert(std::is_same<gsl::index, std::ptrdiff_t>::value,
                   "gsl::index represents wrong arithmetic type");
 }
 
-void f(int& i) { i += 1; }
-
-TEST_CASE("finally_lambda")
+TEST(utils_tests, finally_lambda)
 {
     int i = 0;
     {
         auto _ = finally([&]() { f(i); });
-        CHECK(i == 0);
+        EXPECT_TRUE(i == 0);
     }
-    CHECK(i == 1);
+    EXPECT_TRUE(i == 1);
 }
 
-TEST_CASE("finally_lambda_move")
+TEST(utils_tests, finally_lambda_move)
 {
     int i = 0;
     {
         auto _1 = finally([&]() { f(i); });
         {
             auto _2 = std::move(_1);
-            CHECK(i == 0);
+            EXPECT_TRUE(i == 0);
         }
-        CHECK(i == 1);
+        EXPECT_TRUE(i == 1);
         {
             auto _2 = std::move(_1);
-            CHECK(i == 1);
+            EXPECT_TRUE(i == 1);
         }
-        CHECK(i == 1);
+        EXPECT_TRUE(i == 1);
     }
-    CHECK(i == 1);
+    EXPECT_TRUE(i == 1);
 }
 
-TEST_CASE("finally_function_with_bind")
+TEST(utils_tests, finally_const_lvalue_lambda)
+{
+    int i = 0;
+    {
+        const auto const_lvalue_lambda = [&]() { f(i); };
+        auto _ = finally(const_lvalue_lambda);
+        EXPECT_TRUE(i == 0);
+    }
+    EXPECT_TRUE(i == 1);
+}
+
+TEST(utils_tests, finally_mutable_lvalue_lambda)
+{
+    int i = 0;
+    {
+        auto mutable_lvalue_lambda = [&]() { f(i); };
+        auto _ = finally(mutable_lvalue_lambda);
+        EXPECT_TRUE(i == 0);
+    }
+    EXPECT_TRUE(i == 1);
+}
+
+TEST(utils_tests, finally_function_with_bind)
 {
     int i = 0;
     {
         auto _ = finally(std::bind(&f, std::ref(i)));
-        CHECK(i == 0);
+        EXPECT_TRUE(i == 0);
     }
-    CHECK(i == 1);
+    EXPECT_TRUE(i == 1);
 }
 
-static int j = 0;
-void g() { j += 1; }
-TEST_CASE("finally_function_ptr")
+TEST(utils_tests, finally_function_ptr)
 {
     j = 0;
     {
         auto _ = finally(&g);
-        CHECK(j == 0);
+        EXPECT_TRUE(j == 0);
     }
-    CHECK(j == 1);
+    EXPECT_TRUE(j == 1);
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("narrow_cast")
+TEST(utils_tests, narrow_cast)
 {
     int n = 120;
     char c = narrow_cast<char>(n);
-    CHECK(c == 120);
+    EXPECT_TRUE(c == 120);
 
     n = 300;
     unsigned char uc = narrow_cast<unsigned char>(n);
-    CHECK(uc == 44);
+    EXPECT_TRUE(uc == 44);
 }
 
-GSL_SUPPRESS(con.5) // NO-FORMAT: attribute
-TEST_CASE("narrow")
+#ifndef GSL_KERNEL_MODE
+TEST(utils_tests, narrow)
 {
     int n = 120;
     const char c = narrow<char>(n);
-    CHECK(c == 120);
+    EXPECT_TRUE(c == 120);
 
     n = 300;
-    CHECK_THROWS_AS(narrow<char>(n), narrowing_error);
+    EXPECT_THROW(narrow<char>(n), narrowing_error);
 
     const auto int32_max = std::numeric_limits<int32_t>::max();
     const auto int32_min = std::numeric_limits<int32_t>::min();
 
-    CHECK(narrow<uint32_t>(int32_t(0)) == 0);
-    CHECK(narrow<uint32_t>(int32_t(1)) == 1);
-    CHECK(narrow<uint32_t>(int32_max) == static_cast<uint32_t>(int32_max));
+    EXPECT_TRUE(narrow<uint32_t>(int32_t(0)) == 0);
+    EXPECT_TRUE(narrow<uint32_t>(int32_t(1)) == 1);
+    EXPECT_TRUE(narrow<uint32_t>(int32_max) == static_cast<uint32_t>(int32_max));
 
-    CHECK_THROWS_AS(narrow<uint32_t>(int32_t(-1)), narrowing_error);
-    CHECK_THROWS_AS(narrow<uint32_t>(int32_min), narrowing_error);
+    EXPECT_THROW(narrow<uint32_t>(int32_t(-1)), narrowing_error);
+    EXPECT_THROW(narrow<uint32_t>(int32_min), narrowing_error);
 
     n = -42;
-    CHECK_THROWS_AS(narrow<unsigned>(n), narrowing_error);
+    EXPECT_THROW(narrow<unsigned>(n), narrowing_error);
 
-#if GSL_CONSTEXPR_NARROW
-    static_assert(narrow<char>(120) == 120, "Fix GSL_CONSTEXPR_NARROW");
-#endif
+    EXPECT_TRUE(
+        narrow<std::complex<float>>(std::complex<double>(4, 2)) == std::complex<float>(4, 2));
+    EXPECT_THROW(narrow<std::complex<float>>(std::complex<double>(4.2)), narrowing_error);
+
+    EXPECT_TRUE(narrow<int>(float(1)) == 1);
 }
+#endif // GSL_KERNEL_MODE