Merge pull request #861 from JordanMaples/dev/jomaples/lwg3320

implement LWG3320

.travis.yml

@@ -1,268 +1,519 @@
-# 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
+dist: bionic
 
 cache:
   directories:
     - ${TRAVIS_BUILD_DIR}/deps
 
-matrix:
+stages:
+  - name: Latest     # build jobs to run first and always
+  - name: Validation # run other jobs
+  - name: Legacy     # build with all other supported compilers
+
+jobs:
   include:
 
     ##########################################################################
-    # Clang on OSX
-    # Travis seems to take longer to start OSX instances,
-    # so leave this first for the overall build to be faster
+    # Validate CMake configuration
     ##########################################################################
 
-    # XCode 8.3
-    - env: COMPILER=clang++ BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: CMake 3.1.3 - latest
+      stage: Validation
+      env: &CMAKE_VERSION_LIST
+      - CMAKE_VERSION: '"3.17.0 3.16.5 3.15.7 3.14.7 3.13.5 3.12.4 3.11.4 3.10.3 3.9.6 3.8.2 3.7.2 3.6.3 3.5.2 3.4.3 3.3.2 3.2.3 3.1.3"'
+      - GSL_CXX_STANDARD: 14
+      addons: # Get latest release (candidate)
+        apt:
+          sources:
+          - sourceline: 'deb https://apt.kitware.com/ubuntu/ bionic main'
+            key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
+          - sourceline: 'deb https://apt.kitware.com/ubuntu/ bionic-rc main'
+          packages:
+          - cmake
+      script:
+      - |
+        cd ./build
+        ( set -eu
+          for CMAKE in ${CMAKE_path[@]}; do test_CMake_generate $CMAKE; done
+          export CXX=clang++
+          for CMAKE in ${CMAKE_path[@]}; do test_CMake_generate $CMAKE; done
+        )
+
+    - name: CMake 3.2.3 - 3.17.0
+      stage: Validation
+      os: osx
+      osx_image: xcode11.3
+      env:
+      - CMAKE_VERSION: '"3.17.0 3.16.5 3.15.7 3.14.7 3.13.5 3.12.4 3.11.4 3.10.3 3.9.6 3.8.2 3.7.2 3.6.3 3.5.2 3.4.3 3.3.2 3.2.3"'
+      script:
+      - |
+        cd ./build
+        ( set -eu
+          for CMAKE in ${CMAKE_path[@]}; do test_CMake_generate $CMAKE; done
+        )
+
+    ##########################################################################
+    # AppleClang on OSX
+    ##########################################################################
+
+    # Xcode 8.3
+    - name: AppleClang Xcode-8.3 C++14 Debug
+      stage: Legacy
+      env: 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
+    - name: AppleClang Xcode-8.3 C++14 Release
+      env: 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
+    # Xcode 9.0 earliest C++17 support
+    - name: AppleClang Xcode-9.0 C++17 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=17
       os: osx
-      osx_image: xcode9.1
-      compiler: clang
+      osx_image: xcode9 # AppleClang 9.1.0 same compiler in Xcode 9.0, 9.1 and 9.2
+    - name: AppleClang Xcode-9.0 C++17 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode9
+    - name: AppleClang Xcode-9.0 C++14 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode9
+    - name: AppleClang Xcode-9.0 C++14 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode9
 
-    - env: COMPILER=clang++ BUILD_TYPE=Release GSL_CXX_STANDARD=14
+    # Xcode 9.4
+    - name: AppleClang Xcode-9.4 C++14 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=14
       os: osx
-      osx_image: xcode9.1
-      compiler: clang
+      osx_image: xcode9.4 # AppleClang 9.1.0 same compiler as Xcode 9.3
+    - name: AppleClang Xcode-9.4 C++14 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode9.4
+    - name: AppleClang Xcode-9.4 C++17 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode9.4
+    - name: AppleClang Xcode-9.4 C++17 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode9.4
+
+    # Xcode 10.1
+    - name: AppleClang Xcode-10.1 C++14 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode10.1 # AppleClang 10.0.0 same compiler as Xcode 10.0
+    - name: AppleClang Xcode-10.1 C++14 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode10.1
+    - name: AppleClang Xcode-10.1 C++17 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode10.1
+    - name: AppleClang Xcode-10.1 C++17 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode10.1
+
+    # Xcode 10.3
+    - name: AppleClang Xcode-10.3 C++14 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode10.3 # AppleClang 10.0.1 same compiler as Xcode 10.2
+    - name: AppleClang Xcode-10.3 C++14 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode10.3
+    - name: AppleClang Xcode-10.3 C++17 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode10.3
+    - name: AppleClang Xcode-10.3 C++17 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode10.3
+
+    # Xcode 11.3
+    - name: AppleClang Xcode-11.3 C++17 Debug
+      stage: Latest
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode11.3 # AppleClang 11.0.0 linker update / same as Xcode 11.2
+    - name: AppleClang Xcode-11.3 C++17 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      os: osx
+      osx_image: xcode11.3
+    - name: AppleClang Xcode-11.3 C++14 Debug
+      env: BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode11.3
+    - name: AppleClang Xcode-11.3 C++14 Release
+      env: BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      os: osx
+      osx_image: xcode11.3
 
     ##########################################################################
     # Clang on Linux
     ##########################################################################
 
     # Clang 3.6
-    - env: COMPILER=clang++-3.6 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: Clang-3.6 C++14 Debug
+      stage: Legacy
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.6 C++14 Release
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.7 C++14 Debug
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.7 C++14 Release
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.8 C++14 Debug
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.8 C++14 Release
+      dist: xenial
+      env: CXX=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
+    - name: Clang-3.9 C++14 Debug
+      env: CXX=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
+    - name: Clang-3.9 C++14 Release
+      env: CXX=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
+    - name: Clang-4.0 C++14 Debug
+      env: CXX=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
+    - name: Clang-4.0 C++14 Release
+      env: CXX=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
+    - name: Clang-5.0 C++14 Debug
+      env: CXX=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
+    - name: Clang-5.0 C++14 Release
+      env: CXX=clang++-5.0 BUILD_TYPE=Release GSL_CXX_STANDARD=14
       addons: *clang50
-
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+    - name: Clang-5.0 C++17 Debug
+      env: CXX=clang++-5.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
       addons: *clang50
-
-    - env: COMPILER=clang++-5.0 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+    - name: Clang 5.0 C++17 Release
+      env: CXX=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
+    - name: Clang-6.0 C++14 Debug
+      env: CXX=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
+    - name: Clang 6.0 C++14 Release
+      env: CXX=clang++-6.0 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *clang60
+    - name: Clang-6.0 C++17 Debug
+      env: CXX=clang++-6.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *clang60
+    - name: Clang 6.0 C++17 Release
+      env: CXX=clang++-6.0 BUILD_TYPE=Release GSL_CXX_STANDARD=17
       addons: *clang60
 
-    # Clang 6.0 c++17
-    - env: COMPILER=clang++-6.0 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
-      addons: *clang60
+    # Clang 7 (default on Xenial and Bionic images)
+    - name: Clang-7 C++14 Debug
+      env: CXX=clang++ BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: Clang-7 C++14 Release
+      env: CXX=clang++ BUILD_TYPE=Release GSL_CXX_STANDARD=14
+    - name: Clang-7 C++17 Debug
+      env: CXX=clang++ BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+    - name: Clang-7 C++17 Release
+      env: CXX=clang++ BUILD_TYPE=Release GSL_CXX_STANDARD=17
 
-    - 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
+    # Clang 8
+    - name: Clang-8 C++14 Debug
+      env: CXX=clang++-8 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      addons: &clang8
         apt:
-          packages:
-            - clang-7
-            - g++-7
           sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-7
+          - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-8 main'
+            key_url: https://apt.llvm.org/llvm-snapshot.gpg.key
+          packages:
+          - clang-8
+    - name: Clang-8 C++14 Release
+      env: CXX=clang++-8 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *clang8
+    - name: Clang-8 C++17 Debug
+      env: CXX=clang++-8 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *clang8
+    - name: Clang-8 C++17 Release
+      env: CXX=clang++-8 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      addons: *clang8
 
+    # Clang 9
+    - name: Clang-9 C++14 Debug
+      env: CXX=clang++-9 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      addons: &clang9
+        apt:
+          sources:
+          - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main'
+            key_url: https://apt.llvm.org/llvm-snapshot.gpg.key
+          packages:
+          - clang-9
+    - name: Clang-9 C++14 Release
+      env: CXX=clang++-9 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *clang9
+    - name: Clang-9 C++17 Debug
+      env: CXX=clang++-9 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *clang9
+    - name: Clang-9 C++17 Release
+      env: CXX=clang++-9 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      addons: *clang9
 
-    - 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
+    # Clang 10
+    - name: Clang-10 C++14 Debug
+      stage: Latest
+      env: CXX=clang++-10 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      addons: &clang10
+        apt:
+          sources:
+          - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main'
+            key_url: https://apt.llvm.org/llvm-snapshot.gpg.key
+          packages:
+          - clang-10
+    - name: Clang-10 C++14 Release
+      env: CXX=clang++-10 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *clang10
+    - name: Clang-10 C++17 Debug
+      env: CXX=clang++-10 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *clang10
+    - name: Clang-10 C++17 Release
+      env: CXX=clang++-10 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      addons: *clang10
 
     ##########################################################################
     # 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 5 (default on the Xenial image)
+    - name: GCC-5 C++14 Debug
+      stage: Legacy
+      dist: xenial
+      env: CXX=g++-5 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: GCC-5 C++14 Release
+      dist: xenial
+      env: CXX=g++-5 BUILD_TYPE=Release GSL_CXX_STANDARD=14
 
     # GCC 6
-    - env: COMPILER=g++-6 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: GCC-6 C++14 Debug
+      env: CXX=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
+    - name: GCC-6 C++14 Release
+      env: CXX=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
+    # GCC 7 (default on the Bionic image)
+    - name: GCC-7 C++14 Debug
+      env: CXX=g++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+    - name: GCC-7 C++14 Release
+      env: CXX=g++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+    - name: GCC-7 C++17 Debug
+      env: CXX=g++-7 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+    - name: GCC-7 C++17 Release
+      env: CXX=g++-7 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+
+    # GCC 8
+    - name: GCC-8 C++14 Debug
+      env: CXX=g++-8 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      addons: &gcc8
+        apt:
+          packages: g++-8
+    - name: GCC-8 C++14 Release
+      env: CXX=g++-8 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *gcc8
+    - name: GCC-8 C++17 Debug
+      env: CXX=g++-8 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *gcc8
+    - name: GCC-8 C++17 Release
+      env: CXX=g++-8 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      addons: *gcc8
+
+    # GCC 9
+    - name: GCC-9 C++14 Debug
+      stage: Latest
+      env: CXX=g++-9 BUILD_TYPE=Debug GSL_CXX_STANDARD=14
+      addons: &gcc9
         apt:
-          packages: g++-7
           sources:
-            - ubuntu-toolchain-r-test
+          - sourceline: ppa:ubuntu-toolchain-r/test
+          packages:
+          - g++-9
+    - name: GCC-9 C++14 Release
+      env: CXX=g++-9 BUILD_TYPE=Release GSL_CXX_STANDARD=14
+      addons: *gcc9
+    - name: GCC-9 C++17 Debug
+      env: CXX=g++-9 BUILD_TYPE=Debug GSL_CXX_STANDARD=17
+      addons: *gcc9
+    - name: GCC-9 C++17 Release
+      env: CXX=g++-9 BUILD_TYPE=Release GSL_CXX_STANDARD=17
+      addons: *gcc9
 
-    - 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
+before_install:
+  - |
+    # Configuration
+    JOBS=2 # Travis machines have 2 cores
+    # Dependencies required by the CI (cached directory)
+    DEPS_DIR="${TRAVIS_BUILD_DIR}/deps"
+  - |
+    # Setup
+    mkdir -p "${DEPS_DIR:?}" && cd "${DEPS_DIR:?}"
+    mkdir -p ~/tools && cd ~/tools
+    if [[ ${TRAVIS_OS_NAME:?} == "osx" ]]; then
+      export PATH="/usr/local/opt/coreutils/libexec/gnubin:$PATH"
+    fi
+  - |
+    # Helper functions
+    # usage: if [[ $(check_url '<url>') ]]; then ...
+    function check_url {( set +e
+      if [[ "$1" =~ 'github.com' ]]; then # check for first byte
+        if curl --fail --silent --output /dev/null --connect-timeout 12 --range 0-0 "$1"
+        then echo true; fi
+      else # request head
+        if curl --fail --silent --output /dev/null --connect-timeout 12 --head "$1"
+        then echo true; fi
+      fi
+      return
+    )}
 
 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)
+  # Install a different CMake version (or several)
   ############################################################################
-  - 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
+    # Install CMake versions
+    ( set -euo pipefail
+      if [[ ${CMAKE_VERSION:-} ]]; then
+        if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then
+          OS="Linux"; EXT="sh"
+          if [[ ! ("${CMAKE_VERSION:-}" =~ .+[' '].+) ]]; then
+            # Single entry -> default CMake version
+            CMAKE_DEFAULT_DIR="/usr/local"
+          fi
+        elif [[ "${TRAVIS_OS_NAME}" == "osx" ]]; then OS="Darwin"; EXT="tar.gz"
+        else echo "CMake install not supported for this OS."; exit 1
+        fi
+        CMAKE_INSTALLER="install-cmake.${EXT}"
+      fi
+      for VERSION in ${CMAKE_VERSION:-}; do
+        CMAKE_URL="https://github.com/Kitware/CMake/releases/download/v${VERSION}/cmake-${VERSION}-${OS}-x86_64.${EXT}"
+        if [[ $(check_url "$CMAKE_URL") ]]; then
+          curl -sSL ${CMAKE_URL} -o ${CMAKE_INSTALLER}
+          CMAKE_DIR="${CMAKE_DEFAULT_DIR:-"${HOME}/tools/cmake-${VERSION}"}"
+          mkdir -p ${CMAKE_DIR}
+          if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then
+            chmod +x ${CMAKE_INSTALLER}
+            sudo ./${CMAKE_INSTALLER} --prefix=${CMAKE_DIR} --skip-license
+          else # OSX
+            mkdir -p ./CMake_tmp
+            tar --extract --gzip --file=${CMAKE_INSTALLER} --directory=./CMake_tmp
+            mv ./CMake_tmp/*/CMake.app/Contents/* ${CMAKE_DIR}
+          fi
+          rm --recursive --force ./CMake_tmp ${CMAKE_INSTALLER}
+        else echo 'Invalid url!'; echo "Version: ${VERSION}"
+        fi
+      done
+    )
+    if [[ ${CMAKE_VERSION:-} && "${TRAVIS_OS_NAME:?}" == "osx" && ! ("${CMAKE_VERSION:-}" =~ .+[' '].+) ]]
+    then # Single entry -> default CMake version
+      export PATH=${HOME}/tools/cmake-${CMAKE_VERSION:?}/bin:$PATH
+    fi
+    CMAKE_path=("cmake") # start with installed CMake version
+    for VERSION in ${CMAKE_VERSION:-}; do
+      tmp_path="$HOME/tools/cmake-${VERSION:?}/bin/cmake"
+      if [[ -x "$(command -v ${tmp_path:?})" ]]; then CMAKE_path+=("${tmp_path:?}"); fi
+    done
+    function test_CMake_generate {
+      # $1: cmake or full path to cmake
+      shopt -s extglob
+      if [[ "$1" == "cmake" || -x "$(command -v $1)" && "$1" =~ .*cmake$ ]]; then
+        echo "----------------"
+        $1 --version
+        echo "Configuration = ${BUILD_TYPE:-Debug}"
+        $1 -DCMAKE_BUILD_TYPE=${BUILD_TYPE:-Debug} ${CMAKE_GEN_FLAGS[@]:?} ..
+        rm -rf !(tests/googletest-*)
+        if [[ ! ${BUILD_TYPE:-} ]]; then echo "" && echo "Configuration = Release"
+          $1 -DCMAKE_BUILD_TYPE=Release ${CMAKE_GEN_FLAGS[@]:?} ..
+          rm -rf !(tests/googletest-*)
+        fi
+      else echo "Non existing command: $1"
+      fi
+    }
+  - |
+    # CMake wrapper (Trusty, Xenial & Bionic); restore default behaviour.
+    if [[ "${TRAVIS_OS_NAME:?}" == "linux" &&
+          "$(lsb_release --codename)" =~ (trusty|xenial|bionic)$ ]]
+    then
+      if [[ -x $(command -v /usr/local/bin/cmake) ]]; then
+        function cmake { command /usr/local/bin/cmake $@; }
+      elif [[ -x $(command -v /usr/bin/cmake) ]]; then
+        function cmake { command /usr/bin/cmake $@; }
+      fi
     fi
-  - cmake --version
 
   ############################################################################
   # [linux]: Install the right version of libc++
+  # Based on https://github.com/ldionne/hana/blob/master/.travis.yml
   ############################################################################
   - |
-    LLVM_INSTALL=${DEPS_DIR}/llvm/install
+    LLVM_INSTALL=${DEPS_DIR:?}/llvm/install
     # if in linux and compiler clang and llvm not installed
-    if [[ "${TRAVIS_OS_NAME}" == "linux" && "${CXX%%+*}" == "clang" && -n "$(ls -A ${LLVM_INSTALL})" ]]; then
+    if [[ "${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";
@@ -284,12 +535,17 @@ install:
     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=$GSL_CXX_STANDARD
-  
+  - |
+    cd "${TRAVIS_BUILD_DIR:?}"
+    mkdir build && cd build
+    if [[ ${GSL_CXX_STANDARD:-} ]]; then 
+      CMAKE_GEN_FLAGS=("-DGSL_CXX_STANDARD=$GSL_CXX_STANDARD")
+    fi
+    CMAKE_GEN_FLAGS+=("-Wdev -Werror=dev --warn-uninitialized")
+
 script:
+  # generate build files
+  - cmake .. -DCMAKE_BUILD_TYPE=${BUILD_TYPE:?} ${CMAKE_GEN_FLAGS[@]:?}
   # build and run tests
   - cmake --build . -- -j${JOBS}
   - ctest --output-on-failure -j${JOBS}

CMakeLists.txt

@@ -1,10 +1,13 @@
-cmake_minimum_required(VERSION 3.1.3)
+cmake_minimum_required(VERSION 3.1.3...3.16)
 
 project(GSL CXX)
 
 include(ExternalProject)
 find_package(Git)
 
+# Use GNUInstallDirs to provide the right locations on all platforms
+include(GNUInstallDirs)
+
 # creates a library GSL which is an interface (header files only)
 add_library(GSL INTERFACE)
 
@@ -54,15 +57,13 @@ target_compile_definitions(GSL INTERFACE
 # 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
-        >
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
     )
 else()
     target_include_directories(GSL SYSTEM INTERFACE
-        $<BUILD_INTERFACE:
-            ${CMAKE_CURRENT_SOURCE_DIR}/include
-        >
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
     )
 endif()
 
@@ -77,15 +78,23 @@ if (CMAKE_VERSION VERSION_GREATER 3.7.8)
     # 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
+            $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/GSL.natvis>
         )
     endif()
 endif()
 
+install(TARGETS GSL EXPORT Microsoft.GSLConfig)
 install(
     DIRECTORY include/gsl
-    DESTINATION include
+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
 )
+# Make library importable by other projects
+install(EXPORT Microsoft.GSLConfig NAMESPACE Microsoft.GSL:: DESTINATION share/Microsoft.GSL/cmake)
+export(TARGETS GSL NAMESPACE Microsoft.GSL:: FILE Microsoft.GSLConfig.cmake)
+
+# 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)
 
 option(GSL_TEST "Generate tests." ${GSL_STANDALONE_PROJECT})
 if (GSL_TEST)

README.md

@@ -18,7 +18,7 @@ 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.
 
 # Quick Start
 ## Supported Platforms
@@ -53,7 +53,7 @@ contributing any changes that were necessary back to this project to benefit the
 ## 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`.
 
@@ -77,6 +77,18 @@ 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 +109,14 @@ 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.
+
 ## 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.

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.
+-------------------------------------------------------------------------------

include/gsl/gsl_algorithm

@@ -37,8 +37,8 @@ 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>
+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,

include/gsl/gsl_assert

@@ -17,8 +17,26 @@
 #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_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>
-#include <stdexcept> // for logic_error
+
+#endif // defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS))
 
 //
 // make suppress attributes parse for some compilers
@@ -34,45 +52,18 @@
 #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
+#endif // defined(__clang__) || defined(__GNUC__)
 
 //
 // GSL_ASSUME(cond)
@@ -94,18 +85,16 @@
 
 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)();
+    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);
@@ -117,7 +106,7 @@ namespace details
         return handler;
     }
 
-#endif
+#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
 
     [[noreturn]] inline void terminate() noexcept
     {
@@ -125,48 +114,15 @@ namespace details
         (*gsl::details::get_terminate_handler())();
 #else
         std::terminate();
-#endif
+#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
     }
 
-#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)
 

include/gsl/gsl_byte

@@ -87,6 +87,10 @@
 #define byte_may_alias
 #endif // defined __clang__ || defined __GNUC__
 
+#if GSL_USE_STD_BYTE
+#include <cstddef>
+#endif
+
 namespace gsl
 {
 #if GSL_USE_STD_BYTE

include/gsl/gsl_util

@@ -21,7 +21,6 @@
 
 #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
@@ -97,10 +96,6 @@ 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>
@@ -120,9 +115,9 @@ constexpr
 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 (static_cast<U>(t) != u) gsl::details::terminate();
     if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
-        gsl::details::throw_exception(narrowing_error());
+        gsl::details::terminate();
     return t;
 }
 

include/gsl/multi_span

@@ -57,7 +57,7 @@
 #endif // _MSC_VER < 1910
 #endif // _MSC_VER
 
-#if __clang__ || __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
@@ -2266,7 +2266,7 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #pragma GCC diagnostic pop
 #endif // __GNUC__ > 6
 
-#if __clang__ || __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif
 

include/gsl/pointers

@@ -88,7 +88,6 @@ public:
     {
     }
 
-    not_null(not_null&& other) = default;
     not_null(const not_null& other) = default;
     not_null& operator=(const not_null& other) = default;
 

include/gsl/span

@@ -21,21 +21,18 @@
 #include <gsl/gsl_byte>   // for byte
 #include <gsl/gsl_util>   // for narrow_cast, narrow
 
-#include <algorithm> // for lexicographical_compare
-#include <array>     // for array
-#include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
-#include <iterator>  // for reverse_iterator, distance, random_access_...
-#include <limits>
-#include <stdexcept>
+#include <array>       // for array
+#include <cstddef>     // for ptrdiff_t, size_t, nullptr_t
+#include <iterator>    // for reverse_iterator, distance, random_access_...
 #include <type_traits> // for enable_if_t, declval, is_convertible, inte...
-#include <utility>
-#include <memory> // for std::addressof
 
 #if defined(_MSC_VER) && !defined(__clang__)
 #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 : 4146) // unary minus operator applied to unsigned type, result still unsigned
 #pragma warning(disable : 4702) // unreachable code
 
 // Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
@@ -58,7 +55,7 @@
 
 // GCC 7 does not like the signed unsigned missmatch (size_t ptrdiff_t)
 // While there is a conversion from signed to unsigned, it happens at
-// compiletime, so the compiler wouldn't have to warn indiscriminently, but
+// compiletime, so the compiler wouldn't have to warn indiscriminately, but
 // could check if the source value actually doesn't fit into the target type
 // and only warn in those cases.
 #if defined(__GNUC__) && __GNUC__ > 6
@@ -70,9 +67,9 @@ namespace gsl
 {
 
 // [views.constants], constants
-constexpr const std::ptrdiff_t dynamic_extent = -1;
+constexpr const std::size_t dynamic_extent = static_cast<std::size_t>(-1);
 
-template <class ElementType, std::ptrdiff_t Extent = dynamic_extent>
+template <class ElementType, std::size_t Extent = dynamic_extent>
 class span;
 
 // implementation details
@@ -83,7 +80,7 @@ namespace details
     {
     };
 
-    template <class ElementType, std::ptrdiff_t Extent>
+    template <class ElementType, std::size_t Extent>
     struct is_span_oracle<gsl::span<ElementType, Extent>> : std::true_type
     {
     };
@@ -104,156 +101,189 @@ namespace details
     };
 
     template <class T>
-    struct is_std_array : public is_std_array_oracle<std::remove_cv_t<T>>
+    struct is_std_array : is_std_array_oracle<std::remove_cv_t<T>>
     {
     };
 
-    template <std::ptrdiff_t From, std::ptrdiff_t To>
+    template <std::size_t From, std::size_t To>
     struct is_allowed_extent_conversion
-        : public std::integral_constant<bool, From == To || From == gsl::dynamic_extent ||
-                                                  To == gsl::dynamic_extent>
+        : std::integral_constant<bool, From == To || To == gsl::dynamic_extent>
     {
     };
 
     template <class From, class To>
     struct is_allowed_element_type_conversion
-        : public std::integral_constant<bool, std::is_convertible<From (*)[], To (*)[]>::value>
+        : std::integral_constant<bool, std::is_convertible<From (*)[], To (*)[]>::value>
     {
     };
 
-    template <class Span, bool IsConst>
+    template <class Type>
     class span_iterator
     {
-        using element_type_ = typename Span::element_type;
-
     public:
-#ifdef _MSC_VER
-        // Tell Microsoft standard library that span_iterators are checked.
-        using _Unchecked_type = typename Span::pointer;
-#endif
-
         using iterator_category = std::random_access_iterator_tag;
-        using value_type = std::remove_cv_t<element_type_>;
-        using difference_type = typename Span::index_type;
+        using value_type = std::remove_cv_t<Type>;
+        using difference_type = std::ptrdiff_t;
+        using pointer = Type*;
+        using reference = Type&;
 
-        using reference = std::conditional_t<IsConst, const element_type_, element_type_>&;
-        using pointer = std::add_pointer_t<reference>;
+#ifdef _MSC_VER
+        using _Unchecked_type = pointer;
+#endif // _MSC_VER
+        constexpr span_iterator() = default;
 
-        span_iterator() = default;
-
-        constexpr span_iterator(const Span* span, difference_type idx) noexcept
-            : span_(span), index_(idx)
+        constexpr span_iterator(pointer begin, pointer end, pointer current)
+            : begin_(begin), end_(end), current_(current)
         {}
 
-        friend span_iterator<Span, true>;
-        template <bool B, std::enable_if_t<!B && IsConst>* = nullptr>
-        constexpr span_iterator(const span_iterator<Span, B>& other) noexcept
-            : span_iterator(other.span_, other.index_)
-        {}
-
-        GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-        constexpr reference operator*() const
+        constexpr operator span_iterator<const Type>() const noexcept
         {
-            Expects(index_ != span_->size());
-            return *(span_->data() + index_);
+            return {begin_, end_, current_};
         }
 
-        constexpr pointer operator->() const
+        constexpr reference operator*() const noexcept
         {
-            Expects(index_ != span_->size());
-            return span_->data() + index_;
+            Expects(begin_ && end_);
+            Expects(begin_ <= current_ && current_ < end_);
+            return *current_;
         }
 
-        constexpr span_iterator& operator++()
+        constexpr pointer operator->() const noexcept
         {
-            Expects(0 <= index_ && index_ != span_->size());
-            ++index_;
+            Expects(begin_ && end_);
+            Expects(begin_ <= current_ && current_ < end_);
+            return current_;
+        }
+        constexpr span_iterator& operator++() noexcept
+        {
+            Expects(begin_ && current_ && end_);
+            Expects(current_ < end_);
+            ++current_;
             return *this;
         }
 
-        constexpr span_iterator operator++(int)
+        constexpr span_iterator operator++(int) noexcept
         {
-            auto ret = *this;
-            ++(*this);
+            span_iterator ret = *this;
+            ++*this;
             return ret;
         }
 
-        constexpr span_iterator& operator--()
+        constexpr span_iterator& operator--() noexcept
         {
-            Expects(index_ != 0 && index_ <= span_->size());
-            --index_;
+            Expects(begin_ && end_);
+            Expects(begin_ < current_);
+            --current_;
             return *this;
         }
 
-        constexpr span_iterator operator--(int)
+        constexpr span_iterator operator--(int) noexcept
         {
-            auto ret = *this;
-            --(*this);
+            span_iterator ret = *this;
+            --*this;
             return ret;
         }
 
-        constexpr span_iterator operator+(difference_type n) const
+        constexpr span_iterator& operator+=(const difference_type n) noexcept
         {
-            auto ret = *this;
-            return ret += n;
+            if (n != 0) Expects(begin_ && current_ && end_);
+            if (n > 0) Expects(end_ - current_ >= n);
+            if (n < 0) Expects(current_ - begin_ >= -n);
+            current_ += n;
+            return *this;
         }
 
-        friend constexpr span_iterator operator+(difference_type n, span_iterator const& rhs)
+        constexpr span_iterator operator+(const difference_type n) const noexcept
+        {
+            span_iterator ret = *this;
+            ret += n;
+            return ret;
+        }
+
+        friend constexpr span_iterator operator+(const difference_type n,
+                                                 const span_iterator& rhs) noexcept
         {
             return rhs + n;
         }
 
-        constexpr span_iterator& operator+=(difference_type n)
+        constexpr span_iterator& operator-=(const difference_type n) noexcept
         {
-            Expects((index_ + n) >= 0 && (index_ + n) <= span_->size());
-            index_ += n;
+            if (n != 0) Expects(begin_ && current_ && end_);
+            if (n > 0) Expects(current_ - begin_ >= n);
+            if (n < 0) Expects(end_ - current_ >= -n);
+            current_ -= n;
             return *this;
         }
 
-        constexpr span_iterator operator-(difference_type n) const
+        constexpr span_iterator operator-(const difference_type n) const noexcept
         {
-            auto ret = *this;
-            return ret -= n;
+            span_iterator ret = *this;
+            ret -= n;
+            return ret;
         }
 
-        constexpr span_iterator& operator-=(difference_type n) { return *this += -n; }
-
-        constexpr difference_type operator-(span_iterator rhs) const
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr difference_type operator-(const span_iterator<Type2>& rhs) const noexcept
         {
-            Expects(span_ == rhs.span_);
-            return index_ - rhs.index_;
+            Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
+            return current_ - rhs.current_;
         }
 
-        constexpr reference operator[](difference_type n) const { return *(*this + n); }
-
-        constexpr friend bool operator==(span_iterator lhs, span_iterator rhs) noexcept
+        constexpr reference operator[](const difference_type n) const noexcept
         {
-            return lhs.span_ == rhs.span_ && lhs.index_ == rhs.index_;
+            return *(*this + n);
         }
 
-        constexpr friend bool operator!=(span_iterator lhs, span_iterator rhs) noexcept
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator==(const span_iterator<Type2>& rhs) const noexcept
         {
-            return !(lhs == rhs);
+            Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
+            return current_ == rhs.current_;
         }
 
-        constexpr friend bool operator<(span_iterator lhs, span_iterator rhs) noexcept
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator!=(const span_iterator<Type2>& rhs) const noexcept
         {
-            return lhs.index_ < rhs.index_;
+            return !(*this == rhs);
         }
 
-        constexpr friend bool operator<=(span_iterator lhs, span_iterator rhs) noexcept
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator<(const span_iterator<Type2>& rhs) const noexcept
         {
-            return !(rhs < lhs);
+            Expects(begin_ == rhs.begin_ && end_ == rhs.end_);
+            return current_ < rhs.current_;
         }
 
-        constexpr friend bool operator>(span_iterator lhs, span_iterator rhs) noexcept
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator>(const span_iterator<Type2>& rhs) const noexcept
         {
-            return rhs < lhs;
+            return rhs < *this;
         }
 
-        constexpr friend bool operator>=(span_iterator lhs, span_iterator rhs) noexcept
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator<=(const span_iterator<Type2>& rhs) const noexcept
         {
-            return !(rhs > lhs);
+            return !(rhs < *this);
+        }
+
+        template <
+            class Type2,
+            std::enable_if_t<std::is_same<std::remove_cv_t<Type2>, value_type>::value, int> = 0>
+        constexpr bool operator>=(const span_iterator<Type2>& rhs) const noexcept
+        {
+            return !(*this < rhs);
         }
 
 #ifdef _MSC_VER
@@ -262,22 +292,26 @@ namespace details
         // algorithm calls
         friend constexpr void _Verify_range(span_iterator lhs, span_iterator rhs) noexcept
         { // test that [lhs, rhs) forms a valid range inside an STL algorithm
-            Expects(lhs.span_ == rhs.span_        // range spans have to match
-                    && lhs.index_ <= rhs.index_); // range must not be transposed
+            Expects(lhs.begin_ == rhs.begin_ // range spans have to match
+                    && lhs.end_ == rhs.end_ &&
+                    lhs.current_ <= rhs.current_); // range must not be transposed
         }
 
         constexpr void _Verify_offset(const difference_type n) const noexcept
-        { // test that the iterator *this + n is a valid range in an STL
-            // algorithm call
-            Expects((index_ + n) >= 0 && (index_ + n) <= span_->size());
+        { // test that *this + n is within the range of this call
+            if (n != 0) Expects(begin_ && current_ && end_);
+            if (n > 0) Expects(end_ - current_ >= n);
+            if (n < 0) Expects(current_ - begin_ >= -n);
         }
 
+        // clang-format off
         GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+        // clang-format on
         constexpr pointer _Unwrapped() const noexcept
         { // after seeking *this to a high water mark, or using one of the
             // _Verify_xxx functions above, unwrap this span_iterator to a raw
             // pointer
-            return span_->data() + index_;
+            return current_;
         }
 
         // Tell the STL that span_iterator should not be unwrapped if it can't
@@ -287,61 +321,64 @@ namespace details
 #else
         static constexpr bool _Unwrap_when_unverified = false;
 #endif
+        // clang-format off
         GSL_SUPPRESS(con.3) // NO-FORMAT: attribute // TODO: false positive
+        // clang-format on
         constexpr void _Seek_to(const pointer p) noexcept
         { // adjust the position of *this to previously verified location p
             // after _Unwrapped
-            index_ = p - span_->data();
+            current_ = p;
         }
 #endif
 
-    protected:
-        const Span* span_ = nullptr;
-        std::ptrdiff_t index_ = 0;
+        pointer begin_ = nullptr;
+        pointer end_ = nullptr;
+        pointer current_ = nullptr;
     };
 
-    template <std::ptrdiff_t Ext>
+    template <std::size_t Ext>
     class extent_type
     {
     public:
-        using index_type = std::ptrdiff_t;
+        using size_type = std::size_t;
 
-        static_assert(Ext >= 0, "A fixed-size span must be >= 0 in size.");
+        constexpr extent_type() noexcept = default;
 
-        constexpr extent_type() noexcept {}
-
-        template <index_type Other>
+        template <size_type Other>
         constexpr extent_type(extent_type<Other> ext)
         {
-            static_assert(Other == Ext || Other == dynamic_extent,
+            static_assert(Other == Ext,
                           "Mismatch between fixed-size extent and size of initializing data.");
             Expects(ext.size() == Ext);
         }
 
-        constexpr extent_type(index_type size) { Expects(size == Ext); }
+        constexpr extent_type(size_type size) { Expects(size == Ext); }
 
-        constexpr index_type size() const noexcept { return Ext; }
+        constexpr size_type size() const noexcept { return Ext; }
     };
 
     template <>
     class extent_type<dynamic_extent>
     {
     public:
-        using index_type = std::ptrdiff_t;
+        using size_type = std::size_t;
 
-        template <index_type Other>
+        template <size_type Other>
         explicit constexpr extent_type(extent_type<Other> ext) : size_(ext.size())
         {}
 
-        explicit constexpr extent_type(index_type size) : size_(size) { Expects(size >= 0); }
+        explicit constexpr extent_type(size_type size) : size_(size)
+        {
+            Expects(size != dynamic_extent);
+        }
 
-        constexpr index_type size() const noexcept { return size_; }
+        constexpr size_type size() const noexcept { return size_; }
 
     private:
-        index_type size_;
+        size_type size_;
     };
 
-    template <class ElementType, std::ptrdiff_t Extent, std::ptrdiff_t Offset, std::ptrdiff_t Count>
+    template <class ElementType, std::size_t Extent, std::size_t Offset, std::size_t Count>
     struct calculate_subspan_type
     {
         using type = span<ElementType, Count != dynamic_extent
@@ -351,99 +388,106 @@ namespace details
 } // namespace details
 
 // [span], class template span
-template <class ElementType, std::ptrdiff_t Extent>
+template <class ElementType, std::size_t Extent>
 class span
 {
 public:
     // constants and types
     using element_type = ElementType;
     using value_type = std::remove_cv_t<ElementType>;
-    using index_type = std::ptrdiff_t;
+    using size_type = std::size_t;
     using pointer = element_type*;
+    using const_pointer = const element_type*;
     using reference = element_type&;
+    using const_reference = const element_type&;
+    using difference_type = std::ptrdiff_t;
 
-    using iterator = details::span_iterator<span<ElementType, Extent>, false>;
-    using const_iterator = details::span_iterator<span<ElementType, Extent>, true>;
+    using iterator = details::span_iterator<ElementType>;
     using reverse_iterator = std::reverse_iterator<iterator>;
-    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-
-    using size_type = index_type;
 
 #if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
-    static constexpr const index_type extent{Extent};
+    static constexpr const size_type extent{Extent};
 #else
-    static constexpr index_type extent{Extent};
+    static constexpr size_type extent{Extent};
 #endif
 
     // [span.cons], span constructors, copy, assignment, and destructor
     template <bool Dependent = false,
-              // "Dependent" is needed to make "std::enable_if_t<Dependent || Extent <= 0>" SFINAE,
-              // since "std::enable_if_t<Extent <= 0>" is ill-formed when Extent is greater than 0.
-              class = std::enable_if_t<(Dependent || Extent <= 0)>>
+              // "Dependent" is needed to make "std::enable_if_t<Dependent || Extent == 0 || Extent
+              // == dynamic_extent>" SFINAE, since "std::enable_if_t<Extent == 0 || Extent ==
+              // dynamic_extent>" is ill-formed when Extent is greater than 0.
+              class = std::enable_if_t<(Dependent ||
+                                        details::is_allowed_extent_conversion<0, Extent>::value)>>
     constexpr span() noexcept : storage_(nullptr, details::extent_type<0>())
     {}
 
-    constexpr span(pointer ptr, index_type count) : storage_(ptr, count) {}
+    constexpr span(pointer ptr, size_type count) noexcept : storage_(ptr, count)
+    {
+        if (Extent != dynamic_extent) Expects(count == Extent);
+    }
 
-    constexpr span(pointer firstElem, pointer lastElem)
-        : storage_(firstElem, std::distance(firstElem, lastElem))
-    {}
+    constexpr span(pointer firstElem, pointer lastElem) noexcept
+        : storage_(firstElem, static_cast<std::size_t>(lastElem - firstElem))
+    {
+        if (Extent != dynamic_extent)
+        { Expects(lastElem - firstElem == static_cast<difference_type>(Extent)); }
+    }
 
-    template <std::size_t N>
+    template <std::size_t N,
+              std::enable_if_t<details::is_allowed_extent_conversion<N, Extent>::value, int> = 0>
     constexpr span(element_type (&arr)[N]) noexcept
-        : storage_(KnownNotNull{std::addressof(arr[0])}, details::extent_type<N>())
+        : storage_(KnownNotNull{arr + 0}, details::extent_type<N>())
     {}
 
-    template <std::size_t N, class = std::enable_if_t<(N > 0)>>
-    constexpr span(std::array<std::remove_const_t<element_type>, N>& arr) noexcept
+    template <
+        class T, std::size_t N,
+        std::enable_if_t<(details::is_allowed_extent_conversion<N, Extent>::value &&
+                          details::is_allowed_element_type_conversion<T, element_type>::value),
+                         int> = 0>
+    constexpr span(std::array<T, N>& arr) noexcept
         : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
-    {
-    }
+    {}
 
-    constexpr span(std::array<std::remove_const_t<element_type>, 0>&) noexcept
-        : storage_(static_cast<pointer>(nullptr), details::extent_type<0>())
-    {
-    }
-
-    template <std::size_t N, class = std::enable_if_t<(N > 0)>>
-    constexpr span(const std::array<std::remove_const_t<element_type>, N>& arr) noexcept
+    template <class T, std::size_t N,
+              std::enable_if_t<
+                  (details::is_allowed_extent_conversion<N, Extent>::value &&
+                   details::is_allowed_element_type_conversion<const T, element_type>::value),
+                  int> = 0>
+    constexpr span(const std::array<T, N>& arr) noexcept
         : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
-    {
-    }
+    {}
 
-    constexpr span(const std::array<std::remove_const_t<element_type>, 0>&) noexcept
-        : storage_(static_cast<pointer>(nullptr), details::extent_type<0>())
-    {
-    }
-
-    // NB: the SFINAE here uses .data() as a incomplete/imperfect proxy for the requirement
+    // NB: the SFINAE here uses .data() as an incomplete/imperfect proxy for the requirement
     // on Container to be a contiguous sequence container.
     template <class Container,
               class = std::enable_if_t<
                   !details::is_span<Container>::value && !details::is_std_array<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr span(Container& cont) : span(cont.data(), narrow<index_type>(cont.size()))
+                  std::is_pointer<decltype(std::declval<Container&>().data())>::value &&
+                  std::is_convertible<
+                      std::remove_pointer_t<decltype(std::declval<Container&>().data())> (*)[],
+                      element_type (*)[]>::value>>
+    constexpr span(Container& cont) noexcept : span(cont.data(), cont.size())
     {}
 
     template <class Container,
               class = std::enable_if_t<
                   std::is_const<element_type>::value && !details::is_span<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr span(const Container& cont) : span(cont.data(), narrow<index_type>(cont.size()))
+                  !details::is_std_array<Container>::value &&
+                  std::is_pointer<decltype(std::declval<const Container&>().data())>::value &&
+                  std::is_convertible<std::remove_pointer_t<
+                                          decltype(std::declval<const Container&>().data())> (*)[],
+                                      element_type (*)[]>::value>>
+    constexpr span(const Container& cont) noexcept : span(cont.data(), cont.size())
     {}
 
     constexpr span(const span& other) noexcept = default;
 
     template <
-        class OtherElementType, std::ptrdiff_t OtherExtent,
+        class OtherElementType, std::size_t OtherExtent,
         class = std::enable_if_t<
             details::is_allowed_extent_conversion<OtherExtent, Extent>::value &&
             details::is_allowed_element_type_conversion<OtherElementType, element_type>::value>>
-    constexpr span(const span<OtherElementType, OtherExtent>& other)
+    constexpr span(const span<OtherElementType, OtherExtent>& other) noexcept
         : storage_(other.data(), details::extent_type<OtherExtent>(other.size()))
     {}
 
@@ -451,125 +495,119 @@ public:
     constexpr span& operator=(const span& other) noexcept = default;
 
     // [span.sub], span subviews
-    template <std::ptrdiff_t Count>
-    constexpr span<element_type, Count> first() const
+    template <std::size_t Count>
+    constexpr span<element_type, Count> first() const noexcept
     {
-        Expects(Count >= 0 && Count <= size());
+        Expects(Count <= size());
         return {data(), Count};
     }
 
-    template <std::ptrdiff_t Count>
+    template <std::size_t Count>
+    // clang-format off
     GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-    constexpr span<element_type, Count> last() const
+        // clang-format on
+        constexpr span<element_type, Count> last() const noexcept
     {
-        Expects(Count >= 0 && size() - Count >= 0);
+        Expects(Count <= size());
         return {data() + (size() - Count), Count};
     }
 
-    template <std::ptrdiff_t Offset, std::ptrdiff_t Count = dynamic_extent>
+    template <std::size_t Offset, std::size_t Count = dynamic_extent>
+    // clang-format off
     GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-    constexpr auto subspan() const ->
+        // clang-format on
+        constexpr auto subspan() const noexcept ->
         typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type
     {
-        Expects((Offset >= 0 && size() - Offset >= 0) &&
-                (Count == dynamic_extent || (Count >= 0 && Offset + Count <= size())));
+        Expects((size() >= Offset) && (Count == dynamic_extent || (Count <= size() - Offset)));
 
         return {data() + Offset, Count == dynamic_extent ? size() - Offset : Count};
     }
 
-    constexpr span<element_type, dynamic_extent> first(index_type count) const
+    constexpr span<element_type, dynamic_extent> first(size_type count) const noexcept
     {
-        Expects(count >= 0 && count <= size());
+        Expects(count <= size());
         return {data(), count};
     }
 
-    constexpr span<element_type, dynamic_extent> last(index_type count) const
+    constexpr span<element_type, dynamic_extent> last(size_type count) const noexcept
     {
+        Expects(count <= size());
         return make_subspan(size() - count, dynamic_extent, subspan_selector<Extent>{});
     }
 
-    constexpr span<element_type, dynamic_extent> subspan(index_type offset,
-                                                         index_type count = dynamic_extent) const
+    constexpr span<element_type, dynamic_extent> subspan(size_type offset,
+                                                         size_type count = dynamic_extent) const
+        noexcept
     {
         return make_subspan(offset, count, subspan_selector<Extent>{});
     }
 
     // [span.obs], span observers
-    constexpr index_type size() const noexcept { return storage_.size(); }
-    constexpr index_type size_bytes() const noexcept
+    constexpr size_type size() const noexcept { return storage_.size(); }
+
+    constexpr size_type size_bytes() const noexcept
     {
-        return size() * narrow_cast<index_type>(sizeof(element_type));
+        Expects(size() < dynamic_extent / sizeof(element_type));
+        return size() * sizeof(element_type);
     }
+
     constexpr bool empty() const noexcept { return size() == 0; }
 
     // [span.elem], span element access
+    // clang-format off
     GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-    constexpr reference operator[](index_type idx) const
+    // clang-format on
+    constexpr reference operator[](size_type idx) const noexcept
     {
-        Expects(CheckRange(idx, storage_.size()));
+        Expects(idx < size());
         return data()[idx];
     }
 
-    constexpr reference at(index_type idx) const { return this->operator[](idx); }
-    constexpr reference operator()(index_type idx) const { return this->operator[](idx); }
+    constexpr reference front() const noexcept
+    {
+        Expects(size() > 0);
+        return data()[0];
+    }
+
+    constexpr reference back() const noexcept
+    {
+        Expects(size() > 0);
+        return data()[size() - 1];
+    }
+
     constexpr pointer data() const noexcept { return storage_.data(); }
 
     // [span.iter], span iterator support
-    constexpr iterator begin() const noexcept { return {this, 0}; }
-    constexpr iterator end() const noexcept { return {this, size()}; }
+    constexpr iterator begin() const noexcept
+    {
+        const auto data = storage_.data();
+        return {data, data + size(), data};
+    }
 
-    constexpr const_iterator cbegin() const noexcept { return {this, 0}; }
-    constexpr const_iterator cend() const noexcept { return {this, size()}; }
+    constexpr iterator end() const noexcept
+    {
+        const auto data = storage_.data();
+        const auto endData = data + storage_.size();
+        return {data, endData, endData};
+    }
 
     constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator{end()}; }
     constexpr reverse_iterator rend() const noexcept { return reverse_iterator{begin()}; }
 
-    constexpr const_reverse_iterator crbegin() const noexcept
-    {
-        return const_reverse_iterator{cend()};
-    }
-    constexpr const_reverse_iterator crend() const noexcept
-    {
-        return const_reverse_iterator{cbegin()};
-    }
-
 #ifdef _MSC_VER
     // Tell MSVC how to unwrap spans in range-based-for
     constexpr pointer _Unchecked_begin() const noexcept { return data(); }
     constexpr pointer _Unchecked_end() const noexcept
     {
+        // clang-format off
         GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+        // clang-format on
         return data() + size();
     }
 #endif // _MSC_VER
 
 private:
-    static constexpr bool CheckRange(index_type idx, index_type size) noexcept
-    {
-        // Optimization:
-        //
-        // idx >= 0 && idx < size
-        // =>
-        // static_cast<size_t>(idx) < static_cast<size_t>(size)
-        //
-        // because size >=0 by span construction, and negative idx will
-        // wrap around to a value always greater than size when casted.
-
-        // check if we have enough space to wrap around
-#if defined(__cpp_if_constexpr)
-        if constexpr (sizeof(index_type) <= sizeof(size_t))
-#else
-        if (sizeof(index_type) <= sizeof(size_t))
-#endif
-        {
-            return narrow_cast<size_t>(idx) < narrow_cast<size_t>(size);
-        }
-        else
-        {
-            return idx >= 0 && idx < size;
-        }
-    }
-
     // Needed to remove unnecessary null check in subspans
     struct KnownNotNull
     {
@@ -589,13 +627,13 @@ private:
         constexpr storage_type(KnownNotNull data, OtherExtentType ext)
             : ExtentType(ext), data_(data.p)
         {
-            Expects(ExtentType::size() >= 0);
+            Expects(ExtentType::size() != dynamic_extent);
         }
 
         template <class OtherExtentType>
         constexpr storage_type(pointer data, OtherExtentType ext) : ExtentType(ext), data_(data)
         {
-            Expects(ExtentType::size() >= 0);
+            Expects(ExtentType::size() != dynamic_extent);
             Expects(data || ExtentType::size() == 0);
         }
 
@@ -609,76 +647,56 @@ private:
 
     // The rest is needed to remove unnecessary null check
     // in subspans and constructors from arrays
-    constexpr span(KnownNotNull ptr, index_type count) : storage_(ptr, count) {}
+    constexpr span(KnownNotNull ptr, size_type count) noexcept : storage_(ptr, count) {}
 
-    template <std::ptrdiff_t CallerExtent>
+    template <std::size_t CallerExtent>
     class subspan_selector
     {
     };
 
-    template <std::ptrdiff_t CallerExtent>
-    span<element_type, dynamic_extent> make_subspan(index_type offset, index_type count,
-                                                    subspan_selector<CallerExtent>) const
+    template <std::size_t CallerExtent>
+    constexpr span<element_type, dynamic_extent> make_subspan(size_type offset, size_type count,
+                                                              subspan_selector<CallerExtent>) const
+        noexcept
     {
         const span<element_type, dynamic_extent> tmp(*this);
         return tmp.subspan(offset, count);
     }
 
+    // clang-format off
     GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-    span<element_type, dynamic_extent> make_subspan(index_type offset, index_type count,
-                                                    subspan_selector<dynamic_extent>) const
+    // clang-format on
+    constexpr span<element_type, dynamic_extent>
+    make_subspan(size_type offset, size_type count, subspan_selector<dynamic_extent>) const noexcept
     {
-        Expects(offset >= 0 && size() - offset >= 0);
+        Expects(size() >= offset);
 
         if (count == dynamic_extent) { return {KnownNotNull{data() + offset}, size() - offset}; }
 
-        Expects(count >= 0 && size() - offset >= count);
+        Expects(size() - offset >= count);
         return {KnownNotNull{data() + offset}, count};
     }
 };
 
+#if (defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L))
+
+// Deduction Guides
+template <class Type, std::size_t Extent>
+span(Type (&)[Extent])->span<Type, Extent>;
+
+template <class Type, std::size_t Size>
+span(std::array<Type, Size>&)->span<Type, Size>;
+
+template <class Type, std::size_t Size>
+span(const std::array<Type, Size>&)->span<const Type, Size>;
+
+#endif // ( defined(__cpp_deduction_guides) && (__cpp_deduction_guides >= 201611L) )
+
 #if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
-template <class ElementType, std::ptrdiff_t Extent>
-constexpr const typename span<ElementType, Extent>::index_type span<ElementType, Extent>::extent;
+template <class ElementType, std::size_t Extent>
+constexpr const typename span<ElementType, Extent>::size_type span<ElementType, Extent>::extent;
 #endif
 
-// [span.comparison], span comparison operators
-template <class ElementType, std::ptrdiff_t FirstExtent, std::ptrdiff_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::ptrdiff_t Extent>
-constexpr bool operator!=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l == r);
-}
-
-template <class ElementType, std::ptrdiff_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::ptrdiff_t Extent>
-constexpr bool operator<=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l > r);
-}
-
-template <class ElementType, std::ptrdiff_t Extent>
-constexpr bool operator>(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return r < l;
-}
-
-template <class ElementType, std::ptrdiff_t Extent>
-constexpr bool operator>=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l < r);
-}
-
 namespace details
 {
     // if we only supported compilers with good constexpr support then
@@ -687,93 +705,41 @@ namespace details
     // we should use a narrow_cast<> to go to std::size_t, but older compilers may not see it as
     // constexpr
     // and so will fail compilation of the template
-    template <class ElementType, std::ptrdiff_t Extent>
-    struct calculate_byte_size
-        : std::integral_constant<std::ptrdiff_t,
-                                 static_cast<std::ptrdiff_t>(sizeof(ElementType) *
-                                                             static_cast<std::size_t>(Extent))>
+    template <class ElementType, std::size_t Extent>
+    struct calculate_byte_size : std::integral_constant<std::size_t, sizeof(ElementType) * Extent>
     {
+        static_assert(Extent < dynamic_extent / sizeof(ElementType), "Size is too big.");
     };
 
     template <class ElementType>
     struct calculate_byte_size<ElementType, dynamic_extent>
-        : std::integral_constant<std::ptrdiff_t, dynamic_extent>
+        : std::integral_constant<std::size_t, dynamic_extent>
     {
     };
 } // namespace details
 
 // [span.objectrep], views of object representation
-template <class ElementType, std::ptrdiff_t Extent>
+template <class ElementType, std::size_t Extent>
 span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
 as_bytes(span<ElementType, Extent> s) noexcept
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
 }
 
-template <class ElementType, std::ptrdiff_t Extent,
-          class = std::enable_if_t<!std::is_const<ElementType>::value>>
+template <class ElementType, std::size_t Extent,
+          std::enable_if_t<!std::is_const<ElementType>::value, int> = 0>
 span<byte, details::calculate_byte_size<ElementType, Extent>::value>
-as_writeable_bytes(span<ElementType, Extent> s) noexcept
+as_writable_bytes(span<ElementType, Extent> s) noexcept
 {
+    // clang-format off
     GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    // clang-format on
     return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
 }
 
-//
-// make_span() - Utility functions for creating spans
-//
-template <class ElementType>
-constexpr span<ElementType> make_span(ElementType* ptr,
-                                      typename span<ElementType>::index_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::ptrdiff_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::ptrdiff_t Extent>
-constexpr ElementType& at(span<ElementType, Extent> s, index i)
-{
-    // No bounds checking here because it is done in span::operator[] called below
-    return s[i];
-}
-
 } // namespace gsl
 
 #if defined(_MSC_VER) && !defined(__clang__)

include/gsl/span_ext

@@ -0,0 +1,198 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// 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 <gsl/gsl_util> // for narrow_cast, narrow
+#include <gsl/span>     // for span
+
+#include <algorithm> // for lexicographical_compare
+#include <cstddef>   // for ptrdiff_t, size_t
+#include <utility>
+
+namespace gsl
+{
+
+// [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);
+}
+
+//
+// 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

tests/CMakeLists.txt

@@ -5,27 +5,33 @@ project(GSLTests CXX)
 # 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"
+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(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(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)
+
+add_subdirectory(
+    ${CMAKE_CURRENT_BINARY_DIR}/googletest-src
+    ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
+    EXCLUDE_FROM_ALL
+)
+
 if (MSVC AND (GSL_CXX_STANDARD EQUAL 17))
     set(GSL_CPLUSPLUS_OPT -Zc:__cplusplus -permissive-)
 endif()
@@ -39,14 +45,38 @@ 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
           -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
+          >
         >
     )
 else()
@@ -61,60 +91,77 @@ else()
         -Wpedantic
         -Wshadow
         -Wsign-conversion
+        -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>
+          >
+        >
+        $<$<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
-)
-
-# 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
-    gsl_tests_config
-)
-add_dependencies(test_catch catch)
-set_property(TARGET test_catch PROPERTY FOLDER "GSL_tests")
+set_property(TARGET  PROPERTY FOLDER "GSL_tests")
 
 function(add_gsl_test name)
     add_executable(${name} ${name}.cpp)
     target_link_libraries(${name}
         GSL
-        test_catch
         gsl_tests_config
+        gtest_main
     )
-    add_dependencies(${name} catch)
     add_test(
-      ${name}
-      ${name}
+        ${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(span_ext_tests)
+add_gsl_test(span_compatibility_tests)
 add_gsl_test(multi_span_tests)
 add_gsl_test(strided_span_tests)
 add_gsl_test(string_span_tests)
@@ -142,7 +189,7 @@ 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}
@@ -151,6 +198,8 @@ 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
@@ -181,19 +230,31 @@ 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
-)
-
 function(add_gsl_test_noexcept name)
     add_executable(${name} ${name}.cpp)
     target_link_libraries(${name}
         GSL
         gsl_tests_config_noexcept
+        gtest_main
     )
     add_test(
       ${name}

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           703bd9caab50b139428cea1aaff9974ebee5742e
+  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 +14,26 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#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, CHE...
-
+#include <gtest/gtest.h>
 #include <gsl/gsl_algorithm> // for copy
 #include <gsl/span>          // for span
-
 #include <array>   // for array
 #include <cstddef> // for size_t
 
-namespace gsl {
+namespace
+{
+    static constexpr char deathstring[] = "Expected Death";
+}
+
+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 +46,10 @@ 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 +64,10 @@ 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]);
         }
     }
 
@@ -84,9 +82,10 @@ 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]);
         }
     }
 
@@ -101,17 +100,15 @@ 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 +121,10 @@ 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 +139,10 @@ 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 +157,10 @@ 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 +175,16 @@ 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 +202,13 @@ TEST_CASE("incompatible_type")
 }
 #endif
 
-TEST_CASE("small_destination_span")
+TEST(algorithm_tests, small_destination_span)
 {
+    std::set_terminate([] {
+        std::cerr << "Expected Death. small_destination_span";
+        std::abort();
+    });
+
     std::array<int, 12> src{1, 2, 3, 4};
     std::array<int, 4> dst{};
 
@@ -211,9 +217,9 @@ 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), deathstring);
+    EXPECT_DEATH(copy(src_span_dyn, dst_span_static), deathstring);
+    EXPECT_DEATH(copy(src_span_static, dst_span_dyn), deathstring);
 
 #ifdef CONFIRM_COMPILATION_ERRORS
     copy(src_span_static, dst_span_static);

tests/assertion_tests.cpp

@@ -14,39 +14,48 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#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 <gtest/gtest.h>
 #include <gsl/gsl_assert> // for fail_fast (ptr only), Ensures, Expects
 
 using namespace gsl;
 
+namespace
+{
+static constexpr char deathstring[] = "Expected Death";
+
 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);
+    std::set_terminate([] {
+        std::cerr << "Expected Death. expects";
+        std::abort();
+    });
+
+    EXPECT_TRUE(f(2) == 2);
+    EXPECT_DEATH(f(10), deathstring);
+}
+
+
+TEST(assertion_tests, ensures)
+{
+    std::set_terminate([] {
+        std::cerr << "Expected Death. ensures";
+        std::abort();
+    });
+
+    EXPECT_TRUE(g(2) == 3);
+    EXPECT_DEATH(g(9), deathstring);
 }

tests/at_tests.cpp

@@ -14,13 +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
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK_THROW...
+#include <gtest/gtest.h>
 
 #include <gsl/gsl_util> // for at
 
@@ -29,88 +23,95 @@
 #include <initializer_list> // for initializer_list
 #include <vector>           // for vector
 
+namespace
+{
+    static constexpr char deathstring[] = "Expected Death";
+}
 
-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]);
+        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);
+    std::set_terminate([] {
+        std::cerr << "Expected Death. static_array";
+        std::abort();
+    });
+
+    EXPECT_DEATH(gsl::at(a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(a, 4), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, 4), deathstring);
 }
 
-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)]);
+        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);
+    std::set_terminate([] {
+        std::cerr << "Expected Death. std_array";
+        std::abort();
+    });
+
+    EXPECT_DEATH(gsl::at(a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(a, 4), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, 4), deathstring);
 }
 
-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)]);
+        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);
+    std::set_terminate([] {
+        std::cerr << "Expected Death. std_vector";
+        std::abort();
+    });
+
+    EXPECT_DEATH(gsl::at(a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(a, 4), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(c_a, 4), deathstring);
 }
 
-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);
+        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);
+    std::set_terminate([] {
+        std::cerr << "Expected Death. InitializerList";
+        std::abort();
+    });
+
+    EXPECT_DEATH(gsl::at(a, -1), deathstring);
+    EXPECT_DEATH(gsl::at(a, 4), deathstring);
+    EXPECT_DEATH(gsl::at({1, 2, 3, 4}, -1), deathstring);
+    EXPECT_DEATH(gsl::at({1, 2, 3, 4}, 4), deathstring);
 }
 
 #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};
@@ -132,4 +133,3 @@ static constexpr bool test_constexpr()
 
 static_assert(test_constexpr(), "FAIL");
 #endif
-

tests/bounds_tests.cpp

@@ -14,28 +14,12 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-#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 <gtest/gtest.h>
 
 #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;
 
@@ -44,8 +28,7 @@ namespace
 void use(std::ptrdiff_t&) {}
 }
 
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-TEST_CASE("basic_bounds")
+TEST(bounds_tests, basic_bounds)
 {
     for (auto point : static_bounds<dynamic_range, 3, 4>{2}) {
         for (decltype(point)::size_type j = 0;
@@ -57,9 +40,7 @@ TEST_CASE("basic_bounds")
     }
 }
 
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("bounds_basic")
+TEST(bounds_tests, bounds_basic)
 {
     static_bounds<3, 4, 5> b;
     const auto a = b.slice();
@@ -68,9 +49,7 @@ TEST_CASE("bounds_basic")
     x.slice().slice();
 }
 
-GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("arrayview_iterator")
+TEST(bounds_tests, arrayview_iterator)
 {
     static_bounds<4, dynamic_range, 2> bounds{3};
 
@@ -88,8 +67,7 @@ TEST_CASE("arrayview_iterator")
 #endif
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("bounds_convertible")
+TEST(bounds_tests, bounds_convertible)
 {
     static_bounds<7, 4, 2> b1;
     static_bounds<7, dynamic_range, 2> b2 = b1;
@@ -102,24 +80,23 @@ TEST_CASE("bounds_convertible")
     static_bounds<7, 4, 2> b4 = b3;
     (void) b4;
 
-    static_bounds<dynamic_range> b11;
-
     static_bounds<dynamic_range> b5;
     static_bounds<34> b6;
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. bounds_convertible";
+        std::abort();
+    });
+
     b5 = static_bounds<20>();
-    CHECK_THROWS_AS(b6 = b5, fail_fast);
+    EXPECT_DEATH(b6 = b5, ".*");
     b5 = static_bounds<34>();
     b6 = b5;
 
-    CHECK(b5 == b6);
-    CHECK(b5.size() == b6.size());
+    EXPECT_TRUE(b5 == b6);
+    EXPECT_TRUE(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

@@ -14,13 +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
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+#include <gtest/gtest.h>
 
 #include <gsl/gsl_byte> // for to_byte, to_integer, byte, operator&, ope...
 
@@ -29,104 +23,103 @@ 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);
+    }
+
+    GSL_SUPPRESS(es.49)
+    {
+        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);
 }
 
 }

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>
 
@@ -34,13 +25,13 @@
 #include <string>    // for basic_string, operator==, string, operator<<
 #include <typeinfo>  // for type_info
 
-namespace gsl
-{
-struct fail_fast;
-} // namespace gsl
-
 using namespace gsl;
 
+namespace
+{
+static constexpr char deathstring[] = "Expected Death";
+} //namespace
+
 struct MyBase
 {
 };
@@ -133,10 +124,8 @@ GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
 bool helper_const(not_null<const int*> p) { return *p == 12; }
 
 int* return_pointer() { return nullptr; }
-const int* return_pointer_const() { return nullptr; }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestNotNullConstructors")
+TEST(notnull_tests, TestNotNullConstructors)
 {
     {
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -153,18 +142,22 @@ TEST_CASE("TestNotNullConstructors")
 #endif
     }
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullConstructors";
+        std::abort();
+    });
     {
         // 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)), deathstring);
     }
 
     {
@@ -175,7 +168,7 @@ TEST_CASE("TestNotNullConstructors")
         helper(&t);
         helper_const(&t);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -191,7 +184,7 @@ TEST_CASE("TestNotNullConstructors")
         helper(x);
         helper_const(x);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -205,7 +198,7 @@ TEST_CASE("TestNotNullConstructors")
         helper_const(cp);
         helper_const(x);
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -215,19 +208,18 @@ 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()), deathstring);
+        EXPECT_DEATH(helper_const(return_pointer()), deathstring);
     }
 }
 
 template <typename T>
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
 void ostream_helper(T v)
 {
     not_null<T*> p(&v);
@@ -236,18 +228,18 @@ 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 +250,7 @@ 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 +260,7 @@ 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 +270,25 @@ 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)
 {
+    std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullAssignmentd";
+        std::abort();
+    });
+
     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), deathstring);
 }
 
-TEST_CASE("TestNotNullRawPointerComparison")
+TEST(notnull_tests, TestNotNullRawPointerComparison)
 {
     int ints[2] = {42, 43};
     int* p1 = &ints[0];
@@ -302,34 +297,33 @@ 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 +331,22 @@ 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 +354,30 @@ 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 +386,32 @@ 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 +420,7 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
         helper(not_null{&i});
         helper_const(not_null{&i});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -439,15 +431,20 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
         helper(not_null{p});
         helper_const(not_null{p});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. TestNotNullConstructorTypeDeduction";
+        std::abort();
+    });
+
     {
         auto workaround_macro = []() {
             int* p1 = nullptr;
             const not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), deathstring);
     }
 
     {
@@ -455,14 +452,14 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
             const int* p1 = nullptr;
             const not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), deathstring);
     }
 
     {
         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}), deathstring);
+        EXPECT_DEATH(helper_const(not_null{p}), deathstring);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -475,7 +472,7 @@ TEST_CASE("TestNotNullConstructorTypeDeduction")
 }
 #endif // #if defined(__cplusplus) && (__cplusplus >= 201703L)
 
-TEST_CASE("TestMakeNotNull")
+TEST(notnull_tests, TestMakeNotNull)
 {
     {
         int i = 42;
@@ -484,7 +481,7 @@ TEST_CASE("TestMakeNotNull")
         helper(make_not_null(&i));
         helper_const(make_not_null(&i));
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -495,42 +492,44 @@ TEST_CASE("TestMakeNotNull")
         helper(make_not_null(p));
         helper_const(make_not_null(p));
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. TestMakeNotNull";
+        std::abort();
+    });
+
     {
         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(), deathstring);
     }
 
     {
         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(), deathstring);
     }
 
     {
         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)), deathstring);
+        EXPECT_DEATH(helper_const(make_not_null(p)), deathstring);
     }
 
 #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), deathstring);
+        EXPECT_DEATH(helper(make_not_null(nullptr)), deathstring);
+        EXPECT_DEATH(helper_const(make_not_null(nullptr)), deathstring);
     }
 #endif
 }
-
-static_assert(std::is_nothrow_move_constructible<not_null<void*>>::value,
-              "not_null must be no-throw move constructible");

tests/owner_tests.cpp

@@ -14,14 +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
-
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+#include <gtest/gtest.h>
 
 #include <gsl/pointers> // for owner
 
@@ -30,19 +23,16 @@ using namespace gsl;
 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
     {

tests/span_ext_tests.cpp

@@ -0,0 +1,360 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// 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/gsl_util> // for narrow_cast, at
+#include <gsl/span_ext> // for operator==, operator!=, make_span
+
+#include <array>       // for array
+#include <iostream>    // for cerr
+#include <vector>      // for vector
+
+using namespace std;
+using namespace gsl;
+
+namespace
+{
+static constexpr char deathstring[] = "Expected Death";
+} // namespace
+
+TEST(span_ext_test, make_span_from_pointer_length_constructor)
+{
+    std::set_terminate([] {
+        std::cerr << "Expected Death. from_pointer_length_constructor";
+        std::abort();
+    });
+    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<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(), deathstring);
+    }
+}
+
+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
+     {
+         span<int> s1 = make_span(arr);
+
+         static 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};
+     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};
+     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};
+     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)));
+ }
+
+  TEST(span_ext_test, comparison_operators)
+ {
+     {
+         span<int> s1;
+         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};
+         span<int> s1 = arr;
+         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
+
+         span<int> s1;
+         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};
+         span<int> s1 = arr1;
+         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};
+
+         span<int> s1 = {&arr[0], 2}; // shorter
+         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
+
+         span<int> s1 = arr1;
+         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);
+     }
+ }

tests/strict_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>
 
 namespace gsl
@@ -35,19 +26,20 @@ using namespace gsl;
 
 GSL_SUPPRESS(f.4)  // NO-FORMAT: attribute
 bool helper(not_null<int*> p) { return *p == 12; }
+
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
 bool helper_const(not_null<const int*> p) { return *p == 12; }
 
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
 bool strict_helper(strict_not_null<int*> p) { return *p == 12; }
+
 GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
 bool strict_helper_const(strict_not_null<const int*> p) { return *p == 12; }
 
 int* return_pointer() { return nullptr; }
 const int* return_pointer_const() { return nullptr; }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestStrictNotNull")
+TEST(strict_notnull_tests, TestStrictNotNull)
 {
     {
         // raw ptr <-> strict_not_null
@@ -66,7 +58,7 @@ TEST_CASE("TestStrictNotNull")
         helper(snn1);
         helper_const(snn1);
 
-        CHECK(*snn1 == 42);
+        EXPECT_TRUE(*snn1 == 42);
     }
 
     {
@@ -80,7 +72,7 @@ TEST_CASE("TestStrictNotNull")
         strict_helper_const(snn1);
         strict_helper_const(snn2);
 
-        CHECK(snn1 == snn2);
+        EXPECT_TRUE(snn1 == snn2);
     }
 
     {
@@ -95,8 +87,8 @@ TEST_CASE("TestStrictNotNull")
         helper(snn);
         helper_const(snn);
 
-        CHECK(snn == nn1);
-        CHECK(snn == nn2);
+        EXPECT_TRUE(snn == nn1);
+        EXPECT_TRUE(snn == nn2);
     }
 
     {
@@ -111,16 +103,16 @@ 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
@@ -131,10 +123,18 @@ TEST_CASE("TestStrictNotNull")
 }
 
 #if defined(__cplusplus) && (__cplusplus >= 201703L)
-
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
+namespace
 {
+static constexpr char deathstring[] = "Expected Death";
+}
+
+TEST(strict_notnull_tests, TestStrictNotNullConstructorTypeDeduction)
+{
+    std::set_terminate([] {
+        std::cerr << "Expected Death. TestStrictNotNullConstructorTypeDeduction";
+        std::abort();
+    });
+
     {
         int i = 42;
 
@@ -142,7 +142,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
         helper(strict_not_null{&i});
         helper_const(strict_not_null{&i});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -153,7 +153,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
         helper(strict_not_null{p});
         helper_const(strict_not_null{p});
 
-        CHECK(*x == 42);
+        EXPECT_TRUE(*x == 42);
     }
 
     {
@@ -161,7 +161,7 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
             int* p1 = nullptr;
             const strict_not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), deathstring);
     }
 
     {
@@ -169,14 +169,14 @@ TEST_CASE("TestStrictNotNullConstructorTypeDeduction")
             const int* p1 = nullptr;
             const strict_not_null x{p1};
         };
-        CHECK_THROWS_AS(workaround_macro(), fail_fast);
+        EXPECT_DEATH(workaround_macro(), deathstring);
     }
 
     {
         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}), deathstring);
+        EXPECT_DEATH(helper_const(strict_not_null{p}), deathstring);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -188,6 +188,3 @@ 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

@@ -14,21 +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 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 <gtest/gtest.h>
 #include <gsl/gsl_byte>   // for byte
 #include <gsl/gsl_util>   // for narrow_cast
 #include <gsl/multi_span> // for strided_span, index, multi_span, strided_...
@@ -39,24 +25,80 @@
 #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
 {
+static constexpr char deathstring[] = "Expected Death";
+
 struct BaseClass
 {
 };
 struct DerivedClass : BaseClass
 {
 };
+
+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);
+
+    EXPECT_TRUE(strided.size() == length);
+    EXPECT_TRUE(strided.bounds().index_bounds()[0] == length);
+    for (auto i = 0; i < strided.size(); ++i) {
+        EXPECT_TRUE(strided[i] == av[2 * i + 1]);
+    }
+
+    int idx = 0;
+    for (auto num : strided) {
+        EXPECT_TRUE(num == av[2 * idx + 1]);
+        idx++;
+    }
 }
 
-TEST_CASE("span_section_test")
+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 EXPECT_TRUE macro
+                EXPECT_TRUE(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)
+                EXPECT_TRUE(section[i][j][k] == expected[2 * i + 2 * j + k]);
+    }
+
+    int i = 0;
+    for (const auto num : section) {
+        EXPECT_TRUE(num == expected[i]);
+        i++;
+    }
+}
+
+}
+
+TEST(strided_span_tests, span_section_test)
 {
     int a[30][4][5];
 
@@ -66,51 +108,54 @@ TEST_CASE("span_section_test")
     (void) subsub;
 }
 
-TEST_CASE("span_section")
+TEST(strided_span_tests, 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));
+    EXPECT_TRUE(!av_section_1.empty());
+    EXPECT_TRUE((av_section_1[{0, 0}] == 12));
+    EXPECT_TRUE((av_section_1[{0, 1}] == 13));
+    EXPECT_TRUE((av_section_1[{1, 0}] == 22));
+    EXPECT_TRUE((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));
+    EXPECT_TRUE(!av_section_2.empty());
+    EXPECT_TRUE((av_section_2[{0, 0}] == 24));
+    EXPECT_TRUE((av_section_2[{0, 1}] == 25));
+    EXPECT_TRUE((av_section_2[{1, 0}] == 34));
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_constructors")
+TEST(strided_span_tests, strided_span_constructors)
 {
-    // Check stride constructor
+    // EXPECT_TRUE 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));
+        EXPECT_TRUE(sav1.bounds().index_bounds() == multi_span_index<1>{9});
+        EXPECT_TRUE(sav1.bounds().stride() == 1);
+        EXPECT_TRUE(sav1[0] == 1);
+        EXPECT_TRUE(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));
+        EXPECT_TRUE(sav2.bounds().index_bounds() == multi_span_index<1>{4});
+        EXPECT_TRUE(sav2.bounds().strides() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav2[0] == 1);
+        EXPECT_TRUE(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));
+        EXPECT_TRUE((sav3.bounds().index_bounds() == multi_span_index<2>{2, 2}));
+        EXPECT_TRUE((sav3.bounds().strides() == multi_span_index<2>{6, 2}));
+        EXPECT_TRUE((sav3[{0, 0}]) == 1);
+        EXPECT_TRUE((sav3[{0, 1}]) ==  3);
+        EXPECT_TRUE((sav3[{1, 0}]) == 7);
     }
 
-    // Check multi_span constructor
+    // EXPECT_TRUE multi_span constructor
     {
         int arr[] = {1, 2};
 
@@ -119,9 +164,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav[1] == 2);
 
 #if defined(_MSC_VER) && _MSC_VER > 1800
             // strided_span<const int, 1> sav_c{ {src}, {2, 1} };
@@ -131,9 +176,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_c.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_c.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_c[1] == 2);
 
 #if defined(_MSC_VER) && _MSC_VER > 1800
             strided_span<volatile int, 1> sav_v{src, {2, 1}};
@@ -141,9 +186,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_v.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_v.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_v[1] == 2);
 
 #if defined(_MSC_VER) && _MSC_VER > 1800
             strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
@@ -151,9 +196,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_cv.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_cv[1] == 2);
         }
 
         // From const-qualified source
@@ -161,9 +206,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_c.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_c.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_c[1] == 2);
 
 #if defined(_MSC_VER) && _MSC_VER > 1800
             strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
@@ -172,9 +217,9 @@ TEST_CASE("strided_span_constructors")
                                                        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);
+            EXPECT_TRUE(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_cv.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_cv[1] == 2);
         }
 
         // From volatile-qualified source
@@ -182,9 +227,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_v.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_v.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_v[1] == 2);
 
 #if defined(_MSC_VER) && _MSC_VER > 1800
             strided_span<const volatile int, 1> sav_cv{src, {2, 1}};
@@ -192,9 +237,9 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_cv.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_cv[1] == 2);
         }
 
         // From cv-qualified source
@@ -202,19 +247,19 @@ TEST_CASE("strided_span_constructors")
             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);
+            EXPECT_TRUE(sav_cv.bounds().index_bounds() == multi_span_index<1>{2});
+            EXPECT_TRUE(sav_cv.bounds().strides() == multi_span_index<1>{1});
+            EXPECT_TRUE(sav_cv[1] == 2);
         }
     }
 
-    // Check const-casting constructor
+    // EXPECT_TRUE 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);
+        EXPECT_TRUE(av2[1] == 5);
 
         static_assert(
             std::is_convertible<const multi_span<int, 2>, multi_span<const int, 2>>::value,
@@ -222,34 +267,35 @@ TEST_CASE("strided_span_constructors")
 
         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);
+        EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav.bounds().stride() == 1);
+        EXPECT_TRUE(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
+    // EXPECT_TRUE 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);
+        EXPECT_TRUE(sav1.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav1.bounds().stride() == 1);
+        EXPECT_TRUE(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));
+        EXPECT_TRUE((sav2.bounds().index_bounds() == multi_span_index<2>{3, 2}));
+        EXPECT_TRUE((sav2.bounds().strides() == multi_span_index<2>{2, 1}));
+        EXPECT_TRUE((sav2[{0, 0}]) ==  1);
+        EXPECT_TRUE((sav2[{2, 0}]) == 5);
     }
 
-    // Check const-casting assignment operator
+    // EXPECT_TRUE const-casting assignment operator
     {
         int arr1[2] = {1, 2};
         int arr2[6] = {3, 4, 5, 6, 7, 8};
@@ -257,38 +303,38 @@ TEST_CASE("strided_span_constructors")
         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);
+        EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav.bounds().strides() == multi_span_index<1>{1});
+        EXPECT_TRUE(sav[0] == 1);
+        EXPECT_TRUE(&sav_ref == &sav);
     }
 
-    // Check copy assignment operator
+    // EXPECT_TRUE 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);
+        EXPECT_TRUE(sav1.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav1.bounds().strides() == multi_span_index<1>{1});
+        EXPECT_TRUE(sav1[0] == 3);
+        EXPECT_TRUE(&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);
+        EXPECT_TRUE((sav2.bounds().index_bounds() == multi_span_index<2>{3, 2}));
+        EXPECT_TRUE((sav2.bounds().strides() == multi_span_index<2>{2, 1}));
+        EXPECT_TRUE((sav2[{0, 0}] == 1));
+        EXPECT_TRUE((sav2[{2, 0}] == 5));
+        EXPECT_TRUE(&sav2_ref == &sav2);
     }
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_slice")
+TEST(strided_span_tests, strided_span_slice)
 {
     std::vector<int> data(5 * 10);
     std::iota(begin(data), end(data), 0);
@@ -303,19 +349,18 @@ TEST_CASE("strided_span_slice")
                                           {{5, 10}, {10, 1}}};
 
     strided_span<int, 1> sav_sl = sav[2];
-    CHECK(sav_sl[0] == 20);
-    CHECK(sav_sl[9] == 29);
+    EXPECT_TRUE(sav_sl[0] == 20);
+    EXPECT_TRUE(sav_sl[9] == 29);
 
     strided_span<const int, 1> csav_sl = sav[3];
-    CHECK(csav_sl[0] == 30);
-    CHECK(csav_sl[9] == 39);
+    EXPECT_TRUE(csav_sl[0] == 30);
+    EXPECT_TRUE(csav_sl[9] == 39);
 
-    CHECK(sav[4][0] == 40);
-    CHECK(sav[4][9] == 49);
+    EXPECT_TRUE(sav[4][0] == 40);
+    EXPECT_TRUE(sav[4][9] == 49);
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_column_major")
+TEST(strided_span_tests, strided_span_column_major)
 {
     // strided_span may be used to accommodate more peculiar
     // use cases, such as column-major multidimensional array
@@ -325,119 +370,123 @@ TEST_CASE("strided_span_column_major")
     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));
+    EXPECT_TRUE((cm_sav[{0, 0}] == 1));
+    EXPECT_TRUE((cm_sav[{0, 1}] == 2));
+    EXPECT_TRUE((cm_sav[{1, 0}] == 4));
+    EXPECT_TRUE((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);
+    EXPECT_TRUE(cm_sl[0] == 10);
+    EXPECT_TRUE(cm_sl[1] == 11);
+    EXPECT_TRUE(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));
+    EXPECT_TRUE((cm_sec.bounds().index_bounds() == multi_span_index<2>{3, 2}));
+    EXPECT_TRUE((cm_sec[{0, 0}] == 8));
+    EXPECT_TRUE((cm_sec[{0, 1}] == 9));
+    EXPECT_TRUE((cm_sec[{1, 0}] == 11));
+    EXPECT_TRUE((cm_sec[{2, 1}] == 15));
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_bounds")
+TEST(strided_span_tests, strided_span_bounds)
 {
     int arr[] = {0, 1, 2, 3};
     multi_span<int> av(arr);
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. strided_span_bounds";
+        std::abort();
+    });
+
     {
         // 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);
+        EXPECT_DEATH(av.section(0, 0)[0], deathstring);
+        EXPECT_DEATH(av.section(1, 0)[0], deathstring);
+        EXPECT_DEATH(av.section(1, 1)[1], deathstring);
 
-        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);
+        EXPECT_DEATH(av.section(2, 5), deathstring);
+        EXPECT_DEATH(av.section(5, 2), deathstring);
+        EXPECT_DEATH(av.section(5, 0), deathstring);
+        EXPECT_DEATH(av.section(0, 5), deathstring);
+        EXPECT_DEATH(av.section(5, 5), deathstring);
     }
 
     {
         // zero stride
         strided_span<int, 1> sav{av, {{4}, {}}};
-        CHECK(sav[0] == 0);
-        CHECK(sav[3] == 0);
-        CHECK_THROWS_AS(sav[4], fail_fast);
+        EXPECT_TRUE(sav[0] == 0);
+        EXPECT_TRUE(sav[3] == 0);
+        EXPECT_DEATH(sav[4], deathstring);
     }
 
     {
         // zero extent
         strided_span<int, 1> sav{av, {{}, {1}}};
-        CHECK_THROWS_AS(sav[0], fail_fast);
+        EXPECT_DEATH(sav[0], deathstring);
     }
 
     {
         // zero extent and stride
         strided_span<int, 1> sav{av, {{}, {}}};
-        CHECK_THROWS_AS(sav[0], fail_fast);
+        EXPECT_DEATH(sav[0], deathstring);
     }
 
     {
         // 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);
+        EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{4});
+        EXPECT_TRUE(sav[3] == 3);
+        EXPECT_DEATH(sav[4], deathstring);
     }
 
     {
         // 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);
+        EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav[1] == 1);
+        EXPECT_DEATH(sav[2], deathstring);
     }
 
     {
         // 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);
+        EXPECT_TRUE(sav.bounds().index_bounds() == multi_span_index<1>{2});
+        EXPECT_TRUE(sav[0] == 0);
+        EXPECT_TRUE(sav[1] == 3);
+        EXPECT_DEATH(sav[2], deathstring);
     }
 
     {
         // 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);
+        EXPECT_DEATH((strided_span<int, 1>{arr, {3, 2}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{arr, {3, 3}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{arr, {4, 5}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{arr, {5, 1}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{arr, {5, 5}}), deathstring);
     }
 
     {
         // 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);
+        EXPECT_DEATH((strided_span<int, 1>{av, {3, 2}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av, {3, 3}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av, {4, 5}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av, {5, 1}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av, {5, 5}}), deathstring);
     }
 
     {
         // 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);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 4, {3, 2}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 4, {3, 3}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 4, {4, 5}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 4, {5, 1}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 4, {5, 5}}), deathstring);
+        EXPECT_DEATH((strided_span<int, 1>{av.data(), 2, {2, 2}}), deathstring);
     }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -464,12 +513,16 @@ TEST_CASE("strided_span_bounds")
 #endif
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-TEST_CASE("strided_span_type_conversion")
+TEST(strided_span_tests, strided_span_type_conversion)
 {
     int arr[] = {0, 1, 2, 3};
     multi_span<int> av(arr);
 
+    std::set_terminate([] {
+        std::cerr << "Expected Death. strided_span_type_conversion";
+        std::abort();
+    });
+
     {
         strided_span<int, 1> sav{av.data(), av.size(), {av.size() / 2, 2}};
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -490,10 +543,10 @@ TEST_CASE("strided_span_type_conversion")
         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);
+        EXPECT_TRUE(sav3[0][0] == 0);
+        EXPECT_TRUE(sav3[1][0] == 2);
+        EXPECT_DEATH(sav3[1][1], deathstring);
+        EXPECT_DEATH(sav3[0][1], deathstring);
     }
 
     // retype strided array with regular strides - from multi_span
@@ -503,10 +556,10 @@ TEST_CASE("strided_span_type_conversion")
             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);
+        EXPECT_TRUE(sav3[0][0] == 0);
+        EXPECT_TRUE(sav3[1][0] == 2);
+        EXPECT_DEATH(sav3[1][1], deathstring);
+        EXPECT_DEATH(sav3[0][1], deathstring);
     }
 
     // retype strided array with not enough elements - last dimension of the array is too small
@@ -515,7 +568,7 @@ TEST_CASE("strided_span_type_conversion")
         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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 
     // retype strided array with not enough elements - strides are too small
@@ -524,7 +577,7 @@ TEST_CASE("strided_span_type_conversion")
         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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 
     // retype strided array with not enough elements - last dimension does not divide by the new
@@ -534,7 +587,7 @@ TEST_CASE("strided_span_type_conversion")
         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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 
     // retype strided array with not enough elements - strides does not divide by the new
@@ -544,88 +597,63 @@ TEST_CASE("strided_span_type_conversion")
         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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 
     // 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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 
     // 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);
+        EXPECT_DEATH(sav2.as_strided_span<int>(), deathstring);
     }
 }
 
-GSL_SUPPRESS(con.4) // NO-FORMAT: attribute
-GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-TEST_CASE("empty_strided_spans")
+TEST(strided_span_tests, empty_strided_spans)
 {
+    std::set_terminate([] {
+        std::cerr << "Expected Death. empty_strided_spans";
+        std::abort();
+    });
+
     {
         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);
+        EXPECT_TRUE(empty_sav.bounds().index_bounds() == multi_span_index<1>{0});
+        EXPECT_TRUE(empty_sav.empty());
+        EXPECT_DEATH(empty_sav[0], deathstring);
+        EXPECT_DEATH(empty_sav.begin()[0], deathstring);
+        EXPECT_DEATH(empty_sav.cbegin()[0], deathstring);
 
         for (const auto& v : empty_sav) {
             (void) v;
-            CHECK(false);
+            EXPECT_TRUE(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);
+        EXPECT_TRUE(empty_sav.bounds().index_bounds() == multi_span_index<1>{0});
+        EXPECT_DEATH(empty_sav[0], deathstring);
+        EXPECT_DEATH(empty_sav.begin()[0], deathstring);
+        EXPECT_DEATH(empty_sav.cbegin()[0], deathstring);
 
         for (const auto& v : empty_sav) {
             (void) v;
-            CHECK(false);
+            EXPECT_TRUE(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")
+TEST(strided_span_tests, strided_span_section_iteration)
 {
     int arr[8] = {4, 0, 5, 1, 6, 2, 7, 3};
 
@@ -642,12 +670,7 @@ TEST_CASE("strided_span_section_iteration")
     }
 }
 
-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")
+TEST(strided_span_tests, dynamic_strided_span_section_iteration)
 {
     auto arr = new int[8];
     for (int i = 0; i < 4; ++i) {
@@ -661,39 +684,7 @@ TEST_CASE("dynamic_strided_span_section_iteration")
     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")
+TEST(strided_span_tests, strided_span_section_iteration_3d)
 {
     int arr[3][4][2]{};
     for (auto i = 0; i < 3; ++i) {
@@ -707,12 +698,7 @@ TEST_CASE("strided_span_section_iteration_3d")
     }
 }
 
-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")
+TEST(strided_span_tests, dynamic_strided_span_section_iteration_3d)
 {
     const auto height = 12, width = 2;
     const auto size = height * width;
@@ -744,11 +730,13 @@ TEST_CASE("dynamic_strided_span_section_iteration_3d")
     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")
+TEST(strided_span_tests, strided_span_conversion)
 {
+    std::set_terminate([] {
+        std::cerr << "Expected Death. strided_span_conversion";
+        std::abort();
+    });
+
     // get an multi_span of 'c' values from the list of X's
 
     struct X
@@ -767,8 +755,8 @@ TEST_CASE("strided_span_conversion")
     // 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);
+    EXPECT_TRUE(av.bounds().index_bounds()[0] == 4);
+    EXPECT_TRUE(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],
@@ -778,8 +766,8 @@ TEST_CASE("strided_span_conversion")
     // 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);
+    EXPECT_TRUE(cs.bounds().index_bounds()[0] == 4);
+    EXPECT_TRUE(cs.bounds().index_bounds()[1] == 1);
 
     // transpose to 1x4 array
     strided_bounds<2> reverse_bounds{
@@ -791,16 +779,12 @@ TEST_CASE("strided_span_conversion")
     // 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);
+    EXPECT_TRUE(result.bounds().index_bounds()[0] == 4);
+    EXPECT_DEATH(result.bounds().index_bounds()[1], deathstring);
 
     int i = 0;
     for (auto& num : result) {
-        CHECK(num == arr[i].c);
+        EXPECT_TRUE(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

@@ -14,14 +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
-
-#endif
-
-#include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, TEST_...
+#include <gtest/gtest.h>
 
 #include <gsl/gsl_util> // for narrow, finally, narrow_cast, narrowing_e...
 
@@ -30,104 +23,114 @@
 #include <limits>      // for numeric_limits
 #include <stdint.h>    // for uint32_t, int32_t
 #include <type_traits> // for is_same
+#include <cstddef>     // for std::ptrdiff_t
 
 using namespace gsl;
 
-TEST_CASE("sanity check for gsl::index typedef")
+namespace
+{
+static constexpr char deathstring[] = "Expected Death";
+void f(int& i) { i += 1; }
+static int j = 0;
+void g() { j += 1; }
+}
+
+
+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_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")
+TEST(utils_tests, narrow)
 {
+    std::set_terminate([] {
+        std::cerr << "Expected Death. narrow";
+        std::abort();
+    });
+
     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_DEATH(narrow<char>(n), deathstring);
 
     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_DEATH(narrow<uint32_t>(int32_t(-1)), deathstring);
+    EXPECT_DEATH(narrow<uint32_t>(int32_min), deathstring);
 
     n = -42;
-    CHECK_THROWS_AS(narrow<unsigned>(n), narrowing_error);
+    EXPECT_DEATH(narrow<unsigned>(n), deathstring);
 
 #if GSL_CONSTEXPR_NARROW
     static_assert(narrow<char>(120) == 120, "Fix GSL_CONSTEXPR_NARROW");
 #endif
+
 }