ARROW-14800: [C++] Disambiguate std::launder on MSVC with C++17 enabled

Closes #11806 from pitrou/ARROW-14800-launder-disambiguate Authored-by: Antoine Pitrou <antoine@python.org> Signed-off-by: Krisztián Szűcs <szucs.krisztian@gmail.com>
apache · Dec 1, 2021 · fe9d031 · fe9d031
1 parent 2233ac5
commit fe9d031
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Showing 2 changed files with 9 additions and 5 deletions.
diff --git a/.github/workflows/cpp.yml b/.github/workflows/cpp.yml
@@ -178,7 +178,7 @@ jobs:
           ci/scripts/cpp_test.sh $(pwd) $(pwd)/build
 
   windows:
-    name: AMD64 ${{ matrix.name }} C++
+    name: AMD64 ${{ matrix.name }} C++17
     runs-on: ${{ matrix.os }}
     if: ${{ !contains(github.event.pull_request.title, 'WIP') }}
     timeout-minutes: 45
@@ -197,6 +197,7 @@ jobs:
       ARROW_BUILD_SHARED: ON
       ARROW_BUILD_STATIC: OFF
       ARROW_BUILD_TESTS: ON
+      ARROW_CXXFLAGS: "/std:c++17"
       ARROW_DATASET: ON
       ARROW_FLIGHT: OFF
       ARROW_HDFS: ON
@@ -218,7 +219,7 @@ jobs:
       CMAKE_INSTALL_LIBDIR: bin
       CMAKE_INSTALL_PREFIX: /usr
       CMAKE_UNITY_BUILD: ON
-      NPROC: 2
+      NPROC: 3
     steps:
       - name: Disable Crash Dialogs
         run: |

diff --git a/cpp/src/arrow/util/aligned_storage.h b/cpp/src/arrow/util/aligned_storage.h
@@ -33,13 +33,16 @@ class AlignedStorage {
   static constexpr bool can_memcpy = std::is_trivial<T>::value;
 
 #if __cpp_constexpr >= 201304L  // non-const constexpr
-  constexpr T* get() noexcept { return launder(reinterpret_cast<T*>(&data_)); }
+  constexpr T* get() noexcept {
+    return arrow::internal::launder(reinterpret_cast<T*>(&data_));
+  }
 #else
-  T* get() noexcept { return launder(reinterpret_cast<T*>(&data_)); }
+  T* get() noexcept { return arrow::internal::launder(reinterpret_cast<T*>(&data_)); }
 #endif
 
   constexpr const T* get() const noexcept {
-    return launder(reinterpret_cast<const T*>(&data_));
+    // Use fully qualified name to avoid ambiguities with MSVC (ARROW-14800)
+    return arrow::internal::launder(reinterpret_cast<const T*>(&data_));
   }
 
   void destroy() noexcept {