From be97fc76571fc56b46650857578ad8eb5412a8a8 Mon Sep 17 00:00:00 2001
From: Matthias Maier <tamiko@43-1.org>
Date: Tue, 29 Jun 2021 11:13:13 -0500
Subject: [PATCH] CMake: Add a configuration check for
 DEAL_II_DELETED_MOVE_CONSTRUCTOR_BUG

---
 cmake/checks/check_03_compiler_bugs.cmake | 26 +++++++++++++++++++++++
 include/deal.II/base/config.h.in          |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/cmake/checks/check_03_compiler_bugs.cmake b/cmake/checks/check_03_compiler_bugs.cmake
index f80a8c5350..989bb784fd 100644
--- a/cmake/checks/check_03_compiler_bugs.cmake
+++ b/cmake/checks/check_03_compiler_bugs.cmake
@@ -41,3 +41,29 @@ ENDIF()
 IF(CMAKE_CXX_COMPILER_ID MATCHES "Intel" AND CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL "16.0.1" )
   MESSAGE(FATAL_ERROR "Intel compiler version 16.0.1 is not supported, please update to 16.0.2 or newer!")
 ENDIF()
+
+
+#
+# Check for a regression in gcc-11.1.0 where a deleted move constructor
+# prevents templated constructor from being used. For details see
+#
+#   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100644
+#   https://github.com/dealii/dealii/issues/12244
+#   https://github.com/dealii/dealii/pull/12246
+#
+# - Mathias Anselmann, Matthias Maier, David Wells, 2021
+#
+CHECK_CXX_COMPILER_BUG(
+  "
+  struct NonMovable {
+    NonMovable() = default;
+    NonMovable(NonMovable &&) = delete;
+  };
+  template <class T> struct Maybe {
+    NonMovable mMember;
+    template <typename U> Maybe(Maybe<U> &&) : mMember() {}
+  };
+  void unlucky(Maybe<int> &&x) { Maybe<int> var{(Maybe<int> &&) x}; }
+  int main() { return 0; }
+  "
+  DEAL_II_DELETED_MOVE_CONSTRUCTOR_BUG)
diff --git a/include/deal.II/base/config.h.in b/include/deal.II/base/config.h.in
index e0bd528ebd..071884eeb2 100644
--- a/include/deal.II/base/config.h.in
+++ b/include/deal.II/base/config.h.in
@@ -80,6 +80,8 @@
  * For documentation see cmake/checks/check_03_compiler_bugs.cmake
  */
 
+#cmakedefine DEAL_II_DELETED_MOVE_CONSTRUCTOR_BUG
+
 /***********************************************************************
  * Compiler features:
  *
-- 
2.39.5