From: Daniel Arndt <arndtd@ornl.gov>
Date: Wed, 7 Dec 2022 21:30:20 +0000 (-0500)
Subject: Address Wundefined-var-template
X-Git-Tag: v9.5.0-rc1~749^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c0dc0056cc848686fb9130d8b3e1f803ceb7f3a;p=dealii.git

Address Wundefined-var-template
---

diff --git a/cmake/setup_compiler_flags_gnu.cmake b/cmake/setup_compiler_flags_gnu.cmake
index 08e141fa1e..9c73ffdc9e 100644
--- a/cmake/setup_compiler_flags_gnu.cmake
+++ b/cmake/setup_compiler_flags_gnu.cmake
@@ -126,12 +126,6 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   #
   enable_if_supported(DEAL_II_CXX_FLAGS "-Wno-unsupported-friend")
 
-  #
-  # Disable a diagnostic that warns about potentially uninstantiated static
-  # members. This leads to a ton of false positives.
-  #
-  enable_if_supported(DEAL_II_CXX_FLAGS "-Wno-undefined-var-template")
-
   #
   # Clang versions prior to 3.6 emit a lot of false positives wrt
   # "-Wunused-function". Also suppress warnings for Xcode older than 6.3
diff --git a/include/deal.II/fe/mapping_q1.h b/include/deal.II/fe/mapping_q1.h
index b9b86451b0..4d75d7404e 100644
--- a/include/deal.II/fe/mapping_q1.h
+++ b/include/deal.II/fe/mapping_q1.h
@@ -101,6 +101,9 @@ struct StaticMappingQ1
 
 /** @} */
 
+template <int dim, int spacedim>
+MappingQ<dim, spacedim> StaticMappingQ1<dim, spacedim>::mapping =
+  MappingQ1<dim, spacedim>{};
 
 DEAL_II_NAMESPACE_CLOSE
 
diff --git a/include/deal.II/hp/mapping_collection.h b/include/deal.II/hp/mapping_collection.h
index b562df4405..650a54d296 100644
--- a/include/deal.II/hp/mapping_collection.h
+++ b/include/deal.II/hp/mapping_collection.h
@@ -22,6 +22,7 @@
 
 #include <deal.II/fe/fe.h>
 #include <deal.II/fe/mapping.h>
+#include <deal.II/fe/mapping_q1.h>
 
 #include <deal.II/hp/collection.h>
 
@@ -172,6 +173,13 @@ namespace hp
       push_back(*p);
   }
 
+
+
+  template <int dim, int spacedim>
+  MappingCollection<dim, spacedim>
+    StaticMappingQ1<dim, spacedim>::mapping_collection =
+      MappingCollection<dim, spacedim>(MappingQ1<dim, spacedim>{});
+
 } // namespace hp
 
 
diff --git a/source/fe/mapping_q1.cc b/source/fe/mapping_q1.cc
index 1f8aec3bdf..4dfa0c185b 100644
--- a/source/fe/mapping_q1.cc
+++ b/source/fe/mapping_q1.cc
@@ -35,15 +35,6 @@ MappingQ1<dim, spacedim>::clone() const
   return std::make_unique<MappingQ1<dim, spacedim>>(*this);
 }
 
-//---------------------------------------------------------------------------
-
-
-template <int dim, int spacedim>
-MappingQ<dim, spacedim>
-  StaticMappingQ1<dim, spacedim>::mapping = MappingQ<dim, spacedim>(1);
-
-
-
 //--------------------------- Explicit instantiations -----------------------
 #include "mapping_q1.inst"
 
diff --git a/source/hp/mapping_collection.cc b/source/hp/mapping_collection.cc
index 2d4c5b5de9..2809aa903d 100644
--- a/source/hp/mapping_collection.cc
+++ b/source/hp/mapping_collection.cc
@@ -53,34 +53,6 @@ namespace hp
       std::shared_ptr<const Mapping<dim, spacedim>>(new_mapping.clone()));
   }
 
-  //---------------------------------------------------------------------------
-
-
-  namespace
-  {
-    /**
-     * Create and return a reference to a static MappingQ1 object. We can't
-     * use the one in ::StaticMappingQ1 to initialize the static object below
-     * since we can't make sure that the constructor for that object is run
-     * before we want to use the object (when constructing mapping_collection
-     * below).  Therefore we create a helper function which returns a
-     * reference to a static object that will be constructed the first time
-     * this function is called.
-     */
-    template <int dim, int spacedim>
-    MappingQ<dim, spacedim> &
-    get_static_mapping_q1()
-    {
-      static MappingQ1<dim, spacedim> mapping;
-      return mapping;
-    }
-  } // namespace
-
-  template <int dim, int spacedim>
-  MappingCollection<dim, spacedim>
-    StaticMappingQ1<dim, spacedim>::mapping_collection =
-      MappingCollection<dim, spacedim>(get_static_mapping_q1<dim, spacedim>());
-
 } // namespace hp