From 924bf5ed1971b3fd5e58f640c997e03fd4633b7f Mon Sep 17 00:00:00 2001
From: Markus Blatt <markus@dr-blatt.de>
Date: Fri, 11 Dec 2020 17:38:00 +0100
Subject: [PATCH] Use old style traits class approach to check for face tag
 support.

Old version failed due to a gcc compiler
bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77446 with error:
"non-constant condition for static assertion"
---
 .../aquifers/BlackoilAquiferModel.hpp         | 33 +++++++++++++++----
 .../aquifers/BlackoilAquiferModel_impl.hpp    |  3 +-
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/opm/simulators/aquifers/BlackoilAquiferModel.hpp b/opm/simulators/aquifers/BlackoilAquiferModel.hpp
index 1aceb62eb..bdb2b70b6 100644
--- a/opm/simulators/aquifers/BlackoilAquiferModel.hpp
+++ b/opm/simulators/aquifers/BlackoilAquiferModel.hpp
@@ -44,10 +44,36 @@
 #include <opm/material/densead/Math.hpp>
 
 #include <vector>
+#include <type_traits>
 
 namespace Opm
 {
 
+template<class Grid>
+class SupportsFaceTag
+    : public std::bool_constant<false>
+{};
+
+
+template<>
+class SupportsFaceTag<Dune::CpGrid>
+    : public std::bool_constant<true>
+{};
+
+
+template<>
+class SupportsFaceTag<Dune::PolyhedralGrid<3, 3>>
+    : public std::bool_constant<true>
+{};
+
+#if HAVE_DUNE_ALUGRID
+template<>
+class SupportsFaceTag<Dune::ALUGrid<3, 3, Dune::cube, Dune::nonconforming>>
+    : public std::bool_constant<true>
+{};
+#endif
+
+
 /// Class for handling the blackoil well model.
 template <typename TypeTag>
 class BlackoilAquiferModel
@@ -55,13 +81,6 @@ class BlackoilAquiferModel
     using Simulator = GetPropType<TypeTag, Properties::Simulator>;
     using RateVector = GetPropType<TypeTag, Properties::RateVector>;
 
-    constexpr bool supportsFaceTag(const Dune::CpGrid&){ return true;}
-    constexpr bool supportsFaceTag(const Dune::PolyhedralGrid<3, 3>&){ return true;}
-#if HAVE_DUNE_ALUGRID
-    constexpr bool supportsFaceTag(const Dune::ALUGrid<3, 3, Dune::cube, Dune::nonconforming>&){ return true;}
-#endif
-    template<class G>
-    constexpr bool supportsFaceTag(const G&){ return false;}
 
 public:
     explicit BlackoilAquiferModel(Simulator& simulator);
diff --git a/opm/simulators/aquifers/BlackoilAquiferModel_impl.hpp b/opm/simulators/aquifers/BlackoilAquiferModel_impl.hpp
index e771b6c3b..6901480cc 100644
--- a/opm/simulators/aquifers/BlackoilAquiferModel_impl.hpp
+++ b/opm/simulators/aquifers/BlackoilAquiferModel_impl.hpp
@@ -26,7 +26,8 @@ BlackoilAquiferModel<TypeTag>::BlackoilAquiferModel(Simulator& simulator)
     : simulator_(simulator)
 {
     // Grid needs to support Facetag
-    assert(supportsFaceTag(simulator.vanguard().grid()));
+    using Grid = std::remove_const_t<std::remove_reference_t<decltype(simulator.vanguard().grid())>>;
+    static_assert(SupportsFaceTag<Grid>::value, "Grid has to support assumptions about face tag.");
 
     init();
 }