Compilation bug using Windows Visual Studio 2017

[nicola-giuliani]

I have just installed the latest version of the library on a windows machine using Visual Studio 2017, MSVC 19.16.27034.0. The installation was smooth but I can't compile the test grid_tools_03. The problem lies in the volume function that has changed since release 9.2 (which was working fine).

The error is the following

grid_tools.h(185): error C2059: syntax error: 'template'

[bangerth]

Oh :-( Can you test what happens with a patch such as this?

diff --git a/include/deal.II/grid/grid_tools.h b/include/deal.II/grid/grid_tools.h
index 83b79d759d..b39e43f96b 100644
--- a/include/deal.II/grid/grid_tools.h
+++ b/include/deal.II/grid/grid_tools.h
@@ -184,7 +184,11 @@ namespace GridTools
   volume(const Triangulation<dim, spacedim> &tria,
          const Mapping<dim, spacedim> &      mapping =
            (ReferenceCells::get_hypercube<dim>()
-              .template get_default_linear_mapping<dim, spacedim>()));
+              .
+#ifndef _MSC_VER
+              template
+#endif
+            get_default_linear_mapping<dim, spacedim>()));
 
   /**
    * Return an approximation of the diameter of the smallest active cell of a

[bangerth]

For reference, this is related to #11604.

[nicola-giuliani]

With the patch since _MSC_VER is not defined the error changes
error 2039: 'dealii::get_default_linear_mapping': is not a member of 'dealii::ReferenceCell'

[nicola-giuliani]

const dealii::Mapping<dim, spacedim>& mapping =
(dealii::ReferenceCells::get_hypercube().template get_default_linear_mapping<dim, spacedim>());
dealii::Triangulation<dim, spacedim> tria;
dealii::GridGenerator::hyper_cube(tria);
const double volume1 = dealii::GridTools::volume<dim, spacedim>(tria, mapping); //OK
const double volume2 = dealii::GridTools::volume<dim, spacedim>(tria); //ERROR

[nicola-giuliani]

This is done with the original implementation of volume.

[marcfehling]

@DaneilSun found a solution to the problem in #13593.

The patch just covers a small part of the library. I guess we need to adjust all other occurrences of .template get_default_linear_mapping accordingly.

[drwells]

This is now fixed - further changes are tracked in #13596.