fix compilation by putting back std::move()

diff --git a/source/differentiation/sd/symengine_number_types.cc b/source/differentiation/sd/symengine_number_types.cc
index 2e02a91425806d69898046460d2cac67e1dae536..1a1a4a0d0afa52f8dc74d02af972abd56d923bf9 100644 (file)
--- a/source/differentiation/sd/symengine_number_types.cc
+++ b/source/differentiation/sd/symengine_number_types.cc
@@ -102,8 +102,9 @@ namespace Differentiation
       piecewise_function.emplace_back(expression_otherwise.get_RCP(),
                                       SE::boolTrue);
 
-      // Initialize
-      expression = SE::piecewise(piecewise_function);
+      // Initialize. Note that we need to use a std::move() here for
+      // compatibility with older compilers.
+      expression = SE::piecewise(std::move(piecewise_function)); // NOLINT
     }