Source: fenics-dolfinx Followup-For: Bug #1012923 Judging by https://github.com/doxygen/doxygen/commit/5198966c8d5fec89116d025c74934ac03ea511fa likely needs #include <utility> added to cpp/dolfinx/la/PETScOperator.cpp There are some code rearrangements in dolfinx 0.4, let's check again with that version.