From 363cf6d32fd5915692a71347650d7308127af72c Mon Sep 17 00:00:00 2001
From: Dmitri Naumov <github@naumov.de>
Date: Tue, 9 Mar 2021 23:33:50 +0100
Subject: [PATCH] Replace <boost/optional*> includes with <optional>

---
 Applications/ApplicationsLib/ProjectData.h                | 5 ++---
 Applications/FileIO/AsciiRasterInterface.cpp              | 5 ++---
 Applications/FileIO/AsciiRasterInterface.h                | 4 ++--
 BaseLib/Algorithm.h                                       | 2 +-
 ChemistryLib/Common/CreateReactionRate.cpp                | 2 +-
 ChemistryLib/Common/CreateReactionRate.h                  | 2 +-
 ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.cpp | 5 +++--
 ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.h   | 2 +-
 ChemistryLib/PhreeqcIOData/CreateKineticReactant.cpp      | 5 +++--
 ChemistryLib/PhreeqcIOData/CreateKineticReactant.h        | 2 +-
 ChemistryLib/PhreeqcIOData/CreateSurface.cpp              | 2 +-
 ChemistryLib/PhreeqcIOData/CreateSurface.h                | 2 +-
 ChemistryLib/PhreeqcIOData/CreateUserPunch.cpp            | 2 +-
 ChemistryLib/PhreeqcIOData/CreateUserPunch.h              | 2 +-
 ChemistryLib/PhreeqcIOData/KineticReactant.h              | 2 +-
 .../PhreeqcKernelData/CreateEquilibriumReactants.cpp      | 5 +++--
 .../PhreeqcKernelData/CreateEquilibriumReactants.h        | 2 +-
 ChemistryLib/PhreeqcKernelData/CreateKineticReactant.cpp  | 5 +++--
 ChemistryLib/PhreeqcKernelData/CreateKineticReactant.h    | 2 +-
 GeoLib/SurfaceGrid.h                                      | 3 +--
 MaterialLib/MPL/CreateComponent.h                         | 2 +-
 MaterialLib/MPL/CreatePhase.h                             | 2 +-
 MaterialLib/MPL/CreateProperty.h                          | 3 ++-
 MaterialLib/SolidModels/CreateConstitutiveRelation.h      | 2 +-
 MeshLib/Elements/Element.h                                | 8 +++-----
 MeshLib/IO/MPI_IO/PropertyVectorMetaData.h                | 2 +-
 NumLib/NewtonRaphson.h                                    | 6 +++---
 NumLib/ODESolver/ConvergenceCriterionDeltaX.h             | 3 ++-
 NumLib/ODESolver/ConvergenceCriterionResidual.h           | 3 ++-
 ParameterLib/Parameter.h                                  | 8 +++-----
 ParameterLib/SpatialPosition.h                            | 3 ++-
 ProcessLib/HydroMechanics/CreateHydroMechanicsProcess.h   | 2 +-
 .../LIE/HydroMechanics/CreateHydroMechanicsProcess.h      | 2 +-
 .../LIE/SmallDeformation/CreateSmallDeformationProcess.h  | 2 +-
 ProcessLib/PhaseField/CreatePhaseFieldProcess.h           | 2 +-
 .../RichardsMechanics/CreateRichardsMechanicsProcess.h    | 2 +-
 .../SmallDeformation/CreateSmallDeformationProcess.h      | 2 +-
 .../CreateSmallDeformationNonlocalProcess.h               | 2 +-
 .../CreateThermoHydroMechanicsProcess.h                   | 2 +-
 .../CreateThermoMechanicalPhaseFieldProcess.h             | 2 +-
 ProcessLib/ThermoMechanics/CreateThermoMechanicsProcess.h | 2 +-
 .../CreateThermoRichardsMechanicsProcess.h                | 2 +-
 42 files changed, 63 insertions(+), 62 deletions(-)

diff --git a/Applications/ApplicationsLib/ProjectData.h b/Applications/ApplicationsLib/ProjectData.h
index 3382051ecdc..47b57e49224 100644
--- a/Applications/ApplicationsLib/ProjectData.h
+++ b/Applications/ApplicationsLib/ProjectData.h
@@ -12,16 +12,15 @@
 
 #pragma once
 
-#include <boost/optional/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <string>
 
 #include "BaseLib/ConfigTree.h"
+#include "ChemistryLib/ChemicalSolverInterface.h"
 #include "MaterialLib/MPL/Medium.h"
 #include "MathLib/InterpolationAlgorithms/PiecewiseLinearInterpolation.h"
-
-#include "ChemistryLib/ChemicalSolverInterface.h"
 #include "ParameterLib/CoordinateSystem.h"
 #include "ParameterLib/Parameter.h"
 #include "ProcessLib/Process.h"
diff --git a/Applications/FileIO/AsciiRasterInterface.cpp b/Applications/FileIO/AsciiRasterInterface.cpp
index ea001828e8c..2c54be6a105 100644
--- a/Applications/FileIO/AsciiRasterInterface.cpp
+++ b/Applications/FileIO/AsciiRasterInterface.cpp
@@ -13,12 +13,11 @@
 
 #include "AsciiRasterInterface.h"
 
-#include <boost/optional.hpp>
-#include "BaseLib/Logging.h"
+#include <optional>
 
 #include "BaseLib/FileTools.h"
+#include "BaseLib/Logging.h"
 #include "BaseLib/StringTools.h"
-
 #include "GeoLib/Raster.h"
 
 namespace FileIO
diff --git a/Applications/FileIO/AsciiRasterInterface.h b/Applications/FileIO/AsciiRasterInterface.h
index 4420d88c894..e9fc471eb55 100644
--- a/Applications/FileIO/AsciiRasterInterface.h
+++ b/Applications/FileIO/AsciiRasterInterface.h
@@ -14,9 +14,9 @@
 #pragma once
 
 #include <fstream>
-#include <vector>
+#include <optional>
 #include <string>
-#include <boost/optional.hpp>
+#include <vector>
 
 #include "GeoLib/Raster.h"
 
diff --git a/BaseLib/Algorithm.h b/BaseLib/Algorithm.h
index 861dda11917..b7ebba8c49e 100644
--- a/BaseLib/Algorithm.h
+++ b/BaseLib/Algorithm.h
@@ -11,8 +11,8 @@
 #pragma once
 
 #include <algorithm>
-#include <boost/optional.hpp>
 #include <cassert>
+#include <optional>
 #include <string>
 #include <typeindex>
 #include <typeinfo>
diff --git a/ChemistryLib/Common/CreateReactionRate.cpp b/ChemistryLib/Common/CreateReactionRate.cpp
index a32b049b129..528590df23d 100644
--- a/ChemistryLib/Common/CreateReactionRate.cpp
+++ b/ChemistryLib/Common/CreateReactionRate.cpp
@@ -8,7 +8,7 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include <optional>
 
 #include "BaseLib/ConfigTree.h"
 #include "ChemistryLib/PhreeqcIOData/ReactionRate.h"
diff --git a/ChemistryLib/Common/CreateReactionRate.h b/ChemistryLib/Common/CreateReactionRate.h
index 4b590cf88ca..56a475dec7c 100644
--- a/ChemistryLib/Common/CreateReactionRate.h
+++ b/ChemistryLib/Common/CreateReactionRate.h
@@ -10,7 +10,7 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.cpp b/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.cpp
index e4f90c513a4..2694bdd872d 100644
--- a/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.cpp
+++ b/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.cpp
@@ -8,10 +8,11 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include "CreateEquilibriumReactants.h"
+
+#include <optional>
 
 #include "BaseLib/ConfigTree.h"
-#include "CreateEquilibriumReactants.h"
 #include "EquilibriumReactant.h"
 #include "MeshLib/Mesh.h"
 
diff --git a/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.h b/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.h
index beb4567e53d..abee96be548 100644
--- a/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.h
+++ b/ChemistryLib/PhreeqcIOData/CreateEquilibriumReactants.h
@@ -10,7 +10,7 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ChemistryLib/PhreeqcIOData/CreateKineticReactant.cpp b/ChemistryLib/PhreeqcIOData/CreateKineticReactant.cpp
index 3e1efb03e2e..042bb5d256a 100644
--- a/ChemistryLib/PhreeqcIOData/CreateKineticReactant.cpp
+++ b/ChemistryLib/PhreeqcIOData/CreateKineticReactant.cpp
@@ -8,10 +8,11 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include "CreateKineticReactant.h"
+
+#include <optional>
 
 #include "BaseLib/ConfigTree.h"
-#include "CreateKineticReactant.h"
 #include "KineticReactant.h"
 #include "MeshLib/Mesh.h"
 
diff --git a/ChemistryLib/PhreeqcIOData/CreateKineticReactant.h b/ChemistryLib/PhreeqcIOData/CreateKineticReactant.h
index e1a1ffaaba8..6505717fe89 100644
--- a/ChemistryLib/PhreeqcIOData/CreateKineticReactant.h
+++ b/ChemistryLib/PhreeqcIOData/CreateKineticReactant.h
@@ -10,7 +10,7 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ChemistryLib/PhreeqcIOData/CreateSurface.cpp b/ChemistryLib/PhreeqcIOData/CreateSurface.cpp
index 320ce8718fb..9c526bac265 100644
--- a/ChemistryLib/PhreeqcIOData/CreateSurface.cpp
+++ b/ChemistryLib/PhreeqcIOData/CreateSurface.cpp
@@ -8,7 +8,7 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include <optional>
 
 #include "BaseLib/ConfigTree.h"
 #include "Surface.h"
diff --git a/ChemistryLib/PhreeqcIOData/CreateSurface.h b/ChemistryLib/PhreeqcIOData/CreateSurface.h
index aa09e67c7d0..849dd6fe72f 100644
--- a/ChemistryLib/PhreeqcIOData/CreateSurface.h
+++ b/ChemistryLib/PhreeqcIOData/CreateSurface.h
@@ -10,7 +10,7 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ChemistryLib/PhreeqcIOData/CreateUserPunch.cpp b/ChemistryLib/PhreeqcIOData/CreateUserPunch.cpp
index d67764f5d42..27a038f3db9 100644
--- a/ChemistryLib/PhreeqcIOData/CreateUserPunch.cpp
+++ b/ChemistryLib/PhreeqcIOData/CreateUserPunch.cpp
@@ -8,7 +8,7 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include <optional>
 
 #include "BaseLib/ConfigTree.h"
 #include "MeshLib/Mesh.h"
diff --git a/ChemistryLib/PhreeqcIOData/CreateUserPunch.h b/ChemistryLib/PhreeqcIOData/CreateUserPunch.h
index 337e80b4a78..b7d506a9c7a 100644
--- a/ChemistryLib/PhreeqcIOData/CreateUserPunch.h
+++ b/ChemistryLib/PhreeqcIOData/CreateUserPunch.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
 #include <memory>
+#include <optional>
 
 namespace BaseLib
 {
diff --git a/ChemistryLib/PhreeqcIOData/KineticReactant.h b/ChemistryLib/PhreeqcIOData/KineticReactant.h
index 1859418b92c..93dd3ef9fac 100644
--- a/ChemistryLib/PhreeqcIOData/KineticReactant.h
+++ b/ChemistryLib/PhreeqcIOData/KineticReactant.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional/optional.hpp>
 #include <iosfwd>
+#include <optional>
 #include <string>
 #include <vector>
 
diff --git a/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.cpp b/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.cpp
index 4e395334b3f..d384b9a946a 100644
--- a/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.cpp
+++ b/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.cpp
@@ -8,11 +8,12 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include "CreateEquilibriumReactants.h"
+
+#include <optional>
 #include <vector>
 
 #include "BaseLib/ConfigTree.h"
-#include "CreateEquilibriumReactants.h"
 #include "EquilibriumReactants.h"
 #include "MeshLib/Mesh.h"
 
diff --git a/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.h b/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.h
index ff9b224b709..5696be00a33 100644
--- a/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.h
+++ b/ChemistryLib/PhreeqcKernelData/CreateEquilibriumReactants.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
 #include <memory>
+#include <optional>
 
 #include "EquilibriumReactants.h"
 
diff --git a/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.cpp b/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.cpp
index 9e62e56b735..51f8676bccc 100644
--- a/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.cpp
+++ b/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.cpp
@@ -8,11 +8,12 @@
  *
  */
 
-#include <boost/optional/optional.hpp>
+#include "CreateKineticReactant.h"
+
+#include <optional>
 #include <vector>
 
 #include "BaseLib/ConfigTree.h"
-#include "CreateKineticReactant.h"
 #include "KineticReactant.h"
 #include "MeshLib/Mesh.h"
 
diff --git a/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.h b/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.h
index 12da8a28813..9d7592768f6 100644
--- a/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.h
+++ b/ChemistryLib/PhreeqcKernelData/CreateKineticReactant.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional/optional_fwd.hpp>
 #include <memory>
+#include <optional>
 
 #include "KineticReactant.h"
 
diff --git a/GeoLib/SurfaceGrid.h b/GeoLib/SurfaceGrid.h
index b6de0983ab4..c72914a528e 100644
--- a/GeoLib/SurfaceGrid.h
+++ b/GeoLib/SurfaceGrid.h
@@ -14,10 +14,9 @@
 
 #include <array>
 #include <limits>
+#include <optional>
 #include <vector>
 
-#include <boost/optional.hpp>
-
 #include "AABB.h"
 #include "Point.h"
 
diff --git a/MaterialLib/MPL/CreateComponent.h b/MaterialLib/MPL/CreateComponent.h
index ad47396c493..a74727b66df 100644
--- a/MaterialLib/MPL/CreateComponent.h
+++ b/MaterialLib/MPL/CreateComponent.h
@@ -12,9 +12,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 
 #include "Component.h"
 
diff --git a/MaterialLib/MPL/CreatePhase.h b/MaterialLib/MPL/CreatePhase.h
index 5b50e129c89..c808eedc27d 100644
--- a/MaterialLib/MPL/CreatePhase.h
+++ b/MaterialLib/MPL/CreatePhase.h
@@ -12,9 +12,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/MaterialLib/MPL/CreateProperty.h b/MaterialLib/MPL/CreateProperty.h
index 28b0f79bc8d..f06ffe1dcd8 100644
--- a/MaterialLib/MPL/CreateProperty.h
+++ b/MaterialLib/MPL/CreateProperty.h
@@ -11,9 +11,10 @@
  */
 #pragma once
 
-#include <boost/optional/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
+
 #include "PropertyType.h"
 
 namespace BaseLib
diff --git a/MaterialLib/SolidModels/CreateConstitutiveRelation.h b/MaterialLib/SolidModels/CreateConstitutiveRelation.h
index 926906b5d2e..a382df86675 100644
--- a/MaterialLib/SolidModels/CreateConstitutiveRelation.h
+++ b/MaterialLib/SolidModels/CreateConstitutiveRelation.h
@@ -11,9 +11,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/MeshLib/Elements/Element.h b/MeshLib/Elements/Element.h
index 17d3ce7bbdd..2a29f390996 100644
--- a/MeshLib/Elements/Element.h
+++ b/MeshLib/Elements/Element.h
@@ -15,14 +15,12 @@
 #pragma once
 
 #include <limits>
-#include <boost/optional.hpp>
+#include <optional>
 
 #include "MathLib/Point3d.h"
-
-#include "MeshLib/MeshEnums.h"
-#include "MeshLib/Mesh.h"
 #include "MeshLib/Elements/ElementErrorCode.h"
-
+#include "MeshLib/Mesh.h"
+#include "MeshLib/MeshEnums.h"
 
 namespace MeshLib {
 
diff --git a/MeshLib/IO/MPI_IO/PropertyVectorMetaData.h b/MeshLib/IO/MPI_IO/PropertyVectorMetaData.h
index 4518ecaeadc..4e2f9d2a0b3 100644
--- a/MeshLib/IO/MPI_IO/PropertyVectorMetaData.h
+++ b/MeshLib/IO/MPI_IO/PropertyVectorMetaData.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
+#include <optional>
 #include <string>
-#include <boost/optional.hpp>
 
 namespace MeshLib
 {
diff --git a/NumLib/NewtonRaphson.h b/NumLib/NewtonRaphson.h
index 82a21983b1f..f3c86a44b2c 100644
--- a/NumLib/NewtonRaphson.h
+++ b/NumLib/NewtonRaphson.h
@@ -10,10 +10,10 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
-#include "BaseLib/Logging.h"
-
 #include <Eigen/Dense>
+#include <optional>
+
+#include "BaseLib/Logging.h"
 
 namespace NumLib
 {
diff --git a/NumLib/ODESolver/ConvergenceCriterionDeltaX.h b/NumLib/ODESolver/ConvergenceCriterionDeltaX.h
index 63169f1c2f8..89d80301404 100644
--- a/NumLib/ODESolver/ConvergenceCriterionDeltaX.h
+++ b/NumLib/ODESolver/ConvergenceCriterionDeltaX.h
@@ -10,7 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
+#include <optional>
+
 #include "ConvergenceCriterion.h"
 #include "MathLib/LinAlg/LinAlgEnums.h"
 
diff --git a/NumLib/ODESolver/ConvergenceCriterionResidual.h b/NumLib/ODESolver/ConvergenceCriterionResidual.h
index 0572681c970..dd402f1afd5 100644
--- a/NumLib/ODESolver/ConvergenceCriterionResidual.h
+++ b/NumLib/ODESolver/ConvergenceCriterionResidual.h
@@ -10,7 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
+#include <optional>
+
 #include "ConvergenceCriterion.h"
 #include "MathLib/LinAlg/LinAlgEnums.h"
 
diff --git a/ParameterLib/Parameter.h b/ParameterLib/Parameter.h
index 7262b1231ad..337e6087a0a 100644
--- a/ParameterLib/Parameter.h
+++ b/ParameterLib/Parameter.h
@@ -10,19 +10,17 @@
 
 #pragma once
 
+#include <Eigen/Dense>
 #include <map>
 #include <memory>
+#include <optional>
 #include <utility>
 #include <vector>
 
-#include <Eigen/Dense>
-#include <boost/optional.hpp>
-
 #include "BaseLib/Error.h"
+#include "CoordinateSystem.h"
 #include "MeshLib/Elements/Element.h"
 #include "MeshLib/Node.h"
-
-#include "CoordinateSystem.h"
 #include "SpatialPosition.h"
 
 namespace BaseLib
diff --git a/ParameterLib/SpatialPosition.h b/ParameterLib/SpatialPosition.h
index 8bae9ff0199..75e8080c0d6 100644
--- a/ParameterLib/SpatialPosition.h
+++ b/ParameterLib/SpatialPosition.h
@@ -10,7 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
+#include <optional>
+
 #include "MathLib/TemplatePoint.h"
 
 namespace ParameterLib
diff --git a/ProcessLib/HydroMechanics/CreateHydroMechanicsProcess.h b/ProcessLib/HydroMechanics/CreateHydroMechanicsProcess.h
index d6b89f4d074..f2187922db1 100644
--- a/ProcessLib/HydroMechanics/CreateHydroMechanicsProcess.h
+++ b/ProcessLib/HydroMechanics/CreateHydroMechanicsProcess.h
@@ -10,9 +10,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.h b/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.h
index 9703343e8cf..d6aaa6e89b7 100644
--- a/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.h
+++ b/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/LIE/SmallDeformation/CreateSmallDeformationProcess.h b/ProcessLib/LIE/SmallDeformation/CreateSmallDeformationProcess.h
index 0b332c29fac..c694835b693 100644
--- a/ProcessLib/LIE/SmallDeformation/CreateSmallDeformationProcess.h
+++ b/ProcessLib/LIE/SmallDeformation/CreateSmallDeformationProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/PhaseField/CreatePhaseFieldProcess.h b/ProcessLib/PhaseField/CreatePhaseFieldProcess.h
index 94148eeae9e..41215d9f0da 100644
--- a/ProcessLib/PhaseField/CreatePhaseFieldProcess.h
+++ b/ProcessLib/PhaseField/CreatePhaseFieldProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/RichardsMechanics/CreateRichardsMechanicsProcess.h b/ProcessLib/RichardsMechanics/CreateRichardsMechanicsProcess.h
index 985cade3a00..98d962d7d7f 100644
--- a/ProcessLib/RichardsMechanics/CreateRichardsMechanicsProcess.h
+++ b/ProcessLib/RichardsMechanics/CreateRichardsMechanicsProcess.h
@@ -10,9 +10,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.h b/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.h
index 92669851db3..f7eff7c3a59 100644
--- a/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.h
+++ b/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/SmallDeformationNonlocal/CreateSmallDeformationNonlocalProcess.h b/ProcessLib/SmallDeformationNonlocal/CreateSmallDeformationNonlocalProcess.h
index bc6f5f4f7a1..41306249c47 100644
--- a/ProcessLib/SmallDeformationNonlocal/CreateSmallDeformationNonlocalProcess.h
+++ b/ProcessLib/SmallDeformationNonlocal/CreateSmallDeformationNonlocalProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/ThermoHydroMechanics/CreateThermoHydroMechanicsProcess.h b/ProcessLib/ThermoHydroMechanics/CreateThermoHydroMechanicsProcess.h
index a1491853e8c..07775220cb3 100644
--- a/ProcessLib/ThermoHydroMechanics/CreateThermoHydroMechanicsProcess.h
+++ b/ProcessLib/ThermoHydroMechanics/CreateThermoHydroMechanicsProcess.h
@@ -10,9 +10,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/ThermoMechanicalPhaseField/CreateThermoMechanicalPhaseFieldProcess.h b/ProcessLib/ThermoMechanicalPhaseField/CreateThermoMechanicalPhaseFieldProcess.h
index 961fe10a7ac..99b4bf527d8 100644
--- a/ProcessLib/ThermoMechanicalPhaseField/CreateThermoMechanicalPhaseFieldProcess.h
+++ b/ProcessLib/ThermoMechanicalPhaseField/CreateThermoMechanicalPhaseFieldProcess.h
@@ -10,8 +10,8 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/ThermoMechanics/CreateThermoMechanicsProcess.h b/ProcessLib/ThermoMechanics/CreateThermoMechanicsProcess.h
index e5df4802247..bb0d24ed5d1 100644
--- a/ProcessLib/ThermoMechanics/CreateThermoMechanicsProcess.h
+++ b/ProcessLib/ThermoMechanics/CreateThermoMechanicsProcess.h
@@ -10,9 +10,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
diff --git a/ProcessLib/ThermoRichardsMechanics/CreateThermoRichardsMechanicsProcess.h b/ProcessLib/ThermoRichardsMechanics/CreateThermoRichardsMechanicsProcess.h
index 9e96c7650dc..761938baed3 100644
--- a/ProcessLib/ThermoRichardsMechanics/CreateThermoRichardsMechanicsProcess.h
+++ b/ProcessLib/ThermoRichardsMechanics/CreateThermoRichardsMechanicsProcess.h
@@ -10,9 +10,9 @@
 
 #pragma once
 
-#include <boost/optional.hpp>
 #include <map>
 #include <memory>
+#include <optional>
 #include <vector>
 
 namespace BaseLib
-- 
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