From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Thu, 1 Feb 2024 04:44:11 +0000 (-0700)
Subject: Use DEAL_II_UNREACHABLE() in include/ and source/.
X-Git-Tag: relicensing~68^2~1
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9146ca37dd2505c99ac6eac9ce02071c077fb4cf;p=dealii.git

Use DEAL_II_UNREACHABLE() in include/ and source/.
---

diff --git a/include/deal.II/base/geometry_info.h b/include/deal.II/base/geometry_info.h
index daf0d42c61..c56482e72a 100644
--- a/include/deal.II/base/geometry_info.h
+++ b/include/deal.II/base/geometry_info.h
@@ -2747,7 +2747,7 @@ template <int dim>
 inline RefinementCase<dim>
 RefinementCase<dim>::cut_axis(const unsigned int)
 {
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return static_cast<std::uint8_t>(-1);
 }
 
@@ -3099,7 +3099,7 @@ GeometryInfo<2>::cell_to_child_coordinates(const Point<2>         &p,
         point -= unit_cell_vertex(child_index);
         break;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   return point;
@@ -3172,7 +3172,7 @@ GeometryInfo<3>::cell_to_child_coordinates(const Point<3>         &p,
         point -= unit_cell_vertex(child_index);
         break;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   return point;
@@ -3275,7 +3275,7 @@ GeometryInfo<3>::child_to_cell_coordinates(const Point<3>         &p,
         point *= 0.5;
         break;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   return point;
@@ -3309,7 +3309,7 @@ GeometryInfo<2>::child_to_cell_coordinates(const Point<2>         &p,
         point *= 0.5;
         break;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   return point;
@@ -3625,7 +3625,7 @@ GeometryInfo<2>::subface_ratio(const internal::SubfaceCase<2> &subface_case,
       default:
         // there should be no
         // cases left
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
         break;
     }
 
@@ -3682,7 +3682,7 @@ GeometryInfo<3>::subface_ratio(const internal::SubfaceCase<3> &subface_case,
       default:
         // there should be no
         // cases left
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
         break;
     }
 
diff --git a/include/deal.II/base/hdf5.h b/include/deal.II/base/hdf5.h
index dc5bad3af3..9ab994f817 100644
--- a/include/deal.II/base/hdf5.h
+++ b/include/deal.II/base/hdf5.h
@@ -1352,7 +1352,7 @@ namespace HDF5
         }
 
       // The function should not reach this point
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return {};
     }
 
diff --git a/include/deal.II/base/symmetric_tensor.h b/include/deal.II/base/symmetric_tensor.h
index 3ba5c9abd8..9f12be21fd 100644
--- a/include/deal.II/base/symmetric_tensor.h
+++ b/include/deal.II/base/symmetric_tensor.h
@@ -304,7 +304,7 @@ namespace internal
                     previous_indices[2],
                     new_index};
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             return {};
         }
     }
@@ -2067,7 +2067,7 @@ namespace internal
                     return dim + c;
 
               // should never get here:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               return 0;
             }
         }
@@ -2543,7 +2543,7 @@ namespace internal
                   return {d, e};
 
             // should never get here:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             return {0, 0};
         }
     }
diff --git a/include/deal.II/base/table.h b/include/deal.II/base/table.h
index 5c89443189..31ff756a81 100644
--- a/include/deal.II/base/table.h
+++ b/include/deal.II/base/table.h
@@ -2873,7 +2873,7 @@ namespace MatrixTableIterators
           case Storage::column_major:
             return linear_index % container->n_rows();
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
       return {};
     }
@@ -2892,7 +2892,7 @@ namespace MatrixTableIterators
           case Storage::column_major:
             return linear_index / container->n_rows();
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
       return {};
     }
diff --git a/include/deal.II/base/table_handler.h b/include/deal.II/base/table_handler.h
index 1e019f7e38..b354a893fa 100644
--- a/include/deal.II/base/table_handler.h
+++ b/include/deal.II/base/table_handler.h
@@ -875,7 +875,7 @@ namespace internal
         ar &c              &p;
       }
     else
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
   }
 
 
@@ -934,7 +934,7 @@ namespace internal
           }
 
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
   }
 } // namespace internal
diff --git a/include/deal.II/base/utilities.h b/include/deal.II/base/utilities.h
index 697fc21054..ac56967ac1 100644
--- a/include/deal.II/base/utilities.h
+++ b/include/deal.II/base/utilities.h
@@ -1105,7 +1105,7 @@ namespace Utilities
                   // somehow? that
                   // shouldn't have
                   // happened
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
           }
 
@@ -1179,7 +1179,7 @@ namespace Utilities
                                                   std::vector<char> &)
     {
       // We shouldn't get here:
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
@@ -1269,7 +1269,7 @@ namespace Utilities
       T &)
     {
       // We shouldn't get here:
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
diff --git a/include/deal.II/cgal/triangulation.h b/include/deal.II/cgal/triangulation.h
index 269b4886f2..bbfef45533 100644
--- a/include/deal.II/cgal/triangulation.h
+++ b/include/deal.II/cgal/triangulation.h
@@ -388,7 +388,7 @@ namespace CGALWrappers
             }
         else
           {
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
           }
       }
     else if constexpr (decltype(has_cells(cgal_triangulation)){})
@@ -439,7 +439,7 @@ namespace CGALWrappers
             }
         else
           {
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
           }
       }
     dealii_triangulation.create_triangulation(vertices, cells, subcell_data);
diff --git a/include/deal.II/cgal/utilities.h b/include/deal.II/cgal/utilities.h
index 08928415be..63751b0e65 100644
--- a/include/deal.II/cgal/utilities.h
+++ b/include/deal.II/cgal/utilities.h
@@ -593,7 +593,7 @@ namespace CGALWrappers
       }
     else
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
       }
   }
 
diff --git a/include/deal.II/distributed/cell_data_transfer.templates.h b/include/deal.II/distributed/cell_data_transfer.templates.h
index 2d07185618..3a7691810c 100644
--- a/include/deal.II/distributed/cell_data_transfer.templates.h
+++ b/include/deal.II/distributed/cell_data_transfer.templates.h
@@ -286,7 +286,7 @@ namespace parallel
                 }
 
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
                 break;
             }
         }
@@ -357,7 +357,7 @@ namespace parallel
               }
 
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               break;
           }
     }
diff --git a/include/deal.II/dofs/dof_accessor.templates.h b/include/deal.II/dofs/dof_accessor.templates.h
index 51a7868d30..59f063d2fc 100644
--- a/include/deal.II/dofs/dof_accessor.templates.h
+++ b/include/deal.II/dofs/dof_accessor.templates.h
@@ -481,7 +481,7 @@ namespace internal
       process_object_range(dealii::DoFInvalidAccessor<structdim, dim, spacedim>,
                            const unsigned int)
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 
         return {0, 0};
       }
@@ -1177,7 +1177,7 @@ namespace internal
             vertex_index,
             fe_index,
             [](const auto d) {
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               return d;
             },
             std::integral_constant<int, 0>(),
diff --git a/include/deal.II/fe/fe_data.h b/include/deal.II/fe/fe_data.h
index 0fddc49f1a..99c87db261 100644
--- a/include/deal.II/fe/fe_data.h
+++ b/include/deal.II/fe/fe_data.h
@@ -765,7 +765,7 @@ namespace FiniteElementDomination
 
         default:
           // shouldn't get here
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
 
     return neither_element_dominates;
@@ -891,7 +891,7 @@ FiniteElementData<dim>::n_dofs_per_object(const unsigned int i) const
       case 3:
         return n_dofs_per_hex();
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
   return numbers::invalid_unsigned_int;
 }
diff --git a/include/deal.II/fe/fe_values_views.h b/include/deal.II/fe/fe_values_views.h
index 868ad4b99a..9afe26be20 100644
--- a/include/deal.II/fe/fe_values_views.h
+++ b/include/deal.II/fe/fe_values_views.h
@@ -2459,7 +2459,7 @@ namespace FEValuesViews
             }
         }
     // should not end up here
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return curl_type();
   }
 
diff --git a/include/deal.II/fe/mapping_q_internal.h b/include/deal.II/fe/mapping_q_internal.h
index 5bde81b124..3db783ad85 100644
--- a/include/deal.II/fe/mapping_q_internal.h
+++ b/include/deal.II/fe/mapping_q_internal.h
@@ -178,7 +178,7 @@ namespace internal
         }
       // bogus return to placate compiler. It should not be possible to get
       // here.
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return {std::numeric_limits<double>::quiet_NaN(),
               std::numeric_limits<double>::quiet_NaN()};
     }
@@ -193,7 +193,7 @@ namespace internal
       const Point<spacedim> & /*p*/)
     {
       // It should not be possible to get here
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return {std::numeric_limits<double>::quiet_NaN(),
               std::numeric_limits<double>::quiet_NaN(),
               std::numeric_limits<double>::quiet_NaN()};
diff --git a/include/deal.II/grid/manifold.h b/include/deal.II/grid/manifold.h
index 64ee20410a..53b8cf4252 100644
--- a/include/deal.II/grid/manifold.h
+++ b/include/deal.II/grid/manifold.h
@@ -1254,7 +1254,7 @@ namespace Manifolds
           }
           break;
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
     return points_weights;
diff --git a/include/deal.II/grid/reference_cell.h b/include/deal.II/grid/reference_cell.h
index e159dc9c00..0cf6bc98c8 100644
--- a/include/deal.II/grid/reference_cell.h
+++ b/include/deal.II/grid/reference_cell.h
@@ -2204,7 +2204,7 @@ ReferenceCell::d_linear_shape_function(const Point<dim>  &xi,
               case 2:
                 return xi[std::min(1, dim - 1)];
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
         }
       // see also BarycentricPolynomials<3>::compute_value
@@ -2222,7 +2222,7 @@ ReferenceCell::d_linear_shape_function(const Point<dim>  &xi,
               case 3:
                 return xi[std::min(2, dim - 1)];
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
         }
       // see also ScalarLagrangePolynomialPyramid::compute_value()
@@ -2290,7 +2290,7 @@ ReferenceCell::d_linear_shape_function_gradient(const Point<dim>  &xi,
             case 2:
               return Point<dim>(+0.0, +1.0);
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
       default:
         DEAL_II_NOT_IMPLEMENTED();
@@ -2598,7 +2598,7 @@ ReferenceCell::n_face_orientations(const unsigned int face_no) const
   else if (face_reference_cell(face_no) == ReferenceCells::Triangle)
     return 6;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return numbers::invalid_unsigned_int;
 }
 
diff --git a/include/deal.II/grid/tria_accessor.h b/include/deal.II/grid/tria_accessor.h
index 4a0c59401b..600dfbf5a8 100644
--- a/include/deal.II/grid/tria_accessor.h
+++ b/include/deal.II/grid/tria_accessor.h
@@ -117,13 +117,13 @@ namespace internal
         void
         operator++() const
         {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
         void
         operator--() const
         {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
       };
     };
diff --git a/include/deal.II/grid/tria_accessor.templates.h b/include/deal.II/grid/tria_accessor.templates.h
index 026e698a20..307a7b74de 100644
--- a/include/deal.II/grid/tria_accessor.templates.h
+++ b/include/deal.II/grid/tria_accessor.templates.h
@@ -365,7 +365,7 @@ TriaAccessorBase<structdim, dim, spacedim>::objects() const
   if (structdim == 2 && dim > 2)
     return this->tria->faces->quads;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 
   return this->tria->levels[this->present_level]->cells;
 }
@@ -867,7 +867,7 @@ namespace internal
         const unsigned int,
         const unsigned char)
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
       }
 
 
@@ -893,7 +893,7 @@ namespace internal
                            const unsigned int,
                            const bool)
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
       }
 
 
@@ -905,7 +905,7 @@ namespace internal
       {
         // quads in 2d have no
         // non-standard orientation
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
       }
 
 
@@ -994,7 +994,7 @@ namespace internal
       static std::array<unsigned int, 1>
       get_line_indices_of_cell(const TriaAccessor<1, dim, spacedim> &)
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
         return {};
       }
 
@@ -1107,7 +1107,7 @@ namespace internal
       static std::array<unsigned char, 1>
       get_line_orientations_of_cell(const TriaAccessor<1, dim, spacedim> &)
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
         return {};
       }
 
@@ -2953,7 +2953,7 @@ TriaAccessor<0, 1, spacedim>::copy_from(
   // We cannot convert from TriaAccessorBase to
   // TriaAccessor<0,1,spacedim> because the latter is not derived from
   // the former. We should never get here.
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
@@ -3806,7 +3806,7 @@ CellAccessor<3>::subface_case(const unsigned int face_no) const
       case RefinementCase<3>::cut_xy:
         return dealii::internal::SubfaceCase<3>::case_xy;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
   // we should never get here
   return dealii::internal::SubfaceCase<3>::case_none;
diff --git a/include/deal.II/lac/block_sparsity_pattern.h b/include/deal.II/lac/block_sparsity_pattern.h
index f0cb6f49b8..6e5437b821 100644
--- a/include/deal.II/lac/block_sparsity_pattern.h
+++ b/include/deal.II/lac/block_sparsity_pattern.h
@@ -1071,7 +1071,7 @@ BlockDynamicSparsityPattern::column_number(const size_type    row,
       block_columns += sub_objects[row_index.first][b]->n_cols();
     }
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return 0;
 }
 
diff --git a/include/deal.II/lac/la_parallel_vector.templates.h b/include/deal.II/lac/la_parallel_vector.templates.h
index cba700b26c..3d341e42a5 100644
--- a/include/deal.II/lac/la_parallel_vector.templates.h
+++ b/include/deal.II/lac/la_parallel_vector.templates.h
@@ -242,7 +242,7 @@ namespace LinearAlgebra
                                     }};
 
 #else
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
 #endif
             }
         }
diff --git a/include/deal.II/lac/solver_gmres.h b/include/deal.II/lac/solver_gmres.h
index 72234c8c05..4ef8472bc1 100644
--- a/include/deal.II/lac/solver_gmres.h
+++ b/include/deal.II/lac/solver_gmres.h
@@ -1682,7 +1682,7 @@ SolverGMRES<VectorType>::criterion()
 {
   // dummy implementation. this function is not needed for the present
   // implementation of gmres
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return 0;
 }
 
diff --git a/include/deal.II/lac/sparse_vanka.templates.h b/include/deal.II/lac/sparse_vanka.templates.h
index e78507d94e..99c2f652ed 100644
--- a/include/deal.II/lac/sparse_vanka.templates.h
+++ b/include/deal.II/lac/sparse_vanka.templates.h
@@ -552,7 +552,7 @@ SparseBlockVanka<number>::compute_dof_masks(
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 }
 
diff --git a/include/deal.II/lac/tridiagonal_matrix.h b/include/deal.II/lac/tridiagonal_matrix.h
index 09e59a70b5..2791c9f919 100644
--- a/include/deal.II/lac/tridiagonal_matrix.h
+++ b/include/deal.II/lac/tridiagonal_matrix.h
@@ -310,7 +310,7 @@ TridiagonalMatrix<number>::operator()(size_type i, size_type j) const
   if (j == i + 1)
     return right[i];
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return 0;
 }
 
@@ -337,7 +337,7 @@ TridiagonalMatrix<number>::operator()(size_type i, size_type j)
   if (j == i + 1)
     return right[i];
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return diagonal[0];
 }
 
diff --git a/include/deal.II/matrix_free/cuda_matrix_free.templates.h b/include/deal.II/matrix_free/cuda_matrix_free.templates.h
index 3709471ae3..75e1967a5c 100644
--- a/include/deal.II/matrix_free/cuda_matrix_free.templates.h
+++ b/include/deal.II/matrix_free/cuda_matrix_free.templates.h
@@ -1141,7 +1141,7 @@ namespace CUDAWrappers
     const LinearAlgebra::CUDAWrappers::Vector<Number> &,
     LinearAlgebra::CUDAWrappers::Vector<Number> &) const
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 #endif
 } // namespace CUDAWrappers
diff --git a/include/deal.II/matrix_free/evaluation_kernels_face.h b/include/deal.II/matrix_free/evaluation_kernels_face.h
index a4e61c773c..6ffba4231c 100644
--- a/include/deal.II/matrix_free/evaluation_kernels_face.h
+++ b/include/deal.II/matrix_free/evaluation_kernels_face.h
@@ -1034,7 +1034,7 @@ namespace internal
           // This should never happen since the FE_RaviartThomasNodal is not
           // defined for dim = 1. It prevents compiler warnings of infinite
           // recursion.
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return;
         }
 
@@ -2859,7 +2859,7 @@ namespace internal
           {
             // We should not end up here, this should be caught by
             // FEFaceEvaluationImplGatherEvaluateSelector::supports()
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
           }
         temp1 += 3 * dofs_per_face;
       }
diff --git a/include/deal.II/matrix_free/evaluation_kernels_hanging_nodes.h b/include/deal.II/matrix_free/evaluation_kernels_hanging_nodes.h
index 2612800ff6..5dc2d9c0d5 100644
--- a/include/deal.II/matrix_free/evaluation_kernels_hanging_nodes.h
+++ b/include/deal.II/matrix_free/evaluation_kernels_hanging_nodes.h
@@ -704,7 +704,7 @@ namespace internal
     {
       (void)kind;
 
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
 
       return v > 0; // should not be called
     }
diff --git a/include/deal.II/matrix_free/fe_point_evaluation.h b/include/deal.II/matrix_free/fe_point_evaluation.h
index 8ff84419aa..ff197c6b40 100644
--- a/include/deal.II/matrix_free/fe_point_evaluation.h
+++ b/include/deal.II/matrix_free/fe_point_evaluation.h
@@ -3509,7 +3509,7 @@ FEFacePointEvaluation<n_components_, dim, spacedim, Number>::
               else if (dim == 2)
                 gradient[0] = interpolated_value[0];
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           else if (this->current_face_number / 2 == 2)
             {
@@ -3520,10 +3520,10 @@ FEFacePointEvaluation<n_components_, dim, spacedim, Number>::
                   gradient[2] = interpolated_value[dim];
                 }
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           else
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
       else
         {
@@ -3700,7 +3700,7 @@ FEFacePointEvaluation<n_components_, dim, spacedim, Number>::
               else if (dim == 2)
                 gradient_in_face[0] = gradient[0];
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           else if (this->current_face_number / 2 == 2)
             {
@@ -3711,10 +3711,10 @@ FEFacePointEvaluation<n_components_, dim, spacedim, Number>::
                   gradient_in_face[1] = gradient[1];
                 }
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           else
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
 
           internal::integrate_tensor_product_value_and_gradient<
             is_linear,
diff --git a/include/deal.II/matrix_free/tensor_product_kernels.h b/include/deal.II/matrix_free/tensor_product_kernels.h
index 93fb94d5da..0ae8d2fa77 100644
--- a/include/deal.II/matrix_free/tensor_product_kernels.h
+++ b/include/deal.II/matrix_free/tensor_product_kernels.h
@@ -2071,7 +2071,7 @@ namespace internal
                           const Point<0, Number> &,
                           const unsigned int)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 
 
diff --git a/include/deal.II/meshworker/integration_info.h b/include/deal.II/meshworker/integration_info.h
index c138615eae..b773c7b432 100644
--- a/include/deal.II/meshworker/integration_info.h
+++ b/include/deal.II/meshworker/integration_info.h
@@ -628,7 +628,7 @@ namespace MeshWorker
             ps->get_quadrature(),
             ps->get_update_flags());
         else
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
   }
 #endif
diff --git a/include/deal.II/multigrid/mg_transfer_global_coarsening.templates.h b/include/deal.II/multigrid/mg_transfer_global_coarsening.templates.h
index bdf21af886..bb3e24d4b2 100644
--- a/include/deal.II/multigrid/mg_transfer_global_coarsening.templates.h
+++ b/include/deal.II/multigrid/mg_transfer_global_coarsening.templates.h
@@ -597,7 +597,7 @@ namespace internal
     {
       return FineDoFHandlerViewCell(
         []() {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return false;
         },
         [this, cell](auto &dof_indices) {
@@ -622,16 +622,16 @@ namespace internal
     get_cell_view(const typename DoFHandler<dim>::cell_iterator &,
                   const unsigned int) const override
     {
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
 
       return FineDoFHandlerViewCell(
         []() {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return false;
         },
-        [](auto &) { Assert(false, ExcInternalError()); },
+        [](auto &) { DEAL_II_ASSERT_UNREACHABLE(); },
         []() {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return 0;
         });
     }
@@ -715,7 +715,7 @@ namespace internal
     {
       return FineDoFHandlerViewCell(
         []() {
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return false;
         },
         [this, cell, c](auto &dof_indices) {
diff --git a/include/deal.II/numerics/data_out_dof_data.templates.h b/include/deal.II/numerics/data_out_dof_data.templates.h
index 3f258ecd64..7405726891 100644
--- a/include/deal.II/numerics/data_out_dof_data.templates.h
+++ b/include/deal.II/numerics/data_out_dof_data.templates.h
@@ -693,7 +693,7 @@ namespace internal
             return value.imag();
 
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
 
       return numbers::signaling_nan<double>();
@@ -1173,7 +1173,7 @@ namespace internal
       else if (actual_type == DataVectorType::type_cell_data)
         create_cell_vector(*data, vector);
       else
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
@@ -1926,7 +1926,7 @@ DataOut_DoFData<dim, patch_dim, spacedim, patch_spacedim>::
                  deduced_names.size(), dof_handler->get_fe(0).n_components()));
         break;
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   const auto &data_component_interpretation =
@@ -2165,7 +2165,7 @@ DataOut_DoFData<dim, patch_dim, spacedim, patch_spacedim>::get_dataset_names()
                   }
 
                 default:
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
           }
       }
diff --git a/include/deal.II/numerics/vector_tools_boundary.templates.h b/include/deal.II/numerics/vector_tools_boundary.templates.h
index 533253009d..8ae9d745ec 100644
--- a/include/deal.II/numerics/vector_tools_boundary.templates.h
+++ b/include/deal.II/numerics/vector_tools_boundary.templates.h
@@ -1287,7 +1287,7 @@ namespace VectorTools
     {
       // dummy implementation of above function
       // for all other dimensions
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
diff --git a/include/deal.II/numerics/vector_tools_project.templates.h b/include/deal.II/numerics/vector_tools_project.templates.h
index 43fa6e6b93..e3a7f38a56 100644
--- a/include/deal.II/numerics/vector_tools_project.templates.h
+++ b/include/deal.II/numerics/vector_tools_project.templates.h
@@ -397,7 +397,7 @@ namespace VectorTools
             break;
 
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
     }
 
diff --git a/include/deal.II/trilinos/nox.templates.h b/include/deal.II/trilinos/nox.templates.h
index 951fb22983..bde8680a1a 100644
--- a/include/deal.II/trilinos/nox.templates.h
+++ b/include/deal.II/trilinos/nox.templates.h
@@ -284,7 +284,7 @@ namespace TrilinosWrappers
           if (type == NOX::Abstract::Vector::NormType::MaxNorm)
             return vector->linfty_norm();
 
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
 
           return 0.0;
         }
diff --git a/source/base/data_out_base.cc b/source/base/data_out_base.cc
index 83b0167bb7..b2bc85ca59 100644
--- a/source/base/data_out_base.cc
+++ b/source/base/data_out_base.cc
@@ -1340,7 +1340,7 @@ namespace
     set_node_numbers(const unsigned int /*start*/,
                      const std::array<unsigned int, 0> & /*d1*/)
     {
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return {};
     }
 
@@ -2396,7 +2396,7 @@ namespace DataOutBase
     else
       // we shouldn't get here, since the parameter object should already have
       // checked that the given value is valid
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
   }
 
 
@@ -2590,7 +2590,7 @@ namespace DataOutBase
                   break;
 
                 default:
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
           }
       }
@@ -3740,7 +3740,7 @@ namespace DataOutBase
                   // There aren't any other reference cells in 2d than the
                   // quadrilateral and the triangle. So whatever we got here
                   // can't be any good
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
                 // end of patch
                 out << '\n';
 
@@ -5152,7 +5152,7 @@ namespace DataOutBase
                 default:
                   // VTK doesn't support anything else than vectors with 1, 2,
                   // or 3 components
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
           }
       }
@@ -5934,7 +5934,7 @@ namespace DataOutBase
 
                     default:
                       // Anything else is not yet implemented
-                      Assert(false, ExcInternalError());
+                      DEAL_II_ASSERT_UNREACHABLE();
                   }
               }
             else
@@ -5972,7 +5972,7 @@ namespace DataOutBase
                   }
                 else
                   {
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                   }
 
                 // now put the tensor into data
diff --git a/source/base/hdf5.cc b/source/base/hdf5.cc
index c3851bbc69..3c5e35ad62 100644
--- a/source/base/hdf5.cc
+++ b/source/base/hdf5.cc
@@ -233,12 +233,12 @@ namespace HDF5
           return std::string("H5D_MPIO_CONTIGUOUS_COLLECTIVE");
           break;
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return std::string("Internal error");
           break;
       }
     // The function should not reach this line.
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return std::string("Internal error");
   }
 
@@ -356,7 +356,7 @@ namespace HDF5
           Assert(*hdf5_reference >= 0, ExcMessage("Error at H5Gcreate2"));
           break;
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
   }
@@ -467,7 +467,7 @@ namespace HDF5
           Assert(*hdf5_reference >= 0, ExcMessage("Error at H5Fcreate"));
           break;
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
 
diff --git a/source/base/index_set.cc b/source/base/index_set.cc
index 590a814b4a..19d08bd7de 100644
--- a/source/base/index_set.cc
+++ b/source/base/index_set.cc
@@ -406,7 +406,7 @@ IndexSet::get_view(const IndexSet &mask) const
                                           (own_it->end - own_it->begin));
               }
             else
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
 
       // We considered the overlap of these two intervals. It may of course
       // be that one of them overlaps with another one, but that can only
diff --git a/source/base/parameter_handler.cc b/source/base/parameter_handler.cc
index f17d3af78b..e7da93089b 100644
--- a/source/base/parameter_handler.cc
+++ b/source/base/parameter_handler.cc
@@ -165,7 +165,7 @@ namespace
                 c = 15 * 16;
                 break;
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           switch (s[i + 2])
             {
@@ -218,7 +218,7 @@ namespace
                 c += 15;
                 break;
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
 
           u.push_back(static_cast<char>(c));
diff --git a/source/base/polynomial.cc b/source/base/polynomial.cc
index 68261db079..d2f8717dda 100644
--- a/source/base/polynomial.cc
+++ b/source/base/polynomial.cc
@@ -650,7 +650,7 @@ namespace Polynomials
             break;
           }
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
 
     Assert(x != nullptr, ExcInternalError());
diff --git a/source/base/polynomial_space.cc b/source/base/polynomial_space.cc
index d99890486b..a01b03a523 100644
--- a/source/base/polynomial_space.cc
+++ b/source/base/polynomial_space.cc
@@ -74,7 +74,7 @@ PolynomialSpace<2>::compute_index(const unsigned int i) const
     else
       k += n_1d - iy;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return {{numbers::invalid_unsigned_int, numbers::invalid_unsigned_int}};
 }
 
@@ -104,7 +104,7 @@ PolynomialSpace<3>::compute_index(const unsigned int i) const
       else
         k += n_1d - iy - iz;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return {{numbers::invalid_unsigned_int, numbers::invalid_unsigned_int}};
 }
 
diff --git a/source/base/qprojector.cc b/source/base/qprojector.cc
index 9114743a6a..aa9a07da56 100644
--- a/source/base/qprojector.cc
+++ b/source/base/qprojector.cc
@@ -129,7 +129,7 @@ namespace internal
               eta_translation = int(subface_no / 2) * 0.5;
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               break;
           }
 
@@ -164,7 +164,7 @@ namespace internal
             case 7:
               return rotate(reflect(points), 8 - offset);
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
         return {};
       }
@@ -386,7 +386,7 @@ QProjector<2>::project_to_face(const ReferenceCell   &reference_cell,
               q_points[p] = Point<dim>(0, 1 - quadrature.point(p)[0]);
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
     }
   else if (reference_cell == ReferenceCells::Quadrilateral)
@@ -407,12 +407,12 @@ QProjector<2>::project_to_face(const ReferenceCell   &reference_cell,
               q_points[p] = Point<dim>(quadrature.point(p)[0], 1);
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
     }
   else
     {
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 }
 
@@ -526,7 +526,7 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(0.5 + quadrature.point(p)[0] / 2, 0);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             case 1:
@@ -541,7 +541,7 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                                              0.5 + quadrature.point(p)[0] / 2);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             case 2:
@@ -555,11 +555,11 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(0, 0.5 - quadrature.point(p)[0] / 2);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
     }
   else if (reference_cell == ReferenceCells::Quadrilateral)
@@ -578,7 +578,7 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(0, quadrature.point(p)[0] / 2 + 0.5);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             case 1:
@@ -592,7 +592,7 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(1, quadrature.point(p)[0] / 2 + 0.5);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             case 2:
@@ -606,7 +606,7 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(quadrature.point(p)[0] / 2 + 0.5, 0);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
             case 3:
@@ -620,17 +620,17 @@ QProjector<2>::project_to_subface(const ReferenceCell   &reference_cell,
                       Point<dim>(quadrature.point(p)[0] / 2 + 0.5, 1);
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               break;
 
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
     }
   else
     {
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 }
 
@@ -1408,7 +1408,7 @@ QProjector<dim>::DataSetDescriptor::face(const ReferenceCell &reference_cell,
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
   return numbers::invalid_unsigned_int;
 }
@@ -1549,7 +1549,7 @@ QProjector<dim>::DataSetDescriptor::face(
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
   return numbers::invalid_unsigned_int;
 }
diff --git a/source/base/quadrature_lib.cc b/source/base/quadrature_lib.cc
index 92dc5ea6ba..bd194c400b 100644
--- a/source/base/quadrature_lib.cc
+++ b/source/base/quadrature_lib.cc
@@ -1930,7 +1930,7 @@ QWitherdenVincentSimplex<dim>::QWitherdenVincentSimplex(
                 }
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
         break;
       case 3:
@@ -1985,7 +1985,7 @@ QWitherdenVincentSimplex<dim>::QWitherdenVincentSimplex(
                 }
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
         break;
       case 4:
@@ -2060,7 +2060,7 @@ QWitherdenVincentSimplex<dim>::QWitherdenVincentSimplex(
                 }
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
         break;
       case 5:
@@ -2279,7 +2279,7 @@ namespace
   Quadrature<dim>
   setup_qiterated_1D(const Quadrature<dim> &, const unsigned int)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return Quadrature<dim>();
   }
 
diff --git a/source/base/table_handler.cc b/source/base/table_handler.cc
index 5964e35e85..6e577f98d5 100644
--- a/source/base/table_handler.cc
+++ b/source/base/table_handler.cc
@@ -275,7 +275,7 @@ TableHandler::add_column_to_supercolumn(const std::string &key,
       tex_supercaptions.insert(new_tex_supercaption);
     }
   else
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
@@ -561,7 +561,7 @@ TableHandler::write_text(std::ostream &out, const TextOutputFormat format) const
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
diff --git a/source/cgal/surface_mesh.cc b/source/cgal/surface_mesh.cc
index c9273e7f80..b5bdd406bb 100644
--- a/source/cgal/surface_mesh.cc
+++ b/source/cgal/surface_mesh.cc
@@ -54,7 +54,7 @@ namespace
                    deal2cgal.at(face->vertex_index(2))};
       }
     else
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
 
     if (clockwise_ordering == true)
       std::reverse(indices.begin(), indices.end());
diff --git a/source/distributed/cell_weights.cc b/source/distributed/cell_weights.cc
index fc3cc7bca5..5ca5129afe 100644
--- a/source/distributed/cell_weights.cc
+++ b/source/distributed/cell_weights.cc
@@ -208,7 +208,7 @@ namespace parallel
           break;
 
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
 
diff --git a/source/distributed/grid_refinement.cc b/source/distributed/grid_refinement.cc
index afa4da2312..a0aa4a32ac 100644
--- a/source/distributed/grid_refinement.cc
+++ b/source/distributed/grid_refinement.cc
@@ -376,7 +376,7 @@ namespace internal
               }
             while (true);
 
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             return -1;
           }
         } // namespace RefineAndCoarsenFixedNumber
@@ -482,7 +482,7 @@ namespace internal
               }
             while (true);
 
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             return -1;
           }
         } // namespace RefineAndCoarsenFixedFraction
diff --git a/source/distributed/shared_tria.cc b/source/distributed/shared_tria.cc
index 0628617b78..84f663792c 100644
--- a/source/distributed/shared_tria.cc
+++ b/source/distributed/shared_tria.cc
@@ -443,7 +443,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
       partition();
       this->update_number_cache();
@@ -459,7 +459,7 @@ namespace parallel
     {
       (void)construction_data;
 
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
diff --git a/source/distributed/solution_transfer.cc b/source/distributed/solution_transfer.cc
index a5a645d125..af20515b64 100644
--- a/source/distributed/solution_transfer.cc
+++ b/source/distributed/solution_transfer.cc
@@ -349,7 +349,7 @@ namespace parallel
                 }
 
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
                 break;
             }
         }
@@ -417,7 +417,7 @@ namespace parallel
                 }
 
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
                 break;
             }
         }
diff --git a/source/distributed/tria.cc b/source/distributed/tria.cc
index 8834eff6ef..5df934934f 100644
--- a/source/distributed/tria.cc
+++ b/source/distributed/tria.cc
@@ -1793,7 +1793,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       Assert(
@@ -1819,7 +1819,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       this->update_periodic_face_map();
@@ -1836,7 +1836,7 @@ namespace parallel
     {
       (void)construction_data;
 
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
     }
 
 
@@ -2165,7 +2165,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       // Load attached cell data, if any was stored.
@@ -2240,7 +2240,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       this->update_periodic_face_map();
@@ -2848,7 +2848,7 @@ namespace parallel
               {
                 // the underlying triangulation should not be checking for
                 // distorted cells
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
               }
           }
 
@@ -3003,7 +3003,7 @@ namespace parallel
             {
               // the underlying triangulation should not be checking for
               // distorted cells
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
             }
         }
       while (mesh_changed);
@@ -3468,7 +3468,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       // transfer data after triangulation got updated
@@ -3633,7 +3633,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       // transfer data after triangulation got updated
@@ -3919,7 +3919,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       // The range of ghost_owners might have changed so update that
@@ -3994,7 +3994,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       if (const dealii::parallel::distributed::Triangulation<dim, spacedim>
@@ -4044,7 +4044,7 @@ namespace parallel
         {
           // the underlying triangulation should not be checking for distorted
           // cells
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
         }
 
       this->update_periodic_face_map();
@@ -4321,7 +4321,7 @@ namespace parallel
                     break;
 
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                     break;
                 }
             }
diff --git a/source/dofs/dof_accessor.cc b/source/dofs/dof_accessor.cc
index 692934bd4f..8ffa54426e 100644
--- a/source/dofs/dof_accessor.cc
+++ b/source/dofs/dof_accessor.cc
@@ -79,7 +79,7 @@ DoFInvalidAccessor<structdim, dim, spacedim>::dof_index(
   const unsigned int,
   const types::fe_index) const
 {
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return 0;
 }
 
@@ -92,7 +92,7 @@ DoFInvalidAccessor<structdim, dim, spacedim>::set_dof_index(
   const types::global_dof_index,
   const types::fe_index) const
 {
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/dofs/dof_handler.cc b/source/dofs/dof_handler.cc
index c98c8dd054..64a5b2ec93 100644
--- a/source/dofs/dof_handler.cc
+++ b/source/dofs/dof_handler.cc
@@ -2995,7 +2995,7 @@ DEAL_II_CXX20_REQUIRES((concepts::is_valid_dim_spacedim<dim, spacedim>))
 void DoFHandler<dim, spacedim>::post_distributed_transfer_action()
 {
 #  ifndef DEAL_II_WITH_P4EST
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #  else
   update_active_fe_table();
 
diff --git a/source/dofs/dof_renumbering.cc b/source/dofs/dof_renumbering.cc
index c179014677..8d2d1f22f0 100644
--- a/source/dofs/dof_renumbering.cc
+++ b/source/dofs/dof_renumbering.cc
@@ -940,7 +940,7 @@ namespace DoFRenumbering
           }
 #else
         (void)tria;
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 #endif
       }
     else
@@ -1201,7 +1201,7 @@ namespace DoFRenumbering
           }
 #else
         (void)tria;
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 #endif
       }
     else
diff --git a/source/dofs/dof_tools_constraints.cc b/source/dofs/dof_tools_constraints.cc
index a0b98bb6e6..aeeacbbc26 100644
--- a/source/dofs/dof_tools_constraints.cc
+++ b/source/dofs/dof_tools_constraints.cc
@@ -2766,7 +2766,7 @@ namespace DoFTools
 
                     default:
                       // we shouldn't get here
-                      Assert(false, ExcInternalError());
+                      DEAL_II_ASSERT_UNREACHABLE();
                   }
               }
             else
@@ -3059,7 +3059,7 @@ namespace DoFTools
 
                         default:
                           // we shouldn't get here
-                          Assert(false, ExcInternalError());
+                          DEAL_II_ASSERT_UNREACHABLE();
                       }
                   }
               }
diff --git a/source/fe/fe_hermite.cc b/source/fe/fe_hermite.cc
index ef139d0f3a..f15cad6496 100644
--- a/source/fe/fe_hermite.cc
+++ b/source/fe/fe_hermite.cc
@@ -262,7 +262,7 @@ namespace internal
           cell_extent = data->cell_extents[0];
         }
       else
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 
       const unsigned int regularity      = fe_herm.get_regularity();
       const unsigned int n_dofs_per_cell = fe_herm.n_dofs_per_cell();
@@ -321,7 +321,7 @@ namespace internal
           cell_extents = data->cell_extents;
         }
       else
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 
       const unsigned int regularity      = fe_herm.get_regularity();
       const unsigned int n_dofs_per_cell = fe_herm.n_dofs_per_cell();
@@ -395,7 +395,7 @@ namespace internal
           cell_extents = data->cell_extents;
         }
       else
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 
       const unsigned int regularity      = fe_herm.get_regularity();
       const unsigned int n_dofs_per_cell = fe_herm.n_dofs_per_cell();
diff --git a/source/fe/fe_q_base.cc b/source/fe/fe_q_base.cc
index 9d20b053bf..eae49e57ae 100644
--- a/source/fe/fe_q_base.cc
+++ b/source/fe/fe_q_base.cc
@@ -1165,7 +1165,7 @@ FE_Q_Base<dim, spacedim>::face_to_cell_index(
       switch (dim)
         {
           case 1:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             break;
 
           case 2:
@@ -1193,7 +1193,7 @@ FE_Q_Base<dim, spacedim>::face_to_cell_index(
             break;
 
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
 
       return (this->get_first_line_index() +
@@ -1689,7 +1689,7 @@ FE_Q_Base<dim, spacedim>::has_support_on_face(
     }
 
   // we should not have gotten here
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return false;
 }
 
diff --git a/source/fe/fe_q_bubbles.cc b/source/fe/fe_q_bubbles.cc
index d8b30081f6..290e8ea06c 100644
--- a/source/fe/fe_q_bubbles.cc
+++ b/source/fe/fe_q_bubbles.cc
@@ -85,7 +85,7 @@ namespace internal
               q_fine = std::make_unique<QGauss<dim>>(degree + 1);
               break;
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
 
         Assert(q_fine.get() != nullptr, ExcInternalError());
diff --git a/source/fe/fe_q_hierarchical.cc b/source/fe/fe_q_hierarchical.cc
index 0d4e61f5f7..1485511420 100644
--- a/source/fe/fe_q_hierarchical.cc
+++ b/source/fe/fe_q_hierarchical.cc
@@ -2284,7 +2284,7 @@ FE_Q_Hierarchical<dim>::has_support_on_face(const unsigned int shape_index,
     }
 
   // we should not have gotten here
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return false;
 }
 
diff --git a/source/fe/fe_system.cc b/source/fe/fe_system.cc
index daf7479aaf..14f3e2164a 100644
--- a/source/fe/fe_system.cc
+++ b/source/fe/fe_system.cc
@@ -1053,7 +1053,7 @@ FESystem<dim, spacedim>::face_to_cell_index(
     if (this->system_to_base_index(i) == target)
       return i;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return numbers::invalid_unsigned_int;
 }
 
@@ -1557,7 +1557,7 @@ FESystem<dim, spacedim>::build_interface_constraints()
               {
                 // we should never get here!  (in 1d, the constraints matrix
                 // should be of size zero)
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
                 break;
               }
 
diff --git a/source/fe/fe_values.cc b/source/fe/fe_values.cc
index 7f7087b8e5..c51c16873f 100644
--- a/source/fe/fe_values.cc
+++ b/source/fe/fe_values.cc
@@ -945,7 +945,7 @@ FESubfaceValues<dim, spacedim>::do_reinit(const unsigned int face_no,
                   subface_index = cell->face(face_no)->child_index(1);
                   break;
                 default:
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
             break;
           case internal::SubfaceCase<3>::case_x2y:
@@ -961,11 +961,11 @@ FESubfaceValues<dim, spacedim>::do_reinit(const unsigned int face_no,
                     cell->face(face_no)->child(1)->child_index(subface_no - 1);
                   break;
                 default:
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
               }
             break;
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             break;
         }
       Assert(subface_index != numbers::invalid_unsigned_int,
diff --git a/source/fe/fe_values_views_internal.cc b/source/fe/fe_values_views_internal.cc
index 67768b2926..0e13816f0b 100644
--- a/source/fe/fe_values_views_internal.cc
+++ b/source/fe/fe_values_views_internal.cc
@@ -632,7 +632,7 @@ namespace FEValuesViews
                             }
 
                           default:
-                            Assert(false, ExcInternalError());
+                            DEAL_II_ASSERT_UNREACHABLE();
                         }
                     }
 
diff --git a/source/fe/fe_wedge_p.cc b/source/fe/fe_wedge_p.cc
index 75ecb3c1b2..8357265595 100644
--- a/source/fe/fe_wedge_p.cc
+++ b/source/fe/fe_wedge_p.cc
@@ -134,7 +134,7 @@ FE_WedgePoly<dim, spacedim>::FE_WedgePoly(
       for (const auto &p : fe_quad.get_unit_support_points())
         this->unit_face_support_points[f].emplace_back(p[0], p[1]);
     else
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/fe/mapping.cc b/source/fe/mapping.cc
index e7bc4f7353..cb9a8d96b9 100644
--- a/source/fe/mapping.cc
+++ b/source/fe/mapping.cc
@@ -186,7 +186,7 @@ Mapping<dim, spacedim>::project_real_point_to_unit_point_on_face(
     }
 
   // We should never get here
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return {};
 }
 
diff --git a/source/fe/mapping_q.cc b/source/fe/mapping_q.cc
index fd4ab49ce5..34f88f7903 100644
--- a/source/fe/mapping_q.cc
+++ b/source/fe/mapping_q.cc
@@ -327,7 +327,7 @@ MappingQ<dim, spacedim>::transform_real_to_unit_cell_internal(
   const Point<dim> &) const
 {
   // default implementation (should never be called)
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return {};
 }
 
@@ -543,7 +543,7 @@ MappingQ<dim, spacedim>::transform_real_to_unit_cell(
               default:
                 {
                   // we should get here, based on the if-condition at the top
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
                 }
             }
         }
@@ -1625,7 +1625,7 @@ MappingQ<dim, spacedim>::add_quad_support_points(
   const typename Triangulation<dim, spacedim>::cell_iterator &,
   std::vector<Point<spacedim>> &) const
 {
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/grid/grid_generator.cc b/source/grid/grid_generator.cc
index eb1b64431a..dbda71490b 100644
--- a/source/grid/grid_generator.cc
+++ b/source/grid/grid_generator.cc
@@ -1324,7 +1324,7 @@ namespace GridGenerator
                 // is on the boundary,
                 // but we could not find
                 // on which boundary.
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
 
       for (const auto &cell : tria.cell_iterators())
@@ -1524,7 +1524,7 @@ namespace GridGenerator
                       cell->face(f)->line(j)->set_boundary_id(1);
               }
             else
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
     }
 
@@ -2315,7 +2315,7 @@ namespace GridGenerator
             break;
           }
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
     (void)twisted_data; // make the static analyzer happy
     Assert(
@@ -5892,7 +5892,7 @@ namespace GridGenerator
               new_points[v][2] = -tria_copy.get_vertices()[v][2];
             }
         else
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
 
 
         // the cell data is exactly the same as before
@@ -7811,7 +7811,7 @@ namespace GridGenerator
             break;
           }
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
 
     out_tria.create_triangulation(v, cells, subcelldata);
diff --git a/source/grid/grid_in.cc b/source/grid/grid_in.cc
index 5540a823ed..d008699d9a 100644
--- a/source/grid/grid_in.cc
+++ b/source/grid/grid_in.cc
@@ -521,7 +521,7 @@ GridIn<dim, spacedim>::read_vtk(std::istream &in)
                             cells[i].manifold_id =
                               static_cast<types::manifold_id>(id);
                           else
-                            Assert(false, ExcInternalError());
+                            DEAL_II_ASSERT_UNREACHABLE();
                         }
 
                       if (dim == 3)
@@ -537,7 +537,7 @@ GridIn<dim, spacedim>::read_vtk(std::istream &in)
                                 boundary_quad.manifold_id =
                                   static_cast<types::manifold_id>(id);
                               else
-                                Assert(false, ExcInternalError());
+                                DEAL_II_ASSERT_UNREACHABLE();
                             }
                           for (auto &boundary_line : subcelldata.boundary_lines)
                             {
@@ -550,7 +550,7 @@ GridIn<dim, spacedim>::read_vtk(std::istream &in)
                                 boundary_line.manifold_id =
                                   static_cast<types::manifold_id>(id);
                               else
-                                Assert(false, ExcInternalError());
+                                DEAL_II_ASSERT_UNREACHABLE();
                             }
                         }
                       else if (dim == 2)
@@ -566,7 +566,7 @@ GridIn<dim, spacedim>::read_vtk(std::istream &in)
                                 boundary_line.manifold_id =
                                   static_cast<types::manifold_id>(id);
                               else
-                                Assert(false, ExcInternalError());
+                                DEAL_II_ASSERT_UNREACHABLE();
                             }
                         }
                     }
@@ -1766,7 +1766,7 @@ GridIn<dim, spacedim>::read_comsol_mphtxt(std::istream &in)
                   cells.back().vertices = vertices_for_this_element;
                 }
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
             }
           else
             DEAL_II_NOT_IMPLEMENTED();
@@ -1825,7 +1825,7 @@ GridIn<dim, spacedim>::read_comsol_mphtxt(std::istream &in)
                     cells[cells.size() - n_elements + e].material_id =
                       geometric_entity_index;
                   else
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                 }
               else
                 DEAL_II_NOT_IMPLEMENTED();
@@ -4237,7 +4237,7 @@ GridIn<dim, spacedim>::read(std::istream &in, Format format)
       case Default:
         break;
     }
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/grid/grid_out.cc b/source/grid/grid_out.cc
index 7de2bb91ae..3f920a515f 100644
--- a/source/grid/grid_out.cc
+++ b/source/grid/grid_out.cc
@@ -1353,7 +1353,7 @@ GridOut::write_xfig(const Triangulation<2> &tria,
             out << cell->level_subdomain_id() + 32;
             break;
           default:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
 
       // Depth, unused, fill
@@ -3923,7 +3923,7 @@ GridOut::write_msh_faces(const Triangulation<dim, spacedim> &tria,
                      (face->reference_cell() == ReferenceCells::Line))
               out << ' ' << face->vertex_index(vertex) + 1;
             else
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
           }
         out << '\n';
 
@@ -4711,7 +4711,7 @@ namespace internal
         {
           case 1:
             {
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               break;
             }
 
@@ -5168,7 +5168,7 @@ GridOut::write(const Triangulation<dim, spacedim> &tria,
         return;
     }
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/grid/grid_tools.cc b/source/grid/grid_tools.cc
index e9f675b212..e8cfcb2cce 100644
--- a/source/grid/grid_tools.cc
+++ b/source/grid/grid_tools.cc
@@ -3477,7 +3477,7 @@ namespace GridTools
           else
             {
               // We should not get here. Throw an error.
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
             }
         }
     // Now make sure we send out the rest of the points that we did not find.
diff --git a/source/grid/grid_tools_topology.cc b/source/grid/grid_tools_topology.cc
index 3fc5b0d57f..30aaf67ff1 100644
--- a/source/grid/grid_tools_topology.cc
+++ b/source/grid/grid_tools_topology.cc
@@ -1445,7 +1445,7 @@ namespace GridTools
                         starting_vertex_of_edge[3]))
                 origin_vertex_of_cell = starting_vertex_of_edge[1];
               else
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
 
               break;
             }
diff --git a/source/grid/manifold_lib.cc b/source/grid/manifold_lib.cc
index bde0e13fbb..a97aa1aa77 100644
--- a/source/grid/manifold_lib.cc
+++ b/source/grid/manifold_lib.cc
@@ -2328,7 +2328,7 @@ TransfiniteInterpolationManifold<dim, spacedim>::compute_chart_points(
         case 0:
         case 1:
         case 2:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
         case 3:
           return chart_points[1] + (chart_points[2] - chart_points[0]);
@@ -2341,7 +2341,7 @@ TransfiniteInterpolationManifold<dim, spacedim>::compute_chart_points(
         case 7:
           return 0.5 * (chart_points[2] + chart_points[3]);
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
       }
 
     return {};
@@ -2537,7 +2537,7 @@ TransfiniteInterpolationManifold<dim, spacedim>::compute_chart_points(
   // a valid inversion should have returned a point above. an invalid
   // inversion should have triggered the assertion, so we should never end up
   // here
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
   return typename Triangulation<dim, spacedim>::cell_iterator();
 }
 
diff --git a/source/grid/persistent_tria.cc b/source/grid/persistent_tria.cc
index 81bd8818cd..12981288dd 100644
--- a/source/grid/persistent_tria.cc
+++ b/source/grid/persistent_tria.cc
@@ -152,7 +152,7 @@ PersistentTriangulation<dim, spacedim>::create_triangulation(
 {
   (void)construction_data;
 
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/grid/reference_cell.cc b/source/grid/reference_cell.cc
index 9e0e9c570a..6e9f9f6aa3 100644
--- a/source/grid/reference_cell.cc
+++ b/source/grid/reference_cell.cc
@@ -845,7 +845,7 @@ namespace
                   const Point<dim> & /*p*/,
                   const ReferenceCell /*reference_cell*/)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return std::make_pair(Point<dim>(),
                           std::numeric_limits<double>::signaling_NaN());
   }
@@ -1067,7 +1067,7 @@ ReferenceCell::closest_point(const Point<dim> &p) const
       switch (this->kind)
         {
           case ReferenceCells::Vertex:
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             break;
             // the bounds for each dimension of a hypercube are mutually
             // independent:
diff --git a/source/grid/tria.cc b/source/grid/tria.cc
index 7ce15adee8..ce80da5ec1 100644
--- a/source/grid/tria.cc
+++ b/source/grid/tria.cc
@@ -224,7 +224,7 @@ namespace internal
                 break;
 
               default:
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
                 break;
             }
 
@@ -655,7 +655,7 @@ namespace internal
               break;
 
             default:
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               break;
           }
 
@@ -4077,7 +4077,7 @@ namespace internal
             default:
               // only remaining case is
               // no_refinement, thus an error
-              Assert(false, ExcInternalError());
+              DEAL_II_ASSERT_UNREACHABLE();
               break;
           }
 
@@ -4479,7 +4479,7 @@ namespace internal
                   break;
 
                 default:
-                  Assert(false, ExcInternalError());
+                  DEAL_II_ASSERT_UNREACHABLE();
                   break;
               }
           }
@@ -6085,7 +6085,7 @@ namespace internal
                     }
                   else
                     {
-                      Assert(false, ExcInternalError());
+                      DEAL_II_ASSERT_UNREACHABLE();
                     }
 
                   // Also check whether we have to refine any of the faces and
@@ -6146,7 +6146,7 @@ namespace internal
               }
             else
               {
-                Assert(false, ExcInternalError());
+                DEAL_II_ASSERT_UNREACHABLE();
               }
           }
 
@@ -7331,7 +7331,7 @@ namespace internal
                   else
                     {
                       // we should never get here
-                      Assert(false, ExcInternalError());
+                      DEAL_II_ASSERT_UNREACHABLE();
                     }
 
                   // mark all faces for refinement; checking locally
@@ -8582,7 +8582,7 @@ namespace internal
                         n_new_hexes = 8;
                         break;
                       default:
-                        Assert(false, ExcInternalError());
+                        DEAL_II_ASSERT_UNREACHABLE();
                         break;
                     }
 
@@ -11476,7 +11476,7 @@ namespace internal
                         // untreated enumeration value. However, in that
                         // case we should have aborted much
                         // earlier. thus we should never get here
-                        Assert(false, ExcInternalError());
+                        DEAL_II_ASSERT_UNREACHABLE();
                         break;
                     } // switch (ref_case)
 
@@ -13522,7 +13522,7 @@ namespace
   bool
   get_user_flag(const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return false;
   }
 
@@ -13541,7 +13541,7 @@ namespace
   void
   set_user_flag(const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 
 
@@ -13560,7 +13560,7 @@ namespace
   clear_user_flag(
     const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 } // namespace
 
@@ -13813,7 +13813,7 @@ namespace
   get_user_index(
     const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return numbers::invalid_unsigned_int;
   }
 
@@ -13834,7 +13834,7 @@ namespace
     const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &,
     const unsigned int)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 } // namespace
 
@@ -13959,7 +13959,7 @@ namespace
   get_user_pointer(
     const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return nullptr;
   }
 
@@ -13980,7 +13980,7 @@ namespace
     const TriaIterator<InvalidAccessor<structdim, dim, spacedim>> &,
     void *)
   {
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
   }
 } // namespace
 
diff --git a/source/grid/tria_accessor.cc b/source/grid/tria_accessor.cc
index fc197f6877..0d9a30a923 100644
--- a/source/grid/tria_accessor.cc
+++ b/source/grid/tria_accessor.cc
@@ -224,7 +224,7 @@ namespace
       }
     else
       {
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
         return {};
       }
   }
@@ -1265,7 +1265,7 @@ namespace
         Assert(accessor.reference_cell() != ReferenceCells::Pyramid &&
                  accessor.reference_cell() != ReferenceCells::Wedge,
                ExcNotImplemented());
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
 
         return {};
       }
@@ -2582,7 +2582,7 @@ CellAccessor<dim, spacedim>::neighbor_of_coarser_neighbor(
           // we should never get here,
           // since then we did not find
           // our way back...
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return std::make_pair(numbers::invalid_unsigned_int,
                                 numbers::invalid_unsigned_int);
         }
@@ -2675,7 +2675,7 @@ CellAccessor<dim, spacedim>::neighbor_of_coarser_neighbor(
 
           // we should never get here, since then we did not find our way
           // back...
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           return std::make_pair(numbers::invalid_unsigned_int,
                                 numbers::invalid_unsigned_int);
         }
@@ -3429,7 +3429,7 @@ CellAccessor<dim, spacedim>::neighbor_child_on_subface(
                           requested = mother_face->child(1);
                           break;
                         default:
-                          Assert(false, ExcInternalError());
+                          DEAL_II_ASSERT_UNREACHABLE();
                       }
                     break;
                   case internal::SubfaceCase<3>::case_x2y:
@@ -3444,11 +3444,11 @@ CellAccessor<dim, spacedim>::neighbor_child_on_subface(
                           requested = mother_face->child(1)->child(subface - 1);
                           break;
                         default:
-                          Assert(false, ExcInternalError());
+                          DEAL_II_ASSERT_UNREACHABLE();
                       }
                     break;
                   default:
-                    Assert(false, ExcInternalError());
+                    DEAL_II_ASSERT_UNREACHABLE();
                     break;
                 }
               Assert(requested == neighbor_child->face(neighbor_neighbor),
diff --git a/source/hp/refinement.cc b/source/hp/refinement.cc
index fa3cec1e8d..2a3754e906 100644
--- a/source/hp/refinement.cc
+++ b/source/hp/refinement.cc
@@ -326,7 +326,7 @@ namespace hp
             &dof_handler.get_triangulation()) == nullptr)
         {
 #ifndef DEAL_II_WITH_P4EST
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
 #else
           //
           // parallel implementation with distributed memory
@@ -776,7 +776,7 @@ namespace hp
                           {
                             // Siblings of locally owned cells are all
                             // either also locally owned or ghost cells.
-                            Assert(false, ExcInternalError());
+                            DEAL_II_ASSERT_UNREACHABLE();
                           }
                       }
                   }
diff --git a/source/lac/scalapack.cc b/source/lac/scalapack.cc
index 3430a81256..2211757fcd 100644
--- a/source/lac/scalapack.cc
+++ b/source/lac/scalapack.cc
@@ -2664,7 +2664,7 @@ ScaLAPACKMatrix<NumberType>::save_serial(
 #  ifndef DEAL_II_WITH_HDF5
   (void)filename;
   (void)chunk_size;
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #  else
 
   /*
@@ -2821,7 +2821,7 @@ ScaLAPACKMatrix<NumberType>::save_parallel(
 #  ifndef DEAL_II_WITH_HDF5
   (void)filename;
   (void)chunk_size;
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #  else
 
   const unsigned int n_mpi_processes(
@@ -3075,7 +3075,7 @@ ScaLAPACKMatrix<NumberType>::load_serial(const std::string &filename)
 {
 #  ifndef DEAL_II_WITH_HDF5
   (void)filename;
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #  else
 
   /*
@@ -3253,10 +3253,10 @@ ScaLAPACKMatrix<NumberType>::load_parallel(const std::string &filename)
 {
 #  ifndef DEAL_II_WITH_HDF5
   (void)filename;
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #  else
 #    ifndef H5_HAVE_PARALLEL
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 #    else
 
   const unsigned int n_mpi_processes(
diff --git a/source/non_matching/fe_values.cc b/source/non_matching/fe_values.cc
index c7045b36e9..e8385a68fe 100644
--- a/source/non_matching/fe_values.cc
+++ b/source/non_matching/fe_values.cc
@@ -225,7 +225,7 @@ namespace NonMatching
           }
         default:
           {
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             break;
           }
       }
@@ -445,7 +445,7 @@ namespace NonMatching
           }
         default:
           {
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
             break;
           }
       }
diff --git a/source/numerics/data_out_stack.cc b/source/numerics/data_out_stack.cc
index cce2a6e2d1..5332ab98f7 100644
--- a/source/numerics/data_out_stack.cc
+++ b/source/numerics/data_out_stack.cc
@@ -236,7 +236,7 @@ DataOutStack<dim, spacedim>::add_data_vector(
   // we have either return or Assert
   // statements above, so shouldn't
   // get here!
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/numerics/histogram.cc b/source/numerics/histogram.cc
index aade357751..9057b5ea45 100644
--- a/source/numerics/histogram.cc
+++ b/source/numerics/histogram.cc
@@ -126,7 +126,7 @@ Histogram::evaluate(const std::vector<Vector<number>> &values,
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   // move right bound arbitrarily if
@@ -175,7 +175,7 @@ Histogram::evaluate(const std::vector<Vector<number>> &values,
         }
 
       default:
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     }
 
   // fill the other lists of intervals
diff --git a/source/numerics/solution_transfer.cc b/source/numerics/solution_transfer.cc
index 51f8435bba..ae54635768 100644
--- a/source/numerics/solution_transfer.cc
+++ b/source/numerics/solution_transfer.cc
@@ -579,7 +579,7 @@ SolutionTransfer<dim, VectorType, spacedim>::interpolate(
             }
           // undefined status
           else
-            Assert(false, ExcInternalError());
+            DEAL_II_ASSERT_UNREACHABLE();
         }
     }
 
diff --git a/source/numerics/time_dependent.cc b/source/numerics/time_dependent.cc
index ce770df663..ea9541a2d6 100644
--- a/source/numerics/time_dependent.cc
+++ b/source/numerics/time_dependent.cc
@@ -706,7 +706,7 @@ namespace
         return changed_grid;
       }
 
-    Assert(false, ExcInternalError());
+    DEAL_II_ASSERT_UNREACHABLE();
     return false;
   }
 
@@ -1164,7 +1164,7 @@ TimeStepBase_Tria_Flags::Flags<dim>::Flags()
   , wakeup_level_to_build_grid(0)
   , sleep_level_to_delete_grid(0)
 {
-  Assert(false, ExcInternalError());
+  DEAL_II_ASSERT_UNREACHABLE();
 }
 
 
diff --git a/source/opencascade/manifold_lib.cc b/source/opencascade/manifold_lib.cc
index 8ed7226bc8..38374c8cef 100644
--- a/source/opencascade/manifold_lib.cc
+++ b/source/opencascade/manifold_lib.cc
@@ -64,7 +64,7 @@ namespace OpenCASCADE
         return Handle(BRepAdaptor_Curve)(
           new BRepAdaptor_Curve(TopoDS::Edge(shape)));
 
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return Handle(BRepAdaptor_Curve)(new BRepAdaptor_Curve());
     }
 #  else
@@ -81,7 +81,7 @@ namespace OpenCASCADE
         return Handle(BRepAdaptor_HCurve)(
           new BRepAdaptor_HCurve(TopoDS::Edge(shape)));
 
-      Assert(false, ExcInternalError());
+      DEAL_II_ASSERT_UNREACHABLE();
       return Handle(BRepAdaptor_HCurve)(new BRepAdaptor_HCurve());
     }
 #  endif
diff --git a/source/particles/particle_handler.cc b/source/particles/particle_handler.cc
index f0e21a920f..df6d147959 100644
--- a/source/particles/particle_handler.cc
+++ b/source/particles/particle_handler.cc
@@ -2336,7 +2336,7 @@ namespace Particles
           break;
 
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
 
@@ -2485,7 +2485,7 @@ namespace Particles
           break;
 
         default:
-          Assert(false, ExcInternalError());
+          DEAL_II_ASSERT_UNREACHABLE();
           break;
       }
   }
diff --git a/source/sundials/kinsol.cc b/source/sundials/kinsol.cc
index b82eaac1e0..4e2541078b 100644
--- a/source/sundials/kinsol.cc
+++ b/source/sundials/kinsol.cc
@@ -101,7 +101,7 @@ namespace SUNDIALS
       else if (value == "picard")
         strategy = picard;
       else
-        Assert(false, ExcInternalError());
+        DEAL_II_ASSERT_UNREACHABLE();
     });
     prm.add_parameter("Maximum number of nonlinear iterations",
                       maximum_non_linear_iterations);
@@ -149,7 +149,7 @@ namespace SUNDIALS
                        anderson_qr_orthogonalization =
                          delayed_classical_gram_schmidt;
                      else
-                       Assert(false, ExcInternalError());
+                       DEAL_II_ASSERT_UNREACHABLE();
                    });
     prm.leave_subsection();
   }