From 9a51f8d8f92dbd09d4f66cd24df9302d92bf92a5 Mon Sep 17 00:00:00 2001
From: Jean-Paul Pelteret <jppelteret@gmail.com>
Date: Fri, 1 May 2020 00:02:52 +0200
Subject: [PATCH] Remove MeshWorker::CopyData::operator=(double)

---
 .../20200430Jean-PaulPelteret                 |  6 ++++
 include/deal.II/meshworker/copy_data.h        | 32 -------------------
 2 files changed, 6 insertions(+), 32 deletions(-)
 create mode 100644 doc/news/changes/incompatibilities/20200430Jean-PaulPelteret

diff --git a/doc/news/changes/incompatibilities/20200430Jean-PaulPelteret b/doc/news/changes/incompatibilities/20200430Jean-PaulPelteret
new file mode 100644
index 0000000000..c867e5f34b
--- /dev/null
+++ b/doc/news/changes/incompatibilities/20200430Jean-PaulPelteret
@@ -0,0 +1,6 @@
+Removed: The function `MeshWorker::CopyData::operator=(const double)` has been
+removed, as resetting the state of the `copier` from within a `boundary_worker`
+or `face_worker` is not permitted and can lead to hard to trace bugs within a
+user's code.
+<br>
+(Jean-Paul Pelteret, 2020/04/30)
diff --git a/include/deal.II/meshworker/copy_data.h b/include/deal.II/meshworker/copy_data.h
index 866034034d..63ed18007f 100644
--- a/include/deal.II/meshworker/copy_data.h
+++ b/include/deal.II/meshworker/copy_data.h
@@ -71,19 +71,6 @@ namespace MeshWorker
     CopyData(const CopyData<n_matrices, n_vectors, n_dof_indices> &other) =
       default;
 
-    /**
-     * Allow resetting of all elements of the struct to zero, by simply
-     * calling `(*this) = 0;`
-     *
-     * Notice that the only allowed number here is really `0`. Calling this
-     * function with any other number will trigger an assertion.
-     *
-     * The elements of the arrays of local degrees of freedom indices are
-     * all set to numbers::invalid_dof_index.
-     */
-    void
-    operator=(const double number);
-
     /**
      * An array of local matrices.
      */
@@ -136,25 +123,6 @@ namespace MeshWorker
       local_dof_indices[i].resize(dof_indices_sizes[i++]);
   }
 
-
-
-  template <int n_matrices, int n_vectors, int n_dof_indices>
-  void
-  CopyData<n_matrices, n_vectors, n_dof_indices>::operator=(const double number)
-  {
-    Assert(number == 0.0,
-           ExcMessage("You should only call this method with "
-                      "argument 0.0"));
-
-    for (auto &m : matrices)
-      m = number;
-    for (auto &v : vectors)
-      v = number;
-    for (auto &d : local_dof_indices)
-      for (auto &val : d)
-        val = numbers::invalid_dof_index;
-  }
-
 #endif // DOXYGEN
 } // namespace MeshWorker
 
-- 
2.39.5