diff --git a/src/blackmisc/collection.h b/src/blackmisc/collection.h
index 1fe81225b..72ca06dec 100644
--- a/src/blackmisc/collection.h
+++ b/src/blackmisc/collection.h
@@ -50,13 +50,6 @@ namespace BlackMisc
          */
         CCollection() : m_pimpl(new Pimpl<QSet<T>>(QSet<T>())) {}
 
-        /*!
-         * \brief Constructor.
-         * \tparam C Becomes the collection's implementation type.
-         * \param c Initial value for the collection; typically empty, but could contain elements.
-         */
-        template <class C> CCollection(C c) : m_pimpl(new Pimpl<C>(std::move(c))) {}
-
         /*!
          * \brief Copy constructor.
          * \param other
@@ -69,13 +62,6 @@ namespace BlackMisc
          */
         CCollection(CCollection &&other) : m_pimpl(other.m_pimpl.take()) {}
 
-        /*!
-         * \brief Assignment.
-         * \tparam C Becomes the collection's new implementation type.
-         * \param c New value for the collection; typically empty, but could contain elements.
-         */
-        template <class C> CCollection &operator =(C c) { m_pimpl.reset(new Pimpl<C>(std::move(c))); return *this; }
-
         /*!
          * \brief Copy assignment.
          * \param other
@@ -90,11 +76,19 @@ namespace BlackMisc
          */
         CCollection &operator =(CCollection && other) { m_pimpl.reset(other.m_pimpl.take()); return *this; }
 
+        /*!
+         * \brief Create a new collection with a specific implementation type.
+         * \tparam C Becomes the collection's implementation type.
+         * \param c Initial value for the collection; default is empty, but it could contain elements if desired. The value is copied.
+         * \return
+         */
+        template <class C> static CCollection fromImpl(C c = C()) { return CCollection(new Pimpl<C>(std::move(c))); }
+
         /*!
          * \brief Change the implementation type but keep all the same elements, by copying them into the new implementation.
          * \tparam C Becomes the collection's new implementation type.
          */
-        template <class C> void changeImpl(C = C()) { CCollection c = C(); for (auto i = cbegin(); i != cend(); ++i) c.insert(*i); *this = std::move(c); }
+        template <class C> void changeImpl(C = C()) { auto c = fromImpl(C()); for (auto i = cbegin(); i != cend(); ++i) c.insert(*i); *this = std::move(c); }
 
         /*!
          * \brief Like changeImpl, but uses the implementation type of another collection.
@@ -275,6 +269,8 @@ namespace BlackMisc
         typedef QScopedPointer<PimplBase> PimplPtr;
         PimplPtr m_pimpl;
 
+        CCollection(PimplBase *pimpl) : m_pimpl(pimpl) {} // private ctor used by fromImpl()
+
         // using these methods to access m_pimpl.data() eases the cognitive burden of correctly forwarding const
         PimplBase *pimpl() { return m_pimpl.data(); }
         const PimplBase *pimpl() const { return m_pimpl.data(); }
diff --git a/src/blackmisc/sequence.h b/src/blackmisc/sequence.h
index dbf724299..2fd7ca62d 100644
--- a/src/blackmisc/sequence.h
+++ b/src/blackmisc/sequence.h
@@ -50,13 +50,6 @@ namespace BlackMisc
          */
         CSequence() : m_pimpl(new Pimpl<QList<T>>(QList<T>())) {}
 
-        /*!
-         * \brief Constructor.
-         * \tparam C Becomes the sequence's implementation type.
-         * \param c Initial value for the sequence; typically empty, but could contain elements.
-         */
-        template <class C> CSequence(C c) : m_pimpl(new Pimpl<C>(std::move(c))) {}
-
         /*!
          * \brief Copy constructor.
          * \param other
@@ -69,13 +62,6 @@ namespace BlackMisc
          */
         CSequence(CSequence &&other) : m_pimpl(other.m_pimpl.take()) {}
 
-        /*!
-         * \brief Assignment.
-         * \tparam C Becomes the sequence's new implementation type.
-         * \param c New value for the sequence; typically empty, but could contain elements.
-         */
-        template <class C> CSequence &operator =(C c) { m_pimpl.reset(new Pimpl<C>(std::move(c))); return *this; }
-
         /*!
          * \brief Copy assignment.
          * \param other
@@ -90,11 +76,19 @@ namespace BlackMisc
          */
         CSequence &operator =(CSequence &&other) { m_pimpl.reset(other.m_pimpl.take()); return *this; }
 
+        /*!
+         * \brief Create a new sequence with a specific implementation type.
+         * \tparam C Becomes the sequence's implementation type.
+         * \param c Initial value for the sequence; default is empty, but it could contain elements if desired. The value is copied.
+         * \return
+         */
+        template <class C> static CSequence fromImpl(C c = C()) { return CSequence(new Pimpl<C>(std::move(c))); }
+
         /*!
          * \brief Change the implementation type but keep all the same elements, by copying them into the new implementation.
          * \tparam C Becomes the sequence's new implementation type.
          */
-        template <class C> void changeImpl(C = C()) { CSequence c = C(); for (auto i = cbegin(); i != cend(); ++i) c.push_back(*i); *this = std::move(c); }
+        template <class C> void changeImpl(C = C()) { auto c = fromImpl(C()); for (auto i = cbegin(); i != cend(); ++i) c.push_back(*i); *this = std::move(c); }
 
         /*!
          * \brief Like changeImpl, but uses the implementation type of another sequence.
@@ -508,6 +502,8 @@ namespace BlackMisc
         typedef QScopedPointer<PimplBase> PimplPtr;
         PimplPtr m_pimpl;
 
+        explicit CSequence(PimplBase *pimpl) : m_pimpl(pimpl) {} // private ctor used by fromImpl()
+
         // using these methods to access m_pimpl.data() eases the cognitive burden of correctly forwarding const
         PimplBase *pimpl() { return m_pimpl.data(); }
         const PimplBase *pimpl() const { return m_pimpl.data(); }
diff --git a/tests/blackmisc/testcontainers.cpp b/tests/blackmisc/testcontainers.cpp
index cd9128d66..fbd73612c 100644
--- a/tests/blackmisc/testcontainers.cpp
+++ b/tests/blackmisc/testcontainers.cpp
@@ -3,9 +3,9 @@
  *  License, v. 2.0. If a copy of the MPL was not distributed with this
  *  file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "testcontainers.h"
 #include "blackmisc/collection.h"
 #include "blackmisc/sequence.h"
-#include "testcontainers.h"
 #include <QList>
 #include <QString>
 #include <vector>
@@ -19,7 +19,7 @@ namespace BlackMiscTest
     {
         CCollection<int> c1;
         QVERIFY2(c1.empty(), "Uninitialized collection is empty");
-        CCollection<int> c2 = QList<int>();
+        auto c2 = CCollection<int>::fromImpl(QList<int>());
         QVERIFY2(c1 == c2, "Uninitialized and empty collections are equal");
         c1.changeImpl(std::vector<int>());
         QVERIFY2(c1 == c2, "Two empty collections are equal");
@@ -42,7 +42,7 @@ namespace BlackMiscTest
     {
         CSequence<int> s1;
         QVERIFY2(s1.empty(), "Uninitialized sequence is empty");
-        CSequence<int> s2 = QList<int>();
+        auto s2 = CSequence<int>::fromImpl(QList<int>());
         QVERIFY2(s1 == s2, "Uninitialized and empty sequence are equal");
         s1.changeImpl(std::vector<int>());
         QVERIFY2(s1 == s2, "Two empty sequences are equal");