diff --git a/source/tanya/container/list.d b/source/tanya/container/list.d
index adbd4fd..d0946d9 100644
--- a/source/tanya/container/list.d
+++ b/source/tanya/container/list.d
@@ -215,16 +215,19 @@ struct SList(T)
      * If $(D_PARAM init) is passed by reference, it will be copied.
      *
      * Params:
+     *  R         = Source list type.
      *  init      = Source list.
      *  allocator = Allocator.
      */
-    this(ref SList init, shared Allocator allocator = defaultAllocator)
+    this(R)(ref R init, shared Allocator allocator = defaultAllocator)
+        if (is(Unqual!R == SList))
     {
         this(init[], allocator);
     }
 
     /// Ditto.
-    this(SList init, shared Allocator allocator = defaultAllocator) @trusted
+    this(R)(R init, shared Allocator allocator = defaultAllocator) @trusted
+        if (is(R == SList))
     {
         this(allocator);
         if (allocator is init.allocator)
@@ -734,18 +737,19 @@ struct SList(T)
      *
      * Returns: $(D_KEYWORD this).
      */
-    ref typeof(this) opAssign(R)(const ref R that)
+    ref typeof(this) opAssign(R)(ref R that)
         if (is(Unqual!R == SList))
     {
         return this = that[];
     }
 
     /// Ditto.
-    ref typeof(this) opAssign(R)(const ref R that)
-        if (is(Unqual!R == SList))
+    ref typeof(this) opAssign(R)(R that)
+        if (is(R == SList))
     {
         swap(this.head, that.head);
         swap(this.allocator_, that.allocator_);
+        return this;
     }
 
     /**
diff --git a/source/tanya/container/vector.d b/source/tanya/container/vector.d
index 7f56bf0..1e9360a 100644
--- a/source/tanya/container/vector.d
+++ b/source/tanya/container/vector.d
@@ -225,11 +225,11 @@ struct Vector(T)
      * If $(D_PARAM init) is passed by reference, it will be copied.
      *
      * Params:
-     *  R         = Vector type.
+     *  R         = Source vector type.
      *  init      = Source vector.
      *  allocator = Allocator.
      */
-    this(R)(const ref R init, shared Allocator allocator = defaultAllocator)
+    this(R)(ref R init, shared Allocator allocator = defaultAllocator)
         if (is(Unqual!R == Vector))
     {
         this(allocator);
@@ -1413,7 +1413,7 @@ struct Vector(T)
      *
      * Returns: $(D_KEYWORD this).
      */
-    ref typeof(this) opAssign(R)(const ref R that)
+    ref typeof(this) opAssign(R)(ref R that)
         if (is(Unqual!R == Vector))
     {
         return this = that[];
diff --git a/source/tanya/math/mp.d b/source/tanya/math/mp.d
index e8dcce3..e55829c 100644
--- a/source/tanya/math/mp.d
+++ b/source/tanya/math/mp.d
@@ -245,16 +245,10 @@ struct Integer
     ref Integer opAssign(T)(T value) nothrow @safe @nogc
         if (is(T == Integer))
     {
-        if (this.allocator is value.allocator)
-        {
-            swap(this.rep, value.rep);
-            swap(this.sign, value.sign);
-            swap(this.size, value.size);
-        }
-        else
-        {
-            this = value;
-        }
+        swap(this.rep, value.rep);
+        swap(this.sign, value.sign);
+        swap(this.size, value.size);
+        swap(this.allocator_, value.allocator_);
         return this;
     }