diff --git a/src/include/map_range.h b/src/include/map_range.h
index a6ed316..2726e86 100644
--- a/src/include/map_range.h
+++ b/src/include/map_range.h
@@ -320,7 +320,9 @@ namespace MultiArrayTools
 	constexpr size_t NEXT = Op::SIZE;
 	const ExtType nxpos = last;
 	const size_t pos = mIndPtr->posAt( mOp.get( nxpos ) );
+	//VCHECK(pos);
 	const ExtType npos = last + mExt*pos;
+	//VCHECK(npos.next().next().val());
 	const size_t mnpos = PosForward<ForType::DEFAULT>::valuex(mlast, mStep, pos);
 	mExpr(mnpos, Getter<NEXT>::template getX<ExtType>( npos ) );
     }
@@ -709,7 +711,8 @@ namespace MultiArrayTools
     template <class MapF, class... Ranges>
     size_t MapRange<MapF,Ranges...>::size() const
     {
-	return RPackNum<sizeof...(Ranges)-1>::getSize(mSpace);
+	return mOutRange->size();
+	//return RPackNum<sizeof...(Ranges)-1>::getSize(mSpace);
     }
 
     template <class MapF, class... Ranges>
diff --git a/src/include/multi_array_operation.h b/src/include/multi_array_operation.h
index 10f77fd..be234e9 100644
--- a/src/include/multi_array_operation.h
+++ b/src/include/multi_array_operation.h
@@ -631,6 +631,7 @@ namespace MultiArrayTools
     template <typename T, class OpClass, class... Ranges>
     void OperationMaster<T,OpClass,Ranges...>::performAssignment(std::intptr_t blockIndexNum)
     {
+	CHECK;
 	AssignmentExpr ae(*this, mSecond); // Expression to be executed within loop
 	const auto loop = mSecond.template loop<decltype(mIndex.ifor(1,ae))>( mIndex.ifor(1,ae) );
 	// hidden Loops outside ! -> auto vectorizable
diff --git a/src/include/ranges/index_base.h b/src/include/ranges/index_base.h
index 186e66c..6e7e08d 100644
--- a/src/include/ranges/index_base.h
+++ b/src/include/ranges/index_base.h
@@ -145,6 +145,7 @@ namespace MultiArrayTools
 	mRangePtr = in.mRangePtr;
 	mPos = in.mPos;
 	mMax = in.mMax;
+	return *this;
     }
 
     template <class I, typename MetaType>
@@ -153,6 +154,7 @@ namespace MultiArrayTools
 	mRangePtr = in.mRangePtr;
 	mPos = in.mPos;
 	mMax = in.mMax;
+	return *this;
     }
     
     template <class I, typename MetaType>
diff --git a/src/include/xfor/xfor.h b/src/include/xfor/xfor.h
index 5c3379e..f2e3437 100644
--- a/src/include/xfor/xfor.h
+++ b/src/include/xfor/xfor.h
@@ -188,6 +188,7 @@ namespace MultiArrayHelper
 						    ExtType last) const
     {
 	typedef typename IndexClass::RangeType RangeType;
+	if(mlast == static_cast<size_t>( -1 ) ) { CHECK; }
 	for(size_t pos = 0u; pos != ForBound<RangeType::ISSTATIC>::template bound<RangeType::SIZE>(mMax); ++pos){
 	//for(size_t pos = mSPos; pos != mMax; ++pos){
 	    //const size_t mnpos = PosForward<FT>::value(mlast, mMax, pos);
@@ -200,6 +201,7 @@ namespace MultiArrayHelper
     template <class IndexClass, class Expr, ForType FT>
     inline void For<IndexClass,Expr,FT>::operator()(size_t mlast) const
     {
+	if(mlast == static_cast<size_t>( -1 ) ) { CHECK; }
 	typedef typename IndexClass::RangeType RangeType;
 	const ExtType last;
 	for(size_t pos = 0u; pos != ForBound<RangeType::ISSTATIC>::template bound<RangeType::SIZE>(mMax); ++pos){