Failed spares set use index to own id

Former-commit-id: e4da5bd5d8

src/storage/dft/DFT.cpp

@@ -263,7 +263,7 @@ namespace storm {
                     stream << "\t** " << storm::storage::toChar(state->getElementState(elem->id()));
                     if(elem->isSpareGate()) {
                         size_t useId = state->uses(elem->id());
-                        if(state->isActive(useId)) {
+                        if(useId == elem->id() || state->isActive(useId)) {
                             stream << "actively ";
                         }
                         stream << "using " << useId;
@@ -287,7 +287,7 @@ namespace storm {
                     if(elem->isSpareGate()) {
                         stream << "[";
                         size_t useId = state->uses(elem->id());
-                        if(state->isActive(useId)) {
+                        if(useId == elem->id() || state->isActive(useId)) {
                             stream << "actively ";
                         }
                         stream << "using " << useId << "]";

src/storage/dft/DFTElements.h

@@ -412,12 +412,12 @@ namespace storm {
             }
 
             /**
-             * Finish failed/failsafe spare gate by activating the children and setting the useIndex to zero.
+             * Finish failed/failsafe spare gate by activating the children and setting the useIndex to the spare id.
              * This prevents multiple fail states with different usages or activations.
              * @param state The current state.
              */
             void finalizeSpare(DFTState<ValueType>& state) const {
-                state.setUses(this->mId, 0);
+                state.setUses(this->mId, this->mId);
                 for (auto child : this->children()) {
                     if (!state.isActive(child->id())) {
                         state.activate(child->id());