Internals: Use VL_RESTORER class to save/restore vars. No functional change intended.

src/V3CUse.cpp

@@ -86,12 +86,11 @@ class CUseDTypeVisitor : public AstNVisitor {
         // No class.h, it's inside the class package's h file
         m_stater.newUse(nodep, VUseType::IMP_INCLUDE, nodep->classp()->packagep()->name());
         // Need to include extends() when we implement, but no need for pointers to know
-        bool oldImpOnly = m_impOnly;
+        VL_RESTORER(m_impOnly);
         {
             m_impOnly = true;
             iterateChildren(nodep->classp());  // This also gets all extend classes
         }
-        m_impOnly = oldImpOnly;
     }
     virtual void visit(AstNodeDType* nodep) override {
         if (nodep->user2SetOnce()) return;  // Process once