diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 4a516e6be..24c4d0e12 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -272,12 +272,6 @@ AstNode* AstNode::addNext<AstNode, AstNode>(AstNode* nodep, AstNode* newp) {
     return nodep;
 }
 
-template <>
-AstNode* AstNode::addNextNull<AstNode, AstNode>(AstNode* nodep, AstNode* newp) {
-    if (!newp) return nodep;
-    return addNext(nodep, newp);
-}
-
 void AstNode::addNextHere(AstNode* newp) {
     // Add to m_nextp on exact node passed, not at the end.
     //  This could be at head, tail, or both (single)
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 90a203042..87349cc68 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -1797,19 +1797,9 @@ public:
                       "'T_NodeNext' must be a subtype of 'T_NodeResult'");
         return static_cast<T_NodeResult*>(addNext<AstNode, AstNode>(nodep, newp));
     }
-    // Returns nodep, adds newp (maybe nullptr) to end of nodep's list
-    template <typename T_NodeResult, typename T_NodeNext>
-    static T_NodeResult* addNextNull(T_NodeResult* nodep, T_NodeNext* newp) {
-        static_assert(std::is_base_of<AstNode, T_NodeResult>::value,
-                      "'T_NodeResult' must be a subtype of AstNode");
-        static_assert(std::is_base_of<T_NodeResult, T_NodeNext>::value,
-                      "'T_NodeNext' must be a subtype of 'T_NodeResult'");
-        return static_cast<T_NodeResult*>(addNextNull<AstNode, AstNode>(nodep, newp));
-    }
     inline AstNode* addNext(AstNode* newp);
-    inline AstNode* addNextNull(AstNode* newp);
-    void addNextHere(AstNode* newp);  // Insert newp at this->nextp
     inline void addPrev(AstNode* newp);
+    void addNextHere(AstNode* newp);  // Insert newp at this->nextp
     void addHereThisAsNext(AstNode* newp);  // Adds at old place of this, this becomes next
     void replaceWith(AstNode* newp);  // Replace current node in tree with new node
     AstNode* unlinkFrBack(VNRelinker* linkerp
@@ -2100,8 +2090,13 @@ public:
 // Forward declarations of specializations defined in V3Ast.cpp
 template <>
 AstNode* AstNode::addNext<AstNode, AstNode>(AstNode* nodep, AstNode* newp);
-template <>
-AstNode* AstNode::addNextNull<AstNode, AstNode>(AstNode* nodep, AstNode* newp);
+
+// Inline method implementations
+AstNode* AstNode::addNext(AstNode* newp) { return addNext(this, newp); }
+void AstNode::addPrev(AstNode* newp) {
+    replaceWith(newp);
+    newp->addNext(this);
+}
 
 // Specialisations of privateTypeTest
 #include "V3Ast__gen_impl.h"  // From ./astgen
diff --git a/src/V3AstInlines.h b/src/V3AstInlines.h
index 9ffb7fa5c..2deceda22 100644
--- a/src/V3AstInlines.h
+++ b/src/V3AstInlines.h
@@ -25,13 +25,6 @@
 //######################################################################
 // Inline METHODS
 
-AstNode* AstNode::addNext(AstNode* newp) { return addNext(this, newp); }
-AstNode* AstNode::addNextNull(AstNode* newp) { return addNextNull(this, newp); }
-void AstNode::addPrev(AstNode* newp) {
-    replaceWith(newp);
-    newp->addNext(this);
-}
-
 int AstNode::width() const { return dtypep() ? dtypep()->width() : 0; }
 int AstNode::widthMin() const { return dtypep() ? dtypep()->widthMin() : 0; }
 bool AstNode::width1() const {  // V3Const uses to know it can optimize
diff --git a/src/V3Begin.cpp b/src/V3Begin.cpp
index 9f65dd79a..c9ceec09e 100644
--- a/src/V3Begin.cpp
+++ b/src/V3Begin.cpp
@@ -177,11 +177,7 @@ private:
             AstNode* addsp = nullptr;
             if (AstNode* const stmtsp = nodep->stmtsp()) {
                 stmtsp->unlinkFrBackWithNext();
-                if (addsp) {
-                    addsp = addsp->addNextNull(stmtsp);
-                } else {
-                    addsp = stmtsp;
-                }
+                addsp = AstNode::addNext(addsp, stmtsp);
             }
             if (addsp) {
                 nodep->replaceWith(addsp);
diff --git a/src/V3Coverage.cpp b/src/V3Coverage.cpp
index a5e8b1dc3..04266c492 100644
--- a/src/V3Coverage.cpp
+++ b/src/V3Coverage.cpp
@@ -134,7 +134,7 @@ private:
                 incp->fileline(), new AstVarRef(incp->fileline(), varp, VAccess::WRITE),
                 new AstAdd(incp->fileline(), new AstVarRef(incp->fileline(), varp, VAccess::READ),
                            new AstConst(incp->fileline(), AstConst::WidthedValue(), 32, 1)));
-            incp->addNext(assp);
+            AstNode::addNext<AstNode, AstNode>(incp, assp);
         }
         return incp;
     }
diff --git a/src/V3Descope.cpp b/src/V3Descope.cpp
index 544bac417..835294f74 100644
--- a/src/V3Descope.cpp
+++ b/src/V3Descope.cpp
@@ -139,14 +139,14 @@ private:
                     UINFO(6,
                           "  at " << newfuncp->argTypes() << " und " << funcp->argTypes() << endl);
                     funcp->declPrivate(true);
-                    AstNode* argsp = nullptr;
+                    AstVarRef* argsp = nullptr;
                     for (AstNode* stmtp = newfuncp->argsp(); stmtp; stmtp = stmtp->nextp()) {
                         if (AstVar* const portp = VN_CAST(stmtp, Var)) {
                             if (portp->isIO() && !portp->isFuncReturn()) {
-                                AstNode* const newp = new AstVarRef(
+                                AstVarRef* const newp = new AstVarRef(
                                     portp->fileline(), portp,
                                     portp->isWritable() ? VAccess::WRITE : VAccess::READ);
-                                argsp = argsp ? argsp->addNextNull(newp) : newp;
+                                argsp = AstNode::addNext(argsp, newp);
                             }
                         }
                     }
diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index 2a4ce4bc0..b0a8e4001 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -177,21 +177,17 @@ private:
             const int right = nodep->rangep()->rightConst();
             const int increment = (left > right) ? -1 : 1;
             int offset_from_init = 0;
-            AstNode* addp = nullptr;
+            AstEnumItem* addp = nullptr;
+            FileLine* const flp = nodep->fileline();
             for (int i = left; i != (right + increment); i += increment, offset_from_init++) {
                 const string name = nodep->name() + cvtToStr(i);
                 AstNode* valuep = nullptr;
                 if (nodep->valuep()) {
-                    valuep = new AstAdd(
-                        nodep->fileline(), nodep->valuep()->cloneTree(true),
-                        new AstConst(nodep->fileline(), AstConst::Unsized32(), offset_from_init));
-                }
-                AstNode* const newp = new AstEnumItem(nodep->fileline(), name, nullptr, valuep);
-                if (addp) {
-                    addp = addp->addNextNull(newp);
-                } else {
-                    addp = newp;
+                    valuep
+                        = new AstAdd(flp, nodep->valuep()->cloneTree(true),
+                                     new AstConst(flp, AstConst::Unsized32(), offset_from_init));
                 }
+                addp = AstNode::addNext(addp, new AstEnumItem{flp, name, nullptr, valuep});
             }
             nodep->replaceWith(addp);
             VL_DO_DANGLING(nodep->deleteTree(), nodep);
@@ -372,7 +368,7 @@ private:
         iterateChildren(nodep);
         if (m_varp) {
             nodep->unlinkFrBack();
-            m_varp->addNext(nodep);
+            AstNode::addNext<AstNode, AstNode>(m_varp, nodep);
             // lvalue is true, because we know we have a verilator public_flat_rw
             // but someday we may be more general
             const bool lvalue = m_varp->isSigUserRWPublic();
diff --git a/src/V3ParseGrammar.cpp b/src/V3ParseGrammar.cpp
index 66670338e..5655a1d96 100644
--- a/src/V3ParseGrammar.cpp
+++ b/src/V3ParseGrammar.cpp
@@ -76,7 +76,6 @@ AstArg* V3ParseGrammar::argWrapList(AstNode* nodep) {
         AstNode* const nextp = nodep->nextp();
         AstNode* const exprp = nodep->unlinkFrBack();
         nodep = nextp;
-        // addNext can handle nulls:
         outp = AstNode::addNext(outp, new AstArg(exprp->fileline(), "", exprp));
     }
     VL_DO_DANGLING(tempp->deleteTree(), tempp);
@@ -204,15 +203,17 @@ AstVar* V3ParseGrammar::createVariable(FileLine* fileline, const string& name,
     }
 
     if (GRAMMARP->m_varDecl == VVarType::SUPPLY0) {
-        nodep->addNext(V3ParseGrammar::createSupplyExpr(fileline, nodep->name(), 0));
+        AstNode::addNext<AstNode, AstNode>(
+            nodep, V3ParseGrammar::createSupplyExpr(fileline, nodep->name(), 0));
     }
     if (GRAMMARP->m_varDecl == VVarType::SUPPLY1) {
-        nodep->addNext(V3ParseGrammar::createSupplyExpr(fileline, nodep->name(), 1));
+        AstNode::addNext<AstNode, AstNode>(
+            nodep, V3ParseGrammar::createSupplyExpr(fileline, nodep->name(), 1));
     }
     if (VN_IS(dtypep, ParseTypeDType)) {
         // Parser needs to know what is a type
         AstNode* const newp = new AstTypedefFwd(fileline, name);
-        nodep->addNext(newp);
+        AstNode::addNext<AstNode, AstNode>(nodep, newp);
         SYMP->reinsert(newp);
     }
     // Don't set dtypep in the ranging;
diff --git a/src/V3Slice.cpp b/src/V3Slice.cpp
index c5a993e75..f362c3cb7 100644
--- a/src/V3Slice.cpp
+++ b/src/V3Slice.cpp
@@ -147,7 +147,7 @@ class SliceVisitor final : public VNVisitor {
                                                  cloneAndSel(nodep->rhsp(), elements, offset)),
                                 NodeAssign);
                     if (debug() >= 9) newp->dumpTree(cout, "-new ");
-                    newlistp = AstNode::addNextNull(newlistp, newp);
+                    newlistp = AstNode::addNext(newlistp, newp);
                 }
                 if (debug() >= 9) nodep->dumpTree(cout, " Deslice-Dn: ");
                 nodep->replaceWith(newlistp);
diff --git a/src/V3Task.cpp b/src/V3Task.cpp
index c298f8ed4..0ab7392fd 100644
--- a/src/V3Task.cpp
+++ b/src/V3Task.cpp
@@ -496,7 +496,7 @@ private:
                     // Put assignment in FRONT of all other statements
                     if (AstNode* const afterp = beginp->nextp()) {
                         afterp->unlinkFrBackWithNext();
-                        assp->addNext(afterp);
+                        AstNode::addNext<AstNode, AstNode>(assp, afterp);
                     }
                     beginp->addNext(assp);
                 }
@@ -819,7 +819,7 @@ private:
                     AstVarRef* const refp
                         = new AstVarRef(portp->fileline(), outvscp,
                                         portp->isWritable() ? VAccess::WRITE : VAccess::READ);
-                    argnodesp = argnodesp->addNextNull(refp);
+                    argnodesp = argnodesp->addNext(refp);
 
                     if (portp->isNonOutput()) {
                         std::string frName
@@ -847,7 +847,7 @@ private:
             outvscp->varp()->protect(false);
             AstVarRef* const refp = new AstVarRef(
                 portp->fileline(), outvscp, portp->isWritable() ? VAccess::WRITE : VAccess::READ);
-            argnodesp = argnodesp->addNextNull(refp);
+            argnodesp = argnodesp->addNext(refp);
         }
 
         {  // Call the user function
diff --git a/src/V3Unroll.cpp b/src/V3Unroll.cpp
index 8c9bf96dd..1efbef18b 100644
--- a/src/V3Unroll.cpp
+++ b/src/V3Unroll.cpp
@@ -279,15 +279,15 @@ private:
         }
         if (precondsp) {
             precondsp->unlinkFrBackWithNext();
-            stmtsp = AstNode::addNextNull(stmtsp, precondsp);
+            stmtsp = AstNode::addNext(stmtsp, precondsp);
         }
         if (bodysp) {
             bodysp->unlinkFrBackWithNext();
-            stmtsp = AstNode::addNextNull(stmtsp, bodysp);  // Maybe null if no body
+            stmtsp = AstNode::addNext(stmtsp, bodysp);  // Maybe null if no body
         }
         if (incp && !VN_IS(nodep, GenFor)) {  // Generates don't need to increment loop index
             incp->unlinkFrBackWithNext();
-            stmtsp = AstNode::addNextNull(stmtsp, incp);  // Maybe null if no body
+            stmtsp = AstNode::addNext(stmtsp, incp);  // Maybe null if no body
         }
         // Mark variable to disable some later warnings
         m_forVarp->usedLoopIdx(true);
diff --git a/src/V3VariableOrder.cpp b/src/V3VariableOrder.cpp
index 5bd51933d..53e53788e 100644
--- a/src/V3VariableOrder.cpp
+++ b/src/V3VariableOrder.cpp
@@ -186,7 +186,7 @@ class VariableOrder final {
             for (; it != varps.cend(); ++it) firstp->addNext(*it);
             if (AstNode* const stmtsp = modp->stmtsp()) {
                 stmtsp->unlinkFrBackWithNext();
-                firstp->addNext(stmtsp);
+                AstNode::addNext<AstNode, AstNode>(firstp, stmtsp);
             }
             modp->addStmtp(firstp);
         }
diff --git a/src/astgen b/src/astgen
index 98d0750fe..19a6d0b19 100755
--- a/src/astgen
+++ b/src/astgen
@@ -748,6 +748,7 @@ def write_macros(filename):
                 return static_cast<Ast{t}*>(AstNode::cloneTree(cloneNext));
             }}
             Ast{t}* clonep() const {{ return static_cast<Ast{t}*>(AstNode::clonep()); }}
+            Ast{t}* addNext(Ast{t}* nodep) {{ return static_cast<Ast{t}*>(AstNode::addNext(this, nodep)); }}
             ''',
                       t=node.name)
 
diff --git a/src/verilog.y b/src/verilog.y
index c6a7048de..4d3c38bc3 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -139,7 +139,7 @@ public:
     }
     AstDisplay* createDisplayError(FileLine* fileline) {
         AstDisplay* nodep = new AstDisplay(fileline, VDisplayType::DT_ERROR, "", nullptr, nullptr);
-        nodep->addNext(new AstStop(fileline, true));
+        AstNode::addNext<AstNode, AstNode>(nodep, new AstStop(fileline, true));
         return nodep;
     }
     AstNode* createGatePin(AstNode* exprp) {
@@ -330,6 +330,12 @@ static void UNSUPREAL(FileLine* fileline) {
 
 void yyerror(const char* errmsg) { PARSEP->bisonLastFileline()->v3error(errmsg); }
 
+template <typename T_Node, typename T_Next>
+static T_Node* addNextNull(T_Node* nodep, T_Next* nextp) {
+    if (!nextp) return nodep;
+    return AstNode::addNext<T_Node, T_Next>(nodep, nextp);
+}
+
 //======================================================================
 
 class AstSenTree;
@@ -1138,7 +1144,7 @@ package_itemListE<nodep>:       // IEEE: [{ package_item }]
 
 package_itemList<nodep>:        // IEEE: { package_item }
                 package_item                            { $$ = $1; }
-        |       package_itemList package_item           { $$ = $1->addNextNull($2); }
+        |       package_itemList package_item           { $$ = addNextNull($1, $2); }
         ;
 
 package_item<nodep>:            // ==IEEE: package_item
@@ -1167,7 +1173,7 @@ package_or_generate_item_declaration<nodep>:    // ==IEEE: package_or_generate_i
 
 package_import_declarationList<nodep>:
                 package_import_declaration              { $$ = $1; }
-        |       package_import_declarationList package_import_declaration { $$ = $1->addNextNull($2); }
+        |       package_import_declarationList package_import_declaration { $$ = addNextNull($1, $2); }
         ;
 
 package_import_declaration<nodep>:      // ==IEEE: package_import_declaration
@@ -1176,7 +1182,7 @@ package_import_declaration<nodep>:      // ==IEEE: package_import_declaration
 
 package_import_itemList<nodep>:
                 package_import_item                     { $$ = $1; }
-        |       package_import_itemList ',' package_import_item { $$ = $1->addNextNull($3); }
+        |       package_import_itemList ',' package_import_item { $$ = addNextNull($1, $3); }
         ;
 
 package_import_item<nodep>:     // ==IEEE: package_import_item
@@ -1204,7 +1210,7 @@ package_export_declaration<nodep>: // IEEE: package_export_declaration
 
 package_export_itemList<nodep>:
                 package_export_item                     { $$ = $1; }
-        |       package_export_itemList ',' package_export_item { $$ = $1->addNextNull($3); }
+        |       package_export_itemList ',' package_export_item { $$ = addNextNull($1, $3); }
         ;
 
 package_export_item<nodep>:     // ==IEEE: package_export_item
@@ -1261,7 +1267,7 @@ modFront<nodeModulep>:
 importsAndParametersE<nodep>:   // IEEE: common part of module_declaration, interface_declaration, program_declaration
         //                      // { package_import_declaration } [ parameter_port_list ]
                 parameter_port_listE                    { $$ = $1; }
-        |       package_import_declarationList parameter_port_listE     { $$ = $1->addNextNull($2); }
+        |       package_import_declarationList parameter_port_listE     { $$ = addNextNull($1, $2); }
         ;
 
 udpFront<nodeModulep>:
@@ -1332,12 +1338,12 @@ portsStarE<nodep>:              // IEEE: .* + list_of_ports + list_of_port_decla
 
 list_of_portsE<nodep>:          // IEEE: list_of_ports + list_of_port_declarations
                 portAndTagE                     { $$ = $1; }
-        |       list_of_portsE ',' portAndTagE          { $$ = $1->addNextNull($3); }
+        |       list_of_portsE ',' portAndTagE          { $$ = addNextNull($1, $3); }
         ;
 
 list_of_ports<nodep>:           // IEEE: list_of_ports + list_of_port_declarations
                 portAndTag                      { $$ = $1; }
-        |       list_of_portsE ',' portAndTagE          { $$ = $1->addNextNull($3); }
+        |       list_of_portsE ',' portAndTagE          { $$ = addNextNull($1, $3); }
         ;
 
 portAndTagE<nodep>:
@@ -1375,11 +1381,11 @@ port<nodep>:                    // ==IEEE: port
                 portDirNetE id/*interface*/                      portSig variable_dimensionListE sigAttrListE
                         { $$ = $3; VARDECL(IFACEREF); VARIO(NONE);
                           VARDTYPE(new AstIfaceRefDType($<fl>2,"",*$2));
-                          $$->addNextNull(VARDONEP($$,$4,$5)); }
+                          addNextNull($$, VARDONEP($$,$4,$5)); }
         |       portDirNetE id/*interface*/ '.' idAny/*modport*/ portSig variable_dimensionListE sigAttrListE
                         { $$ = $5; VARDECL(IFACEREF); VARIO(NONE);
                           VARDTYPE(new AstIfaceRefDType($<fl>2, $<fl>4, "", *$2, *$4));
-                          $$->addNextNull(VARDONEP($$,$6,$7)); }
+                          addNextNull($$, VARDONEP($$,$6,$7)); }
         |       portDirNetE yINTERFACE                           portSig rangeListE sigAttrListE
                         { $$ = nullptr; BBUNSUP($<fl>2, "Unsupported: virtual or generic interfaces"); }
         |       portDirNetE yINTERFACE      '.' idAny/*modport*/ portSig rangeListE sigAttrListE
@@ -1430,29 +1436,29 @@ port<nodep>:                    // ==IEEE: port
         //UNSUP         { UNSUP }
         //
         |       portDirNetE data_type           portSig variable_dimensionListE sigAttrListE
-                        { $$=$3; VARDTYPE($2); $$->addNextNull(VARDONEP($$,$4,$5)); }
+                        { $$=$3; VARDTYPE($2); addNextNull($$, VARDONEP($$,$4,$5)); }
         |       portDirNetE yVAR data_type      portSig variable_dimensionListE sigAttrListE
-                        { $$=$4; VARDTYPE($3); $$->addNextNull(VARDONEP($$,$5,$6)); }
+                        { $$=$4; VARDTYPE($3); addNextNull($$, VARDONEP($$,$5,$6)); }
         |       portDirNetE yVAR implicit_typeE portSig variable_dimensionListE sigAttrListE
-                        { $$=$4; VARDTYPE($3); $$->addNextNull(VARDONEP($$,$5,$6)); }
+                        { $$=$4; VARDTYPE($3); addNextNull($$, VARDONEP($$,$5,$6)); }
         |       portDirNetE signing             portSig variable_dimensionListE sigAttrListE
                         { $$=$3; VARDTYPE_NDECL(new AstBasicDType($3->fileline(), LOGIC_IMPLICIT, $2));
-                          $$->addNextNull(VARDONEP($$, $4, $5)); }
+                          addNextNull($$, VARDONEP($$, $4, $5)); }
         |       portDirNetE signingE rangeList  portSig variable_dimensionListE sigAttrListE
                         { $$=$4; VARDTYPE_NDECL(GRAMMARP->addRange(
                                     new AstBasicDType{$3->fileline(), LOGIC_IMPLICIT, $2}, $3, true));
-                          $$->addNextNull(VARDONEP($$, $5, $6)); }
+                          addNextNull($$, VARDONEP($$, $5, $6)); }
         |       portDirNetE /*implicit*/        portSig variable_dimensionListE sigAttrListE
-                        { $$=$2; /*VARDTYPE-same*/ $$->addNextNull(VARDONEP($$,$3,$4)); }
+                        { $$=$2; /*VARDTYPE-same*/ addNextNull($$, VARDONEP($$,$3,$4)); }
         //
         |       portDirNetE data_type           portSig variable_dimensionListE sigAttrListE '=' constExpr
-                        { $$=$3; VARDTYPE($2); if (AstVar* vp = VARDONEP($$, $4, $5)) { $$->addNextNull(vp); vp->valuep($7); } }
+                        { $$=$3; VARDTYPE($2); if (AstVar* vp = VARDONEP($$, $4, $5)) { addNextNull($$, vp); vp->valuep($7); } }
         |       portDirNetE yVAR data_type      portSig variable_dimensionListE sigAttrListE '=' constExpr
-                        { $$=$4; VARDTYPE($3); if (AstVar* vp = VARDONEP($$, $5, $6)) { $$->addNextNull(vp); vp->valuep($8); } }
+                        { $$=$4; VARDTYPE($3); if (AstVar* vp = VARDONEP($$, $5, $6)) { addNextNull($$, vp); vp->valuep($8); } }
         |       portDirNetE yVAR implicit_typeE portSig variable_dimensionListE sigAttrListE '=' constExpr
-                        { $$=$4; VARDTYPE($3); if (AstVar* vp = VARDONEP($$, $5, $6)) { $$->addNextNull(vp); vp->valuep($8); } }
+                        { $$=$4; VARDTYPE($3); if (AstVar* vp = VARDONEP($$, $5, $6)) { addNextNull($$, vp); vp->valuep($8); } }
         |       portDirNetE /*implicit*/        portSig variable_dimensionListE sigAttrListE '=' constExpr
-                        { $$=$2; /*VARDTYPE-same*/ if (AstVar* vp = VARDONEP($$, $3, $4)) { $$->addNextNull(vp); vp->valuep($6); } }
+                        { $$=$2; /*VARDTYPE-same*/ if (AstVar* vp = VARDONEP($$, $3, $4)) { addNextNull($$, vp); vp->valuep($6); } }
         ;
 
 portDirNetE:                    // IEEE: part of port, optional net type and/or direction
@@ -1507,7 +1513,7 @@ interface_itemListE<nodep>:
 
 interface_itemList<nodep>:
                 interface_item                          { $$ = $1; }
-        |       interface_itemList interface_item       { $$ = $1->addNextNull($2); }
+        |       interface_itemList interface_item       { $$ = addNextNull($1, $2); }
         ;
 
 interface_item<nodep>:          // IEEE: interface_item + non_port_interface_item
@@ -1555,7 +1561,7 @@ anonymous_program_itemListE<nodep>:     // IEEE: { anonymous_program_item }
 
 anonymous_program_itemList<nodep>:      // IEEE: { anonymous_program_item }
                 anonymous_program_item                  { $$ = $1; }
-        |       anonymous_program_itemList anonymous_program_item       { $$ = $1->addNextNull($2); }
+        |       anonymous_program_itemList anonymous_program_item       { $$ = addNextNull($1, $2); }
         ;
 
 anonymous_program_item<nodep>:  // ==IEEE: anonymous_program_item
@@ -1602,7 +1608,7 @@ program_itemListE<nodep>:       // ==IEEE: [{ program_item }]
 
 program_itemList<nodep>:        // ==IEEE: { program_item }
                 program_item                            { $$ = $1; }
-        |       program_itemList program_item           { $$ = $1->addNextNull($2); }
+        |       program_itemList program_item           { $$ = addNextNull($1, $2); }
         ;
 
 program_item<nodep>:            // ==IEEE: program_item
@@ -1642,7 +1648,7 @@ modport_declaration<nodep>:             // ==IEEE: modport_declaration
 
 modport_itemList<nodep>:                // IEEE: part of modport_declaration
                 modport_item                            { $$ = $1; }
-        |       modport_itemList ',' modport_item       { $$ = $1->addNextNull($3); }
+        |       modport_itemList ',' modport_item       { $$ = addNextNull($1, $3); }
         ;
 
 modport_item<nodep>:                    // ==IEEE: modport_item
@@ -1653,7 +1659,7 @@ modport_item<nodep>:                    // ==IEEE: modport_item
 
 modportPortsDeclList<nodep>:
                 modportPortsDecl                            { $$ = $1; }
-        |       modportPortsDeclList ',' modportPortsDecl   { $$ = $1->addNextNull($3); }
+        |       modportPortsDeclList ',' modportPortsDecl   { $$ = addNextNull($1, $3); }
         ;
 
 // IEEE: modport_ports_declaration  + modport_simple_ports_declaration
@@ -2004,7 +2010,7 @@ struct_unionDecl<nodeUOrStructDTypep>:  // IEEE: part of data_type
 
 struct_union_memberList<nodep>: // IEEE: { struct_union_member }
                 struct_union_member                             { $$ = $1; }
-        |       struct_union_memberList struct_union_member     { $$ = $1->addNextNull($2); }
+        |       struct_union_memberList struct_union_member     { $$ = addNextNull($1, $2); }
         ;
 
 struct_union_member<nodep>:     // ==IEEE: struct_union_member
@@ -2017,7 +2023,7 @@ struct_union_member<nodep>:     // ==IEEE: struct_union_member
 
 list_of_member_decl_assignments<nodep>: // Derived from IEEE: list_of_variable_decl_assignments
                 member_decl_assignment          { $$ = $1; }
-        |       list_of_member_decl_assignments ',' member_decl_assignment      { $$ = $1->addNextNull($3); }
+        |       list_of_member_decl_assignments ',' member_decl_assignment      { $$ = addNextNull($1, $3); }
         ;
 
 member_decl_assignment<memberDTypep>:   // Derived from IEEE: variable_decl_assignment
@@ -2050,7 +2056,7 @@ member_decl_assignment<memberDTypep>:   // Derived from IEEE: variable_decl_assi
 
 list_of_variable_decl_assignments<varp>:        // ==IEEE: list_of_variable_decl_assignments
                 variable_decl_assignment                { $$ = $1; }
-        |       list_of_variable_decl_assignments ',' variable_decl_assignment  { $$ = VN_CAST($1->addNextNull($3), Var); }
+        |       list_of_variable_decl_assignments ',' variable_decl_assignment  { $$ = addNextNull($1, $3); }
         ;
 
 variable_decl_assignment<varp>: // ==IEEE: variable_decl_assignment
@@ -2080,7 +2086,7 @@ list_of_tf_variable_identifiers<nodep>: // ==IEEE: list_of_tf_variable_identifie
 tf_variable_identifier<varp>:           // IEEE: part of list_of_tf_variable_identifiers
                 id variable_dimensionListE sigAttrListE exprEqE
                         { $$ = VARDONEA($<fl>1,*$1, $2, $3);
-                          if ($4) $$->addNext(new AstAssign($4->fileline(), new AstVarRef($<fl>1, *$1, VAccess::WRITE), $4)); }
+                          if ($4) AstNode::addNext<AstNode, AstNode>($$, new AstAssign($4->fileline(), new AstVarRef($<fl>1, *$1, VAccess::WRITE), $4)); }
         ;
 
 variable_declExpr<nodep>:               // IEEE: part of variable_decl_assignment - rhs of expr
@@ -2096,7 +2102,7 @@ variable_dimensionListE<nodeRangep>:    // IEEE: variable_dimension + empty
 
 variable_dimensionList<nodeRangep>:     // IEEE: variable_dimension + empty
                 variable_dimension                      { $$ = $1; }
-        |       variable_dimensionList variable_dimension       { $$ = VN_CAST($1->addNext($2), NodeRange); }
+        |       variable_dimensionList variable_dimension       { $$ = $1->addNext($2); }
         ;
 
 variable_dimension<nodeRangep>: // ==IEEE: variable_dimension
@@ -2173,7 +2179,7 @@ enum_base_typeE<nodeDTypep>:    // IEEE: enum_base_type
 
 enum_nameList<nodep>:
                 enum_name_declaration                   { $$ = $1; }
-        |       enum_nameList ',' enum_name_declaration { $$ = $1->addNextNull($3); }
+        |       enum_nameList ',' enum_name_declaration { $$ = addNextNull($1, $3); }
         ;
 
 enum_name_declaration<nodep>:   // ==IEEE: enum_name_declaration
@@ -2364,7 +2370,7 @@ dtypeAttrListE<nodep>:
 
 dtypeAttrList<nodep>:
                 dtypeAttr                               { $$ = $1; }
-        |       dtypeAttrList dtypeAttr                 { $$ = $1->addNextNull($2); }
+        |       dtypeAttrList dtypeAttr                 { $$ = addNextNull($1, $2); }
         ;
 
 dtypeAttr<nodep>:
@@ -2385,7 +2391,7 @@ module_itemListE<nodep>:        // IEEE: Part of module_declaration
 
 module_itemList<nodep>:         // IEEE: Part of module_declaration
                 module_item                             { $$ = $1; }
-        |       module_itemList module_item             { $$ = $1->addNextNull($2); }
+        |       module_itemList module_item             { $$ = addNextNull($1, $2); }
         ;
 
 module_item<nodep>:             // ==IEEE: module_item
@@ -2573,7 +2579,7 @@ genItemOrBegin<nodep>:          // Not in IEEE, but our begin isn't under genera
 
 genItemList<nodep>:
                 ~c~genItemOrBegin                       { $$ = $1; }
-        |       ~c~genItemList ~c~genItemOrBegin        { $$ = $1->addNextNull($2); }
+        |       ~c~genItemList ~c~genItemOrBegin        { $$ = addNextNull($1, $2); }
         ;
 
 //UNSUPc_genItemList<nodep>:  // (for checkers)
@@ -2641,7 +2647,7 @@ loop_generate_construct<nodep>: // ==IEEE: loop_generate_construct
 genvar_initialization<nodep>:   // ==IEEE: genvar_initialization
                 varRefBase '=' expr                     { $$ = new AstAssign($2,$1,$3); }
         |       yGENVAR genvar_identifierDecl '=' constExpr
-                        { $$ = $2; $2->addNext(new AstAssign($3, new AstVarRef($2->fileline(), $2, VAccess::WRITE), $4)); }
+                        { $$ = $2; AstNode::addNext<AstNode, AstNode>($$, new AstAssign($3, new AstVarRef($2->fileline(), $2, VAccess::WRITE), $4)); }
         ;
 
 genvar_iteration<nodep>:        // ==IEEE: genvar_iteration
@@ -2763,7 +2769,7 @@ netSig<varp>:                   // IEEE: net_decl_assignment -  one element from
                           auto* const assignp = new AstAssignW{$3, new AstVarRef{$<fl>1, *$1, VAccess::WRITE}, $4};
                           if (GRAMMARP->m_netStrengthp) assignp->strengthSpecp(GRAMMARP->m_netStrengthp->cloneTree(false));
                           if ($$->delayp()) assignp->addTimingControlp($$->delayp()->unlinkFrBack());  // IEEE 1800-2017 10.3.3
-                          $$->addNext(assignp); }        |       netId variable_dimensionList sigAttrListE
+                          AstNode::addNext<AstNode, AstNode>($$, assignp); }        |       netId variable_dimensionList sigAttrListE
                         { $$ = VARDONEA($<fl>1,*$1, $2, $3); }
         ;
 
@@ -2779,7 +2785,7 @@ sigAttrListE<nodep>:
 
 sigAttrList<nodep>:
                 sigAttr                                 { $$ = $1; }
-        |       sigAttrList sigAttr                     { $$ = $1->addNextNull($2); }
+        |       sigAttrList sigAttr                     { $$ = addNextNull($1, $2); }
         ;
 
 sigAttr<nodep>:
@@ -2806,7 +2812,7 @@ rangeListE<nodeRangep>:         // IEEE: [{packed_dimension}]
 
 rangeList<nodeRangep>:          // IEEE: {packed_dimension}
                 anyrange                                { $$ = $1; }
-        |       rangeList anyrange                      { $$ = $1; $1->addNext($2); }
+        |       rangeList anyrange                      { $$ = $1->addNext($2); }
         ;
 
 //UNSUPbit_selectE<fl>:  // IEEE: constant_bit_select (IEEE included empty)
@@ -2828,7 +2834,7 @@ packed_dimensionListE<nodeRangep>:      // IEEE: [{ packed_dimension }]
 
 packed_dimensionList<nodeRangep>:       // IEEE: { packed_dimension }
                 packed_dimension                        { $$ = $1; }
-        |       packed_dimensionList packed_dimension   { $$ = VN_CAST($1->addNext($2), NodeRange); }
+        |       packed_dimensionList packed_dimension   { $$ = $1->addNext($2); }
         ;
 
 packed_dimension<nodeRangep>:   // ==IEEE: packed_dimension
@@ -2857,7 +2863,7 @@ param_assignment<varp>:         // ==IEEE: param_assignment
 
 list_of_param_assignments<varp>:        // ==IEEE: list_of_param_assignments
                 param_assignment                        { $$ = $1; }
-        |       list_of_param_assignments ',' param_assignment  { $$ = $1; $1->addNext($3); }
+        |       list_of_param_assignments ',' param_assignment  { $$ = $1->addNext($3); }
         ;
 
 type_assignment<varp>:          // ==IEEE: type_assignment
@@ -2868,7 +2874,7 @@ type_assignment<varp>:          // ==IEEE: type_assignment
 
 list_of_type_assignments<varp>:         // ==IEEE: list_of_type_assignments
                 type_assignment                         { $$ = $1; }
-        |       list_of_type_assignments ',' type_assignment    { $$ = $1; $1->addNext($3); }
+        |       list_of_type_assignments ',' type_assignment    { $$ = $1->addNext($3); }
         ;
 
 list_of_defparam_assignments<nodep>:    //== IEEE: list_of_defparam_assignments
@@ -2948,7 +2954,7 @@ instRangeListE<nodeRangep>:
 
 instRangeList<nodeRangep>:
                 instRange                               { $$ = $1; }
-        |       instRangeList instRange                 { $$ = VN_CAST($1->addNextNull($2), Range); }
+        |       instRangeList instRange                 { $$ = addNextNull($1, $2); }
         ;
 
 instRange<nodeRangep>:
@@ -2968,12 +2974,12 @@ cellpinList<pinp>:
 
 cellparamItList<pinp>:          // IEEE: list_of_parameter_assignmente
                 cellparamItemE                          { $$ = $1; }
-        |       cellparamItList ',' cellparamItemE      { $$ = VN_CAST($1->addNextNull($3), Pin); }
+        |       cellparamItList ',' cellparamItemE      { $$ = addNextNull($1, $3); }
         ;
 
 cellpinItList<pinp>:            // IEEE: list_of_port_connections
                 cellpinItemE                            { $$ = $1; }
-        |       cellpinItList ',' cellpinItemE          { $$ = VN_CAST($1->addNextNull($3), Pin); }
+        |       cellpinItList ',' cellpinItemE          { $$ = addNextNull($1, $3); }
         ;
 
 cellparamItemE<pinp>:           // IEEE: named_parameter_assignment + empty
@@ -3051,11 +3057,11 @@ event_control<senTreep>:        // ==IEEE: event_control
 event_expression<senItemp>:     // IEEE: event_expression - split over several
         //UNSUP                 // Below are all removed
                 senitem                                 { $$ = $1; }
-        |       event_expression yOR senitem            { $$ = VN_CAST($1->addNextNull($3), SenItem); }
-        |       event_expression ',' senitem            { $$ = VN_CAST($1->addNextNull($3), SenItem); } /* Verilog 2001 */
+        |       event_expression yOR senitem            { $$ = addNextNull($1, $3); }
+        |       event_expression ',' senitem            { $$ = addNextNull($1, $3); } /* Verilog 2001 */
         //UNSUP                 // Above are all removed, replace with:
         //UNSUP ev_expr                                 { $$ = $1; }
-        //UNSUP event_expression ',' ev_expr %prec yOR  { $$ = VN_CAST($1->addNextNull($3), SenItem); }
+        //UNSUP event_expression ',' ev_expr %prec yOR  { $$ = addNextNull($1, $3); }
         ;
 
 senitem<senItemp>:              // IEEE: part of event_expression, non-'OR' ',' terms
@@ -3167,7 +3173,7 @@ par_blockFrontPreId<forkp>:     // IEEE: part of par_block/stmt with leading id
 blockDeclStmtList<nodep>:       // IEEE: { block_item_declaration } { statement or null }
         //                      // The spec seems to suggest a empty declaration isn't ok, but most simulators take it
                 block_item_declarationList              { $$ = $1; }
-        |       block_item_declarationList stmtList     { $$ = $1->addNextNull($2); }
+        |       block_item_declarationList stmtList     { $$ = addNextNull($1, $2); }
         |       stmtList                                { $$ = $1; }
         ;
 
@@ -3178,7 +3184,7 @@ blockDeclStmtListE<nodep>:      // IEEE: [ { block_item_declaration } { statemen
 
 block_item_declarationList<nodep>:      // IEEE: [ block_item_declaration ]
                 block_item_declaration                  { $$ = $1; }
-        |       block_item_declarationList block_item_declaration       { $$ = $1->addNextNull($2); }
+        |       block_item_declarationList block_item_declaration       { $$ = addNextNull($1, $2); }
         ;
 
 block_item_declaration<nodep>:  // ==IEEE: block_item_declaration
@@ -3189,7 +3195,7 @@ block_item_declaration<nodep>:  // ==IEEE: block_item_declaration
 
 stmtList<nodep>:
                 stmtBlock                               { $$ = $1; }
-        |       stmtList stmtBlock                      { $$ = $2 ? $1->addNext($2) : $1; }
+        |       stmtList stmtBlock                      { $$ = addNextNull($1, $2); }
         ;
 
 stmt<nodep>:                    // IEEE: statement_or_null == function_statement_or_null
@@ -3488,23 +3494,23 @@ case_itemList<caseItemp>:       // IEEE: { case_item + ... }
                 caseCondList colon stmtBlock                    { $$ = new AstCaseItem{$2, $1, $3}; }
         |       yDEFAULT colon stmtBlock                        { $$ = new AstCaseItem{$1, nullptr, $3}; }
         |       yDEFAULT stmtBlock                              { $$ = new AstCaseItem{$1, nullptr, $2}; }
-        |       case_itemList caseCondList colon stmtBlock      { $$ = $1; $1->addNext(new AstCaseItem{$3, $2, $4}); }
-        |       case_itemList yDEFAULT stmtBlock                { $$ = $1; $1->addNext(new AstCaseItem{$2, nullptr, $3}); }
-        |       case_itemList yDEFAULT colon stmtBlock          { $$ = $1; $1->addNext(new AstCaseItem{$2, nullptr, $4}); }
+        |       case_itemList caseCondList colon stmtBlock      { $$ = $1->addNext(new AstCaseItem{$3, $2, $4}); }
+        |       case_itemList yDEFAULT stmtBlock                { $$ = $1->addNext(new AstCaseItem{$2, nullptr, $3}); }
+        |       case_itemList yDEFAULT colon stmtBlock          { $$ = $1->addNext(new AstCaseItem{$2, nullptr, $4}); }
         ;
 
 case_inside_itemList<caseItemp>:        // IEEE: { case_inside_item + open_range_list ... }
                 open_range_list colon stmtBlock                 { $$ = new AstCaseItem{$2, $1, $3}; }
         |       yDEFAULT colon stmtBlock                        { $$ = new AstCaseItem{$1, nullptr, $3}; }
         |       yDEFAULT stmtBlock                              { $$ = new AstCaseItem{$1, nullptr, $2}; }
-        |       case_inside_itemList open_range_list colon stmtBlock { $$ = $1; $1->addNext(new AstCaseItem{$3, $2, $4}); }
-        |       case_inside_itemList yDEFAULT stmtBlock         { $$ = $1; $1->addNext(new AstCaseItem{$2, nullptr, $3}); }
-        |       case_inside_itemList yDEFAULT colon stmtBlock   { $$ = $1; $1->addNext(new AstCaseItem{$2, nullptr, $4}); }
+        |       case_inside_itemList open_range_list colon stmtBlock { $$ = $1->addNext(new AstCaseItem{$3, $2, $4}); }
+        |       case_inside_itemList yDEFAULT stmtBlock         { $$ = $1->addNext(new AstCaseItem{$2, nullptr, $3}); }
+        |       case_inside_itemList yDEFAULT colon stmtBlock   { $$ = $1->addNext(new AstCaseItem{$2, nullptr, $4}); }
         ;
 
 open_range_list<nodep>:         // ==IEEE: open_range_list + open_value_range
                 open_value_range                        { $$ = $1; }
-        |       open_range_list ',' open_value_range    { $$ = $1; $1->addNext($3); }
+        |       open_range_list ',' open_value_range    { $$ = $1->addNext($3); }
         ;
 
 open_value_range<nodep>:        // ==IEEE: open_value_range
@@ -3523,7 +3529,7 @@ value_range<nodep>:             // ==IEEE: value_range
 
 caseCondList<nodep>:            // IEEE: part of case_item
                 expr                                    { $$ = $1; }
-        |       caseCondList ',' expr                   { $$ = $1; $1->addNext($3); }
+        |       caseCondList ',' expr                   { $$ = $1->addNext($3); }
         ;
 
 patternNoExpr<nodep>:           // IEEE: pattern **Excluding Expr*
@@ -3540,7 +3546,7 @@ patternNoExpr<nodep>:           // IEEE: pattern **Excluding Expr*
 
 patternList<nodep>:             // IEEE: part of pattern
                 patternOne                              { $$ = $1; }
-        |       patternList ',' patternOne              { $$ = $1->addNextNull($3); }
+        |       patternList ',' patternOne              { $$ = addNextNull($1, $3); }
         ;
 
 patternOne<nodep>:              // IEEE: part of pattern
@@ -3552,7 +3558,7 @@ patternOne<nodep>:              // IEEE: part of pattern
 
 patternMemberList<nodep>:       // IEEE: part of pattern and assignment_pattern
                 patternMemberOne                        { $$ = $1; }
-        |       patternMemberList ',' patternMemberOne  { $$ = $1->addNextNull($3); }
+        |       patternMemberList ',' patternMemberOne  { $$ = addNextNull($1, $3); }
         ;
 
 patternMemberOne<patMemberp>:   // IEEE: part of pattern and assignment_pattern
@@ -3634,7 +3640,7 @@ for_stepE<nodep>:               // IEEE: for_step + empty
 
 for_step<nodep>:                // IEEE: for_step
                 for_step_assignment                     { $$ = $1; }
-        |       for_step ',' for_step_assignment        { $$ = AstNode::addNextNull($1, $3); }
+        |       for_step ',' for_step_assignment        { $$ = addNextNull($1, $3); }
         ;
 
 for_step_assignment<nodep>:  // ==IEEE: for_step_assignment
@@ -3653,7 +3659,7 @@ for_step_assignment<nodep>:  // ==IEEE: for_step_assignment
 
 loop_variables<nodep>:          // IEEE: loop_variables
                 parseRefBase                            { $$ = $1; }
-        |       loop_variables ',' parseRefBase         { $$ = $1; $$->addNext($3); }
+        |       loop_variables ',' parseRefBase         { $$ = $1->addNext($3); }
         |       ',' parseRefBase                        { $$ = new AstEmpty{$1}; $$->addNext($2); }
         ;
 
@@ -4009,7 +4015,7 @@ exprOrDataType<nodep>:          // expr | data_type: combined to prevent conflic
 
 //UNSUPexprOrDataTypeList<nodep>:
 //UNSUP         exprOrDataType                          { $$ = $1; }
-//UNSUP |       exprOrDataTypeList ',' exprOrDataType   { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       exprOrDataTypeList ',' exprOrDataType   { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 list_of_argumentsE<nodep>:      // IEEE: [list_of_arguments]
@@ -4018,7 +4024,7 @@ list_of_argumentsE<nodep>:      // IEEE: [list_of_arguments]
                         { if (VN_IS($1, Arg) && VN_CAST($1, Arg)->emptyConnectNoNext()) {
                               $1->deleteTree(); $$ = nullptr;  // Mis-created when have 'func()'
                           } else { $$ = $1; } }
-        |       argsExprListE ',' argsDottedList        { $$ = $1->addNextNull($3); }
+        |       argsExprListE ',' argsDottedList        { $$ = addNextNull($1, $3); }
         ;
 
 task_declaration<nodeFTaskp>:   // ==IEEE: task_declaration
@@ -4160,20 +4166,20 @@ fIdScoped<funcp>:               // IEEE: part of function_body_declaration/task_
         ;
 
 tfGuts<nodep>:
-                '(' tf_port_listE ')' ';' tfBodyE       { $$ = $2->addNextNull($5); }
+                '(' tf_port_listE ')' ';' tfBodyE       { $$ = addNextNull($2, $5); }
         |       ';' tfBodyE                             { $$ = $2; }
         ;
 
 tfBodyE<nodep>:                 // IEEE: part of function_body_declaration/task_body_declaration
                 /* empty */                             { $$ = nullptr; }
         |       tf_item_declarationList                 { $$ = $1; }
-        |       tf_item_declarationList stmtList        { $$ = $1->addNextNull($2); }
+        |       tf_item_declarationList stmtList        { $$ = addNextNull($1, $2); }
         |       stmtList                                { $$ = $1; }
         ;
 
 tf_item_declarationList<nodep>:
                 tf_item_declaration                     { $$ = $1; }
-        |       tf_item_declarationList tf_item_declaration     { $$ = $1->addNextNull($2); }
+        |       tf_item_declarationList tf_item_declaration     { $$ = addNextNull($1, $2); }
         ;
 
 tf_item_declaration<nodep>:     // ==IEEE: tf_item_declaration
@@ -4196,7 +4202,7 @@ tf_port_listE<nodep>:           // IEEE: tf_port_list + empty
 
 tf_port_listList<nodep>:        // IEEE: part of tf_port_list
                 tf_port_item                            { $$ = $1; }
-        |       tf_port_listList ',' tf_port_item       { $$ = $1->addNextNull($3); }
+        |       tf_port_listList ',' tf_port_item       { $$ = addNextNull($1, $3); }
         ;
 
 tf_port_item<nodep>:            // ==IEEE: tf_port_item
@@ -4629,7 +4635,7 @@ exprStrText<nodep>:
 
 cStrList<nodep>:
                 exprStrText                             { $$ = $1; }
-        |       exprStrText ',' cStrList                { $$ = $1; $1->addNext($3); }
+        |       exprStrText ',' cStrList                { $$ = $1->addNext($3); }
         ;
 
 cateList<nodep>:
@@ -4645,20 +4651,20 @@ exprListE<nodep>:
 
 exprList<nodep>:
                 expr                                    { $$ = $1; }
-        |       exprList ',' expr                       { $$ = $1; $1->addNext($3); }
+        |       exprList ',' expr                       { $$ = $1->addNext($3); }
         ;
 
 exprDispList<nodep>:            // exprList for within $display
                 expr                                    { $$ = $1; }
-        |       exprDispList ',' expr                   { $$ = $1; $1->addNext($3); }
+        |       exprDispList ',' expr                   { $$ = $1->addNext($3); }
         //                      // ,, creates a space in $display
         |       exprDispList ',' /*empty*/
-                        { $$ = $1; $1->addNext(new AstConst($<fl>2, AstConst::VerilogStringLiteral(), " ")); }
+                        { $$ = $1->addNext(new AstConst($<fl>2, AstConst::VerilogStringLiteral(), " ")); }
         ;
 
 vrdList<nodep>:
                 idClassSel                              { $$ = $1; }
-        |       vrdList ',' idClassSel                  { $$ = $1; $1->addNext($3); }
+        |       vrdList ',' idClassSel                  { $$ = $1->addNext($3); }
         ;
 
 commaVRDListE<nodep>:
@@ -4678,7 +4684,7 @@ argsExprListE<nodep>:           // IEEE: part of list_of_arguments
 
 //UNSUPpev_argsExprListE<nodep>:  // IEEE: part of list_of_arguments - pev_expr at bottom
 //UNSUP         pev_argsExprOneE                        { $$ = $1; }
-//UNSUP |       pev_argsExprListE ',' pev_argsExprOneE  { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       pev_argsExprListE ',' pev_argsExprOneE  { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 argsExprOneE<nodep>:            // IEEE: part of list_of_arguments
@@ -4693,12 +4699,12 @@ argsExprOneE<nodep>:            // IEEE: part of list_of_arguments
 
 argsDottedList<nodep>:          // IEEE: part of list_of_arguments
                 argsDotted                              { $$ = $1; }
-        |       argsDottedList ',' argsDotted           { $$ = $1->addNextNull($3); }
+        |       argsDottedList ',' argsDotted           { $$ = addNextNull($1, $3); }
         ;
 
 //UNSUPpev_argsDottedList<nodep>:  // IEEE: part of list_of_arguments - pev_expr at bottom
 //UNSUP         pev_argsDotted                          { $$ = $1; }
-//UNSUP |       pev_argsDottedList ',' pev_argsDotted   { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       pev_argsDottedList ',' pev_argsDotted   { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 argsDotted<nodep>:              // IEEE: part of list_of_arguments
@@ -4988,7 +4994,7 @@ combinational_body<nodep>:      // IEEE: combinational_body + sequential_body
 
 tableEntryList<nodep>:  // IEEE: { combinational_entry | sequential_entry }
                 tableEntry                              { $$ = $1; }
-        |       tableEntryList tableEntry               { $$ = $1->addNextNull($2); }
+        |       tableEntryList tableEntry               { $$ = addNextNull($1, $2); }
         ;
 
 tableEntry<nodep>:      // IEEE: combinational_entry + sequential_entry
@@ -5084,7 +5090,7 @@ variable_lvalueConcList<nodep>: // IEEE: part of variable_lvalue: '{' variable_l
 
 //UNSUPvariable_lvalueList<nodep>:  // IEEE: part of variable_lvalue: variable_lvalue { ',' variable_lvalue }
 //UNSUP         variable_lvalue                         { $$ = $1; }
-//UNSUP |       variable_lvalueList ',' variable_lvalue { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       variable_lvalueList ',' variable_lvalue { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 // VarRef to dotted, and/or arrayed, and/or bit-ranged variable
@@ -5162,9 +5168,9 @@ idArrayedForeach<nodep>:        // IEEE: id + select (under foreach expression)
         //                      // IEEE: loop_variables (under foreach expression)
         //                      // To avoid conflicts we allow expr as first element, must post-check
         |       idArrayed '[' expr ',' loop_variables ']'
-                        { $3 = AstNode::addNextNull($3, $5); $$ = new AstSelLoopVars($2, $1, $3); }
+                        { $3 = addNextNull($3, $5); $$ = new AstSelLoopVars($2, $1, $3); }
         |       idArrayed '[' ',' loop_variables ']'
-                        { $4 = AstNode::addNextNull(static_cast<AstNode*>(new AstEmpty{$3}), $4); $$ = new AstSelLoopVars($2, $1, $4); }
+                        { $4 = addNextNull(static_cast<AstNode*>(new AstEmpty{$3}), $4); $$ = new AstSelLoopVars($2, $1, $4); }
         ;
 
 // VarRef without any dots or vectorizaion
@@ -5243,7 +5249,7 @@ clocking_declaration<nodep>:            // IEEE: clocking_declaration  (INCOMPLE
 
 //UNSUPclocking_itemList:  // IEEE: [ clocking_item ]
 //UNSUP         clocking_item                           { $$ = $1; }
-//UNSUP |       clocking_itemList clocking_item         { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       clocking_itemList clocking_item         { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPclocking_item:  // ==IEEE: clocking_item
@@ -5548,7 +5554,7 @@ property_spec<nodep>:                   // IEEE: property_spec
 
 //UNSUPproperty_case_itemList<nodep>:  // IEEE: {property_case_item}
 //UNSUP         property_case_item                      { $$ = $1; }
-//UNSUP |       property_case_itemList ',' property_case_item   { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       property_case_itemList ',' property_case_item   { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 //UNSUPproperty_case_item<nodep>:  // ==IEEE: property_case_item
@@ -5805,7 +5811,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPcoverage_spec_or_optionList<nodep>:  // IEEE: {coverage_spec_or_option}
 //UNSUP         coverage_spec_or_option                 { $$ = $1; }
-//UNSUP |       coverage_spec_or_optionList coverage_spec_or_option     { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       coverage_spec_or_optionList coverage_spec_or_option     { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPcoverage_spec_or_option<nodep>:  // ==IEEE: coverage_spec_or_option
@@ -5846,7 +5852,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPbins_or_optionsList<nodep>:  // IEEE: { bins_or_options ';' }
 //UNSUP         bins_or_options ';'                     { $$ = $1; }
-//UNSUP |       bins_or_optionsList bins_or_options ';' { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       bins_or_optionsList bins_or_options ';' { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPbins_or_options<nodep>:  // ==IEEE: bins_or_options
@@ -5882,7 +5888,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPcovergroup_range_list:  // ==IEEE: covergroup_range_list
 //UNSUP         covergroup_value_range                  { $$ = $1; }
-//UNSUP |       covergroup_range_list ',' covergroup_value_range        { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       covergroup_range_list ',' covergroup_value_range        { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 //UNSUPtrans_list:  // ==IEEE: trans_list
@@ -5909,7 +5915,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPrepeat_range:  // ==IEEE: repeat_range
 //UNSUP         cgexpr                                  { $$ = $1; }
-//UNSUP |       cgexpr ':' cgexpr                       { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       cgexpr ':' cgexpr                       { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 //UNSUPcover_cross:  // ==IEEE: cover_cross
@@ -5918,13 +5924,13 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 //UNSUP ;
 
 //UNSUPlist_of_cross_items<nodep>:  // ==IEEE: list_of_cross_items
-//UNSUP         cross_item ',' cross_item               { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP         cross_item ',' cross_item               { $$ = addNextNull($1, $3); }
 //UNSUP |       cross_item ',' cross_item ',' cross_itemList    { }
 //UNSUP ;
 
 //UNSUPcross_itemList<nodep>:  // IEEE: part of list_of_cross_items
 //UNSUP         cross_item                              { $$ = nullptr; }
-//UNSUP |       cross_itemList ',' cross_item           { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       cross_itemList ',' cross_item           { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 //UNSUPcross_item<nodep>:  // ==IEEE: cross_item
@@ -5940,7 +5946,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPcross_body_itemSemiList:  // IEEE: part of cross_body
 //UNSUP         cross_body_item ';'                     { $$ = $1; }
-//UNSUP |       cross_body_itemSemiList cross_body_item ';' { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       cross_body_itemSemiList cross_body_item ';' { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPcross_body_item<nodep>:  // ==IEEE: cross_body_item
@@ -6020,7 +6026,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPproductionList<nodep>:  // IEEE: production+
 //UNSUP         production                              { $$ = $1; }
-//UNSUP |       productionList production               { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       productionList production               { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPproduction<nodep>:  // ==IEEE: production
@@ -6036,7 +6042,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPrs_ruleList<nodep>:  // IEEE: rs_rule+ part of production
 //UNSUP         rs_rule                                 { $$ = $1; }
-//UNSUP |       rs_ruleList '|' rs_rule                 { $$ = AstNode::addNextNull($1, $3); }
+//UNSUP |       rs_ruleList '|' rs_rule                 { $$ = addNextNull($1, $3); }
 //UNSUP ;
 
 //UNSUPrs_rule<nodep>:  // ==IEEE: rs_rule
@@ -6064,7 +6070,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPrs_code_blockItemList<nodep>:  // IEEE: part of rs_code_block
 //UNSUP         rs_code_blockItem                       { $$ = $1; }
-//UNSUP |       rs_code_blockItemList rs_code_blockItem         { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       rs_code_blockItemList rs_code_blockItem         { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPrs_code_blockItem<nodep>:  // IEEE: part of rs_code_block
@@ -6074,7 +6080,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPrs_prodList<nodep>:  // IEEE: rs_prod+
 //UNSUP         rs_prod                                 { $$ = $1; }
-//UNSUP |       rs_prodList rs_prod                     { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       rs_prodList rs_prod                     { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPrs_prod<nodep>:  // ==IEEE: rs_prod
@@ -6091,7 +6097,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPproduction_itemList<nodep>:  // IEEE: production_item+
 //UNSUP         production_item                         { $$ = $1; }
-//UNSUP |       production_itemList production_item     { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       production_itemList production_item     { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPproduction_item<nodep>:  // ==IEEE: production_item
@@ -6101,7 +6107,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPrs_case_itemList<nodep>:  // IEEE: rs_case_item+
 //UNSUP         rs_case_item                            { $$ = $1; }
-//UNSUP |       rs_case_itemList rs_case_item           { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       rs_case_itemList rs_case_item           { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPrs_case_item<nodep>:  // ==IEEE: rs_case_item
@@ -6137,7 +6143,7 @@ complex_pexpr<nodep>:  // IEEE: part of property_expr, see comments there
 
 //UNSUPchecker_or_generate_itemList<nodep>:  // IEEE: { checker_or_generate_itemList }
 //UNSUP         checker_or_generate_item                { $$ = $1; }
-//UNSUP |       checker_or_generate_itemList checker_or_generate_item   { $$ = AstNode::addNextNull($1, $2); }
+//UNSUP |       checker_or_generate_itemList checker_or_generate_item   { $$ = addNextNull($1, $2); }
 //UNSUP ;
 
 //UNSUPchecker_or_generate_item<nodep>:  // ==IEEE: checker_or_generate_item
@@ -6256,7 +6262,7 @@ classImplementsE<nodep>:        // IEEE: part of class_declaration
 classImplementsList<nodep>:     // IEEE: part of class_declaration
         //                      // All 1800-2012
                 class_typeExtImpList                    { $$ = nullptr; BBUNSUP($1, "Unsupported: implements class"); }
-        |       classImplementsList ',' class_typeExtImpList    { $$ = AstNode::addNextNull($1, $3); }
+        |       classImplementsList ',' class_typeExtImpList    { $$ = addNextNull($1, $3); }
         ;
 
 class_typeExtImpList<nodep>:    // IEEE: class_type: "[package_scope] id [ parameter_value_assignment ]"
@@ -6383,7 +6389,7 @@ class_itemListE<nodep>:
 
 class_itemList<nodep>:
                 class_item                              { $$ = $1; }
-        |       class_itemList class_item               { $$ = AstNode::addNextNull($1, $2); }
+        |       class_itemList class_item               { $$ = addNextNull($1, $2); }
         ;
 
 class_item<nodep>:                      // ==IEEE: class_item
@@ -6468,7 +6474,7 @@ constraint_block<nodep>:  // ==IEEE: constraint_block
 
 constraint_block_itemList<nodep>:  // IEEE: { constraint_block_item }
                 constraint_block_item                           { $$ = $1; }
-        |       constraint_block_itemList constraint_block_item { $$ = AstNode::addNextNull($1, $2); }
+        |       constraint_block_itemList constraint_block_item { $$ = addNextNull($1, $2); }
         ;
 
 constraint_block_item<nodep>:  // ==IEEE: constraint_block_item
@@ -6479,7 +6485,7 @@ constraint_block_item<nodep>:  // ==IEEE: constraint_block_item
 
 solve_before_list<nodep>:  // ==IEEE: solve_before_list
                 constraint_primary                              { $$ = $1; }
-        |       solve_before_list ',' constraint_primary        { $$ = AstNode::addNextNull($1, $3); }
+        |       solve_before_list ',' constraint_primary        { $$ = addNextNull($1, $3); }
         ;
 
 constraint_primary<nodep>:  // ==IEEE: constraint_primary
@@ -6490,7 +6496,7 @@ constraint_primary<nodep>:  // ==IEEE: constraint_primary
 
 constraint_expressionList<nodep>:  // ==IEEE: { constraint_expression }
                 constraint_expression                           { $$ = $1; }
-        |       constraint_expressionList constraint_expression { $$ = AstNode::addNextNull($1, $2); }
+        |       constraint_expressionList constraint_expression { $$ = addNextNull($1, $2); }
         ;
 
 constraint_expression<nodep>:  // ==IEEE: constraint_expression
@@ -6518,7 +6524,7 @@ constraint_set<nodep>:  // ==IEEE: constraint_set
 
 dist_list<nodep>:  // ==IEEE: dist_list
                 dist_item                               { $$ = $1; }
-        |       dist_list ',' dist_item                 { $$ = AstNode::addNextNull($1, $3); }
+        |       dist_list ',' dist_item                 { $$ = addNextNull($1, $3); }
         ;
 
 dist_item<nodep>:  // ==IEEE: dist_item + dist_weight