diff --git a/src/V3Cdc.cpp b/src/V3Cdc.cpp
index 22d2d0333..f4e8f2bd8 100644
--- a/src/V3Cdc.cpp
+++ b/src/V3Cdc.cpp
@@ -495,7 +495,7 @@ private:
         UINFO(3, __FUNCTION__ << ": " << endl);
 
         // Trace all sources and sinks
-        for (int traceDests = 0; traceDests < 2; ++traceDests) {
+        for (const bool& traceDests : {false, true}) {
             UINFO(9, " Trace Direction " << (traceDests ? "dst" : "src") << endl);
             m_graph.userClearVertices();  // user1: bool - was analyzed
             for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp = itp->verticesNextp()) {
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index 49dc1a377..29161330b 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -404,11 +404,11 @@ class ConstBitOpTreeVisitor final : public AstNVisitor {
             VL_RESTORER(m_curOpp);
             VL_RESTORER(m_leafp);
 
-            for (int i = 0; i < 2; ++i) {
+            for (const bool& right : {false, true}) {
                 Restorer restorer{*this};
                 LeafInfo leafInfo;
                 m_leafp = &leafInfo;
-                m_curOpp = i == 0 ? nodep->lhsp() : nodep->rhsp();
+                m_curOpp = right ? nodep->rhsp() : nodep->lhsp();
                 const bool origFailed = m_failed;
                 iterate(m_curOpp);
                 if (leafInfo.m_constp || m_failed) {
diff --git a/src/V3EmitCSyms.cpp b/src/V3EmitCSyms.cpp
index 412773feb..de012617e 100644
--- a/src/V3EmitCSyms.cpp
+++ b/src/V3EmitCSyms.cpp
@@ -631,7 +631,7 @@ void EmitCSyms::emitSymImp() {
     emitSymImpPreamble();
 
     if (v3Global.opt.savable()) {
-        for (int de = 0; de < 2; ++de) {
+        for (const bool& de : {false, true}) {
             const string classname = de ? "VerilatedDeserialize" : "VerilatedSerialize";
             const string funcname = de ? "__Vdeserialize" : "__Vserialize";
             const string op = de ? ">>" : "<<";
diff --git a/src/V3EmitMk.cpp b/src/V3EmitMk.cpp
index 23e89fea8..b27ef2fbb 100644
--- a/src/V3EmitMk.cpp
+++ b/src/V3EmitMk.cpp
@@ -80,7 +80,7 @@ public:
 
         of.puts("\n### Object file lists...\n");
         for (int support = 0; support < 3; ++support) {
-            for (int slow = 0; slow < 2; ++slow) {
+            for (const bool& slow : {false, true}) {
                 if (support == 2) {
                     of.puts("# Global classes, need linked once per executable");
                 } else if (support) {
diff --git a/src/V3Partition.cpp b/src/V3Partition.cpp
index 0bff6bde5..1b9441c0c 100644
--- a/src/V3Partition.cpp
+++ b/src/V3Partition.cpp
@@ -996,8 +996,7 @@ static V3GraphEdge* partBlastEdgep(GraphWay way, V3GraphEdge* edgep) {
 // non-transitive edges only ever increase.
 static void partMergeEdgesFrom(V3Graph* mtasksp, LogicMTask* recipientp, LogicMTask* donorp,
                                V3Scoreboard<MergeCandidate, uint32_t>* sbp) {
-    for (unsigned wi = 0; wi < 2; ++wi) {
-        const GraphWay way = wi ? GraphWay::REVERSE : GraphWay::FORWARD;
+    for (const auto& way : {GraphWay::FORWARD, GraphWay::REVERSE}) {
         for (V3GraphEdge* edgep = donorp->beginp(way); edgep; edgep = partBlastEdgep(way, edgep)) {
             MTaskEdge* tedgep = MTaskEdge::cast(edgep);
             if (sbp && !tedgep->removedFromSb()) sbp->removeElem(tedgep);