diff --git a/include/verilated_imp.h b/include/verilated_imp.h
index a84aa13ba..afbcc76b0 100644
--- a/include/verilated_imp.h
+++ b/include/verilated_imp.h
@@ -268,8 +268,8 @@ protected:
     // MEMBERS
     union VerilatedImpU {  ///< Enclose in an union to call ctor/dtor manually
         VerilatedImpData v;
-        VerilatedImpU() {}
-        ~VerilatedImpU() {}
+        VerilatedImpU() {}  // Can't be = default;
+        ~VerilatedImpU() {}  // Can't be = default;
     };
     static VerilatedImpU s_s;  ///< Static Singleton; One and only static this
 
diff --git a/include/verilated_sym_props.h b/include/verilated_sym_props.h
index ca2689108..9d3b13732 100644
--- a/include/verilated_sym_props.h
+++ b/include/verilated_sym_props.h
@@ -37,15 +37,13 @@
 
 // See also V3Ast::VNumRange
 class VerilatedRange {
-    int m_left;
-    int m_right;
+    int m_left = 0;
+    int m_right = 0;
 
 protected:
     friend class VerilatedVarProps;
     friend class VerilatedScope;
-    VerilatedRange()
-        : m_left{0}
-        , m_right{0} {}
+    VerilatedRange() {}
     VerilatedRange(int left, int right)
         : m_left{left}
         , m_right{right} {}
diff --git a/include/verilated_vpi.cpp b/include/verilated_vpi.cpp
index e1a2977a3..58e17aa87 100644
--- a/include/verilated_vpi.cpp
+++ b/include/verilated_vpi.cpp
@@ -211,7 +211,7 @@ public:
 class VerilatedVpioVar : public VerilatedVpio {
     const VerilatedVar* m_varp;
     const VerilatedScope* m_scopep;
-    vluint8_t* m_prevDatap;  // Previous value of data, for cbValueChange
+    vluint8_t* m_prevDatap = nullptr;  // Previous value of data, for cbValueChange
     union {
         vluint8_t u8[4];
         vluint32_t u32;
@@ -219,7 +219,7 @@ class VerilatedVpioVar : public VerilatedVpio {
     vluint32_t m_entSize;  // memoized variable size
 protected:
     void* m_varDatap;  // varp()->datap() adjusted for array entries
-    vlsint32_t m_index;
+    vlsint32_t m_index = 0;
     const VerilatedRange& get_range() const {
         // Determine number of dimensions and return outermost
         return (m_varp->dims() > 1) ? m_varp->unpacked() : m_varp->packed();
@@ -228,9 +228,7 @@ protected:
 public:
     VerilatedVpioVar(const VerilatedVar* varp, const VerilatedScope* scopep)
         : m_varp{varp}
-        , m_scopep{scopep}
-        , m_index{0} {
-        m_prevDatap = nullptr;
+        , m_scopep{scopep} {
         m_mask.u32 = VL_MASK_I(varp->packed().elements());
         m_entSize = varp->entSize();
         m_varDatap = varp->datap();
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 0c37dde78..ff2b5a8bc 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -977,8 +977,8 @@ inline std::ostream& operator<<(std::ostream& os, const VParseRefExp& rhs) {
 
 class VNumRange {
 public:
-    int m_hi;  // HI part, HI always >= LO
-    int m_lo;  // LO
+    int m_hi = 0;  // HI part, HI always >= LO
+    int m_lo = 0;  // LO
     union {
         int mu_flags;
         struct {
@@ -1001,19 +1001,13 @@ public:
     //
     class LeftRight {};
     VNumRange()
-        : m_hi{0}
-        , m_lo{0}
-        , mu_flags{0} {}
+        : mu_flags{0} {}
     VNumRange(int hi, int lo, bool littleEndian)
-        : m_hi{0}
-        , m_lo{0}
-        , mu_flags{0} {
+        : mu_flags{0} {
         init(hi, lo, littleEndian);
     }
     VNumRange(LeftRight, int left, int right)
-        : m_hi{0}
-        , m_lo{0}
-        , mu_flags{0} {
+        : mu_flags{0} {
         init((right > left) ? right : left, (right > left) ? left : right, (right > left));
     }
     ~VNumRange() {}
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index 94cbc43e2..165f60dec 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -5348,7 +5348,7 @@ public:
 class AstRand : public AstNodeTermop {
     // Return a random number, based upon width()
 private:
-    bool m_reset;  // Random reset, versus always random
+    bool m_reset = false;  // Random reset, versus always random
 public:
     AstRand(FileLine* fl, AstNodeDType* dtp, bool reset)
         : ASTGEN_SUPER(fl)
@@ -5356,8 +5356,7 @@ public:
         dtypep(dtp);
     }
     explicit AstRand(FileLine* fl)
-        : ASTGEN_SUPER(fl)
-        , m_reset{false} {}
+        : ASTGEN_SUPER(fl) {}
     ASTNODE_NODE_FUNCS(Rand)
     virtual string emitVerilog() override { return "%f$random"; }
     virtual string emitC() override {
diff --git a/src/V3File.cpp b/src/V3File.cpp
index ed7749481..f2cc0f6a9 100644
--- a/src/V3File.cpp
+++ b/src/V3File.cpp
@@ -67,13 +67,12 @@ class V3FileDependImp {
     class DependFile {
         // A single file
         bool m_target;  // True if write, else read
-        bool m_exists;
+        bool m_exists = true;
         string m_filename;  // Filename
         struct stat m_stat;  // Stat information
     public:
         DependFile(const string& filename, bool target)
             : m_target{target}
-            , m_exists{true}
             , m_filename{filename} {
             m_stat.st_ctime = 0;
             m_stat.st_mtime = 0;
diff --git a/src/V3FileLine.cpp b/src/V3FileLine.cpp
index 5d048f101..a68d2348d 100644
--- a/src/V3FileLine.cpp
+++ b/src/V3FileLine.cpp
@@ -143,14 +143,7 @@ std::ostream& operator<<(std::ostream& os, VFileContent* contentp) {
 // FileLine class functions
 
 // Sort of a singleton
-FileLine::FileLine(FileLine::EmptySecret)
-    : m_firstLineno{0}
-    , m_firstColumn{0}
-    , m_lastLineno{0}
-    , m_lastColumn{0}
-    , m_contentLineno{0}
-    , m_contentp{nullptr}
-    , m_parent{nullptr} {
+FileLine::FileLine(FileLine::EmptySecret) {
     m_filenameno = singleton().nameToNumber(FileLine::builtInFilename());
 
     m_warnOn = 0;
diff --git a/src/V3FileLine.h b/src/V3FileLine.h
index 757a4275c..e6c1941ff 100644
--- a/src/V3FileLine.h
+++ b/src/V3FileLine.h
@@ -93,16 +93,16 @@ class FileLine {
 
     // MEMBERS
     // Columns here means number of chars from beginning (i.e. tabs count as one)
-    int m_firstLineno;  // `line corrected token's first line number
-    int m_firstColumn;  // `line corrected token's first column number
-    int m_lastLineno;  // `line corrected token's last line number
-    int m_lastColumn;  // `line corrected token's last column number
+    int m_firstLineno = 0;  // `line corrected token's first line number
+    int m_firstColumn = 0;  // `line corrected token's first column number
+    int m_lastLineno = 0;  // `line corrected token's last line number
+    int m_lastColumn = 0;  // `line corrected token's last column number
     int m_filenameno;  // `line corrected filename number
-    int m_contentLineno;  // Line number within source stream
-    VFileContent* m_contentp;  // Source text contents line is within
-    FileLine* m_parent;  // Parent line that included this line
+    int m_contentLineno = 0;  // Line number within source stream
+    VFileContent* m_contentp = nullptr;  // Source text contents line is within
+    FileLine* m_parent = nullptr;  // Parent line that included this line
     std::bitset<V3ErrorCode::_ENUM_MAX> m_warnOn;
-    bool m_waive;  // Waive warning
+    bool m_waive = false;  // Waive warning
 
 protected:
     // User routines should never need to change line numbers
@@ -126,16 +126,8 @@ private:
 
 public:
     explicit FileLine(const string& filename)
-        : m_firstLineno{0}
-        , m_firstColumn{0}
-        , m_lastLineno{0}
-        , m_lastColumn{0}
-        , m_filenameno{singleton().nameToNumber(filename)}
-        , m_contentLineno{0}
-        , m_contentp{nullptr}
-        , m_parent{nullptr}
-        , m_warnOn{defaultFileLine().m_warnOn}
-        , m_waive{false} {}
+        : m_filenameno{singleton().nameToNumber(filename)}
+        , m_warnOn{defaultFileLine().m_warnOn} {}
     explicit FileLine(FileLine* fromp)
         : m_firstLineno{fromp->m_firstLineno}
         , m_firstColumn{fromp->m_firstColumn}
diff --git a/src/V3GraphPathChecker.cpp b/src/V3GraphPathChecker.cpp
index 2497f35ca..bc8401c90 100644
--- a/src/V3GraphPathChecker.cpp
+++ b/src/V3GraphPathChecker.cpp
@@ -51,8 +51,7 @@ struct GraphPCNode {
 // GraphPathChecker implementation
 
 GraphPathChecker::GraphPathChecker(const V3Graph* graphp, V3EdgeFuncP edgeFuncp)
-    : GraphAlg<const V3Graph>{graphp, edgeFuncp}
-    , m_generation{0} {
+    : GraphAlg<const V3Graph>{graphp, edgeFuncp} {
     for (V3GraphVertex* vxp = graphp->verticesBeginp(); vxp; vxp = vxp->verticesNextp()) {
         // Setup tracking structure for each node.  If delete a vertex
         // there would be a leak, but ok as accept only const V3Graph*'s.
diff --git a/src/V3GraphPathChecker.h b/src/V3GraphPathChecker.h
index e50daf064..b32e360c1 100644
--- a/src/V3GraphPathChecker.h
+++ b/src/V3GraphPathChecker.h
@@ -34,7 +34,7 @@ class GraphPathChecker : GraphAlg<const V3Graph> {
     // the graph. Each node is marked with the last generation that scanned
     // it, to enable asserting there are no cycles, and to avoid recursing
     // through the same node twice while searching for a path.
-    vluint64_t m_generation;
+    vluint64_t m_generation = 0;
 
 public:
     // CONSTRUCTORS
diff --git a/src/V3OrderGraph.h b/src/V3OrderGraph.h
index a0cc562ef..e24db578a 100644
--- a/src/V3OrderGraph.h
+++ b/src/V3OrderGraph.h
@@ -124,7 +124,7 @@ public:
 class OrderEitherVertex : public V3GraphVertex {
     AstScope* m_scopep;  // Scope the vertex is in
     AstSenTree* m_domainp;  // Clock domain (nullptr = to be computed as we iterate)
-    bool m_isFromInput;  // From input, or derived therefrom (conservatively false)
+    bool m_isFromInput = false;  // From input, or derived therefrom (conservatively false)
 protected:
     OrderEitherVertex(V3Graph* graphp, const OrderEitherVertex& old)
         : V3GraphVertex{graphp, old}
@@ -136,8 +136,7 @@ public:
     OrderEitherVertex(V3Graph* graphp, AstScope* scopep, AstSenTree* domainp)
         : V3GraphVertex{graphp}
         , m_scopep{scopep}
-        , m_domainp{domainp}
-        , m_isFromInput{false} {}
+        , m_domainp{domainp} {}
     virtual ~OrderEitherVertex() override {}
     virtual OrderEitherVertex* clone(V3Graph* graphp) const override = 0;
     // Methods
@@ -200,8 +199,8 @@ public:
 
 class OrderVarVertex : public OrderEitherVertex {
     AstVarScope* m_varScp;
-    bool m_isClock;  // Used as clock
-    bool m_isDelayed;  // Set in a delayed assignment
+    bool m_isClock = false;  // Used as clock
+    bool m_isDelayed = false;  // Set in a delayed assignment
 protected:
     OrderVarVertex(V3Graph* graphp, const OrderVarVertex& old)
         : OrderEitherVertex{graphp, old}
@@ -212,9 +211,7 @@ protected:
 public:
     OrderVarVertex(V3Graph* graphp, AstScope* scopep, AstVarScope* varScp)
         : OrderEitherVertex{graphp, scopep, nullptr}
-        , m_varScp{varScp}
-        , m_isClock{false}
-        , m_isDelayed{false} {}
+        , m_varScp{varScp} {}
     virtual ~OrderVarVertex() override {}
     virtual OrderVarVertex* clone(V3Graph* graphp) const override = 0;
     virtual OrderVEdgeType type() const override = 0;
diff --git a/src/V3Stats.h b/src/V3Stats.h
index ad5985110..5b6129e63 100644
--- a/src/V3Stats.h
+++ b/src/V3Stats.h
@@ -28,12 +28,11 @@ class AstNetlist;
 
 class VDouble0 {
     // Double counter, initializes to zero for easy use
-    double m_d;  ///< Count of occurrences/ value
+    double m_d = 0.0;  ///< Count of occurrences/ value
 public:
     // METHODS
-    VDouble0()
-        : m_d{0.0} {}
-    ~VDouble0() {}
+    VDouble0() = default;
+    ~VDouble0() = default;
 
     // Implicit conversion operators:
     explicit VDouble0(const vluint64_t v)
@@ -73,7 +72,7 @@ class V3Statistic {
     string m_stage;  ///< Runtime stage
     bool m_sumit;  ///< Do summation of similar stats
     bool m_perf;  ///< Performance section
-    bool m_printit;  ///< Print the results
+    bool m_printit = true;  ///< Print the results
 public:
     // METHODS
     string stage() const { return m_stage; }
@@ -94,8 +93,7 @@ public:
         , m_count{count}
         , m_stage{stage}
         , m_sumit{sumit}
-        , m_perf{perf}
-        , m_printit{true} {}
+        , m_perf{perf} {}
     virtual ~V3Statistic() {}
 };