diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 78e29bdbe..c9d7abd9f 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -1555,8 +1555,7 @@ static VCastable computeCastableImp(const AstNodeDType* toDtp, const AstNodeDTyp
             return VCastable::ENUM_IMPLICIT;
         if (fromNumericable) return VCastable::ENUM_EXPLICIT;
     } else if (VN_IS(toDtp, ClassRefDType) && VN_IS(fromConstp, Const)) {
-        if (VN_IS(fromConstp, Const) && VN_AS(fromConstp, Const)->num().isNull())
-            return VCastable::COMPATIBLE;
+        if (fromConstp->isNull()) return VCastable::COMPATIBLE;
     } else if (VN_IS(toDtp, ClassRefDType) && VN_IS(fromDtp, ClassRefDType)) {
         const auto toClassp = VN_AS(toDtp, ClassRefDType)->classp();
         const auto fromClassp = VN_AS(fromDtp, ClassRefDType)->classp();
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 0126271dd..c36829cb2 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -2082,6 +2082,7 @@ public:
     // ACCESSORS for specific types
     // Alas these can't be virtual or they break when passed a nullptr
     inline bool isClassHandleValue() const;
+    inline bool isNull() const;
     inline bool isZero() const;
     inline bool isOne() const;
     inline bool isNeqZero() const;
diff --git a/src/V3AstInlines.h b/src/V3AstInlines.h
index 8a1e1f96f..a20ee58d6 100644
--- a/src/V3AstInlines.h
+++ b/src/V3AstInlines.h
@@ -49,6 +49,7 @@ bool AstNode::isClassHandleValue() const {
     return (VN_IS(this, Const) && VN_AS(this, Const)->num().isNull())
            || VN_IS(dtypep(), ClassRefDType);
 }
+bool AstNode::isNull() const { return VN_IS(this, Const) && VN_AS(this, Const)->num().isNull(); }
 bool AstNode::isZero() const {
     return (VN_IS(this, Const) && VN_AS(this, Const)->num().isEqZero());
 }
diff --git a/src/V3Cast.cpp b/src/V3Cast.cpp
index 8a6df2876..613be4798 100644
--- a/src/V3Cast.cpp
+++ b/src/V3Cast.cpp
@@ -82,8 +82,7 @@ class CastVisitor final : public VNVisitor {
     }
     void ensureCast(AstNodeExpr* nodep) {
         if (castSize(nodep->backp()) != castSize(nodep) || !nodep->user1()) {
-            const AstConst* const constp = VN_CAST(nodep, Const);
-            if (!(constp && constp->num().isNull())) insertCast(nodep, castSize(nodep->backp()));
+            if (!nodep->isNull()) insertCast(nodep, castSize(nodep->backp()));
         }
     }
     void ensureLower32Cast(AstCCast* nodep) {
@@ -202,7 +201,7 @@ class CastVisitor final : public VNVisitor {
         // Constants are of unknown size if smaller than 33 bits, because
         // we're too lazy to wrap every constant in the universe in
         // ((IData)#).
-        nodep->user1(nodep->isQuad() || nodep->isWide() || nodep->num().isNull());
+        nodep->user1(nodep->isQuad() || nodep->isWide() || nodep->isNull());
     }
 
     // Null dereference protection
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index aee14cc61..b1dfcd85d 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -6560,8 +6560,8 @@ class WidthVisitor final : public VNVisitor {
             AstNodeDType* const rhsDtypep = rhsp->dtypep()->skipRefp();
             if (AstClassRefDType* const rhsClassRefp = VN_CAST(rhsDtypep, ClassRefDType)) {
                 if (isBaseClassRecurse(lhsClassRefp->classp(), rhsClassRefp->classp())) return;
-            } else if (auto* const constp = VN_CAST(rhsp, Const)) {
-                if (constp->num().isNull()) return;
+            } else if (rhsp->isNull()) {
+                return;
             }
             nodep->v3error(side << " expects a " << lhsClassRefp->prettyTypeName() << ", got "
                                 << rhsDtypep->prettyTypeName());