diff --git a/src/libdredd/src/mutate_visitor.cc b/src/libdredd/src/mutate_visitor.cc
index c77fb119..582611c1 100644
--- a/src/libdredd/src/mutate_visitor.cc
+++ b/src/libdredd/src/mutate_visitor.cc
@@ -140,7 +140,8 @@ bool MutateVisitor::TraverseDecl(clang::Decl* decl) {
   if (const auto* var_decl = llvm::dyn_cast<clang::VarDecl>(decl)) {
     if (var_decl->isConstexpr() || var_decl->hasConstantInitialization()) {
       // Because Dredd's mutations occur dynamically, they cannot be applied to
-      // C++ constexprs, which require compile-time evaluation.
+      // C++ constexprs or variables that require constant initialization as
+      // these both require compile-time evaluation.
       return true;
     }
     if (!compiler_instance_->getLangOpts().CPlusPlus &&