diff --git a/include/yaml-cpp/emitterdef.h b/include/yaml-cpp/emitterdef.h
index 20d7c43..0b42695 100644
--- a/include/yaml-cpp/emitterdef.h
+++ b/include/yaml-cpp/emitterdef.h
@@ -9,7 +9,7 @@
 
 namespace YAML {
 struct EmitterNodeType {
-  enum value { None, Property, Scalar, FlowSeq, BlockSeq, FlowMap, BlockMap };
+  enum value { NoType, Property, Scalar, FlowSeq, BlockSeq, FlowMap, BlockMap };
 };
 }
 
diff --git a/src/collectionstack.h b/src/collectionstack.h
index d135973..2302786 100644
--- a/src/collectionstack.h
+++ b/src/collectionstack.h
@@ -12,14 +12,14 @@
 
 namespace YAML {
 struct CollectionType {
-  enum value { None, BlockMap, BlockSeq, FlowMap, FlowSeq, CompactMap };
+  enum value { NoCollection, BlockMap, BlockSeq, FlowMap, FlowSeq, CompactMap };
 };
 
 class CollectionStack {
  public:
   CollectionType::value GetCurCollectionType() const {
     if (collectionStack.empty())
-      return CollectionType::None;
+      return CollectionType::NoCollection;
     return collectionStack.top();
   }
 
diff --git a/src/emitter.cpp b/src/emitter.cpp
index c942358..ebeb059 100644
--- a/src/emitter.cpp
+++ b/src/emitter.cpp
@@ -146,7 +146,7 @@ void Emitter::EmitBeginDoc() {
   if (!good())
     return;
 
-  if (m_pState->CurGroupType() != GroupType::None) {
+  if (m_pState->CurGroupType() != GroupType::NoType) {
     m_pState->SetError("Unexpected begin document");
     return;
   }
@@ -168,7 +168,7 @@ void Emitter::EmitEndDoc() {
   if (!good())
     return;
 
-  if (m_pState->CurGroupType() != GroupType::None) {
+  if (m_pState->CurGroupType() != GroupType::NoType) {
     m_pState->SetError("Unexpected begin document");
     return;
   }
@@ -248,7 +248,7 @@ void Emitter::EmitNewline() {
   if (!good())
     return;
 
-  PrepareNode(EmitterNodeType::None);
+  PrepareNode(EmitterNodeType::NoType);
   m_stream << "\n";
   m_pState->SetNonContent();
 }
@@ -259,7 +259,7 @@ bool Emitter::CanEmitNewline() const { return true; }
 // E.g., if we're in a sequence, write the "- "
 void Emitter::PrepareNode(EmitterNodeType::value child) {
   switch (m_pState->CurGroupNodeType()) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       PrepareTopNode(child);
       break;
     case EmitterNodeType::FlowSeq:
@@ -282,16 +282,16 @@ void Emitter::PrepareNode(EmitterNodeType::value child) {
 }
 
 void Emitter::PrepareTopNode(EmitterNodeType::value child) {
-  if (child == EmitterNodeType::None)
+  if (child == EmitterNodeType::NoType)
     return;
 
   if (m_pState->CurGroupChildCount() > 0 && m_stream.col() > 0) {
-    if (child != EmitterNodeType::None)
+    if (child != EmitterNodeType::NoType)
       EmitBeginDoc();
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -323,7 +323,7 @@ void Emitter::FlowSeqPrepareNode(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -344,7 +344,7 @@ void Emitter::BlockSeqPrepareNode(EmitterNodeType::value child) {
   const std::size_t curIndent = m_pState->CurIndent();
   const std::size_t nextIndent = curIndent + m_pState->CurGroupIndent();
 
-  if (child == EmitterNodeType::None)
+  if (child == EmitterNodeType::NoType)
     return;
 
   if (!m_pState->HasBegunContent()) {
@@ -356,7 +356,7 @@ void Emitter::BlockSeqPrepareNode(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -405,7 +405,7 @@ void Emitter::FlowMapPrepareLongKey(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -433,7 +433,7 @@ void Emitter::FlowMapPrepareLongKeyValue(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -464,7 +464,7 @@ void Emitter::FlowMapPrepareSimpleKey(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -492,7 +492,7 @@ void Emitter::FlowMapPrepareSimpleKeyValue(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -533,7 +533,7 @@ void Emitter::BlockMapPrepareLongKey(EmitterNodeType::value child) {
   const std::size_t curIndent = m_pState->CurIndent();
   const std::size_t childCount = m_pState->CurGroupChildCount();
 
-  if (child == EmitterNodeType::None)
+  if (child == EmitterNodeType::NoType)
     return;
 
   if (!m_pState->HasBegunContent()) {
@@ -548,7 +548,7 @@ void Emitter::BlockMapPrepareLongKey(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -565,7 +565,7 @@ void Emitter::BlockMapPrepareLongKey(EmitterNodeType::value child) {
 void Emitter::BlockMapPrepareLongKeyValue(EmitterNodeType::value child) {
   const std::size_t curIndent = m_pState->CurIndent();
 
-  if (child == EmitterNodeType::None)
+  if (child == EmitterNodeType::NoType)
     return;
 
   if (!m_pState->HasBegunContent()) {
@@ -575,7 +575,7 @@ void Emitter::BlockMapPrepareLongKeyValue(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -592,7 +592,7 @@ void Emitter::BlockMapPrepareSimpleKey(EmitterNodeType::value child) {
   const std::size_t curIndent = m_pState->CurIndent();
   const std::size_t childCount = m_pState->CurGroupChildCount();
 
-  if (child == EmitterNodeType::None)
+  if (child == EmitterNodeType::NoType)
     return;
 
   if (!m_pState->HasBegunNode()) {
@@ -602,7 +602,7 @@ void Emitter::BlockMapPrepareSimpleKey(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -625,7 +625,7 @@ void Emitter::BlockMapPrepareSimpleKeyValue(EmitterNodeType::value child) {
   }
 
   switch (child) {
-    case EmitterNodeType::None:
+    case EmitterNodeType::NoType:
       break;
     case EmitterNodeType::Property:
     case EmitterNodeType::Scalar:
@@ -871,7 +871,7 @@ Emitter& Emitter::Write(const _Comment& comment) {
   if (!good())
     return *this;
 
-  PrepareNode(EmitterNodeType::None);
+  PrepareNode(EmitterNodeType::NoType);
 
   if (m_stream.col() > 0)
     m_stream << Indentation(m_pState->GetPreCommentIndent());
diff --git a/src/emitterstate.cpp b/src/emitterstate.cpp
index 1836565..a0874ac 100644
--- a/src/emitterstate.cpp
+++ b/src/emitterstate.cpp
@@ -98,7 +98,7 @@ EmitterNodeType::value EmitterState::NextGroupType(
 
   // can't happen
   assert(false);
-  return EmitterNodeType::None;
+  return EmitterNodeType::NoType;
 }
 
 void EmitterState::StartedDoc() {
@@ -168,17 +168,17 @@ void EmitterState::EndedGroup(GroupType::value type) {
 
 EmitterNodeType::value EmitterState::CurGroupNodeType() const {
   if (m_groups.empty())
-    return EmitterNodeType::None;
+    return EmitterNodeType::NoType;
 
   return m_groups.top().NodeType();
 }
 
 GroupType::value EmitterState::CurGroupType() const {
-  return m_groups.empty() ? GroupType::None : m_groups.top().type;
+  return m_groups.empty() ? GroupType::NoType : m_groups.top().type;
 }
 
 FlowType::value EmitterState::CurGroupFlowType() const {
-  return m_groups.empty() ? FlowType::None : m_groups.top().flowType;
+  return m_groups.empty() ? FlowType::NoType : m_groups.top().flowType;
 }
 
 int EmitterState::CurGroupIndent() const {
diff --git a/src/emitterstate.h b/src/emitterstate.h
index 3f56116..2ddec76 100644
--- a/src/emitterstate.h
+++ b/src/emitterstate.h
@@ -22,10 +22,10 @@ struct FmtScope {
   enum value { Local, Global };
 };
 struct GroupType {
-  enum value { None, Seq, Map };
+  enum value { NoType, Seq, Map };
 };
 struct FlowType {
-  enum value { None, Flow, Block };
+  enum value { NoType, Flow, Block };
 };
 
 class EmitterState {
@@ -170,7 +170,7 @@ class EmitterState {
 
       // can't get here
       assert(false);
-      return EmitterNodeType::None;
+      return EmitterNodeType::NoType;
     }
   };