diff --git a/src/async_wrap.cc b/src/async_wrap.cc
index d5a62951a7d5c7..77922bd04adac7 100644
--- a/src/async_wrap.cc
+++ b/src/async_wrap.cc
@@ -151,9 +151,6 @@ void AsyncWrap::EmitAfter(Environment* env, double async_id) {
        env->async_hooks_after_function());
 }
 
-// TODO(addaleax): Remove once we're on C++17.
-constexpr double AsyncWrap::kInvalidAsyncId;
-
 static void SetupHooks(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
diff --git a/src/node_blob.cc b/src/node_blob.cc
index 4643da4c17496c..0d23158256cd9b 100644
--- a/src/node_blob.cc
+++ b/src/node_blob.cc
@@ -482,8 +482,6 @@ InternalFieldInfo* BlobBindingData::Serialize(int index) {
   return info;
 }
 
-constexpr FastStringKey BlobBindingData::type_name;
-
 void Blob::RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(Blob::New);
   registry->Register(Blob::ToArrayBuffer);
diff --git a/src/node_file.cc b/src/node_file.cc
index c7c73669a17ff7..115a9fc9bfc287 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -2449,9 +2449,6 @@ InternalFieldInfo* BindingData::Serialize(int index) {
   return info;
 }
 
-// TODO(addaleax): Remove once we're on C++17.
-constexpr FastStringKey BindingData::type_name;
-
 void Initialize(Local<Object> target,
                 Local<Value> unused,
                 Local<Context> context,
diff --git a/src/node_http2.cc b/src/node_http2.cc
index eb33da6eae785e..9c609f802b8695 100644
--- a/src/node_http2.cc
+++ b/src/node_http2.cc
@@ -3135,9 +3135,6 @@ void Http2State::MemoryInfo(MemoryTracker* tracker) const {
   tracker->TrackField("root_buffer", root_buffer);
 }
 
-// TODO(addaleax): Remove once we're on C++17.
-constexpr FastStringKey Http2State::type_name;
-
 // Set up the process.binding('http2') binding.
 void Initialize(Local<Object> target,
                 Local<Value> unused,
diff --git a/src/node_http_parser.cc b/src/node_http_parser.cc
index b2160512c72839..d70e15b8c03f01 100644
--- a/src/node_http_parser.cc
+++ b/src/node_http_parser.cc
@@ -107,9 +107,6 @@ class BindingData : public BaseObject {
   SET_MEMORY_INFO_NAME(BindingData)
 };
 
-// TODO(addaleax): Remove once we're on C++17.
-constexpr FastStringKey BindingData::type_name;
-
 // helper class for the Parser
 struct StringPtr {
   StringPtr() {
diff --git a/src/node_process_methods.cc b/src/node_process_methods.cc
index bc5d41382f20f1..350a7094baad59 100644
--- a/src/node_process_methods.cc
+++ b/src/node_process_methods.cc
@@ -448,8 +448,6 @@ static void ReallyExit(const FunctionCallbackInfo<Value>& args) {
 
 namespace process {
 
-constexpr FastStringKey BindingData::type_name;
-
 BindingData::BindingData(Environment* env, v8::Local<v8::Object> object)
     : SnapshotableObject(env, object, type_int) {
   Local<ArrayBuffer> ab = ArrayBuffer::New(env->isolate(), kBufferSize);
diff --git a/src/node_v8.cc b/src/node_v8.cc
index c1098e2d339578..de3d3daad501f6 100644
--- a/src/node_v8.cc
+++ b/src/node_v8.cc
@@ -142,9 +142,6 @@ void BindingData::MemoryInfo(MemoryTracker* tracker) const {
                       heap_code_statistics_buffer);
 }
 
-// TODO(addaleax): Remove once we're on C++17.
-constexpr FastStringKey BindingData::type_name;
-
 void CachedDataVersionTag(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   Local<Integer> result =