diff --git a/.clang-format b/.clang-format
index 32f7f3ab3c..6847e23056 100644
--- a/.clang-format
+++ b/.clang-format
@@ -3,6 +3,8 @@
 
 BasedOnStyle: Google
 
+Standard: Cpp11  # TODO(strager): c++20
+
 IncludeBlocks: Merge
 IncludeCategories: [
 	# These headers must be included after <Windows.h>:
diff --git a/src/quick-lint-js/configuration/change-detecting-filesystem.h b/src/quick-lint-js/configuration/change-detecting-filesystem.h
index 04a5e09c1e..338bb9054a 100644
--- a/src/quick-lint-js/configuration/change-detecting-filesystem.h
+++ b/src/quick-lint-js/configuration/change-detecting-filesystem.h
@@ -211,9 +211,9 @@ class Change_Detecting_Filesystem_Win32 : public Configuration_Filesystem {
   Windows_Handle_File_Ref io_completion_port_;
   ::ULONG_PTR completion_key_;
 
-  Hash_Map<Canonical_Path, std::unique_ptr<Watched_Directory> >
+  Hash_Map<Canonical_Path, std::unique_ptr<Watched_Directory>>
       watched_directories_;
-  std::vector<std::unique_ptr<Watched_Directory> >
+  std::vector<std::unique_ptr<Watched_Directory>>
       cancelling_watched_directories_;
   std::vector<Watch_IO_Error> watch_errors_;
 };
diff --git a/src/quick-lint-js/io/event-loop-poll.h b/src/quick-lint-js/io/event-loop-poll.h
index 18a9e542eb..70069af608 100644
--- a/src/quick-lint-js/io/event-loop-poll.h
+++ b/src/quick-lint-js/io/event-loop-poll.h
@@ -42,7 +42,7 @@ class Poll_Event_Loop : public Event_Loop_Base<Derived> {
       Platform_File_Ref pipe = this->const_derived().get_readable_pipe();
       QLJS_SLOW_ASSERT(pipe.is_pipe_non_blocking());
 
-      Fixed_Vector< ::pollfd, 3> pollfds;
+      Fixed_Vector<::pollfd, 3> pollfds;
 
       Fixed_Vector_Size read_pipe_index = pollfds.size();
       pollfds.push_back(
@@ -73,7 +73,7 @@ class Poll_Event_Loop : public Event_Loop_Base<Derived> {
 #endif
 
       QLJS_ASSERT(pollfds.size() > 0);
-      int rc = ::poll(pollfds.data(), narrow_cast< ::nfds_t>(pollfds.size()),
+      int rc = ::poll(pollfds.data(), narrow_cast<::nfds_t>(pollfds.size()),
                       /*timeout=*/-1);
       if (rc == -1) {
         QLJS_UNIMPLEMENTED();
diff --git a/src/quick-lint-js/logging/trace-flusher.h b/src/quick-lint-js/logging/trace-flusher.h
index 726ff0b520..208a86f0a3 100644
--- a/src/quick-lint-js/logging/trace-flusher.h
+++ b/src/quick-lint-js/logging/trace-flusher.h
@@ -161,7 +161,7 @@ class Trace_Flusher {
 
   struct Shared_State {
     std::vector<Trace_Flusher_Backend*> backends;
-    std::vector<std::unique_ptr<Registered_Thread> > registered_threads;
+    std::vector<std::unique_ptr<Registered_Thread>> registered_threads;
     Trace_Flusher_Thread_Index next_thread_index = 1;
     bool stop_flushing_thread = false;
 
diff --git a/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.cpp b/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.cpp
index 4c03975e77..fb8d200e6d 100644
--- a/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.cpp
+++ b/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.cpp
@@ -31,7 +31,7 @@ JSON_RPC_Message_Handler::~JSON_RPC_Message_Handler() = default;
 LSP_JSON_RPC_Message_Parser::LSP_JSON_RPC_Message_Parser(
     JSON_RPC_Message_Handler* handler)
     : handler_(handler),
-      json_parser_(std::make_unique< ::simdjson::ondemand::parser>()) {}
+      json_parser_(std::make_unique<::simdjson::ondemand::parser>()) {}
 
 LSP_JSON_RPC_Message_Parser::~LSP_JSON_RPC_Message_Parser() = default;
 
diff --git a/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.h b/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.h
index fe5e135c50..0bcedf9ff3 100644
--- a/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.h
+++ b/src/quick-lint-js/lsp/lsp-json-rpc-message-parser.h
@@ -83,7 +83,7 @@ class LSP_JSON_RPC_Message_Parser
   void write_invalid_request_error_response();
 
   JSON_RPC_Message_Handler* handler_;
-  std::unique_ptr< ::simdjson::ondemand::parser> json_parser_;
+  std::unique_ptr<::simdjson::ondemand::parser> json_parser_;
   Outgoing_JSON_RPC_Message_Queue error_responses_;
 
   friend Message_Parser;
diff --git a/src/quick-lint-js/lsp/lsp-server.h b/src/quick-lint-js/lsp/lsp-server.h
index 8b1e8551fe..ec59fe73d5 100644
--- a/src/quick-lint-js/lsp/lsp-server.h
+++ b/src/quick-lint-js/lsp/lsp-server.h
@@ -120,7 +120,7 @@ struct LSP_Documents {
   };
 
   // Key: URI
-  Hash_Map<String8, std::unique_ptr<Document_Base> > documents;
+  Hash_Map<String8, std::unique_ptr<Document_Base>> documents;
 };
 
 // A Linting_LSP_Server_Handler listens for JavaScript code changes and notifies
diff --git a/src/quick-lint-js/lsp/lsp-workspace-configuration.cpp b/src/quick-lint-js/lsp/lsp-workspace-configuration.cpp
index d96093bbf6..ea8ca177e6 100644
--- a/src/quick-lint-js/lsp/lsp-workspace-configuration.cpp
+++ b/src/quick-lint-js/lsp/lsp-workspace-configuration.cpp
@@ -82,7 +82,7 @@ bool LSP_Workspace_Configuration::process_response(
 
 bool LSP_Workspace_Configuration::process_notification(
     ::simdjson::ondemand::object settings) {
-  for (simdjson::simdjson_result< ::simdjson::ondemand::field> setting_field :
+  for (simdjson::simdjson_result<::simdjson::ondemand::field> setting_field :
        settings) {
     std::string_view name;
     if (setting_field.unescaped_key().get(name) != ::simdjson::SUCCESS) {
diff --git a/test/quick-lint-js/fake-configuration-filesystem.h b/test/quick-lint-js/fake-configuration-filesystem.h
index b4738addbb..3a6f66bbe1 100644
--- a/test/quick-lint-js/fake-configuration-filesystem.h
+++ b/test/quick-lint-js/fake-configuration-filesystem.h
@@ -45,7 +45,7 @@ class Fake_Configuration_Filesystem : public Configuration_Filesystem {
   void clear();
 
  private:
-  Hash_Map<Canonical_Path, Heap_Function<Read_File_Result()> > files_;
+  Hash_Map<Canonical_Path, Heap_Function<Read_File_Result()>> files_;
 };
 }
 
diff --git a/test/test-lsp-json-rpc-message-parser.cpp b/test/test-lsp-json-rpc-message-parser.cpp
index 69ea90f6d9..e9fc98fd50 100644
--- a/test/test-lsp-json-rpc-message-parser.cpp
+++ b/test/test-lsp-json-rpc-message-parser.cpp
@@ -49,7 +49,7 @@ struct Test_JSON_RPC_Message_Handler : public JSON_RPC_Message_Handler {
 };
 
 std::string json_get_string(
-    ::simdjson::simdjson_result< ::simdjson::ondemand::value>&& value) {
+    ::simdjson::simdjson_result<::simdjson::ondemand::value>&& value) {
   std::string_view s = "<not found>";
   EXPECT_EQ(value.get(s), ::simdjson::error_code::SUCCESS);
   return std::string(s);
@@ -285,7 +285,7 @@ TEST(Test_LSP_JSON_RPC_Message_Parser, single_notification_with_reply) {
       this->pending_notifications.push_back(reply);
     }
 
-    std::vector< ::boost::json::value> pending_notifications;
+    std::vector<::boost::json::value> pending_notifications;
   };
   Mock_LSP_Server_Handler handler;
   Spy_LSP_Endpoint_Remote remote;
diff --git a/test/test-lsp-server.cpp b/test/test-lsp-server.cpp
index 9e88d2de98..523cca5c23 100644
--- a/test/test-lsp-server.cpp
+++ b/test/test-lsp-server.cpp
@@ -151,7 +151,7 @@ TEST_F(Test_Linting_LSP_Server, initialize) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> responses = this->client->responses();
+  std::vector<::boost::json::object> responses = this->client->responses();
   ASSERT_EQ(responses.size(), 1);
   ::boost::json::object response = responses[0];
   EXPECT_EQ(response["id"], 1);
@@ -215,7 +215,7 @@ TEST_F(Test_Linting_LSP_Server, initialize_with_different_request_ids) {
     this->server->flush_error_responses(*this->client);
     this->handler->flush_pending_notifications(*this->client);
 
-    std::vector< ::boost::json::object> responses = this->client->responses();
+    std::vector<::boost::json::object> responses = this->client->responses();
     ASSERT_EQ(responses.size(), 1);
     EXPECT_EQ(responses[0]["id"], test.id);
   }
@@ -243,7 +243,7 @@ TEST_F(Test_Linting_LSP_Server, loads_config_after_client_initialization) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> requests = this->client->requests();
+  std::vector<::boost::json::object> requests = this->client->requests();
   ASSERT_EQ(requests.size(), 1);
   ::boost::json::object request = requests[0];
   EXPECT_EQ(look_up(request, "method"), "workspace/configuration");
@@ -269,7 +269,7 @@ TEST_F(Test_Linting_LSP_Server, stores_config_values_after_config_response) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> requests = this->client->requests();
+  std::vector<::boost::json::object> requests = this->client->requests();
   ASSERT_EQ(requests.size(), 1);
   ::boost::json::object config_request = requests[0];
   ::boost::json::value config_request_id = look_up(config_request, "id");
@@ -322,7 +322,7 @@ TEST_F(Test_Linting_LSP_Server, config_can_be_set_with_initialize_request) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> responses = this->client->responses();
+  std::vector<::boost::json::object> responses = this->client->responses();
   ASSERT_EQ(responses.size(), 1);
   EXPECT_EQ(responses[0]["id"], 100);
 
@@ -485,7 +485,7 @@ TEST_F(Test_Linting_LSP_Server, shutdown) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> responses = this->client->responses();
+  std::vector<::boost::json::object> responses = this->client->responses();
   ASSERT_EQ(responses.size(), 1);
   ::boost::json::object response = responses[0];
   EXPECT_EQ(response["id"], 10);
@@ -593,7 +593,7 @@ TEST_F(Test_Linting_LSP_Server, opening_document_lints) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object response = notifications[0];
@@ -1693,7 +1693,7 @@ TEST_F(Test_Linting_LSP_Server,
 
   EXPECT_TRUE(after_config_was_loaded);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_THAT(notifications, ElementsAreArray({::testing::_}));
   ::boost::json::object notification = notifications[0];
@@ -1885,7 +1885,7 @@ TEST_F(Test_Linting_LSP_Server, opening_js_file_with_unreadable_config_lints) {
   EXPECT_THAT(this->lint_calls, ElementsAreArray({u8"testjs"}))
       << "should have linted despite config file being unloadable";
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 2);
   std::size_t showMessageIndex =
@@ -1949,7 +1949,7 @@ TEST_F(Test_Linting_LSP_Server,
   EXPECT_THAT(this->lint_calls, ElementsAreArray({u8"testjs"}))
       << "should have linted despite config file being unloadable";
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 2);
   std::size_t showMessageIndex =
@@ -2024,7 +2024,7 @@ TEST_F(Test_Linting_LSP_Server, making_config_file_unreadable_relints) {
       << "should have linted twice: once on open, and once after config file "
          "changed";
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 2);
   std::size_t showMessageIndex =
@@ -2057,7 +2057,7 @@ TEST_F(Test_Linting_LSP_Server, opening_broken_config_file_shows_diagnostics) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object response = notifications[0];
@@ -2122,7 +2122,7 @@ TEST_F(Test_Linting_LSP_Server,
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object response = notifications[0];
@@ -2355,7 +2355,7 @@ TEST_F(Test_Linting_LSP_Server, showing_io_errors_shows_only_first) {
   });
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object show_message_message = notifications[0];
@@ -2385,7 +2385,7 @@ TEST_F(Test_Linting_LSP_Server, showing_io_errors_shows_only_first_ever) {
   });
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> notifications =
+  std::vector<::boost::json::object> notifications =
       this->client->notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object show_message_message = notifications[0];
@@ -2437,7 +2437,7 @@ TEST_F(Test_Linting_LSP_Server, unimplemented_method_in_request_returns_error) {
   this->server->flush_error_responses(*this->client);
   this->handler->flush_pending_notifications(*this->client);
 
-  std::vector< ::boost::json::object> responses = this->client->responses();
+  std::vector<::boost::json::object> responses = this->client->responses();
   ASSERT_EQ(responses.size(), 1);
   ::boost::json::object response = responses[0];
   EXPECT_EQ(look_up(response, "id"), 10);
@@ -2650,7 +2650,7 @@ TEST(Test_LSP_JavaScript_Linter,
   server.flush_error_responses(client);
   handler.flush_pending_notifications(client);
 
-  std::vector< ::boost::json::object> notifications = client.notifications();
+  std::vector<::boost::json::object> notifications = client.notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object notification = notifications[0];
   EXPECT_EQ(look_up(notification, "method"), "textDocument/publishDiagnostics");
@@ -2683,7 +2683,7 @@ TEST(Test_LSP_JavaScript_Linter,
   server.flush_error_responses(client);
   handler.flush_pending_notifications(client);
 
-  std::vector< ::boost::json::object> notifications = client.notifications();
+  std::vector<::boost::json::object> notifications = client.notifications();
   ASSERT_EQ(notifications.size(), 1);
   ::boost::json::object notification = notifications[0];
   EXPECT_EQ(look_up(notification, "method"), "textDocument/publishDiagnostics");
diff --git a/test/test-pipe-writer.cpp b/test/test-pipe-writer.cpp
index 652d76566c..a04657ae94 100644
--- a/test/test-pipe-writer.cpp
+++ b/test/test-pipe-writer.cpp
@@ -53,7 +53,7 @@ Byte_Buffer byte_buffer_of(String8_View data) {
 }
 
 TEST_F(Test_Pipe_Writer, large_write_sends_fully) {
-  std::future<Result<Padded_String, Read_File_IO_Error> > data_future =
+  std::future<Result<Padded_String, Read_File_IO_Error>> data_future =
       std::async(std::launch::async, [this] {
         return read_file("<pipe>", this->pipe.reader.ref());
       });