10 files changed, 18 insertions, 19 deletions
diff --git a/src/mongo/db/pipeline/accumulator.h b/src/mongo/db/pipeline/accumulator.h
index 801c356020f..1a2986cb374 100644
--- a/src/mongo/db/pipeline/accumulator.h
+++ b/src/mongo/db/pipeline/accumulator.h
@@ -33,6 +33,7 @@
 
 #include <boost/intrusive_ptr.hpp>
 #include <boost/optional.hpp>
+#include <functional>
 #include <vector>
 
 #include "mongo/base/init.h"
@@ -41,7 +42,6 @@
 #include "mongo/db/pipeline/expression_context.h"
 #include "mongo/db/pipeline/value.h"
 #include "mongo/db/pipeline/value_comparator.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/stdx/unordered_set.h"
 #include "mongo/util/summation.h"
 
diff --git a/src/mongo/db/pipeline/document_path_support.cpp b/src/mongo/db/pipeline/document_path_support.cpp
index d89f122463c..3da0790b574 100644
--- a/src/mongo/db/pipeline/document_path_support.cpp
+++ b/src/mongo/db/pipeline/document_path_support.cpp
@@ -49,8 +49,7 @@ namespace {
  * If 'value' is an array, invokes 'callback' once on each element of 'value'. Otherwise, if 'value'
  * is not missing, invokes 'callback' on 'value' itself.
  */
-void invokeCallbackOnTrailingValue(const Value& value,
-                                   stdx::function<void(const Value&)> callback) {
+void invokeCallbackOnTrailingValue(const Value& value, std::function<void(const Value&)> callback) {
     if (value.isArray()) {
         for (auto&& finalValue : value.getArray()) {
             if (!finalValue.missing()) {
@@ -65,7 +64,7 @@ void invokeCallbackOnTrailingValue(const Value& value,
 void visitAllValuesAtPathHelper(Document doc,
                                 const FieldPath& path,
                                 size_t fieldPathIndex,
-                                stdx::function<void(const Value&)> callback) {
+                                std::function<void(const Value&)> callback) {
     invariant(path.getPathLength() > 0 && fieldPathIndex < path.getPathLength());
 
     // The first field in the path must be treated as a field name, even if it is numeric as in
@@ -116,7 +115,7 @@ void visitAllValuesAtPathHelper(Document doc,
 
 void visitAllValuesAtPath(const Document& doc,
                           const FieldPath& path,
-                          stdx::function<void(const Value&)> callback) {
+                          std::function<void(const Value&)> callback) {
     visitAllValuesAtPathHelper(doc, path, 0, callback);
 }
 
diff --git a/src/mongo/db/pipeline/document_path_support.h b/src/mongo/db/pipeline/document_path_support.h
index 7b035ccb3c2..e35ea59e441 100644
--- a/src/mongo/db/pipeline/document_path_support.h
+++ b/src/mongo/db/pipeline/document_path_support.h
@@ -29,6 +29,7 @@
 
 #pragma once
 
+#include <functional>
 #include <vector>
 
 #include "mongo/db/pipeline/document.h"
@@ -36,7 +37,6 @@
 #include "mongo/db/pipeline/field_path.h"
 #include "mongo/db/pipeline/value.h"
 #include "mongo/db/pipeline/value_comparator.h"
-#include "mongo/stdx/functional.h"
 
 namespace mongo {
 namespace document_path_support {
@@ -50,7 +50,7 @@ namespace document_path_support {
  */
 void visitAllValuesAtPath(const Document& doc,
                           const FieldPath& path,
-                          stdx::function<void(const Value&)> callback);
+                          std::function<void(const Value&)> callback);
 
 /**
  * Returns the element at 'path' in 'doc', or a missing Value if the path does not fully exist.
diff --git a/src/mongo/db/pipeline/document_source.h b/src/mongo/db/pipeline/document_source.h
index 84d724231fc..6d8547d3da2 100644
--- a/src/mongo/db/pipeline/document_source.h
+++ b/src/mongo/db/pipeline/document_source.h
@@ -33,6 +33,7 @@
 
 #include <boost/intrusive_ptr.hpp>
 #include <boost/optional.hpp>
+#include <functional>
 #include <list>
 #include <memory>
 #include <string>
@@ -54,7 +55,6 @@
 #include "mongo/db/pipeline/stage_constraints.h"
 #include "mongo/db/pipeline/value.h"
 #include "mongo/db/query/explain_options.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/util/intrusive_counter.h"
 
 namespace mongo {
@@ -129,7 +129,7 @@ class Document;
 
 class DocumentSource : public RefCountable {
 public:
-    using Parser = stdx::function<std::list<boost::intrusive_ptr<DocumentSource>>(
+    using Parser = std::function<std::list<boost::intrusive_ptr<DocumentSource>>(
         BSONElement, const boost::intrusive_ptr<ExpressionContext>&)>;
 
     using ChangeStreamRequirement = StageConstraints::ChangeStreamRequirement;
diff --git a/src/mongo/db/pipeline/expression.h b/src/mongo/db/pipeline/expression.h
index 706d5bde44a..3ee13d4ea5e 100644
--- a/src/mongo/db/pipeline/expression.h
+++ b/src/mongo/db/pipeline/expression.h
@@ -33,6 +33,7 @@
 
 #include <algorithm>
 #include <boost/intrusive_ptr.hpp>
+#include <functional>
 #include <map>
 #include <pcre.h>
 #include <string>
@@ -49,7 +50,6 @@
 #include "mongo/db/pipeline/variables.h"
 #include "mongo/db/query/datetime/date_time_support.h"
 #include "mongo/db/server_options.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/util/intrusive_counter.h"
 #include "mongo/util/str.h"
 
@@ -91,7 +91,7 @@ class DocumentSource;
 
 class Expression : public RefCountable {
 public:
-    using Parser = stdx::function<boost::intrusive_ptr<Expression>(
+    using Parser = std::function<boost::intrusive_ptr<Expression>(
         const boost::intrusive_ptr<ExpressionContext>&, BSONElement, const VariablesParseState&)>;
 
     /**
diff --git a/src/mongo/db/pipeline/granularity_rounder.h b/src/mongo/db/pipeline/granularity_rounder.h
index e88d159176d..f96c6f4662c 100644
--- a/src/mongo/db/pipeline/granularity_rounder.h
+++ b/src/mongo/db/pipeline/granularity_rounder.h
@@ -29,13 +29,13 @@
 
 #pragma once
 
+#include <functional>
 #include <vector>
 
 #include "mongo/base/init.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/db/pipeline/expression_context.h"
 #include "mongo/db/pipeline/value.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/util/intrusive_counter.h"
 
 namespace mongo {
@@ -75,7 +75,7 @@ namespace mongo {
  */
 class GranularityRounder : public RefCountable {
 public:
-    using Rounder = stdx::function<boost::intrusive_ptr<GranularityRounder>(
+    using Rounder = std::function<boost::intrusive_ptr<GranularityRounder>(
         const boost::intrusive_ptr<ExpressionContext>&)>;
 
     /**
diff --git a/src/mongo/db/pipeline/lite_parsed_document_source.h b/src/mongo/db/pipeline/lite_parsed_document_source.h
index 7fb21cb37bf..af311de66fc 100644
--- a/src/mongo/db/pipeline/lite_parsed_document_source.h
+++ b/src/mongo/db/pipeline/lite_parsed_document_source.h
@@ -30,6 +30,7 @@
 #pragma once
 
 #include <boost/optional.hpp>
+#include <functional>
 #include <memory>
 #include <vector>
 
@@ -37,7 +38,6 @@
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/pipeline/aggregation_request.h"
 #include "mongo/db/repl/read_concern_args.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/stdx/unordered_set.h"
 
@@ -61,7 +61,7 @@ public:
      * which this aggregation is being performed, and the BSONElement will be the element whose
      * field name is the name of this stage (e.g. the first and only element in {$limit: 1}).
      */
-    using Parser = stdx::function<std::unique_ptr<LiteParsedDocumentSource>(
+    using Parser = std::function<std::unique_ptr<LiteParsedDocumentSource>(
         const AggregationRequest&, const BSONElement&)>;
 
     /**
diff --git a/src/mongo/db/pipeline/lookup_set_cache.h b/src/mongo/db/pipeline/lookup_set_cache.h
index 0a68a65d086..11c28852f34 100644
--- a/src/mongo/db/pipeline/lookup_set_cache.h
+++ b/src/mongo/db/pipeline/lookup_set_cache.h
@@ -36,13 +36,13 @@
 #include <boost/multi_index/sequenced_index.hpp>
 #include <boost/multi_index_container.hpp>
 #include <boost/optional.hpp>
+#include <functional>
 #include <vector>
 
 #include "mongo/base/string_data_comparator_interface.h"
 #include "mongo/db/pipeline/document.h"
 #include "mongo/db/pipeline/value.h"
 #include "mongo/db/pipeline/value_comparator.h"
-#include "mongo/stdx/functional.h"
 
 namespace mongo {
 
diff --git a/src/mongo/db/pipeline/pipeline.cpp b/src/mongo/db/pipeline/pipeline.cpp
index 439d4d9ab88..23484931890 100644
--- a/src/mongo/db/pipeline/pipeline.cpp
+++ b/src/mongo/db/pipeline/pipeline.cpp
@@ -684,7 +684,7 @@ boost::intrusive_ptr<DocumentSource> Pipeline::popFrontWithName(StringData targe
 }
 
 boost::intrusive_ptr<DocumentSource> Pipeline::popFrontWithNameAndCriteria(
-    StringData targetStageName, stdx::function<bool(const DocumentSource* const)> predicate) {
+    StringData targetStageName, std::function<bool(const DocumentSource* const)> predicate) {
     if (_sources.empty() || _sources.front()->getSourceName() != targetStageName) {
         return nullptr;
     }
diff --git a/src/mongo/db/pipeline/pipeline.h b/src/mongo/db/pipeline/pipeline.h
index 06c35e36c1c..75249314225 100644
--- a/src/mongo/db/pipeline/pipeline.h
+++ b/src/mongo/db/pipeline/pipeline.h
@@ -29,6 +29,7 @@
 
 #pragma once
 
+#include <functional>
 #include <list>
 #include <vector>
 
@@ -42,7 +43,6 @@
 #include "mongo/db/query/query_knobs_gen.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/s/query/async_results_merger_params_gen.h"
-#include "mongo/stdx/functional.h"
 #include "mongo/util/intrusive_counter.h"
 #include "mongo/util/timer.h"
 
@@ -315,7 +315,7 @@ public:
      * stage. Returns nullptr if there is no first stage which meets these criteria.
      */
     boost::intrusive_ptr<DocumentSource> popFrontWithNameAndCriteria(
-        StringData targetStageName, stdx::function<bool(const DocumentSource* const)> predicate);
+        StringData targetStageName, std::function<bool(const DocumentSource* const)> predicate);
 
     /**
      * PipelineD is a "sister" class that has additional functionality for the Pipeline. It exists