SERVER-42046: Remove redundant moves from query code

Since C++17 return value optimization is mandatory and no longer considered as copy elision (https://en.cppreference.com/w/cpp/language/copy_elision). This means that in some cases `return std::move(value)` can be replaced with just `return value`. We refactor Query code to remove these redundant moves. GCC 9.0.1 was used to detect such places in codebase

34 files changed, 65 insertions, 65 deletions

diff --git a/src/mongo/db/matcher/expression_algo.cpp b/src/mongo/db/matcher/expression_algo.cpp
index 11e9cf89047..1665bbd956e 100644
--- a/src/mongo/db/matcher/expression_algo.cpp
+++ b/src/mongo/db/matcher/expression_algo.cpp
@@ -255,7 +255,7 @@ unique_ptr<MatchExpression> createAndOfNodes(std::vector<unique_ptr<MatchExpress
         splitAnd->add(expr.release());
     }
 
-    return std::move(splitAnd);
+    return splitAnd;
 }
 
 /**
@@ -271,7 +271,7 @@ unique_ptr<MatchExpression> createNorOfNodes(std::vector<unique_ptr<MatchExpress
         splitNor->add(expr.release());
     }
 
-    return std::move(splitNor);
+    return splitNor;
 }
 
 void applyRenamesToExpression(MatchExpression* expr, const StringMap<std::string>& renames) {
diff --git a/src/mongo/db/matcher/expression_arity.h b/src/mongo/db/matcher/expression_arity.h
index 0c1b57f3cf9..f3e13361443 100644
--- a/src/mongo/db/matcher/expression_arity.h
+++ b/src/mongo/db/matcher/expression_arity.h
@@ -130,7 +130,7 @@ public:
             clone->setTag(getTag()->clone());
         }
 
-        return std::move(clone);
+        return clone;
     }
 
 protected:
diff --git a/src/mongo/db/matcher/expression_array.h b/src/mongo/db/matcher/expression_array.h
index 67fe81b8e6a..ed5c1a35e32 100644
--- a/src/mongo/db/matcher/expression_array.h
+++ b/src/mongo/db/matcher/expression_array.h
@@ -82,7 +82,7 @@ public:
         if (getTag()) {
             e->setTag(getTag()->clone());
         }
-        return std::move(e);
+        return e;
     }
 
     virtual void debugString(StringBuilder& debug, int indentationLevel) const;
@@ -145,7 +145,7 @@ public:
         if (getTag()) {
             e->setTag(getTag()->clone());
         }
-        return std::move(e);
+        return e;
     }
 
     virtual void debugString(StringBuilder& debug, int indentationLevel) const;
@@ -190,7 +190,7 @@ public:
         if (getTag()) {
             e->setTag(getTag()->clone());
         }
-        return std::move(e);
+        return e;
     }
 
     size_t numChildren() const override {
diff --git a/src/mongo/db/matcher/expression_expr.cpp b/src/mongo/db/matcher/expression_expr.cpp
index 45d033a31a9..ff82c4f7557 100644
--- a/src/mongo/db/matcher/expression_expr.cpp
+++ b/src/mongo/db/matcher/expression_expr.cpp
@@ -121,7 +121,7 @@ std::unique_ptr<MatchExpression> ExprMatchExpression::shallowClone() const {
     if (_rewriteResult) {
         clone->_rewriteResult = _rewriteResult->clone();
     }
-    return std::move(clone);
+    return clone;
 }
 
 MatchExpression::ExpressionOptimizerFunc ExprMatchExpression::getOptimizer() const {
diff --git a/src/mongo/db/matcher/expression_geo.cpp b/src/mongo/db/matcher/expression_geo.cpp
index 0a8853680b1..721dbe7553f 100644
--- a/src/mongo/db/matcher/expression_geo.cpp
+++ b/src/mongo/db/matcher/expression_geo.cpp
@@ -416,7 +416,7 @@ std::unique_ptr<MatchExpression> GeoMatchExpression::shallowClone() const {
     if (getTag()) {
         next->setTag(getTag()->clone());
     }
-    return std::move(next);
+    return next;
 }
 
 //
@@ -473,6 +473,6 @@ std::unique_ptr<MatchExpression> GeoNearMatchExpression::shallowClone() const {
     if (getTag()) {
         next->setTag(getTag()->clone());
     }
-    return std::move(next);
+    return next;
 }
 }  // namespace mongo
diff --git a/src/mongo/db/matcher/expression_internal_expr_eq.cpp b/src/mongo/db/matcher/expression_internal_expr_eq.cpp
index 4c7e32f353b..83d84254c32 100644
--- a/src/mongo/db/matcher/expression_internal_expr_eq.cpp
+++ b/src/mongo/db/matcher/expression_internal_expr_eq.cpp
@@ -63,7 +63,7 @@ std::unique_ptr<MatchExpression> InternalExprEqMatchExpression::shallowClone() c
     if (getTag()) {
         clone->setTag(getTag()->clone());
     }
-    return std::move(clone);
+    return clone;
 }
 
 }  //  namespace mongo
diff --git a/src/mongo/db/matcher/expression_leaf.cpp b/src/mongo/db/matcher/expression_leaf.cpp
index c10790906e0..09eb4eeec68 100644
--- a/src/mongo/db/matcher/expression_leaf.cpp
+++ b/src/mongo/db/matcher/expression_leaf.cpp
@@ -403,7 +403,7 @@ std::unique_ptr<MatchExpression> InMatchExpression::shallowClone() const {
             static_cast<RegexMatchExpression*>(regex->shallowClone().release()));
         next->_regexes.push_back(std::move(clonedRegex));
     }
-    return std::move(next);
+    return next;
 }
 
 bool InMatchExpression::contains(const BSONElement& e) const {
@@ -578,7 +578,7 @@ MatchExpression::ExpressionOptimizerFunc InMatchExpression::getOptimizer() const
             if (expression->getTag()) {
                 simplifiedExpression->setTag(expression->getTag()->clone());
             }
-            return std::move(simplifiedExpression);
+            return simplifiedExpression;
         } else if (equalitySet.size() == 1 && regexList.empty()) {
             // Simplify IN of exactly one equality to be an EqualityMatchExpression.
             auto simplifiedExpression = std::make_unique<EqualityMatchExpression>(
@@ -588,7 +588,7 @@ MatchExpression::ExpressionOptimizerFunc InMatchExpression::getOptimizer() const
                 simplifiedExpression->setTag(expression->getTag()->clone());
             }
 
-            return std::move(simplifiedExpression);
+            return simplifiedExpression;
         }
 
         return expression;
diff --git a/src/mongo/db/matcher/expression_leaf.h b/src/mongo/db/matcher/expression_leaf.h
index 68d4fb10924..5dfef220b99 100644
--- a/src/mongo/db/matcher/expression_leaf.h
+++ b/src/mongo/db/matcher/expression_leaf.h
@@ -209,7 +209,7 @@ public:
             e->setTag(getTag()->clone());
         }
         e->setCollator(_collator);
-        return std::move(e);
+        return e;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -241,7 +241,7 @@ public:
             e->setTag(getTag()->clone());
         }
         e->setCollator(_collator);
-        return std::move(e);
+        return e;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -273,7 +273,7 @@ public:
             e->setTag(getTag()->clone());
         }
         e->setCollator(_collator);
-        return std::move(e);
+        return e;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -305,7 +305,7 @@ public:
             e->setTag(getTag()->clone());
         }
         e->setCollator(_collator);
-        return std::move(e);
+        return e;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -337,7 +337,7 @@ public:
             e->setTag(getTag()->clone());
         }
         e->setCollator(_collator);
-        return std::move(e);
+        return e;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -372,7 +372,7 @@ public:
         if (getTag()) {
             e->setTag(getTag()->clone());
         }
-        return std::move(e);
+        return e;
     }
 
     bool matchesSingleElement(const BSONElement&, MatchDetails* details = nullptr) const final;
@@ -427,7 +427,7 @@ public:
         if (getTag()) {
             m->setTag(getTag()->clone());
         }
-        return std::move(m);
+        return m;
     }
 
     bool matchesSingleElement(const BSONElement&, MatchDetails* details = nullptr) const final;
@@ -473,7 +473,7 @@ public:
         if (getTag()) {
             e->setTag(getTag()->clone());
         }
-        return std::move(e);
+        return e;
     }
 
     bool matchesSingleElement(const BSONElement&, MatchDetails* details = nullptr) const final;
@@ -687,7 +687,7 @@ public:
         if (getTag()) {
             bitTestMatchExpression->setTag(getTag()->clone());
         }
-        return std::move(bitTestMatchExpression);
+        return bitTestMatchExpression;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -725,7 +725,7 @@ public:
         if (getTag()) {
             bitTestMatchExpression->setTag(getTag()->clone());
         }
-        return std::move(bitTestMatchExpression);
+        return bitTestMatchExpression;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -763,7 +763,7 @@ public:
         if (getTag()) {
             bitTestMatchExpression->setTag(getTag()->clone());
         }
-        return std::move(bitTestMatchExpression);
+        return bitTestMatchExpression;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
@@ -801,7 +801,7 @@ public:
         if (getTag()) {
             bitTestMatchExpression->setTag(getTag()->clone());
         }
-        return std::move(bitTestMatchExpression);
+        return bitTestMatchExpression;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/expression_text.cpp b/src/mongo/db/matcher/expression_text.cpp
index 7220f1ce153..429fba332fd 100644
--- a/src/mongo/db/matcher/expression_text.cpp
+++ b/src/mongo/db/matcher/expression_text.cpp
@@ -108,7 +108,7 @@ std::unique_ptr<MatchExpression> TextMatchExpression::shallowClone() const {
     if (getTag()) {
         expr->setTag(getTag()->clone());
     }
-    return std::move(expr);
+    return expr;
 }
 
 }  // namespace mongo
diff --git a/src/mongo/db/matcher/expression_text_noop.cpp b/src/mongo/db/matcher/expression_text_noop.cpp
index e0dfdbc551e..93dce710777 100644
--- a/src/mongo/db/matcher/expression_text_noop.cpp
+++ b/src/mongo/db/matcher/expression_text_noop.cpp
@@ -56,7 +56,7 @@ std::unique_ptr<MatchExpression> TextNoOpMatchExpression::shallowClone() const {
     if (getTag()) {
         expr->setTag(getTag()->clone());
     }
-    return std::move(expr);
+    return expr;
 }
 
 }  // namespace mongo
diff --git a/src/mongo/db/matcher/expression_tree.cpp b/src/mongo/db/matcher/expression_tree.cpp
index ec32d07a233..c4add8176f1 100644
--- a/src/mongo/db/matcher/expression_tree.cpp
+++ b/src/mongo/db/matcher/expression_tree.cpp
@@ -151,7 +151,7 @@ MatchExpression::ExpressionOptimizerFunc ListOfMatchExpression::getOptimizer() c
                 // Simplify NOR of exactly one operand to NOT of that operand.
                 auto simplifiedExpression = std::make_unique<NotMatchExpression>(children.front());
                 children.clear();
-                return std::move(simplifiedExpression);
+                return simplifiedExpression;
             }
         }
 
diff --git a/src/mongo/db/matcher/expression_tree.h b/src/mongo/db/matcher/expression_tree.h
index b552386efc6..dd773d1652f 100644
--- a/src/mongo/db/matcher/expression_tree.h
+++ b/src/mongo/db/matcher/expression_tree.h
@@ -127,7 +127,7 @@ public:
         if (getTag()) {
             self->setTag(getTag()->clone());
         }
-        return std::move(self);
+        return self;
     }
 
     virtual void debugString(StringBuilder& debug, int indentationLevel = 0) const;
@@ -166,7 +166,7 @@ public:
         if (getTag()) {
             self->setTag(getTag()->clone());
         }
-        return std::move(self);
+        return self;
     }
 
     virtual void debugString(StringBuilder& debug, int indentationLevel = 0) const;
@@ -205,7 +205,7 @@ public:
         if (getTag()) {
             self->setTag(getTag()->clone());
         }
-        return std::move(self);
+        return self;
     }
 
     virtual void debugString(StringBuilder& debug, int indentationLevel = 0) const;
@@ -233,7 +233,7 @@ public:
         if (getTag()) {
             self->setTag(getTag()->clone());
         }
-        return std::move(self);
+        return self;
     }
 
     virtual bool matches(const MatchableDocument* doc, MatchDetails* details = nullptr) const {
diff --git a/src/mongo/db/matcher/expression_type.h b/src/mongo/db/matcher/expression_type.h
index 7f7fef89705..13839e47190 100644
--- a/src/mongo/db/matcher/expression_type.h
+++ b/src/mongo/db/matcher/expression_type.h
@@ -75,7 +75,7 @@ public:
         if (getTag()) {
             expr->setTag(getTag()->clone());
         }
-        return std::move(expr);
+        return expr;
     }
 
     bool matchesSingleElement(const BSONElement& elem, MatchDetails* details = nullptr) const {
@@ -219,7 +219,7 @@ public:
         if (getTag()) {
             expr->setTag(getTag()->clone());
         }
-        return std::move(expr);
+        return expr;
     }
 
     void debugString(StringBuilder& debug, int indentationLevel) const final {
diff --git a/src/mongo/db/matcher/expression_where.cpp b/src/mongo/db/matcher/expression_where.cpp
index 2518da25484..72ff8e8ae09 100644
--- a/src/mongo/db/matcher/expression_where.cpp
+++ b/src/mongo/db/matcher/expression_where.cpp
@@ -117,6 +117,6 @@ unique_ptr<MatchExpression> WhereMatchExpression::shallowClone() const {
     if (getTag()) {
         e->setTag(getTag()->clone());
     }
-    return std::move(e);
+    return e;
 }
 }  // namespace mongo
diff --git a/src/mongo/db/matcher/rewrite_expr.cpp b/src/mongo/db/matcher/rewrite_expr.cpp
index bda2d8eed24..ef2cb036cc2 100644
--- a/src/mongo/db/matcher/rewrite_expr.cpp
+++ b/src/mongo/db/matcher/rewrite_expr.cpp
@@ -97,7 +97,7 @@ std::unique_ptr<MatchExpression> RewriteExpr::_rewriteAndExpression(
     }
 
     if (andMatch->numChildren() > 0) {
-        return std::move(andMatch);
+        return andMatch;
     }
 
     return nullptr;
@@ -118,7 +118,7 @@ std::unique_ptr<MatchExpression> RewriteExpr::_rewriteOrExpression(
     }
 
     if (orMatch->numChildren() > 0) {
-        return std::move(orMatch);
+        return orMatch;
     }
 
     return nullptr;
@@ -166,7 +166,7 @@ std::unique_ptr<MatchExpression> RewriteExpr::_buildComparisonMatchExpression(
         std::make_unique<InternalExprEqMatchExpression>(fieldAndValue.fieldName(), fieldAndValue);
     eqMatchExpr->setCollator(_collator);
 
-    return std::move(eqMatchExpr);
+    return eqMatchExpr;
 }
 
 bool RewriteExpr::_canRewriteComparison(
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_all_elem_match_from_index.cpp b/src/mongo/db/matcher/schema/expression_internal_schema_all_elem_match_from_index.cpp
index 356b7f5081d..1d83970844c 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_all_elem_match_from_index.cpp
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_all_elem_match_from_index.cpp
@@ -52,7 +52,7 @@ std::unique_ptr<MatchExpression> InternalSchemaAllElemMatchFromIndexMatchExpress
     if (getTag()) {
         clone->setTag(getTag()->clone());
     }
-    return std::move(clone);
+    return clone;
 }
 
 bool InternalSchemaAllElemMatchFromIndexMatchExpression::equivalent(
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_eq.cpp b/src/mongo/db/matcher/schema/expression_internal_schema_eq.cpp
index d8a5f27f789..b3a0554982c 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_eq.cpp
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_eq.cpp
@@ -87,7 +87,7 @@ std::unique_ptr<MatchExpression> InternalSchemaEqMatchExpression::shallowClone()
     if (getTag()) {
         clone->setTag(getTag()->clone());
     }
-    return std::move(clone);
+    return clone;
 }
 
 }  //  namespace mongo
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_fmod.h b/src/mongo/db/matcher/schema/expression_internal_schema_fmod.h
index 8f77d0e23aa..fd16fa9e220 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_fmod.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_fmod.h
@@ -47,7 +47,7 @@ public:
         if (getTag()) {
             m->setTag(getTag()->clone());
         }
-        return std::move(m);
+        return m;
     }
 
     bool matchesSingleElement(const BSONElement& e, MatchDetails* details = nullptr) const final;
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_match_array_index.cpp b/src/mongo/db/matcher/schema/expression_internal_schema_match_array_index.cpp
index 991f9240521..b529fb9188a 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_match_array_index.cpp
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_match_array_index.cpp
@@ -91,7 +91,7 @@ std::unique_ptr<MatchExpression> InternalSchemaMatchArrayIndexMatchExpression::s
     if (getTag()) {
         clone->setTag(getTag()->clone());
     }
-    return std::move(clone);
+    return clone;
 }
 
 MatchExpression::ExpressionOptimizerFunc
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_max_items.h b/src/mongo/db/matcher/schema/expression_internal_schema_max_items.h
index 09b8128fc70..4077b43f5f3 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_max_items.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_max_items.h
@@ -54,7 +54,7 @@ public:
         if (getTag()) {
             maxItems->setTag(getTag()->clone());
         }
-        return std::move(maxItems);
+        return maxItems;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_max_length.h b/src/mongo/db/matcher/schema/expression_internal_schema_max_length.h
index 71ba6513c9e..eb26a28f897 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_max_length.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_max_length.h
@@ -52,7 +52,7 @@ public:
         if (getTag()) {
             maxLen->setTag(getTag()->clone());
         }
-        return std::move(maxLen);
+        return maxLen;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_max_properties.h b/src/mongo/db/matcher/schema/expression_internal_schema_max_properties.h
index 6394f962028..af76365a8dd 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_max_properties.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_max_properties.h
@@ -64,7 +64,7 @@ public:
         if (getTag()) {
             maxProperties->setTag(getTag()->clone());
         }
-        return std::move(maxProperties);
+        return maxProperties;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_min_items.h b/src/mongo/db/matcher/schema/expression_internal_schema_min_items.h
index 1c5ad039a9d..1e631ce59f0 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_min_items.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_min_items.h
@@ -54,7 +54,7 @@ public:
         if (getTag()) {
             minItems->setTag(getTag()->clone());
         }
-        return std::move(minItems);
+        return minItems;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_min_length.h b/src/mongo/db/matcher/schema/expression_internal_schema_min_length.h
index b6162443eaf..eb26bac606b 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_min_length.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_min_length.h
@@ -52,7 +52,7 @@ public:
         if (getTag()) {
             minLen->setTag(getTag()->clone());
         }
-        return std::move(minLen);
+        return minLen;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_min_properties.h b/src/mongo/db/matcher/schema/expression_internal_schema_min_properties.h
index 4e41b986934..f78d0123d3d 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_min_properties.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_min_properties.h
@@ -64,7 +64,7 @@ public:
         if (getTag()) {
             minProperties->setTag(getTag()->clone());
         }
-        return std::move(minProperties);
+        return minProperties;
     }
 
     void acceptVisitor(MatchExpressionMutableVisitor* visitor) final {
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_unique_items.cpp b/src/mongo/db/matcher/schema/expression_internal_schema_unique_items.cpp
index bf4c9ebe647..dd2f9e382ff 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_unique_items.cpp
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_unique_items.cpp
@@ -70,6 +70,6 @@ std::unique_ptr<MatchExpression> InternalSchemaUniqueItemsMatchExpression::shall
     if (getTag()) {
         clone->setTag(getTag()->clone());
     }
-    return std::move(clone);
+    return clone;
 }
 }  // namespace mongo
diff --git a/src/mongo/db/matcher/schema/expression_internal_schema_xor.h b/src/mongo/db/matcher/schema/expression_internal_schema_xor.h
index 435a601e879..88a8d355c25 100644
--- a/src/mongo/db/matcher/schema/expression_internal_schema_xor.h
+++ b/src/mongo/db/matcher/schema/expression_internal_schema_xor.h
@@ -56,7 +56,7 @@ public:
         if (getTag()) {
             xorCopy->setTag(getTag()->clone());
         }
-        return std::move(xorCopy);
+        return xorCopy;
     }
 
     void debugString(StringBuilder& debug, int indentationLevel = 0) const final;
diff --git a/src/mongo/db/matcher/schema/json_schema_parser.cpp b/src/mongo/db/matcher/schema/json_schema_parser.cpp
index df3c683d493..a3fec7baf1d 100644
--- a/src/mongo/db/matcher/schema/json_schema_parser.cpp
+++ b/src/mongo/db/matcher/schema/json_schema_parser.cpp
@@ -151,7 +151,7 @@ std::unique_ptr<MatchExpression> makeRestriction(const MatcherTypeSet& restricti
     orExpr->add(notExpr.release());
     orExpr->add(restrictionExpr.release());
 
-    return std::move(orExpr);
+    return orExpr;
 }
 
 StatusWith<std::unique_ptr<InternalSchemaTypeExpression>> parseType(
@@ -431,7 +431,7 @@ StatusWith<StringDataSet> parseRequired(BSONElement requiredElt) {
                               << "' cannot be an empty array"};
     }
 
-    return std::move(properties);
+    return properties;
 }
 
 /**
diff --git a/src/mongo/db/pipeline/aggregation_request.h b/src/mongo/db/pipeline/aggregation_request.h
index 7788ec962aa..454c246feb2 100644
--- a/src/mongo/db/pipeline/aggregation_request.h
+++ b/src/mongo/db/pipeline/aggregation_request.h
@@ -87,7 +87,7 @@ public:
             pipeline.push_back(elem.embeddedObject().getOwned());
         }
 
-        return std::move(pipeline);
+        return pipeline;
     }
 
 
diff --git a/src/mongo/db/pipeline/document_source_graph_lookup.cpp b/src/mongo/db/pipeline/document_source_graph_lookup.cpp
index 5f6214400df..e41af70452b 100644
--- a/src/mongo/db/pipeline/document_source_graph_lookup.cpp
+++ b/src/mongo/db/pipeline/document_source_graph_lookup.cpp
@@ -614,7 +614,7 @@ intrusive_ptr<DocumentSource> DocumentSourceGraphLookUp::createFromBson(
                                       maxDepth,
                                       boost::none));
 
-    return std::move(newSource);
+    return newSource;
 }
 
 void DocumentSourceGraphLookUp::addInvolvedCollections(
diff --git a/src/mongo/db/pipeline/document_source_group.cpp b/src/mongo/db/pipeline/document_source_group.cpp
index 7c49d810871..cf31fd10c6e 100644
--- a/src/mongo/db/pipeline/document_source_group.cpp
+++ b/src/mongo/db/pipeline/document_source_group.cpp
@@ -238,7 +238,7 @@ DocumentSource::GetNextResult DocumentSourceGroup::getNextStandard() {
     if (++groupsIterator == _groups->end())
         dispose();
 
-    return std::move(out);
+    return out;
 }
 
 void DocumentSourceGroup::doDispose() {
diff --git a/src/mongo/db/pipeline/expression.h b/src/mongo/db/pipeline/expression.h
index 0f770dc0b0e..f65b9fef6c1 100644
--- a/src/mongo/db/pipeline/expression.h
+++ b/src/mongo/db/pipeline/expression.h
@@ -342,7 +342,7 @@ public:
         ExpressionVector args = parseArguments(expCtx, bsonExpr, vps);
         expr->validateArguments(args);
         expr->_children = std::move(args);
-        return std::move(expr);
+        return expr;
     }
 
 protected:
diff --git a/src/mongo/db/pipeline/pipeline_metadata_tree.h b/src/mongo/db/pipeline/pipeline_metadata_tree.h
index 1a22c452590..ace901cd38f 100644
--- a/src/mongo/db/pipeline/pipeline_metadata_tree.h
+++ b/src/mongo/db/pipeline/pipeline_metadata_tree.h
@@ -218,7 +218,7 @@ inline std::pair<boost::optional<Stage<T>>, std::function<T(const T&)>> makeTree
                                             stageAndReshapeContents.second,
                                             *source,
                                             propagator);
-    return std::move(stageAndReshapeContents);
+    return stageAndReshapeContents;
 }
 
 template <typename T>
diff --git a/src/mongo/db/query/planner_access.cpp b/src/mongo/db/query/planner_access.cpp
index 75234e79e43..a0f98e7734a 100644
--- a/src/mongo/db/query/planner_access.cpp
+++ b/src/mongo/db/query/planner_access.cpp
@@ -254,7 +254,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeCollectionScan(
         }
     }
 
-    return std::move(csn);
+    return csn;
 }
 
 std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeLeafNode(
@@ -288,7 +288,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeLeafNode(
             ret->addPointMeta = query.metadataDeps()[DocumentMetadataFields::kGeoNearPoint];
             ret->addDistMeta = query.metadataDeps()[DocumentMetadataFields::kGeoNearDist];
 
-            return std::move(ret);
+            return ret;
         } else {
             auto ret = std::make_unique<GeoNear2DSphereNode>(index);
             ret->nq = &nearExpr->getData();
@@ -296,7 +296,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeLeafNode(
             ret->addPointMeta = query.metadataDeps()[DocumentMetadataFields::kGeoNearPoint];
             ret->addDistMeta = query.metadataDeps()[DocumentMetadataFields::kGeoNearDist];
 
-            return std::move(ret);
+            return ret;
         }
     } else if (MatchExpression::TEXT == expr->matchType()) {
         // We must not keep the expression node around.
@@ -315,7 +315,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeLeafNode(
             ++(ret->numPrefixFields);
         }
 
-        return std::move(ret);
+        return ret;
     } else {
         // Note that indexKeyPattern.firstElement().fieldName() may not equal expr->path()
         // because expr might be inside an array operator that provides a path prefix.
@@ -336,7 +336,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::makeLeafNode(
 
         IndexBoundsBuilder::translate(expr, keyElt, index, &isn->bounds.fields[pos], tightnessOut);
 
-        return std::move(isn);
+        return isn;
     }
 }
 
@@ -1135,7 +1135,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::buildIndexedAnd(
         fetch->filter = std::move(clonedRoot);
         // Takes ownership of 'andResult'.
         fetch->children.push_back(andResult.release());
-        return std::move(fetch);
+        return fetch;
     }
 
     // If there are any nodes still attached to the AND, we can't answer them using the
@@ -1302,7 +1302,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::_buildIndexedDataAccess(
                 auto fetch = std::make_unique<FetchNode>();
                 fetch->filter = std::move(ownedRoot);
                 fetch->children.push_back(soln.release());
-                return std::move(fetch);
+                return fetch;
             }
         } else if (Indexability::arrayUsesIndexOnChildren(root)) {
             std::unique_ptr<QuerySolutionNode> solution;
@@ -1326,7 +1326,7 @@ std::unique_ptr<QuerySolutionNode> QueryPlannerAccess::_buildIndexedDataAccess(
             auto fetch = std::make_unique<FetchNode>();
             fetch->filter = std::move(ownedRoot);
             fetch->children.push_back(solution.release());
-            return std::move(fetch);
+            return fetch;
         }
     }