Avoid emitting std::move for built-in C++ scalar types

Author: wravery

include/SchemaLoader.h

@@ -20,7 +20,8 @@
 namespace graphql::generator {
 
 // These are the set of built-in types in GraphQL.
-enum class [[nodiscard]] BuiltinType {
+enum class [[nodiscard]] BuiltinType
+{
 	Int,
 	Float,
 	String,
@@ -75,7 +76,8 @@ using EnumTypeList = std::vector<EnumType>;
 // Input types are complex types that have a set of named fields. Each field may be
 // a scalar type (including lists or non-null wrappers) or another nested input type,
 // but it cannot include output object types.
-enum class [[nodiscard]] InputFieldType {
+enum class [[nodiscard]] InputFieldType
+{
 	Builtin,
 	Scalar,
 	Enum,
@@ -136,7 +138,8 @@ using UnionTypeList = std::vector<UnionType>;
 // field may be a scalar type (including lists or non-null wrappers) or another nested
 // output type, but it cannot include input object types. Each field can also take
 // optional arguments which are all input types.
-enum class [[nodiscard]] OutputFieldType {
+enum class [[nodiscard]] OutputFieldType
+{
 	Builtin,
 	Scalar,
 	Enum,
@@ -264,6 +267,8 @@ class [[nodiscard]] SchemaLoader
 	[[nodiscard]] static std::string getOutputCppAccessor(const OutputField& field) noexcept;
 	[[nodiscard]] static std::string getOutputCppResolver(const OutputField& field) noexcept;
 
+	[[nodiscard]] static bool shouldMoveInputField(const InputField& field) noexcept;
+
 private:
 	[[nodiscard]] static bool isExtension(const peg::ast_node& definition) noexcept;
 

samples/learn/schema/StarWarsSchema.cpp

@@ -87,7 +87,7 @@ learn::ReviewInput Argument<learn::ReviewInput>::convert(const response::Value&
 	auto valueCommentary = service::ModifiedArgument<std::string>::require<service::TypeModifier::Nullable>("commentary", value);
 
 	return learn::ReviewInput {
-		std::move(valueStars),
+		valueStars,
 		std::move(valueCommentary)
 	};
 }

samples/today/nointrospection/TodaySchema.cpp

@@ -105,7 +105,7 @@ today::CompleteTaskInput Argument<today::CompleteTaskInput>::convert(const respo
 
 	return today::CompleteTaskInput {
 		std::move(valueId),
-		std::move(valueTestTaskState),
+		valueTestTaskState,
 		std::move(valueIsComplete),
 		std::move(valueClientMutationId)
 	};

samples/today/schema/TodaySchema.cpp

@@ -105,7 +105,7 @@ today::CompleteTaskInput Argument<today::CompleteTaskInput>::convert(const respo
 
 	return today::CompleteTaskInput {
 		std::move(valueId),
-		std::move(valueTestTaskState),
+		valueTestTaskState,
 		std::move(valueIsComplete),
 		std::move(valueClientMutationId)
 	};

samples/validation/schema/ArgumentsObject.cpp

@@ -158,7 +158,7 @@ service::AwaitableResolver Arguments::resolveOptionalNonNullBooleanArgField(serv
 
 	auto pairOptionalBooleanArg = service::ModifiedArgument<bool>::find("optionalBooleanArg", params.arguments);
 	auto argOptionalBooleanArg = (pairOptionalBooleanArg.second
-		? std::move(pairOptionalBooleanArg.first)
+		? pairOptionalBooleanArg.first
 		: service::ModifiedArgument<bool>::require("optionalBooleanArg", defaultArguments));
 	std::unique_lock resolverLock(_resolverMutex);
 	service::SelectionSetParams selectionSetParams { static_cast<const service::SelectionSetParams&>(params) };

src/SchemaGenerator.cpp

@@ -1441,10 +1441,25 @@ void Result<)cpp" << _loader.getSchemaNamespace()
 )cpp";
 				}
 
+				const bool shouldMove = SchemaLoader::shouldMoveInputField(inputField);
+
 				firstField = false;
 				fieldName[0] =
 					static_cast<char>(std::toupper(static_cast<unsigned char>(fieldName[0])));
-				sourceFile << R"cpp(		std::move(value)cpp" << fieldName << R"cpp())cpp";
+
+				sourceFile << R"cpp(		)cpp";
+
+				if (shouldMove)
+				{
+					sourceFile << R"cpp(std::move()cpp";
+				}
+
+				sourceFile << R"cpp(value)cpp" << fieldName;
+
+				if (shouldMove)
+				{
+					sourceFile << R"cpp())cpp";
+				}
 			}
 
 			sourceFile << R"cpp(
@@ -2396,7 +2411,8 @@ service::AwaitableResolver )cpp"
 
 		if (!_loader.isIntrospection())
 		{
-			sourceFile << R"cpp(	service::SelectionSetParams selectionSetParams { static_cast<const service::SelectionSetParams&>(params) };
+			sourceFile
+				<< R"cpp(	service::SelectionSetParams selectionSetParams { static_cast<const service::SelectionSetParams&>(params) };
 	auto directives = std::move(params.fieldDirectives);
 )cpp";
 		}
@@ -2775,8 +2791,23 @@ std::string Generator::getArgumentDeclaration(const InputField& argument, const
 							<< argument.name << R"cpp(", )cpp" << argumentsToken << R"cpp();
 	auto )cpp" << prefixToken
 							<< argumentName << R"cpp( = (pair)cpp" << argumentName << R"cpp(.second
-		? std::move(pair)cpp"
-							<< argumentName << R"cpp(.first)
+		? )cpp";
+
+		const bool shouldMove = SchemaLoader::shouldMoveInputField(argument);
+
+		if (shouldMove)
+		{
+			argumentDeclaration << R"cpp(std::move()cpp";
+		}
+
+		argumentDeclaration << R"cpp(pair)cpp" << argumentName << R"cpp(.first)cpp";
+
+		if (shouldMove)
+		{
+			argumentDeclaration << R"cpp())cpp";
+		}
+
+		argumentDeclaration << R"cpp(
 		: )cpp" << getArgumentAccessType(argument)
 							<< R"cpp(::require)cpp" << getTypeModifiers(argument.modifiers)
 							<< R"cpp((")cpp" << argument.name << R"cpp(", )cpp" << defaultToken

src/SchemaLoader.cpp

@@ -1873,6 +1873,48 @@ std::string SchemaLoader::getOutputCppResolver(const OutputField& field) noexcep
 	return getJoinedCppName(R"cpp(resolve)cpp"sv, field.name);
 }
 
+bool SchemaLoader::shouldMoveInputField(const InputField& field) noexcept
+{
+	bool shouldMove = true;
+
+	switch (field.fieldType)
+	{
+		case InputFieldType::Builtin:
+		{
+			if (field.modifiers.empty() || field.modifiers.front() == service::TypeModifier::None)
+			{
+				const auto& builtinTypes = getBuiltinTypes();
+
+				switch (builtinTypes.at(field.type))
+				{
+					case BuiltinType::Int:
+					case BuiltinType::Float:
+					case BuiltinType::Boolean:
+						shouldMove = false;
+						break;
+
+					default:
+						break;
+				}
+			}
+
+			break;
+		}
+
+		case InputFieldType::Enum:
+		{
+			shouldMove =
+				field.modifiers.empty() || field.modifiers.front() == service::TypeModifier::None;
+			break;
+		}
+
+		default:
+			break;
+	}
+
+	return shouldMove;
+}
+
 std::string SchemaLoader::getJoinedCppName(
 	std::string_view prefix, std::string_view fieldName) noexcept
 {