Make use of C++17 std::optional<> instead of boost::optional<>.

libsolidity/ast/AST.h

@@ -36,6 +36,7 @@
 #include <json/json.h>
 
 #include <memory>
+#include <optional>
 #include <string>
 #include <vector>
 
@@ -912,10 +913,10 @@ public:
 	ElementaryTypeName(
 		SourceLocation const& _location,
 		ElementaryTypeNameToken const& _elem,
-		boost::optional<StateMutability> _stateMutability = {}
+		std::optional<StateMutability> _stateMutability = {}
 	): TypeName(_location), m_type(_elem), m_stateMutability(_stateMutability)
 	{
-		solAssert(!_stateMutability.is_initialized() || _elem.token() == Token::Address, "");
+		solAssert(!_stateMutability.has_value() || _elem.token() == Token::Address, "");
 	}
 
 	void accept(ASTVisitor& _visitor) override;
@@ -923,11 +924,11 @@ public:
 
 	ElementaryTypeNameToken const& typeName() const { return m_type; }
 
-	boost::optional<StateMutability> const& stateMutability() const { return m_stateMutability; }
+	std::optional<StateMutability> const& stateMutability() const { return m_stateMutability; }
 
 private:
 	ElementaryTypeNameToken m_type;
-	boost::optional<StateMutability> m_stateMutability; ///< state mutability for address type
+	std::optional<StateMutability> m_stateMutability; ///< state mutability for address type
 };
 
 /**

libsolidity/ast/ASTAnnotations.h

@@ -26,10 +26,9 @@
 #include <libsolidity/ast/ASTEnums.h>
 #include <libsolidity/ast/ExperimentalFeatures.h>
 
-#include <boost/optional.hpp>
-
 #include <map>
 #include <memory>
+#include <optional>
 #include <set>
 #include <vector>
 
@@ -183,7 +182,7 @@ struct ExpressionAnnotation: ASTAnnotation
 
 	/// Types and - if given - names of arguments if the expr. is a function
 	/// that is called, used for overload resoultion
-	boost::optional<FuncCallArguments> arguments;
+	std::optional<FuncCallArguments> arguments;
 };
 
 struct IdentifierAnnotation: ExpressionAnnotation

libsolidity/ast/ASTJsonConverter.cpp

@@ -148,7 +148,7 @@ Json::Value ASTJsonConverter::typePointerToJson(TypePointer _tp, bool _short)
 	return typeDescriptions;
 
 }
-Json::Value ASTJsonConverter::typePointerToJson(boost::optional<FuncCallArguments> const& _tps)
+Json::Value ASTJsonConverter::typePointerToJson(std::optional<FuncCallArguments> const& _tps)
 {
 	if (_tps)
 	{

libsolidity/ast/ASTJsonConverter.h

@@ -27,10 +27,12 @@
 #include <liblangutil/Exceptions.h>
 
 #include <json/json.h>
+
+#include <algorithm>
+#include <optional>
 #include <ostream>
 #include <stack>
 #include <vector>
-#include <algorithm>
 
 namespace langutil
 {
@@ -169,7 +171,7 @@ private:
 		return json;
 	}
 	static Json::Value typePointerToJson(TypePointer _tp, bool _short = false);
-	static Json::Value typePointerToJson(boost::optional<FuncCallArguments> const& _tps);
+	static Json::Value typePointerToJson(std::optional<FuncCallArguments> const& _tps);
 	void appendExpressionAttributes(
 		std::vector<std::pair<std::string, Json::Value>> &_attributes,
 		ExpressionAnnotation const& _annotation

libsolidity/ast/TypeProvider.h

@@ -22,6 +22,7 @@
 #include <array>
 #include <map>
 #include <memory>
+#include <optional>
 #include <utility>
 
 namespace dev

libsolidity/ast/Types.cpp

@@ -1812,10 +1812,10 @@ TypePointer ArrayType::decodingType() const
 
 TypeResult ArrayType::interfaceType(bool _inLibrary) const
 {
-	if (_inLibrary && m_interfaceType_library.is_initialized())
+	if (_inLibrary && m_interfaceType_library.has_value())
 		return *m_interfaceType_library;
 
-	if (!_inLibrary && m_interfaceType.is_initialized())
+	if (!_inLibrary && m_interfaceType.has_value())
 		return *m_interfaceType;
 
 	TypeResult result{TypePointer{}};
@@ -2106,10 +2106,10 @@ MemberList::MemberMap StructType::nativeMembers(ContractDefinition const*) const
 
 TypeResult StructType::interfaceType(bool _inLibrary) const
 {
-	if (_inLibrary && m_interfaceType_library.is_initialized())
+	if (_inLibrary && m_interfaceType_library.has_value())
 		return *m_interfaceType_library;
 
-	if (!_inLibrary && m_interfaceType.is_initialized())
+	if (!_inLibrary && m_interfaceType.has_value())
 		return *m_interfaceType;
 
 	TypeResult result{TypePointer{}};
@@ -2166,7 +2166,7 @@ TypeResult StructType::interfaceType(bool _inLibrary) const
 		}
 	};
 
-	m_recursive = m_recursive.get() || (CycleDetector<StructDefinition>(visitor).run(structDefinition()) != nullptr);
+	m_recursive = m_recursive.value() || (CycleDetector<StructDefinition>(visitor).run(structDefinition()) != nullptr);
 
 	std::string const recursiveErrMsg = "Recursive type not allowed for public or external contract functions.";
 
@@ -2179,13 +2179,13 @@ TypeResult StructType::interfaceType(bool _inLibrary) const
 		else
 			m_interfaceType_library = TypeProvider::withLocation(this, DataLocation::Memory, true);
 
-		if (m_recursive.get())
+		if (m_recursive.value())
 			m_interfaceType = TypeResult::err(recursiveErrMsg);
 
 		return *m_interfaceType_library;
 	}
 
-	if (m_recursive.get())
+	if (m_recursive.value())
 		m_interfaceType = TypeResult::err(recursiveErrMsg);
 	else if (!result.message().empty())
 		m_interfaceType = result;

libsolidity/ast/Types.h

@@ -31,11 +31,11 @@
 #include <libdevcore/CommonIO.h>
 #include <libdevcore/Result.h>
 
-#include <boost/optional.hpp>
 #include <boost/rational.hpp>
 
 #include <map>
 #include <memory>
+#include <optional>
 #include <set>
 #include <string>
 
@@ -769,8 +769,8 @@ private:
 	Type const* m_baseType;
 	bool m_hasDynamicLength = true;
 	u256 m_length;
-	mutable boost::optional<TypeResult> m_interfaceType;
-	mutable boost::optional<TypeResult> m_interfaceType_library;
+	mutable std::optional<TypeResult> m_interfaceType;
+	mutable std::optional<TypeResult> m_interfaceType_library;
 };
 
 /**
@@ -865,12 +865,12 @@ public:
 
 	bool recursive() const
 	{
-		if (m_recursive.is_initialized())
-			return m_recursive.get();
+		if (m_recursive.has_value())
+			return m_recursive.value();
 
 		interfaceType(false);
 
-		return m_recursive.get();
+		return m_recursive.value();
 	}
 
 	std::unique_ptr<ReferenceType> copyForLocation(DataLocation _location, bool _isPointer) const override;
@@ -898,9 +898,9 @@ public:
 private:
 	StructDefinition const& m_struct;
 	// Caches for interfaceType(bool)
-	mutable boost::optional<TypeResult> m_interfaceType;
-	mutable boost::optional<TypeResult> m_interfaceType_library;
-	mutable boost::optional<bool> m_recursive;
+	mutable std::optional<TypeResult> m_interfaceType;
+	mutable std::optional<TypeResult> m_interfaceType_library;
+	mutable std::optional<bool> m_recursive;
 };
 
 /**