virtual modifiers (in Abstract contracts) allow empty bodies

libsolidity/ast/AST.h

@@ -969,7 +969,7 @@ private:
 /**
  * Definition of a function modifier.
  */
-class ModifierDefinition: public CallableDeclaration, public StructurallyDocumented
+class ModifierDefinition: public CallableDeclaration, public StructurallyDocumented, public ImplementationOptional
 {
 public:
 	ModifierDefinition(
@@ -980,18 +980,19 @@ public:
 		ASTPointer<ParameterList> const& _parameters,
 		bool _isVirtual,
 		ASTPointer<OverrideSpecifier> const& _overrides,
-		ASTPointer<Block> _body
+		ASTPointer<Block> const& _body
 	):
 		CallableDeclaration(_id, _location, _name, Visibility::Internal, _parameters, _isVirtual, _overrides),
 		StructurallyDocumented(_documentation),
-		m_body(std::move(_body))
+		ImplementationOptional(_body != nullptr),
+		m_body(_body)
 	{
 	}
 
 	void accept(ASTVisitor& _visitor) override;
 	void accept(ASTConstVisitor& _visitor) const override;
 
-	Block const& body() const { return *m_body; }
+	Block const& body() const { solAssert(m_body, ""); return *m_body; }
 
 	TypePointer type() const override;
 

libsolidity/ast/ASTAnnotations.h

@@ -140,8 +140,8 @@ struct StructDeclarationAnnotation: TypeDeclarationAnnotation
 
 struct ContractDefinitionAnnotation: TypeDeclarationAnnotation, StructurallyDocumentedAnnotation
 {
-	/// List of functions without a body. Can also contain functions from base classes.
-	std::vector<FunctionDefinition const*> unimplementedFunctions;
+	/// List of functions and modifiers without a body. Can also contain functions from base classes.
+	std::vector<Declaration const*> unimplementedDeclarations;
 	/// List of all (direct and indirect) base contracts in order from derived to
 	/// base, including the contract itself.
 	std::vector<ContractDefinition const*> linearizedBaseContracts;

libsolidity/ast/ASTJsonConverter.cpp

@@ -272,7 +272,7 @@ bool ASTJsonConverter::visit(ContractDefinition const& _node)
 		make_pair("documentation", _node.documentation() ? toJson(*_node.documentation()) : Json::nullValue),
 		make_pair("contractKind", contractKind(_node.contractKind())),
 		make_pair("abstract", _node.abstract()),
-		make_pair("fullyImplemented", _node.annotation().unimplementedFunctions.empty()),
+		make_pair("fullyImplemented", _node.annotation().unimplementedDeclarations.empty()),
 		make_pair("linearizedBaseContracts", getContainerIds(_node.annotation().linearizedBaseContracts)),
 		make_pair("baseContracts", toJson(_node.baseContracts())),
 		make_pair("contractDependencies", getContainerIds(_node.annotation().contractDependencies, true)),
@@ -407,7 +407,7 @@ bool ASTJsonConverter::visit(ModifierDefinition const& _node)
 		make_pair("parameters", toJson(_node.parameterList())),
 		make_pair("virtual", _node.markedVirtual()),
 		make_pair("overrides", _node.overrides() ? toJson(*_node.overrides()) : Json::nullValue),
-		make_pair("body", toJson(_node.body()))
+		make_pair("body", _node.isImplemented() ? toJson(_node.body()) : Json::nullValue)
 	};
 	if (!_node.annotation().baseFunctions.empty())
 		attributes.emplace_back(make_pair("baseModifiers", getContainerIds(_node.annotation().baseFunctions, true)));

libsolidity/ast/ASTJsonImporter.cpp

@@ -453,7 +453,7 @@ ASTPointer<ModifierDefinition> ASTJsonImporter::createModifierDefinition(Json::V
 		createParameterList(member(_node, "parameters")),
 		memberAsBool(_node, "virtual"),
 		_node["overrides"].isNull() ? nullptr : createOverrideSpecifier(member(_node, "overrides")),
-		createBlock(member(_node, "body"))
+		_node["body"].isNull() ? nullptr: createBlock(member(_node, "body"))
 	);
 }
 

libsolidity/ast/AST_accept.h

@@ -288,7 +288,8 @@ void ModifierDefinition::accept(ASTVisitor& _visitor)
 		m_parameters->accept(_visitor);
 		if (m_overrides)
 			m_overrides->accept(_visitor);
-		m_body->accept(_visitor);
+		if (m_body)
+			m_body->accept(_visitor);
 	}
 	_visitor.endVisit(*this);
 }
@@ -302,7 +303,8 @@ void ModifierDefinition::accept(ASTConstVisitor& _visitor) const
 		m_parameters->accept(_visitor);
 		if (m_overrides)
 			m_overrides->accept(_visitor);
-		m_body->accept(_visitor);
+		if (m_body)
+			m_body->accept(_visitor);
 	}
 	_visitor.endVisit(*this);
 }

libsolidity/ast/Types.h

@@ -1390,7 +1390,6 @@ public:
 	std::string richIdentifier() const override;
 	bool operator==(Type const& _other) const override;
 	std::string toString(bool _short) const override;
-
 protected:
 	std::vector<std::tuple<std::string, TypePointer>> makeStackItems() const override { return {}; }
 private: