6 files changed, 25 insertions, 17 deletions
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index bc85349b..ae253f0c 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -762,19 +762,22 @@ public:
 	ModifierInvocation(
 		SourceLocation const& _location,
 		ASTPointer<Identifier> const& _name,
-		std::vector<ASTPointer<Expression>> _arguments
+		std::unique_ptr<std::vector<ASTPointer<Expression>>> _arguments
 	):
-		ASTNode(_location), m_modifierName(_name), m_arguments(_arguments) {}
+		ASTNode(_location), m_modifierName(_name), m_arguments(std::move(_arguments)) {}
 
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 
 	ASTPointer<Identifier> const& name() const { return m_modifierName; }
-	std::vector<ASTPointer<Expression>> const& arguments() const { return m_arguments; }
+	// Returns nullptr if no argument list was given (``mod``).
+	// If an argument list is given (``mod(...)``), the arguments are returned
+	// as a vector of expressions. Note that this vector can be empty (``mod()``).
+	std::vector<ASTPointer<Expression>> const* arguments() const { return m_arguments.get(); }
 
 private:
 	ASTPointer<Identifier> m_modifierName;
-	std::vector<ASTPointer<Expression>> m_arguments;
+	std::unique_ptr<std::vector<ASTPointer<Expression>>> m_arguments;
 };
 
 /**
diff --git a/libsolidity/ast/ASTAnnotations.h b/libsolidity/ast/ASTAnnotations.h
index 3d4236cc..5cbe42bd 100644
--- a/libsolidity/ast/ASTAnnotations.h
+++ b/libsolidity/ast/ASTAnnotations.h
@@ -90,6 +90,9 @@ struct ContractDefinitionAnnotation: TypeDeclarationAnnotation, DocumentedAnnota
 	/// List of contracts this contract creates, i.e. which need to be compiled first.
 	/// Also includes all contracts from @a linearizedBaseContracts.
 	std::set<ContractDefinition const*> contractDependencies;
+	/// Mapping containing the nodes that define the arguments for base constructors.
+	/// These can either be inheritance specifiers or modifier invocations.
+	std::map<FunctionDefinition const*, ASTNode const*> baseConstructorArguments;
 };
 
 struct FunctionDefinitionAnnotation: ASTAnnotation, DocumentedAnnotation
diff --git a/libsolidity/ast/ASTJsonConverter.cpp b/libsolidity/ast/ASTJsonConverter.cpp
index 94932eca..95ba3089 100644
--- a/libsolidity/ast/ASTJsonConverter.cpp
+++ b/libsolidity/ast/ASTJsonConverter.cpp
@@ -268,7 +268,7 @@ bool ASTJsonConverter::visit(InheritanceSpecifier const& _node)
 {
 	setJsonNode(_node, "InheritanceSpecifier", {
 		make_pair("baseName", toJson(_node.name())),
-		make_pair("arguments", _node.arguments() ? toJson(*_node.arguments()) : Json::Value(Json::arrayValue))
+		make_pair("arguments", _node.arguments() ? toJson(*_node.arguments()) : Json::nullValue)
 	});
 	return false;
 }
@@ -378,7 +378,7 @@ bool ASTJsonConverter::visit(ModifierInvocation const& _node)
 {
 	setJsonNode(_node, "ModifierInvocation", {
 		make_pair("modifierName", toJson(*_node.name())),
-		make_pair("arguments", toJson(_node.arguments()))
+		make_pair("arguments", _node.arguments() ? toJson(*_node.arguments()) : Json::nullValue)
 	});
 	return false;
 }
diff --git a/libsolidity/ast/AST_accept.h b/libsolidity/ast/AST_accept.h
index dac414fc..aeff6e4a 100644
--- a/libsolidity/ast/AST_accept.h
+++ b/libsolidity/ast/AST_accept.h
@@ -264,7 +264,8 @@ void ModifierInvocation::accept(ASTVisitor& _visitor)
 	if (_visitor.visit(*this))
 	{
 		m_modifierName->accept(_visitor);
-		listAccept(m_arguments, _visitor);
+		if (m_arguments)
+			listAccept(*m_arguments, _visitor);
 	}
 	_visitor.endVisit(*this);
 }
@@ -274,7 +275,8 @@ void ModifierInvocation::accept(ASTConstVisitor& _visitor) const
 	if (_visitor.visit(*this))
 	{
 		m_modifierName->accept(_visitor);
-		listAccept(m_arguments, _visitor);
+		if (m_arguments)
+			listAccept(*m_arguments, _visitor);
 	}
 	_visitor.endVisit(*this);
 }
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index de359ec6..21353080 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -839,10 +839,10 @@ TypePointer RationalNumberType::binaryOperatorResult(Token::Value _operator, Typ
 {
 	if (_other->category() == Category::Integer || _other->category() == Category::FixedPoint)
 	{
-		auto mobile = mobileType();
-		if (!mobile)
+		auto commonType = Type::commonType(shared_from_this(), _other);
+		if (!commonType)
 			return TypePointer();
-		return mobile->binaryOperatorResult(_operator, _other);
+		return commonType->binaryOperatorResult(_operator, _other);
 	}
 	else if (_other->category() != category())
 		return TypePointer();
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index aa46520f..05f506f1 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -403,7 +403,7 @@ private:
 };
 
 /**
- * Integer and fixed point constants either literals or computed. 
+ * Integer and fixed point constants either literals or computed.
  * Example expressions: 2, 3.14, 2+10.2, ~10.
  * There is one distinct type per value.
  */
@@ -415,7 +415,7 @@ public:
 
 	/// @returns true if the literal is a valid integer.
 	static std::tuple<bool, rational> isValidLiteral(Literal const& _literal);
-	
+
 	explicit RationalNumberType(rational const& _value):
 		m_value(_value)
 	{}
@@ -436,7 +436,7 @@ public:
 
 	/// @returns the smallest integer type that can hold the value or an empty pointer if not possible.
 	std::shared_ptr<IntegerType const> integerType() const;
-	/// @returns the smallest fixed type that can  hold the value or incurs the least precision loss. 
+	/// @returns the smallest fixed type that can  hold the value or incurs the least precision loss.
 	/// If the integer part does not fit, returns an empty pointer.
 	std::shared_ptr<FixedPointType const> fixedPointType() const;
 
@@ -778,7 +778,7 @@ public:
 	virtual std::string canonicalName() const override;
 	virtual std::string signatureInExternalFunction(bool _structsByName) const override;
 
-	/// @returns a function that peforms the type conversion between a list of struct members
+	/// @returns a function that performs the type conversion between a list of struct members
 	/// and a memory struct of this type.
 	FunctionTypePointer constructorType() const;
 
@@ -1039,7 +1039,7 @@ public:
 		return *m_declaration;
 	}
 	bool hasDeclaration() const { return !!m_declaration; }
-	/// @returns true if the the result of this function only depends on its arguments
+	/// @returns true if the result of this function only depends on its arguments
 	/// and it does not modify the state.
 	/// Currently, this will only return true for internal functions like keccak and ecrecover.
 	bool isPure() const;
@@ -1056,7 +1056,7 @@ public:
 	bool bound() const { return m_bound; }
 
 	/// @returns a copy of this type, where gas or value are set manually. This will never set one
-	/// of the parameters to fals.
+	/// of the parameters to false.
 	TypePointer copyAndSetGasOrValue(bool _setGas, bool _setValue) const;
 
 	/// @returns a copy of this function type where all return parameters of dynamic size are