Merge pull request #3824 from ethereum/baseArgumentsEmptyParenthesis

Error when using empty parentheses for base class constructors that r…

3 files changed, 12 insertions, 7 deletions

diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index 56bb412c..bc85349b 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -425,19 +425,22 @@ public:
 	InheritanceSpecifier(
 		SourceLocation const& _location,
 		ASTPointer<UserDefinedTypeName> const& _baseName,
-		std::vector<ASTPointer<Expression>> _arguments
+		std::unique_ptr<std::vector<ASTPointer<Expression>>> _arguments
 	):
-		ASTNode(_location), m_baseName(_baseName), m_arguments(_arguments) {}
+		ASTNode(_location), m_baseName(_baseName), m_arguments(std::move(_arguments)) {}
 
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 
 	UserDefinedTypeName const& name() const { return *m_baseName; }
-	std::vector<ASTPointer<Expression>> const& arguments() const { return m_arguments; }
+	// Returns nullptr if no argument list was given (``C``).
+	// If an argument list is given (``C(...)``), the arguments are returned
+	// as a vector of expressions. Note that this vector can be empty (``C()``).
+	std::vector<ASTPointer<Expression>> const* arguments() const { return m_arguments.get(); }
 
 private:
 	ASTPointer<UserDefinedTypeName> m_baseName;
-	std::vector<ASTPointer<Expression>> m_arguments;
+	std::unique_ptr<std::vector<ASTPointer<Expression>>> m_arguments;
 };
 
 /**
diff --git a/libsolidity/ast/ASTJsonConverter.cpp b/libsolidity/ast/ASTJsonConverter.cpp
index 4fef67c3..94932eca 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", toJson(_node.arguments()))
+		make_pair("arguments", _node.arguments() ? toJson(*_node.arguments()) : Json::Value(Json::arrayValue))
 	});
 	return false;
 }
diff --git a/libsolidity/ast/AST_accept.h b/libsolidity/ast/AST_accept.h
index 70ee997e..dac414fc 100644
--- a/libsolidity/ast/AST_accept.h
+++ b/libsolidity/ast/AST_accept.h
@@ -94,7 +94,8 @@ void InheritanceSpecifier::accept(ASTVisitor& _visitor)
 	if (_visitor.visit(*this))
 	{
 		m_baseName->accept(_visitor);
-		listAccept(m_arguments, _visitor);
+		if (m_arguments)
+			listAccept(*m_arguments, _visitor);
 	}
 	_visitor.endVisit(*this);
 }
@@ -104,7 +105,8 @@ void InheritanceSpecifier::accept(ASTConstVisitor& _visitor) const
 	if (_visitor.visit(*this))
 	{
 		m_baseName->accept(_visitor);
-		listAccept(m_arguments, _visitor);
+		if (m_arguments)
+			listAccept(*m_arguments, _visitor);
 	}
 	_visitor.endVisit(*this);
 }