Check for circular references in constant variables.

libsolidity/analysis/PostTypeChecker.h

@@ -0,0 +1,69 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <libsolidity/analysis/TypeChecker.h>
+#include <libsolidity/ast/Types.h>
+#include <libsolidity/ast/ASTAnnotations.h>
+#include <libsolidity/ast/ASTForward.h>
+#include <libsolidity/ast/ASTVisitor.h>
+
+namespace dev
+{
+namespace solidity
+{
+
+/**
+ * This module performs analyses on the AST that are done after type checking and assignments of types:
+ *  - whether there are circular references in constant state variables
+ * @TODO factor out each use-case into an individual class (but do the traversal only once)
+ */
+class PostTypeChecker: private ASTConstVisitor
+{
+public:
+	/// @param _errors the reference to the list of errors and warnings to add them found during type checking.
+	PostTypeChecker(ErrorList& _errors): m_errors(_errors) {}
+
+	bool check(ASTNode const& _astRoot);
+
+private:
+	/// Adds a new error to the list of errors.
+	void typeError(SourceLocation const& _location, std::string const& _description);
+
+	virtual bool visit(ContractDefinition const& _contract) override;
+	virtual void endVisit(ContractDefinition const& _contract) override;
+
+	virtual bool visit(VariableDeclaration const& _declaration) override;
+	virtual void endVisit(VariableDeclaration const& _declaration) override;
+
+	virtual bool visit(Identifier const& _identifier) override;
+
+	VariableDeclaration const* findCycle(
+		VariableDeclaration const* _startingFrom,
+		std::set<VariableDeclaration const*> const& _seen = {}
+	);
+
+	ErrorList& m_errors;
+
+	VariableDeclaration const* m_currentConstVariable = nullptr;
+	std::vector<VariableDeclaration const*> m_constVariables; ///< Required for determinism.
+	std::map<VariableDeclaration const*, std::set<VariableDeclaration const*>> m_constVariableDependencies;
+};
+
+}
+}