errors instead of exceptions

Conflicts:
	libsolidity/CompilerStack.cpp
	libsolidity/NameAndTypeResolver.cpp
	libsolidity/NameAndTypeResolver.h
	libsolidity/TypeChecker.cpp
	test/libsolidity/SolidityNameAndTypeResolution.cpp

10 files changed, 337 insertions, 155 deletions

diff --git a/libsolidity/CompilerContext.cpp b/libsolidity/CompilerContext.cpp
index fa7f9c77..0ba7af5b 100644
--- a/libsolidity/CompilerContext.cpp
+++ b/libsolidity/CompilerContext.cpp
@@ -137,7 +137,7 @@ ModifierDefinition const& CompilerContext::functionModifier(string const& _name)
 			if (modifier->name() == _name)
 				return *modifier.get();
 	BOOST_THROW_EXCEPTION(InternalCompilerError()
-						  << errinfo_comment("Function modifier " + _name + " not found."));
+		<< errinfo_comment("Function modifier " + _name + " not found."));
 }
 
 unsigned CompilerContext::baseStackOffsetOfVariable(Declaration const& _declaration) const
diff --git a/libsolidity/CompilerStack.cpp b/libsolidity/CompilerStack.cpp
index 519f785b..3887999a 100644
--- a/libsolidity/CompilerStack.cpp
+++ b/libsolidity/CompilerStack.cpp
@@ -97,30 +97,41 @@ void CompilerStack::setSource(string const& _sourceCode)
 
 bool CompilerStack::parse()
 {
+	// todo not sure about clear. can contain warnings
 	m_errors.clear();
 
 	for (auto& sourcePair: m_sources)
 	{
 		sourcePair.second.scanner->reset();
-		sourcePair.second.ast = Parser().parse(sourcePair.second.scanner);
+		sourcePair.second.ast = Parser(m_errors).parse(sourcePair.second.scanner); // todo check for errors
 	}
+	if (!Error::containsOnlyWarnings(m_errors))
+		// errors while parsing. sould stop before type checking
+		return false;
+
 	resolveImports();
 
 	m_globalContext = make_shared<GlobalContext>();
+	bool success = true;
 	NameAndTypeResolver resolver(m_globalContext->declarations(), m_errors);
 	for (Source const* source: m_sourceOrder)
-		resolver.registerDeclarations(*source->ast);
+		success = success && resolver.registerDeclarations(*source->ast);
 	for (Source const* source: m_sourceOrder)
 		for (ASTPointer<ASTNode> const& node: source->ast->nodes())
 			if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(node.get()))
 			{
 				m_globalContext->setCurrentContract(*contract);
-				resolver.updateDeclaration(*m_globalContext->currentThis());
-				resolver.updateDeclaration(*m_globalContext->currentSuper());
-				resolver.resolveNamesAndTypes(*contract);
+				success = success && resolver.updateDeclaration(*m_globalContext->currentThis());
+				success = success && resolver.updateDeclaration(*m_globalContext->currentSuper());
+				success = success && resolver.resolveNamesAndTypes(*contract);
 				m_contracts[contract->name()].contract = contract;
 			}
 
+	if (!success)
+	{
+		m_parseSuccessful = false;
+		return m_parseSuccessful;
+	}
 	InterfaceHandler interfaceHandler;
 	bool typesFine = true;
 	for (Source const* source: m_sourceOrder)
@@ -137,6 +148,7 @@ bool CompilerStack::parse()
 				}
 				else
 					typesFine = false;
+
 				m_contracts[contract->name()].contract = contract;
 				m_errors += typeChecker.errors();
 			}
@@ -253,9 +265,8 @@ string const& CompilerStack::metadata(string const& _contractName, Documentation
 	if (!m_parseSuccessful)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));
 
-	Contract const& currentContract = contract(_contractName);
-
 	std::unique_ptr<string const>* doc;
+	Contract const& currentContract = contract(_contractName);
 
 	// checks wheather we already have the documentation
 	switch (_type)
@@ -346,9 +357,10 @@ void CompilerStack::resolveImports()
 				if (!m_sources.count(id))
 					BOOST_THROW_EXCEPTION(
 						Error(Error::Type::ParserError)
-							  << errinfo_sourceLocation(import->location())
-							  << errinfo_comment("Source not found.")
+							<< errinfo_sourceLocation(import->location())
+							<< errinfo_comment("Source not found.")
 					);
+
 				toposort(&m_sources[id]);
 			}
 		sourceOrder.push_back(_source);
@@ -414,10 +426,12 @@ CompilerStack::Source const& CompilerStack::source(string const& _sourceName) co
 	auto it = m_sources.find(_sourceName);
 	if (it == m_sources.end())
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Given source file not found."));
+
 	return it->second;
 }
 
 CompilerStack::Contract::Contract(): interfaceHandler(make_shared<InterfaceHandler>()) {}
 
+
 }
 }
diff --git a/libsolidity/CompilerStack.h b/libsolidity/CompilerStack.h
index 5b128868..e47f558b 100644
--- a/libsolidity/CompilerStack.h
+++ b/libsolidity/CompilerStack.h
@@ -167,6 +167,7 @@ public:
 	/// @returns the list of errors that occured during parsing and type checking.
 	ErrorList const& errors() const { return m_errors; }
 
+
 private:
 	/**
 	 * Information pertaining to one source unit, filled gradually during parsing and compilation.
diff --git a/libsolidity/Exceptions.h b/libsolidity/Exceptions.h
index 5a1b827c..92c009ef 100644
--- a/libsolidity/Exceptions.h
+++ b/libsolidity/Exceptions.h
@@ -26,11 +26,18 @@
 #include <utility>
 #include <libdevcore/Exceptions.h>
 #include <libevmasm/SourceLocation.h>
+#include <libsolidity/Utils.h>
 
 namespace dev
 {
 namespace solidity
 {
+class Error;
+using ErrorList = std::vector<std::shared_ptr<Error const>>;
+
+struct CompilerError: virtual Exception {};
+struct InternalCompilerError: virtual Exception {};
+struct fatalError: virtual Exception {}; //todo rename to FatalError
 
 class Error: virtual public Exception
 {
@@ -41,7 +48,6 @@ public:
 		DocstringParsingError,
 		ParserError,
 		TypeError,
-
 		Warning
 	};
 
@@ -65,22 +71,39 @@ public:
 				m_typeName = "Warning";
 				break;
 			default:
-				m_typeName = "Error";
+				solAssert(false, "");
 				break;
 		}
 	}
 
-	Type const type() { return m_type; } const
+	Type type() const { return m_type; }
 	std::string const& typeName() const { return m_typeName; }
 
+
+	/// helper functions
+	static Error const* containsErrorOfType(ErrorList const& _list, Error::Type _type)
+	{
+		for (auto e: _list)
+		{
+			if(e->type() == _type)
+				return e.get();
+		}
+		return nullptr;
+	}
+	static bool containsOnlyWarnings(ErrorList const& _list)
+	{
+		for (auto e: _list)
+		{
+			if(e->type() != Type::Warning)
+				return false;
+		}
+		return true;
+	}
 private:
 	Type m_type;
 	std::string m_typeName;
 };
 
-struct CompilerError: virtual Exception {};
-struct InternalCompilerError: virtual Exception {};
-struct FatalError: virtual Exception {};
 
 using errorSourceLocationInfo = std::pair<std::string, SourceLocation>;
 
@@ -96,7 +119,6 @@ public:
 };
 
 
-using ErrorList = std::vector<std::shared_ptr<Error const>>;
 using errinfo_sourceLocation = boost::error_info<struct tag_sourceLocation, SourceLocation>;
 using errinfo_secondarySourceLocation = boost::error_info<struct tag_secondarySourceLocation, SecondarySourceLocation>;
 
diff --git a/libsolidity/NameAndTypeResolver.cpp b/libsolidity/NameAndTypeResolver.cpp
index 3591c07a..934be0e3 100644
--- a/libsolidity/NameAndTypeResolver.cpp
+++ b/libsolidity/NameAndTypeResolver.cpp
@@ -42,81 +42,105 @@ NameAndTypeResolver::NameAndTypeResolver(
 		m_scopes[nullptr].registerDeclaration(*declaration);
 }
 
-void NameAndTypeResolver::registerDeclarations(SourceUnit& _sourceUnit)
+bool NameAndTypeResolver::registerDeclarations(SourceUnit& _sourceUnit)
 {
 	// The helper registers all declarations in m_scopes as a side-effect of its construction.
-	DeclarationRegistrationHelper registrar(m_scopes, _sourceUnit);
+	try
+	{
+		DeclarationRegistrationHelper registrar(m_scopes, _sourceUnit, m_errors);
+	}
+	catch (fatalError)
+	{
+		return false;
+	}
+	return true;
 }
 
-void NameAndTypeResolver::resolveNamesAndTypes(ContractDefinition& _contract)
+bool NameAndTypeResolver::resolveNamesAndTypes(ContractDefinition& _contract)
 {
-	m_currentScope = &m_scopes[nullptr];
+	try
+	{
+		m_currentScope = &m_scopes[nullptr];
 
-	for (ASTPointer<InheritanceSpecifier> const& baseContract: _contract.baseContracts())
-		ReferencesResolver resolver(*baseContract, *this, &_contract, nullptr);
+		for (ASTPointer<InheritanceSpecifier> const& baseContract: _contract.baseContracts())
+			ReferencesResolver resolver(*baseContract, *this, &_contract, nullptr);
 
-	m_currentScope = &m_scopes[&_contract];
+		m_currentScope = &m_scopes[&_contract];
 
-	linearizeBaseContracts(_contract);
-	std::vector<ContractDefinition const*> properBases(
-		++_contract.annotation().linearizedBaseContracts.begin(),
-		_contract.annotation().linearizedBaseContracts.end()
-	);
+		linearizeBaseContracts(_contract);
+		std::vector<ContractDefinition const*> properBases(
+			++_contract.annotation().linearizedBaseContracts.begin(),
+			_contract.annotation().linearizedBaseContracts.end()
+		);
 
-	for (ContractDefinition const* base: properBases)
-		importInheritedScope(*base);
+		for (ContractDefinition const* base: properBases)
+			importInheritedScope(*base);
 
-	for (ASTPointer<StructDefinition> const& structDef: _contract.definedStructs())
-		ReferencesResolver resolver(*structDef, *this, &_contract, nullptr);
-	for (ASTPointer<EnumDefinition> const& enumDef: _contract.definedEnums())
-		ReferencesResolver resolver(*enumDef, *this, &_contract, nullptr);
-	for (ASTPointer<VariableDeclaration> const& variable: _contract.stateVariables())
-		ReferencesResolver resolver(*variable, *this, &_contract, nullptr);
-	for (ASTPointer<EventDefinition> const& event: _contract.events())
-		ReferencesResolver resolver(*event, *this, &_contract, nullptr);
+		for (ASTPointer<StructDefinition> const& structDef: _contract.definedStructs())
+			ReferencesResolver resolver(*structDef, *this, &_contract, nullptr);
+		for (ASTPointer<EnumDefinition> const& enumDef: _contract.definedEnums())
+			ReferencesResolver resolver(*enumDef, *this, &_contract, nullptr);
+		for (ASTPointer<VariableDeclaration> const& variable: _contract.stateVariables())
+			ReferencesResolver resolver(*variable, *this, &_contract, nullptr);
+		for (ASTPointer<EventDefinition> const& event: _contract.events())
+			ReferencesResolver resolver(*event, *this, &_contract, nullptr);
 
-	// these can contain code, only resolve parameters for now
-	for (ASTPointer<ModifierDefinition> const& modifier: _contract.functionModifiers())
-	{
-		m_currentScope = &m_scopes[modifier.get()];
-		ReferencesResolver resolver(*modifier, *this, &_contract, nullptr);
-	}
-	for (ASTPointer<FunctionDefinition> const& function: _contract.definedFunctions())
-	{
-		m_currentScope = &m_scopes[function.get()];
-		ReferencesResolver referencesResolver(
-			*function,
-			*this,
-			&_contract,
-			function->returnParameterList().get()
-		);
-	}
+		// these can contain code, only resolve parameters for now
+		for (ASTPointer<ModifierDefinition> const& modifier: _contract.functionModifiers())
+		{
+			m_currentScope = &m_scopes[modifier.get()];
+			ReferencesResolver resolver(*modifier, *this, &_contract, nullptr);
+		}
+		for (ASTPointer<FunctionDefinition> const& function: _contract.definedFunctions())
+		{
+			m_currentScope = &m_scopes[function.get()];
+			ReferencesResolver referencesResolver(
+				*function,
+				*this,
+				&_contract,
+				function->returnParameterList().get()
+			);
+		}
 
-	m_currentScope = &m_scopes[&_contract];
+		m_currentScope = &m_scopes[&_contract];
 
-	// now resolve references inside the code
-	for (ASTPointer<ModifierDefinition> const& modifier: _contract.functionModifiers())
-	{
-		m_currentScope = &m_scopes[modifier.get()];
-		ReferencesResolver resolver(*modifier, *this, &_contract, nullptr, true);
+		// now resolve references inside the code
+		for (ASTPointer<ModifierDefinition> const& modifier: _contract.functionModifiers())
+		{
+			m_currentScope = &m_scopes[modifier.get()];
+			ReferencesResolver resolver(*modifier, *this, &_contract, nullptr, true);
+		}
+		for (ASTPointer<FunctionDefinition> const& function: _contract.definedFunctions())
+		{
+			m_currentScope = &m_scopes[function.get()];
+			ReferencesResolver referencesResolver(
+				*function,
+				*this,
+				&_contract,
+				function->returnParameterList().get(),
+				true
+			);
+		}
 	}
-	for (ASTPointer<FunctionDefinition> const& function: _contract.definedFunctions())
+	catch (fatalError const& _e)
 	{
-		m_currentScope = &m_scopes[function.get()];
-		ReferencesResolver referencesResolver(
-			*function,
-			*this,
-			&_contract,
-			function->returnParameterList().get(),
-			true
-		);
+		return false;
 	}
+	return true;
 }
 
-void NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
+bool NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
 {
-	m_scopes[nullptr].registerDeclaration(_declaration, false, true);
-	solAssert(_declaration.scope() == nullptr, "Updated declaration outside global scope.");
+	try
+	{
+		m_scopes[nullptr].registerDeclaration(_declaration, false, true);
+		solAssert(_declaration.scope() == nullptr, "Updated declaration outside global scope.");
+	}
+	catch(fatalError _error)
+	{
+		return false;
+	}
+	return true;
 }
 
 vector<Declaration const*> NameAndTypeResolver::resolveName(ASTString const& _name, Declaration const* _scope) const
@@ -164,11 +188,8 @@ vector<Declaration const*> NameAndTypeResolver::cleanedDeclarations(
 		FunctionType functionType(functionDefinition);
 		for (auto parameter: functionType.parameterTypes() + functionType.returnParameterTypes())
 			if (!parameter)
-				BOOST_THROW_EXCEPTION(
-					Error(Error::Type::DeclarationError) <<
-					errinfo_sourceLocation(_identifier.location()) <<
-					errinfo_comment("Function type can not be used in this context")
-				);
+				reportFatalDeclarationError(_identifier.location(), "Function type can not be used in this context");
+
 		if (uniqueFunctions.end() == find_if(
 			uniqueFunctions.begin(),
 			uniqueFunctions.end(),
@@ -194,7 +215,7 @@ void NameAndTypeResolver::importInheritedScope(ContractDefinition const& _base)
 				m_currentScope->registerDeclaration(*declaration);
 }
 
-void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract) const
+void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract)
 {
 	// order in the lists is from derived to base
 	// list of lists to linearize, the last element is the list of direct bases
@@ -204,19 +225,19 @@ void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract)
 		Identifier const& baseName = baseSpecifier->name();
 		auto base = dynamic_cast<ContractDefinition const*>(baseName.annotation().referencedDeclaration);
 		if (!base)
-			BOOST_THROW_EXCEPTION(baseName.createTypeError("Contract expected."));
+			reportFatalTypeError(baseName.createTypeError("Contract expected."));
 		// "push_front" has the effect that bases mentioned later can overwrite members of bases
 		// mentioned earlier
 		input.back().push_front(base);
 		vector<ContractDefinition const*> const& basesBases = base->annotation().linearizedBaseContracts;
 		if (basesBases.empty())
-			BOOST_THROW_EXCEPTION(baseName.createTypeError("Definition of base has to precede definition of derived contract"));
+			reportFatalTypeError(baseName.createTypeError("Definition of base has to precede definition of derived contract"));
 		input.push_front(list<ContractDefinition const*>(basesBases.begin(), basesBases.end()));
 	}
 	input.back().push_front(&_contract);
 	vector<ContractDefinition const*> result = cThreeMerge(input);
 	if (result.empty())
-		BOOST_THROW_EXCEPTION(_contract.createTypeError("Linearization of inheritance graph impossible"));
+		reportFatalTypeError(_contract.createTypeError("Linearization of inheritance graph impossible"));
 	_contract.annotation().linearizedBaseContracts = result;
 	_contract.annotation().contractDependencies.insert(result.begin() + 1, result.end());
 }
@@ -272,9 +293,53 @@ vector<_T const*> NameAndTypeResolver::cThreeMerge(list<list<_T const*>>& _toMer
 	return result;
 }
 
-DeclarationRegistrationHelper::DeclarationRegistrationHelper(map<ASTNode const*, DeclarationContainer>& _scopes,
-															 ASTNode& _astRoot):
-	m_scopes(_scopes), m_currentScope(nullptr)
+void NameAndTypeResolver::reportDeclarationError(
+	SourceLocation _sourceLoction,
+	string const& _description,
+	SourceLocation _secondarySourceLocation = SourceLocation(),
+	string const& _secondaryDescription = ""
+)
+{
+	auto err = make_shared<Error>(Error::Type::DeclarationError); // todo remove Error?
+	*err <<
+			errinfo_sourceLocation(_sourceLoction) <<
+			errinfo_comment(_description) <<
+			errinfo_secondarySourceLocation(
+				SecondarySourceLocation().append(_secondaryDescription, _secondarySourceLocation)
+			);
+
+	m_errors.push_back(err);
+}
+
+void NameAndTypeResolver::reportFatalDeclarationError(
+	SourceLocation _sourceLoction,
+	string _description
+)
+{
+	reportDeclarationError(_sourceLoction, _description);
+	BOOST_THROW_EXCEPTION(fatalError());
+}
+
+void NameAndTypeResolver::reportTypeError(Error _e)
+{
+	m_errors.push_back(make_shared<Error>(_e));
+}
+
+void NameAndTypeResolver::reportFatalTypeError(Error _e)
+{
+	reportTypeError(_e);
+	BOOST_THROW_EXCEPTION(fatalError());
+}
+
+
+DeclarationRegistrationHelper::DeclarationRegistrationHelper(
+	map<ASTNode const*, DeclarationContainer>& _scopes,
+	ASTNode& _astRoot,
+	ErrorList& _errors
+):
+	m_scopes(_scopes),
+	m_currentScope(nullptr),
+	m_errors(_errors)
 {
 	_astRoot.accept(*this);
 }
@@ -409,13 +474,11 @@ void DeclarationRegistrationHelper::registerDeclaration(Declaration& _declaratio
 			secondDeclarationLocation = _declaration.location();
 		}
 
-		BOOST_THROW_EXCEPTION(
-			Error(Error::Type::DeclarationError) <<
-			errinfo_sourceLocation(secondDeclarationLocation) <<
-			errinfo_comment("Identifier already declared.") <<
-			errinfo_secondarySourceLocation(
-				SecondarySourceLocation().append("The previous declaration is here:", firstDeclarationLocation)
-			)
+		declarationError(
+			secondDeclarationLocation,
+			"Identifier already declared.",
+			firstDeclarationLocation,
+			"The previous declaration is here:"
 		);
 	}
 
@@ -440,5 +503,32 @@ string DeclarationRegistrationHelper::currentCanonicalName() const
 	return ret;
 }
 
+void DeclarationRegistrationHelper::declarationError(
+	SourceLocation _sourceLoction,
+	string const& _description,
+	SourceLocation _secondarySourceLocation = SourceLocation(),
+	string const& _secondaryDescription = ""
+)
+{
+	auto err = make_shared<Error>(Error::Type::DeclarationError);
+	*err <<
+			errinfo_sourceLocation(_sourceLoction) <<
+			errinfo_comment(_description) <<
+			errinfo_secondarySourceLocation(
+				SecondarySourceLocation().append(_secondaryDescription, _secondarySourceLocation)
+			);
+
+	m_errors.push_back(err);
+}
+
+void DeclarationRegistrationHelper::fatalDeclarationError(
+	SourceLocation _sourceLoction,
+	string const& _description
+)
+{
+	declarationError(_sourceLoction, _description);
+	BOOST_THROW_EXCEPTION(fatalError());
+}
+
 }
 }
diff --git a/libsolidity/NameAndTypeResolver.h b/libsolidity/NameAndTypeResolver.h
index d5afb29a..9587fcfe 100644
--- a/libsolidity/NameAndTypeResolver.h
+++ b/libsolidity/NameAndTypeResolver.h
@@ -44,12 +44,15 @@ class NameAndTypeResolver: private boost::noncopyable
 public:
 	NameAndTypeResolver(std::vector<Declaration const*> const& _globals, ErrorList& _errors);
 	/// Registers all declarations found in the source unit.
-	void registerDeclarations(SourceUnit& _sourceUnit);
+	/// @returns false in case of type error.
+	bool registerDeclarations(SourceUnit& _sourceUnit);
 	/// Resolves all names and types referenced from the given contract.
-	void resolveNamesAndTypes(ContractDefinition& _contract);
+	/// @returns false in case of type error.
+	bool resolveNamesAndTypes(ContractDefinition& _contract);
 	/// Updates the given global declaration (used for "this"). Not to be used with declarations
 	/// that create their own scope.
-	void updateDeclaration(Declaration const& _declaration);
+	/// @returns false in case of type error.
+	bool updateDeclaration(Declaration const& _declaration);
 
 	/// Resolves the given @a _name inside the scope @a _scope. If @a _scope is omitted,
 	/// the global scope is used (i.e. the one containing only the contract).
@@ -66,7 +69,7 @@ public:
 	Declaration const* pathFromCurrentScope(std::vector<ASTString> const& _path, bool _recursive = true) const;
 
 	/// returns the vector of declarations without repetitions
-	static std::vector<Declaration const*> cleanedDeclarations(
+	std::vector<Declaration const*> cleanedDeclarations(
 		Identifier const& _identifier,
 		std::vector<Declaration const*> const& _declarations
 	);
@@ -78,8 +81,8 @@ private:
 	/// into the current scope if they are not present already.
 	void importInheritedScope(ContractDefinition const& _base);
 
-	/// Computes "C3-Linearization" of base contracts and stores it inside the contract.
-	void linearizeBaseContracts(ContractDefinition& _contract) const;
+	/// Computes "C3-Linearization" of base contracts and stores it inside the contract. Reports errors if any
+	void linearizeBaseContracts(ContractDefinition& _contract);
 	/// Computes the C3-merge of the given list of lists of bases.
 	/// @returns the linearized vector or an empty vector if linearization is not possible.
 	template <class _T>
@@ -90,6 +93,21 @@ private:
 	/// not contain code.
 	std::map<ASTNode const*, DeclarationContainer> m_scopes;
 
+	// creates the Declaration error and adds it in the errors list
+	void reportDeclarationError(
+		SourceLocation _sourceLoction,
+		std::string const& _description,
+		SourceLocation _secondarySourceLocation,
+		std::string const& _secondaryDescription
+	);
+	// creates the Declaration error and adds it in the errors list and throws FatalError
+	void reportFatalDeclarationError(SourceLocation _sourceLoction, std::string _description);
+
+	// creates the Declaration error and adds it in the errors list
+	void reportTypeError(Error _e);
+	// creates the Declaration error and adds it in the errors list and throws FatalError
+	void reportFatalTypeError(Error _e);
+
 	DeclarationContainer* m_currentScope = nullptr;
 	ErrorList& m_errors;
 };
@@ -101,7 +119,7 @@ private:
 class DeclarationRegistrationHelper: private ASTVisitor
 {
 public:
-	DeclarationRegistrationHelper(std::map<ASTNode const*, DeclarationContainer>& _scopes, ASTNode& _astRoot);
+	DeclarationRegistrationHelper(std::map<ASTNode const*, DeclarationContainer>& _scopes, ASTNode& _astRoot, ErrorList& _errors);
 
 private:
 	bool visit(ContractDefinition& _contract) override;
@@ -126,10 +144,20 @@ private:
 
 	/// @returns the canonical name of the current scope.
 	std::string currentCanonicalName() const;
+	// creates the Declaration error and adds it in the errors list
+	void declarationError(
+		SourceLocation _sourceLoction,
+		std::string const& _description,
+		SourceLocation _secondarySourceLocation,
+		std::string const& _secondaryDescription
+	);
+	// creates the Declaration error and adds it in the errors list and throws FatalError
+	void fatalDeclarationError(SourceLocation _sourceLoction, std::string const& _description);
 
 	std::map<ASTNode const*, DeclarationContainer>& m_scopes;
 	Declaration const* m_currentScope;
 	VariableScope* m_currentFunction;
+	ErrorList& m_errors;
 };
 
 }
diff --git a/libsolidity/Parser.cpp b/libsolidity/Parser.cpp
index ce13098e..491af369 100644
--- a/libsolidity/Parser.cpp
+++ b/libsolidity/Parser.cpp
@@ -66,25 +66,35 @@ private:
 
 ASTPointer<SourceUnit> Parser::parse(shared_ptr<Scanner> const& _scanner)
 {
-	m_scanner = _scanner;
-	ASTNodeFactory nodeFactory(*this);
-	vector<ASTPointer<ASTNode>> nodes;
-	while (m_scanner->currentToken() != Token::EOS)
-	{
-		switch (auto token = m_scanner->currentToken())
+	try{
+		m_scanner = _scanner;
+		ASTNodeFactory nodeFactory(*this);
+		vector<ASTPointer<ASTNode>> nodes;
+		while (m_scanner->currentToken() != Token::EOS)
 		{
-		case Token::Import:
-			nodes.push_back(parseImportDirective());
-			break;
-		case Token::Contract:
-		case Token::Library:
-			nodes.push_back(parseContractDefinition(token == Token::Library));
-			break;
-		default:
-			BOOST_THROW_EXCEPTION(createParserError(std::string("Expected import directive or contract definition.")));
+			switch (auto token = m_scanner->currentToken())
+			{
+			case Token::Import:
+				nodes.push_back(parseImportDirective());
+				break;
+			case Token::Contract:
+			case Token::Library:
+				nodes.push_back(parseContractDefinition(token == Token::Library));
+				break;
+			default:
+				fatalParserError(std::string("Expected import directive or contract definition."));
+			}
 		}
+		return nodeFactory.createNode<SourceUnit>(nodes);
+	}
+	catch(fatalError const& _error)
+	{
+		return nullptr;
+	}
+	catch(Exception const& _e)
+	{
+		return nullptr;
 	}
-	return nodeFactory.createNode<SourceUnit>(nodes);
 }
 
 std::shared_ptr<const string> const& Parser::sourceName() const
@@ -107,7 +117,7 @@ ASTPointer<ImportDirective> Parser::parseImportDirective()
 	ASTNodeFactory nodeFactory(*this);
 	expectToken(Token::Import);
 	if (m_scanner->currentToken() != Token::StringLiteral)
-		BOOST_THROW_EXCEPTION(createParserError("Expected string literal (URL)."));
+		fatalParserError(std::string("Expected string literal (URL)."));
 	ASTPointer<ASTString> url = getLiteralAndAdvance();
 	nodeFactory.markEndPosition();
 	expectToken(Token::Semicolon);
@@ -165,7 +175,7 @@ ASTPointer<ContractDefinition> Parser::parseContractDefinition(bool _isLibrary)
 		else if (currentTokenValue == Token::Event)
 			events.push_back(parseEventDefinition());
 		else
-			BOOST_THROW_EXCEPTION(createParserError("Function, variable, struct or modifier declaration expected."));
+			fatalParserError(std::string("Function, variable, struct or modifier declaration expected."));
 	}
 	nodeFactory.markEndPosition();
 	expectToken(Token::RBrace);
@@ -249,7 +259,7 @@ ASTPointer<FunctionDefinition> Parser::parseFunctionDefinition(ASTString const*
 		else if (Token::isVisibilitySpecifier(token))
 		{
 			if (visibility != Declaration::Visibility::Default)
-				BOOST_THROW_EXCEPTION(createParserError("Multiple visibility specifiers."));
+				fatalParserError(std::string("Multiple visibility specifiers."));
 			visibility = parseVisibilitySpecifier(token);
 		}
 		else
@@ -326,7 +336,7 @@ ASTPointer<EnumDefinition> Parser::parseEnumDefinition()
 			break;
 		expectToken(Token::Comma);
 		if (m_scanner->currentToken() != Token::Identifier)
-			BOOST_THROW_EXCEPTION(createParserError("Expected Identifier after ','"));
+			fatalParserError(std::string("Expected Identifier after ','"));
 	}
 
 	nodeFactory.markEndPosition();
@@ -362,7 +372,7 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 		if (_options.isStateVariable && Token::isVariableVisibilitySpecifier(token))
 		{
 			if (visibility != Declaration::Visibility::Default)
-				BOOST_THROW_EXCEPTION(createParserError("Visibility already specified."));
+				fatalParserError(std::string("Visibility already specified."));
 			visibility = parseVisibilitySpecifier(token);
 		}
 		else
@@ -374,9 +384,9 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 			else if (_options.allowLocationSpecifier && Token::isLocationSpecifier(token))
 			{
 				if (location != VariableDeclaration::Location::Default)
-					BOOST_THROW_EXCEPTION(createParserError("Location already specified."));
+					fatalParserError(std::string("Location already specified."));
 				if (!type)
-					BOOST_THROW_EXCEPTION(createParserError("Location specifier needs explicit type name."));
+					fatalParserError(std::string("Location specifier needs explicit type name."));
 				location = (
 					token == Token::Memory ?
 					VariableDeclaration::Location::Memory :
@@ -513,7 +523,7 @@ ASTPointer<TypeName> Parser::parseTypeName(bool _allowVar)
 	else if (token == Token::Var)
 	{
 		if (!_allowVar)
-			BOOST_THROW_EXCEPTION(createParserError("Expected explicit type name."));
+			fatalParserError(std::string("Expected explicit type name."));
 		m_scanner->next();
 	}
 	else if (token == Token::Mapping)
@@ -532,7 +542,7 @@ ASTPointer<TypeName> Parser::parseTypeName(bool _allowVar)
 		type = nodeFactory.createNode<UserDefinedTypeName>(identifierPath);
 	}
 	else
-		BOOST_THROW_EXCEPTION(createParserError("Expected type name"));
+		fatalParserError(std::string("Expected type name"));
 
 	if (type)
 		// Parse "[...]" postfixes for arrays.
@@ -555,7 +565,7 @@ ASTPointer<Mapping> Parser::parseMapping()
 	expectToken(Token::Mapping);
 	expectToken(Token::LParen);
 	if (!Token::isElementaryTypeName(m_scanner->currentToken()))
-		BOOST_THROW_EXCEPTION(createParserError("Expected elementary type name for mapping key type"));
+		fatalParserError(std::string("Expected elementary type name for mapping key type"));
 	ASTPointer<ElementaryTypeName> keyType;
 	keyType = ASTNodeFactory(*this).createNode<ElementaryTypeName>(m_scanner->currentToken());
 	m_scanner->next();
@@ -1011,7 +1021,7 @@ ASTPointer<Expression> Parser::parsePrimaryExpression()
 			m_scanner->next();
 		}
 		else
-			BOOST_THROW_EXCEPTION(createParserError("Expected primary expression."));
+			fatalParserError(std::string("Expected primary expression."));
 		break;
 	}
 	return expression;
@@ -1122,7 +1132,7 @@ ASTPointer<Expression> Parser::expressionFromIndexAccessStructure(
 void Parser::expectToken(Token::Value _value)
 {
 	if (m_scanner->currentToken() != _value)
-		BOOST_THROW_EXCEPTION(createParserError(string("Expected token ") + string(Token::name(_value))));
+		fatalParserError(std::string(string("Expected token ") + string(Token::name(_value))));
 	m_scanner->next();
 }
 
@@ -1130,7 +1140,7 @@ Token::Value Parser::expectAssignmentOperator()
 {
 	Token::Value op = m_scanner->currentToken();
 	if (!Token::isAssignmentOp(op))
-		BOOST_THROW_EXCEPTION(createParserError("Expected assignment operator"));
+		fatalParserError(std::string("Expected assignment operator"));
 	m_scanner->next();
 	return op;
 }
@@ -1138,7 +1148,7 @@ Token::Value Parser::expectAssignmentOperator()
 ASTPointer<ASTString> Parser::expectIdentifierToken()
 {
 	if (m_scanner->currentToken() != Token::Identifier)
-		BOOST_THROW_EXCEPTION(createParserError("Expected identifier"));
+		fatalParserError(std::string("Expected identifier"));
 	return getLiteralAndAdvance();
 }
 
@@ -1156,13 +1166,21 @@ ASTPointer<ParameterList> Parser::createEmptyParameterList()
 	return nodeFactory.createNode<ParameterList>(vector<ASTPointer<VariableDeclaration>>());
 }
 
-Error Parser::createParserError(string const& _description) const
+void Parser::parserError(string const& _description)
 {
-	return Error(Error::Type::ParserError) <<
-		errinfo_sourceLocation(SourceLocation(position(), position(), sourceName())) <<
-		errinfo_comment(_description);
+	auto err = make_shared<Error>(Error::Type::ParserError);
+	*err <<
+			errinfo_sourceLocation(SourceLocation(position(), position(), sourceName())) <<
+			errinfo_comment(_description);
+
+	m_errors.push_back(err);
 }
 
+void Parser::fatalParserError(string const& _description)
+{
+	parserError(_description);
+	BOOST_THROW_EXCEPTION(fatalError());
+}
 
 }
 }
diff --git a/libsolidity/Parser.h b/libsolidity/Parser.h
index c9acb47d..3fc3768e 100644
--- a/libsolidity/Parser.h
+++ b/libsolidity/Parser.h
@@ -34,7 +34,8 @@ class Scanner;
 class Parser
 {
 public:
-	Parser() {}
+	Parser(ErrorList& errors):
+		m_errors(errors){};
 
 	ASTPointer<SourceUnit> parse(std::shared_ptr<Scanner> const& _scanner);
 	std::shared_ptr<std::string const> const& sourceName() const;
@@ -145,13 +146,19 @@ private:
 	/// Creates an empty ParameterList at the current location (used if parameters can be omitted).
 	ASTPointer<ParameterList> createEmptyParameterList();
 
-	/// Creates a @ref ParserError exception and annotates it with the current position and the
+	/// Creates a @ref ParserError and annotates it with the current position and the
 	/// given @a _description.
-	Error createParserError(std::string const& _description) const;
+	void parserError(std::string const& _description);
+
+	/// Creates a @ref ParserError and annotates it with the current position and the
+	/// given @a _description. Throws the FatalError.
+	void fatalParserError(std::string const& _description);
 
 	std::shared_ptr<Scanner> m_scanner;
 	/// Flag that signifies whether '_' is parsed as a PlaceholderStatement or a regular identifier.
 	bool m_insideModifier = false;
+	/// The reference to the list of errors and warning to add errors/warnings during parsing
+	ErrorList& m_errors;
 };
 
 }
diff --git a/libsolidity/TypeChecker.cpp b/libsolidity/TypeChecker.cpp
index e3264429..cc7ad2f3 100644
--- a/libsolidity/TypeChecker.cpp
+++ b/libsolidity/TypeChecker.cpp
@@ -36,24 +36,26 @@ bool TypeChecker::checkTypeRequirements(const ContractDefinition& _contract)
 	{
 		visit(_contract);
 	}
-	catch (FatalError const&)
+	catch (fatalError const&)
 	{
 		// We got a fatal error which required to stop further type checking, but we can
 		// continue normally from here.
 		if (m_errors.empty())
 			throw; // Something is weird here, rather throw again.
 	}
-	bool success = true;
-	for (auto const& it: m_errors)
-	{
-		Error const& e = dynamic_cast<Error const&>(it.get());
-		if (e.type() != Error::Type::Warning)
-		{
-			success = false;
-			break;
-		}
-	}
-	return success;
+
+return	Error::containsOnlyWarnings(m_errors);
+//	bool success = true;
+//	for (auto const& it: m_errors)
+//	{
+//		auto e = dynamic_cast<Error const*>(it.get());
+//		if (e->type() != Error::Type::Warning)
+//		{
+//			success = false;
+//			break;
+//		}
+//	}
+//	return success;
 }
 
 TypePointer const& TypeChecker::type(Expression const& _expression) const
@@ -1255,7 +1257,7 @@ void TypeChecker::requireLValue(Expression const& _expression)
 
 void TypeChecker::typeError(ASTNode const& _node, string const& _description)
 {
-	auto err = make_shared<Error>(Error(Error::Type::TypeError));;
+	auto err = make_shared<Error>(Error::Type::TypeError);
 	*err <<
 		errinfo_sourceLocation(_node.location()) <<
 		errinfo_comment(_description);
@@ -1266,5 +1268,5 @@ void TypeChecker::typeError(ASTNode const& _node, string const& _description)
 void TypeChecker::fatalTypeError(ASTNode const& _node, string const& _description)
 {
 	typeError(_node, _description);
-	BOOST_THROW_EXCEPTION(FatalError());
+	BOOST_THROW_EXCEPTION(fatalError());
 }
diff --git a/libsolidity/TypeChecker.h b/libsolidity/TypeChecker.h
index c654c698..de095e3b 100644
--- a/libsolidity/TypeChecker.h
+++ b/libsolidity/TypeChecker.h
@@ -42,26 +42,26 @@ namespace solidity
 class TypeChecker: private ASTConstVisitor
 {
 public:
+	/// @_errors the reference to the list of errors and warnings to add them found during type checking.
+	TypeChecker(ErrorList& _errors): m_errors(_errors) {}
+
 	/// Performs type checking on the given contract and all of its sub-nodes.
 	/// @returns true iff all checks passed. Note even if all checks passed, errors() can still contain warnings
 	bool checkTypeRequirements(ContractDefinition const& _contract);
 
-	/// @returns the list of errors and warnings found during type checking.
-	ErrorList const& errors() const { return m_errors; }
-
 	/// @returns the type of an expression and asserts that it is present.
 	TypePointer const& type(Expression const& _expression) const;
 	/// @returns the type of the given variable and throws if the type is not present
 	/// (this can happen for variables with non-explicit types before their types are resolved)
 	TypePointer const& type(VariableDeclaration const& _variable) const;
 
+private:
 	/// Adds a new error to the list of errors.
 	void typeError(ASTNode const& _node, std::string const& _description);
 
 	/// Adds a new error to the list of errors and throws to abort type checking.
 	void fatalTypeError(ASTNode const& _node, std::string const& _description);
 
-private:
 	virtual bool visit(ContractDefinition const& _contract) override;
 	/// Checks that two functions defined in this contract with the same name have different
 	/// arguments and that there is at most one constructor.
@@ -114,7 +114,7 @@ private:
 	/// Runs type checks on @a _expression to infer its type and then checks that it is an LValue.
 	void requireLValue(Expression const& _expression);
 
-	ErrorList m_errors;
+	ErrorList& m_errors;
 };
 
 }