Merge remote-tracking branch 'ethereum/develop' into sol_overloadingFunctions

23 files changed, 1312 insertions, 654 deletions

diff --git a/AST.cpp b/AST.cpp
index 09c03ef6..ada4a01d 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -21,6 +21,7 @@
  */
 
 #include <algorithm>
+#include <boost/range/adaptor/reversed.hpp>
 #include <libsolidity/Utils.h>
 #include <libsolidity/AST.h>
 #include <libsolidity/ASTVisitor.h>
@@ -52,6 +53,7 @@ void ContractDefinition::checkTypeRequirements()
 		baseSpecifier->checkTypeRequirements();
 
 	checkIllegalOverrides();
+	checkAbstractFunctions();
 
 	FunctionDefinition const* constructor = getConstructor();
 	if (constructor && !constructor->getReturnParameters().empty())
@@ -60,6 +62,7 @@ void ContractDefinition::checkTypeRequirements()
 
 	FunctionDefinition const* fallbackFunction = nullptr;
 	for (ASTPointer<FunctionDefinition> const& function: getDefinedFunctions())
+	{
 		if (function->getName().empty())
 		{
 			if (fallbackFunction)
@@ -71,6 +74,9 @@ void ContractDefinition::checkTypeRequirements()
 					BOOST_THROW_EXCEPTION(fallbackFunction->getParameterList().createTypeError("Fallback function cannot take parameters."));
 			}
 		}
+		if (!function->isFullyImplemented())
+			setFullyImplemented(false);
+	}
 	for (ASTPointer<ModifierDefinition> const& modifier: getFunctionModifiers())
 		modifier->checkTypeRequirements();
 
@@ -98,7 +104,7 @@ void ContractDefinition::checkTypeRequirements()
 		if (hashes.count(hash))
 			BOOST_THROW_EXCEPTION(createTypeError(
 									  std::string("Function signature hash collision for ") +
-									  it.second->getCanonicalSignature()));
+									  it.second->externalSignature()));
 		hashes.insert(hash);
 	}
 }
@@ -134,6 +140,28 @@ FunctionDefinition const* ContractDefinition::getFallbackFunction() const
 	return nullptr;
 }
 
+void ContractDefinition::checkAbstractFunctions()
+{
+	map<string, bool> functions;
+
+	// Search from base to derived
+	for (ContractDefinition const* contract: boost::adaptors::reverse(getLinearizedBaseContracts()))
+		for (ASTPointer<FunctionDefinition> const& function: contract->getDefinedFunctions())
+		{
+			string const& name = function->getName();
+			if (!function->isFullyImplemented() && functions.count(name) && functions[name])
+				BOOST_THROW_EXCEPTION(function->createTypeError("Redeclaring an already implemented function as abstract"));
+			functions[name] = function->isFullyImplemented();
+		}
+
+	for (auto const& it: functions)
+		if (!it.second)
+		{
+			setFullyImplemented(false);
+			break;
+		}
+}
+
 void ContractDefinition::checkIllegalOverrides() const
 {
 	// TODO unify this at a later point. for this we need to put the constness and the access specifier
@@ -203,8 +231,8 @@ vector<pair<FixedHash<4>, FunctionTypePointer>> const& ContractDefinition::getIn
 		{
 			for (ASTPointer<FunctionDefinition> const& f: contract->getDefinedFunctions())
 			{
-				string functionSignature = f->getCanonicalSignature();
-				if (f->isPublic() && !f->isConstructor() && !f->getName().empty() && signaturesSeen.count(functionSignature) == 0)
+				string functionSignature = f->externalSignature();
+				if (f->isPartOfExternalInterface() && signaturesSeen.count(functionSignature) == 0)
 				{
 					functionsSeen.insert(f->getName());
 					signaturesSeen.insert(functionSignature);
@@ -214,11 +242,12 @@ vector<pair<FixedHash<4>, FunctionTypePointer>> const& ContractDefinition::getIn
 			}
 
 			for (ASTPointer<VariableDeclaration> const& v: contract->getStateVariables())
-				if (v->isPublic() && functionsSeen.count(v->getName()) == 0)
+				if (functionsSeen.count(v->getName()) == 0 && v->isPartOfExternalInterface())
 				{
 					FunctionType ftype(*v);
+					solAssert(v->getType().get(), "");
 					functionsSeen.insert(v->getName());
-					FixedHash<4> hash(dev::sha3(ftype.getCanonicalSignature(v->getName())));
+					FixedHash<4> hash(dev::sha3(ftype.externalSignature(v->getName())));
 					m_interfaceFunctionList->push_back(make_pair(hash, make_shared<FunctionType>(*v)));
 				}
 		}
@@ -322,25 +351,35 @@ TypePointer FunctionDefinition::getType(ContractDefinition const*) const
 void FunctionDefinition::checkTypeRequirements()
 {
 	for (ASTPointer<VariableDeclaration> const& var: getParameters() + getReturnParameters())
+	{
 		if (!var->getType()->canLiveOutsideStorage())
 			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
+		if (getVisibility() >= Visibility::Public && !(var->getType()->externalType()))
+		{
+			// todo delete when will be implemented arrays as parameter type in internal functions
+			if (getVisibility() == Visibility::Public && var->getType()->getCategory() == Type::Category::Array)
+				BOOST_THROW_EXCEPTION(var->createTypeError("Arrays only implemented for external functions."));
+			else
+				BOOST_THROW_EXCEPTION(var->createTypeError("Internal type is not allowed for public and external functions."));
+		}
+	}
 	for (ASTPointer<ModifierInvocation> const& modifier: m_functionModifiers)
 		modifier->checkTypeRequirements(isConstructor() ?
 			dynamic_cast<ContractDefinition const&>(*getScope()).getBaseContracts() :
 			vector<ASTPointer<InheritanceSpecifier>>());
-
-	m_body->checkTypeRequirements();
+	if (m_body)
+		m_body->checkTypeRequirements();
 }
 
-string FunctionDefinition::getCanonicalSignature() const
+string FunctionDefinition::externalSignature() const
 {
-	return FunctionType(*this).getCanonicalSignature(getName());
+	return FunctionType(*this).externalSignature(getName());
 }
 
 bool VariableDeclaration::isLValue() const
 {
-	// External function parameters are Read-Only
-	return !isExternalFunctionParameter();
+	// External function parameters and constant declared variables are Read-Only
+	return !isExternalFunctionParameter() && !m_isConstant;
 }
 
 void VariableDeclaration::checkTypeRequirements()
@@ -349,10 +388,24 @@ void VariableDeclaration::checkTypeRequirements()
 	// sets the type.
 	// Note that assignments before the first declaration are legal because of the special scoping
 	// rules inherited from JavaScript.
+	if (m_isConstant)
+	{
+		if (!dynamic_cast<ContractDefinition const*>(getScope()))
+			BOOST_THROW_EXCEPTION(createTypeError("Illegal use of \"constant\" specifier."));
+		if ((m_type && !m_type->isValueType()) || !m_value)
+			BOOST_THROW_EXCEPTION(createTypeError("Unitialized \"constant\" variable."));
+	}
 	if (!m_value)
 		return;
 	if (m_type)
+	{
 		m_value->expectType(*m_type);
+		if (m_isStateVariable && !m_type->externalType() && getVisibility() >= Visibility::Public)
+			BOOST_THROW_EXCEPTION(createTypeError("Internal type is not allowed for state variables."));
+
+		if (!FunctionType(*this).externalType())
+			BOOST_THROW_EXCEPTION(createTypeError("Internal type is not allowed for public state variables."));
+	}
 	else
 	{
 		// no type declared and no previous assignment, infer the type
@@ -437,6 +490,8 @@ void EventDefinition::checkTypeRequirements()
 			numIndexed++;
 		if (!var->getType()->canLiveOutsideStorage())
 			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
+		if (!var->getType()->externalType())
+			BOOST_THROW_EXCEPTION(var->createTypeError("Internal type is not allowed as event parameter type."));
 	}
 	if (numIndexed > 3)
 		BOOST_THROW_EXCEPTION(createTypeError("More than 3 indexed arguments for event."));
@@ -681,6 +736,8 @@ void NewExpression::checkTypeRequirements()
 	m_contract = dynamic_cast<ContractDefinition const*>(m_contractName->getReferencedDeclaration());
 	if (!m_contract)
 		BOOST_THROW_EXCEPTION(createTypeError("Identifier is not a contract."));
+	if (!m_contract->isFullyImplemented())
+		BOOST_THROW_EXCEPTION(m_contract->createTypeError("Trying to create an instance of an abstract contract."));
 	shared_ptr<ContractType const> contractType = make_shared<ContractType>(*m_contract);
 	TypePointers const& parameterTypes = contractType->getConstructorType()->getParameterTypes();
 	m_type = make_shared<FunctionType>(parameterTypes, TypePointers{contractType},
@@ -720,7 +777,7 @@ void IndexAccess::checkTypeRequirements()
 			BOOST_THROW_EXCEPTION(createTypeError("Index expression cannot be omitted."));
 		m_index->expectType(IntegerType(256));
 		if (type.isByteArray())
-			m_type = make_shared<IntegerType>(8, IntegerType::Modifier::Hash);
+			m_type = make_shared<FixedBytesType>(1);
 		else
 			m_type = type.getBaseType();
 		m_isLValue = type.getLocation() != ArrayType::Location::CallData;
diff --git a/AST.h b/AST.h
index 6cc7f742..fd50eb95 100644
--- a/AST.h
+++ b/AST.h
@@ -156,6 +156,7 @@ public:
 	/// contract types.
 	virtual TypePointer getType(ContractDefinition const* m_currentContract = nullptr) const = 0;
 	virtual bool isLValue() const { return false; }
+	virtual bool isPartOfExternalInterface() const { return false; };
 
 protected:
 	virtual Visibility getDefaultVisibility() const { return Visibility::Public; }
@@ -195,6 +196,22 @@ protected:
 	ASTPointer<ASTString> m_documentation;
 };
 
+/**
+ * Abstract class that is added to AST nodes that can be marked as not being fully implemented
+ */
+class ImplementationOptional
+{
+public:
+	explicit ImplementationOptional(bool _implemented): m_implemented(_implemented) {}
+
+	/// @return whether this node is fully implemented or not
+	bool isFullyImplemented() const { return m_implemented; }
+	void setFullyImplemented(bool _implemented) {  m_implemented = _implemented; }
+
+protected:
+	bool m_implemented;
+};
+
 /// @}
 
 /**
@@ -202,20 +219,24 @@ protected:
  * document order. It first visits all struct declarations, then all variable declarations and
  * finally all function declarations.
  */
-class ContractDefinition: public Declaration, public Documented
+class ContractDefinition: public Declaration, public Documented, public ImplementationOptional
 {
 public:
-	ContractDefinition(SourceLocation const& _location,
-					   ASTPointer<ASTString> const& _name,
-					   ASTPointer<ASTString> const& _documentation,
-					   std::vector<ASTPointer<InheritanceSpecifier>> const& _baseContracts,
-					   std::vector<ASTPointer<StructDefinition>> const& _definedStructs,
-					   std::vector<ASTPointer<EnumDefinition>> const& _definedEnums,
-					   std::vector<ASTPointer<VariableDeclaration>> const& _stateVariables,
-					   std::vector<ASTPointer<FunctionDefinition>> const& _definedFunctions,
-					   std::vector<ASTPointer<ModifierDefinition>> const& _functionModifiers,
-					   std::vector<ASTPointer<EventDefinition>> const& _events):
-		Declaration(_location, _name), Documented(_documentation),
+	ContractDefinition(
+		SourceLocation const& _location,
+		ASTPointer<ASTString> const& _name,
+		ASTPointer<ASTString> const& _documentation,
+		std::vector<ASTPointer<InheritanceSpecifier>> const& _baseContracts,
+		std::vector<ASTPointer<StructDefinition>> const& _definedStructs,
+		std::vector<ASTPointer<EnumDefinition>> const& _definedEnums,
+		std::vector<ASTPointer<VariableDeclaration>> const& _stateVariables,
+		std::vector<ASTPointer<FunctionDefinition>> const& _definedFunctions,
+		std::vector<ASTPointer<ModifierDefinition>> const& _functionModifiers,
+		std::vector<ASTPointer<EventDefinition>> const& _events
+	):
+		Declaration(_location, _name),
+		Documented(_documentation),
+		ImplementationOptional(true),
 		m_baseContracts(_baseContracts),
 		m_definedStructs(_definedStructs),
 		m_definedEnums(_definedEnums),
@@ -262,6 +283,7 @@ public:
 
 private:
 	void checkIllegalOverrides() const;
+	void checkAbstractFunctions();
 
 	std::vector<std::pair<FixedHash<4>, FunctionTypePointer>> const& getInterfaceFunctionList() const;
 
@@ -377,24 +399,29 @@ private:
 	std::vector<ASTPointer<VariableDeclaration>> m_parameters;
 };
 
-class FunctionDefinition: public Declaration, public VariableScope, public Documented
+class FunctionDefinition: public Declaration, public VariableScope, public Documented, public ImplementationOptional
 {
 public:
-	FunctionDefinition(SourceLocation const& _location, ASTPointer<ASTString> const& _name,
-					Declaration::Visibility _visibility, bool _isConstructor,
-					ASTPointer<ASTString> const& _documentation,
-					ASTPointer<ParameterList> const& _parameters,
-					bool _isDeclaredConst,
-					std::vector<ASTPointer<ModifierInvocation>> const& _modifiers,
-					ASTPointer<ParameterList> const& _returnParameters,
-					ASTPointer<Block> const& _body):
-	Declaration(_location, _name, _visibility), Documented(_documentation),
-	m_isConstructor(_isConstructor),
-	m_parameters(_parameters),
-	m_isDeclaredConst(_isDeclaredConst),
-	m_functionModifiers(_modifiers),
-	m_returnParameters(_returnParameters),
-	m_body(_body)
+	FunctionDefinition(
+		SourceLocation const& _location,
+		ASTPointer<ASTString> const& _name,
+		Declaration::Visibility _visibility, bool _isConstructor,
+		ASTPointer<ASTString> const& _documentation,
+		ASTPointer<ParameterList> const& _parameters,
+		bool _isDeclaredConst,
+		std::vector<ASTPointer<ModifierInvocation>> const& _modifiers,
+		ASTPointer<ParameterList> const& _returnParameters,
+		ASTPointer<Block> const& _body
+	):
+		Declaration(_location, _name, _visibility),
+		Documented(_documentation),
+		ImplementationOptional(_body != nullptr),
+		m_isConstructor(_isConstructor),
+		m_parameters(_parameters),
+		m_isDeclaredConst(_isDeclaredConst),
+		m_functionModifiers(_modifiers),
+		m_returnParameters(_returnParameters),
+		m_body(_body)
 	{}
 
 	virtual void accept(ASTVisitor& _visitor) override;
@@ -415,14 +442,15 @@ public:
 			getVisibility() >= Visibility::Internal;
 	}
 	virtual TypePointer getType(ContractDefinition const*) const override;
+	virtual bool isPartOfExternalInterface() const override { return isPublic() && !m_isConstructor && !getName().empty(); }
 
 	/// Checks that all parameters have allowed types and calls checkTypeRequirements on the body.
 	void checkTypeRequirements();
 
-	/// @returns the canonical signature of the function
+	/// @returns the external signature of the function
 	/// That consists of the name of the function followed by the types of the
 	/// arguments separated by commas all enclosed in parentheses without any spaces.
-	std::string getCanonicalSignature() const;
+	std::string externalSignature() const;
 
 private:
 	bool m_isConstructor;
@@ -440,13 +468,23 @@ private:
 class VariableDeclaration: public Declaration
 {
 public:
-	VariableDeclaration(SourceLocation const& _location, ASTPointer<TypeName> const& _type,
-							ASTPointer<ASTString> const& _name, ASTPointer<Expression> _value,
-							Visibility _visibility,
-							bool _isStateVar = false, bool _isIndexed = false):
-			Declaration(_location, _name, _visibility),
-			m_typeName(_type), m_value(_value),
-			m_isStateVariable(_isStateVar), m_isIndexed(_isIndexed) {}
+	VariableDeclaration(
+		SourceLocation const& _location,
+		ASTPointer<TypeName> const& _type,
+		ASTPointer<ASTString> const& _name,
+		ASTPointer<Expression> _value,
+		Visibility _visibility,
+		bool _isStateVar = false,
+		bool _isIndexed = false,
+		bool _isConstant = false
+	):
+		Declaration(_location, _name, _visibility),
+		m_typeName(_type),
+		m_value(_value),
+		m_isStateVariable(_isStateVar),
+		m_isIndexed(_isIndexed),
+		m_isConstant(_isConstant){}
+
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 
@@ -459,21 +497,24 @@ public:
 	void setType(std::shared_ptr<Type const> const& _type) { m_type = _type; }
 
 	virtual bool isLValue() const override;
+	virtual bool isPartOfExternalInterface() const override { return isPublic() && !m_isConstant; }
 
 	void checkTypeRequirements();
 	bool isLocalVariable() const { return !!dynamic_cast<FunctionDefinition const*>(getScope()); }
 	bool isExternalFunctionParameter() const;
 	bool isStateVariable() const { return m_isStateVariable; }
 	bool isIndexed() const { return m_isIndexed; }
+	bool isConstant() const { return m_isConstant; }
 
 protected:
 	Visibility getDefaultVisibility() const override { return Visibility::Internal; }
 
 private:
 	ASTPointer<TypeName> m_typeName;    ///< can be empty ("var")
-	ASTPointer<Expression> m_value;		///< the assigned value, can be missing
+	ASTPointer<Expression> m_value;     ///< the assigned value, can be missing
 	bool m_isStateVariable;             ///< Whether or not this is a contract state variable
 	bool m_isIndexed;                   ///< Whether this is an indexed variable (used by events).
+	bool m_isConstant;                  ///< Whether the variable is a compile-time constant.
 
 	std::shared_ptr<Type const> m_type; ///< derived type, initially empty
 };
@@ -538,17 +579,24 @@ private:
 class EventDefinition: public Declaration, public VariableScope, public Documented
 {
 public:
-	EventDefinition(SourceLocation const& _location,
-					ASTPointer<ASTString> const& _name,
-					ASTPointer<ASTString> const& _documentation,
-					ASTPointer<ParameterList> const& _parameters):
-		Declaration(_location, _name), Documented(_documentation), m_parameters(_parameters) {}
+	EventDefinition(
+		SourceLocation const& _location,
+		ASTPointer<ASTString> const& _name,
+		ASTPointer<ASTString> const& _documentation,
+		ASTPointer<ParameterList> const& _parameters,
+		bool _anonymous = false
+	):
+		Declaration(_location, _name),
+		Documented(_documentation),
+		m_parameters(_parameters),
+		m_anonymous(_anonymous){}
 
 	virtual void accept(ASTVisitor& _visitor) override;
 	virtual void accept(ASTConstVisitor& _visitor) const override;
 
 	std::vector<ASTPointer<VariableDeclaration>> const& getParameters() const { return m_parameters->getParameters(); }
 	ParameterList const& getParameterList() const { return *m_parameters; }
+	bool isAnonymous() const { return m_anonymous; }
 
 	virtual TypePointer getType(ContractDefinition const* = nullptr) const override
 	{
@@ -559,6 +607,7 @@ public:
 
 private:
 	ASTPointer<ParameterList> m_parameters;
+	bool m_anonymous = false;
 };
 
 /**
diff --git a/AST_accept.h b/AST_accept.h
index 81ede8fc..3557f877 100644
--- a/AST_accept.h
+++ b/AST_accept.h
@@ -175,7 +175,8 @@ void FunctionDefinition::accept(ASTVisitor& _visitor)
 		if (m_returnParameters)
 			m_returnParameters->accept(_visitor);
 		listAccept(m_functionModifiers, _visitor);
-		m_body->accept(_visitor);
+		if (m_body)
+			m_body->accept(_visitor);
 	}
 	_visitor.endVisit(*this);
 }
@@ -188,7 +189,8 @@ void FunctionDefinition::accept(ASTConstVisitor& _visitor) const
 		if (m_returnParameters)
 			m_returnParameters->accept(_visitor);
 		listAccept(m_functionModifiers, _visitor);
-		m_body->accept(_visitor);
+		if (m_body)
+			m_body->accept(_visitor);
 	}
 	_visitor.endVisit(*this);
 }
diff --git a/ArrayUtils.cpp b/ArrayUtils.cpp
index f0d7d6a8..58031390 100644
--- a/ArrayUtils.cpp
+++ b/ArrayUtils.cpp
@@ -34,8 +34,10 @@ using namespace solidity;
 
 void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const
 {
-	// stack layout: [source_ref] target_ref (top)
-	// need to leave target_ref on the stack at the end
+	// this copies source to target and also clears target if it was larger
+	// need to leave "target_ref target_byte_off" on the stack at the end
+
+	// stack layout: [source_ref] [source_byte_off] [source length] target_ref target_byte_off (top)
 	solAssert(_targetType.getLocation() == ArrayType::Location::Storage, "");
 	solAssert(
 		_sourceType.getLocation() == ArrayType::Location::CallData ||
@@ -47,14 +49,26 @@ void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType cons
 	Type const* targetBaseType = _targetType.isByteArray() ? &uint256 : &(*_targetType.getBaseType());
 	Type const* sourceBaseType = _sourceType.isByteArray() ? &uint256 : &(*_sourceType.getBaseType());
 
-	// this copies source to target and also clears target if it was larger
-
 	// TODO unroll loop for small sizes
 
-	// stack: source_ref [source_length] target_ref
+	bool sourceIsStorage = _sourceType.getLocation() == ArrayType::Location::Storage;
+	bool directCopy = sourceIsStorage && sourceBaseType->isValueType() && *sourceBaseType == *targetBaseType;
+	bool haveByteOffsetSource = !directCopy && sourceIsStorage && sourceBaseType->getStorageBytes() <= 16;
+	bool haveByteOffsetTarget = !directCopy && targetBaseType->getStorageBytes() <= 16;
+	unsigned byteOffsetSize = (haveByteOffsetSource ? 1 : 0) + (haveByteOffsetTarget ? 1 : 0);
+
+	// stack: source_ref [source_byte_off] [source_length] target_ref target_byte_off
 	// store target_ref
+	// arrays always start at zero byte offset, pop offset
+	m_context << eth::Instruction::POP;
 	for (unsigned i = _sourceType.getSizeOnStack(); i > 0; --i)
 		m_context << eth::swapInstruction(i);
+	// stack: target_ref source_ref [source_byte_off] [source_length]
+	if (sourceIsStorage)
+		// arrays always start at zero byte offset, pop offset
+		m_context << eth::Instruction::POP;
+	// stack: target_ref source_ref [source_length]
+	// retrieve source length
 	if (_sourceType.getLocation() != ArrayType::Location::CallData || !_sourceType.isDynamicallySized())
 		retrieveLength(_sourceType); // otherwise, length is already there
 	// stack: target_ref source_ref source_length
@@ -73,6 +87,7 @@ void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType cons
 		m_context
 			<< eth::Instruction::POP << eth::Instruction::POP
 			<< eth::Instruction::POP << eth::Instruction::POP;
+		m_context << u256(0);
 		return;
 	}
 	// compute hashes (data positions)
@@ -88,8 +103,8 @@ void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType cons
 	// stack: target_ref target_data_end source_length target_data_pos source_ref
 	// skip copying if source length is zero
 	m_context << eth::Instruction::DUP3 << eth::Instruction::ISZERO;
-	eth::AssemblyItem copyLoopEnd = m_context.newTag();
-	m_context.appendConditionalJumpTo(copyLoopEnd);
+	eth::AssemblyItem copyLoopEndWithoutByteOffset = m_context.newTag();
+	m_context.appendConditionalJumpTo(copyLoopEndWithoutByteOffset);
 
 	if (_sourceType.getLocation() == ArrayType::Location::Storage && _sourceType.isDynamicallySized())
 		CompilerUtils(m_context).computeHashStatic();
@@ -98,88 +113,172 @@ void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType cons
 	convertLengthToSize(_sourceType);
 	m_context << eth::Instruction::DUP3 << eth::Instruction::ADD;
 	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
+	if (haveByteOffsetTarget)
+		m_context << u256(0);
+	if (haveByteOffsetSource)
+		m_context << u256(0);
+	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset]
 	eth::AssemblyItem copyLoopStart = m_context.newTag();
 	m_context << copyLoopStart;
 	// check for loop condition
 	m_context
-		<< eth::Instruction::DUP3 << eth::Instruction::DUP2
+		<< eth::dupInstruction(3 + byteOffsetSize) << eth::dupInstruction(2 + byteOffsetSize)
 		<< eth::Instruction::GT << eth::Instruction::ISZERO;
+	eth::AssemblyItem copyLoopEnd = m_context.newTag();
 	m_context.appendConditionalJumpTo(copyLoopEnd);
-	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
+	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset]
 	// copy
 	if (sourceBaseType->getCategory() == Type::Category::Array)
 	{
-		m_context << eth::Instruction::DUP3 << eth::Instruction::DUP3;
+		solAssert(byteOffsetSize == 0, "Byte offset for array as base type.");
+		m_context << eth::Instruction::DUP3;
+		if (sourceIsStorage)
+			m_context << u256(0);
+		m_context << eth::dupInstruction(sourceIsStorage ? 4 : 3) << u256(0);
 		copyArrayToStorage(
 			dynamic_cast<ArrayType const&>(*targetBaseType),
 			dynamic_cast<ArrayType const&>(*sourceBaseType)
 		);
-		m_context << eth::Instruction::POP;
+		m_context << eth::Instruction::POP << eth::Instruction::POP;
+	}
+	else if (directCopy)
+	{
+		solAssert(byteOffsetSize == 0, "Byte offset for direct copy.");
+		m_context
+			<< eth::Instruction::DUP3 << eth::Instruction::SLOAD
+			<< eth::Instruction::DUP3 << eth::Instruction::SSTORE;
 	}
 	else
 	{
-		m_context << eth::Instruction::DUP3;
+		// Note that we have to copy each element on its own in case conversion is involved.
+		// We might copy too much if there is padding at the last element, but this way end
+		// checking is easier.
+		// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset]
+		m_context << eth::dupInstruction(3 + byteOffsetSize);
 		if (_sourceType.getLocation() == ArrayType::Location::Storage)
+		{
+			if (haveByteOffsetSource)
+				m_context << eth::Instruction::DUP2;
+			else
+				m_context << u256(0);
 			StorageItem(m_context, *sourceBaseType).retrieveValue(SourceLocation(), true);
+		}
 		else if (sourceBaseType->isValueType())
 			CompilerUtils(m_context).loadFromMemoryDynamic(*sourceBaseType, true, true, false);
 		else
 			solAssert(false, "Copying of unknown type requested: " + sourceBaseType->toString());
-		m_context << eth::dupInstruction(2 + sourceBaseType->getSizeOnStack());
+		// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] <source_value>...
+		solAssert(2 + byteOffsetSize + sourceBaseType->getSizeOnStack() <= 16, "Stack too deep.");
+		// fetch target storage reference
+		m_context << eth::dupInstruction(2 + byteOffsetSize + sourceBaseType->getSizeOnStack());
+		if (haveByteOffsetTarget)
+			m_context << eth::dupInstruction(1 + byteOffsetSize + sourceBaseType->getSizeOnStack());
+		else
+			m_context << u256(0);
 		StorageItem(m_context, *targetBaseType).storeValue(*sourceBaseType, SourceLocation(), true);
 	}
+	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset]
 	// increment source
-	m_context
-		<< eth::Instruction::SWAP2
-		<< (_sourceType.getLocation() == ArrayType::Location::Storage ?
-			sourceBaseType->getStorageSize() :
-			sourceBaseType->getCalldataEncodedSize())
-		<< eth::Instruction::ADD
-		<< eth::Instruction::SWAP2;
+	if (haveByteOffsetSource)
+		incrementByteOffset(sourceBaseType->getStorageBytes(), 1, haveByteOffsetTarget ? 5 : 4);
+	else
+		m_context
+			<< eth::swapInstruction(2 + byteOffsetSize)
+			<< (sourceIsStorage ? sourceBaseType->getStorageSize() : sourceBaseType->getCalldataEncodedSize())
+			<< eth::Instruction::ADD
+			<< eth::swapInstruction(2 + byteOffsetSize);
 	// increment target
-	m_context
-		<< eth::Instruction::SWAP1
-		<< targetBaseType->getStorageSize()
-		<< eth::Instruction::ADD
-		<< eth::Instruction::SWAP1;
+	if (haveByteOffsetTarget)
+		incrementByteOffset(targetBaseType->getStorageBytes(), byteOffsetSize, byteOffsetSize + 2);
+	else
+		m_context
+			<< eth::swapInstruction(1 + byteOffsetSize)
+			<< targetBaseType->getStorageSize()
+			<< eth::Instruction::ADD
+			<< eth::swapInstruction(1 + byteOffsetSize);
 	m_context.appendJumpTo(copyLoopStart);
 	m_context << copyLoopEnd;
+	if (haveByteOffsetTarget)
+	{
+		// clear elements that might be left over in the current slot in target
+		// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end target_byte_offset [source_byte_offset]
+		m_context << eth::dupInstruction(byteOffsetSize) << eth::Instruction::ISZERO;
+		eth::AssemblyItem copyCleanupLoopEnd = m_context.appendConditionalJump();
+		m_context << eth::dupInstruction(2 + byteOffsetSize) << eth::dupInstruction(1 + byteOffsetSize);
+		StorageItem(m_context, *targetBaseType).setToZero(SourceLocation(), true);
+		incrementByteOffset(targetBaseType->getStorageBytes(), byteOffsetSize, byteOffsetSize + 2);
+		m_context.appendJumpTo(copyLoopEnd);
+
+		m_context << copyCleanupLoopEnd;
+		m_context << eth::Instruction::POP; // might pop the source, but then target is popped next
+	}
+	if (haveByteOffsetSource)
+		m_context << eth::Instruction::POP;
+	m_context << copyLoopEndWithoutByteOffset;
 
 	// zero-out leftovers in target
-	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
+	// stack: target_ref target_data_end source_data_pos target_data_pos_updated source_data_end
 	m_context << eth::Instruction::POP << eth::Instruction::SWAP1 << eth::Instruction::POP;
 	// stack: target_ref target_data_end target_data_pos_updated
 	clearStorageLoop(*targetBaseType);
 	m_context << eth::Instruction::POP;
+	m_context << u256(0);
 }
 
 void ArrayUtils::clearArray(ArrayType const& _type) const
 {
+	unsigned stackHeightStart = m_context.getStackHeight();
 	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
+	if (_type.getBaseType()->getStorageBytes() < 32)
+	{
+		solAssert(_type.getBaseType()->isValueType(), "Invalid storage size for non-value type.");
+		solAssert(_type.getBaseType()->getStorageSize() <= 1, "Invalid storage size for type.");
+	}
+	if (_type.getBaseType()->isValueType())
+		solAssert(_type.getBaseType()->getStorageSize() <= 1, "Invalid size for value type.");
+
+	m_context << eth::Instruction::POP; // remove byte offset
 	if (_type.isDynamicallySized())
 		clearDynamicArray(_type);
 	else if (_type.getLength() == 0 || _type.getBaseType()->getCategory() == Type::Category::Mapping)
 		m_context << eth::Instruction::POP;
-	else if (_type.getLength() < 5) // unroll loop for small arrays @todo choose a good value
+	else if (_type.getBaseType()->isValueType() && _type.getStorageSize() <= 5)
 	{
-		solAssert(!_type.isByteArray(), "");
+		// unroll loop for small arrays @todo choose a good value
+		// Note that we loop over storage slots here, not elements.
+		for (unsigned i = 1; i < _type.getStorageSize(); ++i)
+			m_context
+				<< u256(0) << eth::Instruction::DUP2 << eth::Instruction::SSTORE
+				<< u256(1) << eth::Instruction::ADD;
+		m_context << u256(0) << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
+	}
+	else if (!_type.getBaseType()->isValueType() && _type.getLength() <= 4)
+	{
+		// unroll loop for small arrays @todo choose a good value
+		solAssert(_type.getBaseType()->getStorageBytes() >= 32, "Invalid storage size.");
 		for (unsigned i = 1; i < _type.getLength(); ++i)
 		{
+			m_context << u256(0);
 			StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), false);
-			m_context << u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD;
+			m_context
+				<< eth::Instruction::POP
+				<< u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD;
 		}
+		m_context << u256(0);
 		StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), true);
 	}
 	else
 	{
-		solAssert(!_type.isByteArray(), "");
-		m_context
-			<< eth::Instruction::DUP1 << u256(_type.getLength())
-			<< u256(_type.getBaseType()->getStorageSize())
-			<< eth::Instruction::MUL << eth::Instruction::ADD << eth::Instruction::SWAP1;
-		clearStorageLoop(*_type.getBaseType());
+		m_context << eth::Instruction::DUP1 << _type.getLength();
+		convertLengthToSize(_type);
+		m_context << eth::Instruction::ADD << eth::Instruction::SWAP1;
+		if (_type.getBaseType()->getStorageBytes() < 32)
+			clearStorageLoop(IntegerType(256));
+		else
+			clearStorageLoop(*_type.getBaseType());
 		m_context << eth::Instruction::POP;
 	}
+	solAssert(m_context.getStackHeight() == stackHeightStart - 2, "");
 }
 
 void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
@@ -187,6 +286,7 @@ void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
 	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
 	solAssert(_type.isDynamicallySized(), "");
 
+	unsigned stackHeightStart = m_context.getStackHeight();
 	// fetch length
 	m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
 	// set length to zero
@@ -196,23 +296,27 @@ void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
 	// compute data positions
 	m_context << eth::Instruction::SWAP1;
 	CompilerUtils(m_context).computeHashStatic();
-	// stack: len data_pos (len is in slots for byte array and in items for other arrays)
+	// stack: len data_pos
 	m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD
 		<< eth::Instruction::SWAP1;
 	// stack: data_pos_end data_pos
-	if (_type.isByteArray())
+	if (_type.isByteArray() || _type.getBaseType()->getStorageBytes() < 32)
 		clearStorageLoop(IntegerType(256));
 	else
 		clearStorageLoop(*_type.getBaseType());
 	// cleanup
 	m_context << eth::Instruction::POP;
+	solAssert(m_context.getStackHeight() == stackHeightStart - 1, "");
 }
 
 void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
 {
 	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
 	solAssert(_type.isDynamicallySized(), "");
+	if (!_type.isByteArray() && _type.getBaseType()->getStorageBytes() < 32)
+		solAssert(_type.getBaseType()->isValueType(), "Invalid storage size for non-value type.");
 
+	unsigned stackHeightStart = m_context.getStackHeight();
 	eth::AssemblyItem resizeEnd = m_context.newTag();
 
 	// stack: ref new_length
@@ -240,7 +344,7 @@ void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
 	// stack: ref new_length data_pos new_size delete_end
 	m_context << eth::Instruction::SWAP2 << eth::Instruction::ADD;
 	// stack: ref new_length delete_end delete_start
-	if (_type.isByteArray())
+	if (_type.isByteArray() || _type.getBaseType()->getStorageBytes() < 32)
 		clearStorageLoop(IntegerType(256));
 	else
 		clearStorageLoop(*_type.getBaseType());
@@ -248,10 +352,12 @@ void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
 	m_context << resizeEnd;
 	// cleanup
 	m_context << eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
+	solAssert(m_context.getStackHeight() == stackHeightStart - 2, "");
 }
 
 void ArrayUtils::clearStorageLoop(Type const& _type) const
 {
+	unsigned stackHeightStart = m_context.getStackHeight();
 	if (_type.getCategory() == Type::Category::Mapping)
 	{
 		m_context << eth::Instruction::POP;
@@ -266,13 +372,16 @@ void ArrayUtils::clearStorageLoop(Type const& _type) const
 	eth::AssemblyItem zeroLoopEnd = m_context.newTag();
 	m_context.appendConditionalJumpTo(zeroLoopEnd);
 	// delete
+	m_context << u256(0);
 	StorageItem(m_context, _type).setToZero(SourceLocation(), false);
+	m_context << eth::Instruction::POP;
 	// increment
 	m_context << u256(1) << eth::Instruction::ADD;
 	m_context.appendJumpTo(loopStart);
 	// cleanup
 	m_context << zeroLoopEnd;
 	m_context << eth::Instruction::POP;
+	solAssert(m_context.getStackHeight() == stackHeightStart - 1, "");
 }
 
 void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType, bool _pad) const
@@ -282,7 +391,20 @@ void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType, bool _pad) con
 		if (_arrayType.isByteArray())
 			m_context << u256(31) << eth::Instruction::ADD
 				<< u256(32) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
-		else if (_arrayType.getBaseType()->getStorageSize() > 1)
+		else if (_arrayType.getBaseType()->getStorageSize() <= 1)
+		{
+			unsigned baseBytes = _arrayType.getBaseType()->getStorageBytes();
+			if (baseBytes == 0)
+				m_context << eth::Instruction::POP << u256(1);
+			else if (baseBytes <= 16)
+			{
+				unsigned itemsPerSlot = 32 / baseBytes;
+				m_context
+					<< u256(itemsPerSlot - 1) << eth::Instruction::ADD
+					<< u256(itemsPerSlot) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
+			}
+		}
+		else
 			m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL;
 	}
 	else
@@ -318,3 +440,143 @@ void ArrayUtils::retrieveLength(ArrayType const& _arrayType) const
 	}
 }
 
+void ArrayUtils::accessIndex(ArrayType const& _arrayType) const
+{
+	ArrayType::Location location = _arrayType.getLocation();
+	eth::Instruction load =
+		location == ArrayType::Location::Storage ? eth::Instruction::SLOAD :
+		location == ArrayType::Location::Memory ? eth::Instruction::MLOAD :
+		eth::Instruction::CALLDATALOAD;
+
+	// retrieve length
+	if (!_arrayType.isDynamicallySized())
+		m_context << _arrayType.getLength();
+	else if (location == ArrayType::Location::CallData)
+		// length is stored on the stack
+		m_context << eth::Instruction::SWAP1;
+	else
+		m_context << eth::Instruction::DUP2 << load;
+	// stack: <base_ref> <index> <length>
+	// check out-of-bounds access
+	m_context << eth::Instruction::DUP2 << eth::Instruction::LT;
+	eth::AssemblyItem legalAccess = m_context.appendConditionalJump();
+	// out-of-bounds access throws exception (just STOP for now)
+	m_context << eth::Instruction::STOP;
+
+	m_context << legalAccess;
+	// stack: <base_ref> <index>
+	if (_arrayType.isByteArray())
+		switch (location)
+		{
+		case ArrayType::Location::Storage:
+			// byte array index storage lvalue on stack (goal):
+			// <ref> <byte_number> = <base_ref + index / 32> <index % 32>
+			m_context << u256(32) << eth::Instruction::SWAP2;
+			CompilerUtils(m_context).computeHashStatic();
+			// stack: 32 index data_ref
+			m_context
+				<< eth::Instruction::DUP3 << eth::Instruction::DUP3
+				<< eth::Instruction::DIV << eth::Instruction::ADD
+			// stack: 32 index (data_ref + index / 32)
+				<< eth::Instruction::SWAP2 << eth::Instruction::SWAP1
+				<< eth::Instruction::MOD;
+			break;
+		case ArrayType::Location::CallData:
+			// no lvalue, just retrieve the value
+			m_context
+				<< eth::Instruction::ADD << eth::Instruction::CALLDATALOAD
+				<< ((u256(0xff) << (256 - 8)))  << eth::Instruction::AND;
+			break;
+		case ArrayType::Location::Memory:
+			solAssert(false, "Memory lvalues not yet implemented.");
+		}
+	else
+	{
+		// stack: <base_ref> <index>
+		m_context << eth::Instruction::SWAP1;
+		if (_arrayType.isDynamicallySized())
+		{
+			if (location == ArrayType::Location::Storage)
+				CompilerUtils(m_context).computeHashStatic();
+			else if (location == ArrayType::Location::Memory)
+				m_context << u256(32) << eth::Instruction::ADD;
+		}
+		// stack: <index> <data_ref>
+		switch (location)
+		{
+		case ArrayType::Location::CallData:
+			m_context
+				<< eth::Instruction::SWAP1 << _arrayType.getBaseType()->getCalldataEncodedSize()
+				<< eth::Instruction::MUL << eth::Instruction::ADD;
+			if (_arrayType.getBaseType()->isValueType())
+				CompilerUtils(m_context).loadFromMemoryDynamic(*_arrayType.getBaseType(), true, true, false);
+			break;
+		case ArrayType::Location::Storage:
+			m_context << eth::Instruction::SWAP1;
+			if (_arrayType.getBaseType()->getStorageBytes() <= 16)
+			{
+				// stack: <data_ref> <index>
+				// goal:
+				// <ref> <byte_number> = <base_ref + index / itemsPerSlot> <(index % itemsPerSlot) * byteSize>
+				unsigned byteSize = _arrayType.getBaseType()->getStorageBytes();
+				solAssert(byteSize != 0, "");
+				unsigned itemsPerSlot = 32 / byteSize;
+				m_context << u256(itemsPerSlot) << eth::Instruction::SWAP2;
+				// stack: itemsPerSlot index data_ref
+				m_context
+					<< eth::Instruction::DUP3 << eth::Instruction::DUP3
+					<< eth::Instruction::DIV << eth::Instruction::ADD
+				// stack: itemsPerSlot index (data_ref + index / itemsPerSlot)
+					<< eth::Instruction::SWAP2 << eth::Instruction::SWAP1
+					<< eth::Instruction::MOD
+					<< u256(byteSize) << eth::Instruction::MUL;
+			}
+			else
+			{
+				if (_arrayType.getBaseType()->getStorageSize() != 1)
+					m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL;
+				m_context << eth::Instruction::ADD << u256(0);
+			}
+			break;
+		case ArrayType::Location::Memory:
+			solAssert(false, "Memory lvalues not yet implemented.");
+		}
+	}
+}
+
+void ArrayUtils::incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const
+{
+	solAssert(_byteSize < 32, "");
+	solAssert(_byteSize != 0, "");
+	// We do the following, but avoiding jumps:
+	// byteOffset += byteSize
+	// if (byteOffset + byteSize > 32)
+	// {
+	//     storageOffset++;
+	//     byteOffset = 0;
+	// }
+	if (_byteOffsetPosition > 1)
+		m_context << eth::swapInstruction(_byteOffsetPosition - 1);
+	m_context << u256(_byteSize) << eth::Instruction::ADD;
+	if (_byteOffsetPosition > 1)
+		m_context << eth::swapInstruction(_byteOffsetPosition - 1);
+	// compute, X := (byteOffset + byteSize - 1) / 32, should be 1 iff byteOffset + bytesize > 32
+	m_context
+		<< u256(32) << eth::dupInstruction(1 + _byteOffsetPosition) << u256(_byteSize - 1)
+		<< eth::Instruction::ADD << eth::Instruction::DIV;
+	// increment storage offset if X == 1 (just add X to it)
+	// stack: X
+	m_context
+		<< eth::swapInstruction(_storageOffsetPosition) << eth::dupInstruction(_storageOffsetPosition + 1)
+		<< eth::Instruction::ADD << eth::swapInstruction(_storageOffsetPosition);
+	// stack: X
+	// set source_byte_offset to zero if X == 1 (using source_byte_offset *= 1 - X)
+	m_context << u256(1) << eth::Instruction::SUB;
+	// stack: 1 - X
+	if (_byteOffsetPosition == 1)
+		m_context << eth::Instruction::MUL;
+	else
+		m_context
+			<< eth::dupInstruction(_byteOffsetPosition + 1) << eth::Instruction::MUL
+			<< eth::swapInstruction(_byteOffsetPosition) << eth::Instruction::POP;
+}
diff --git a/ArrayUtils.h b/ArrayUtils.h
index 31cca817..dab40e2d 100644
--- a/ArrayUtils.h
+++ b/ArrayUtils.h
@@ -41,19 +41,19 @@ public:
 
 	/// Copies an array to an array in storage. The arrays can be of different types only if
 	/// their storage representation is the same.
-	/// Stack pre: [source_reference] target_reference
-	/// Stack post: target_reference
+	/// Stack pre: source_reference [source_byte_offset/source_length] target_reference target_byte_offset
+	/// Stack post: target_reference target_byte_offset
 	void copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const;
 	/// Clears the given dynamic or static array.
-	/// Stack pre: reference
+	/// Stack pre: storage_ref storage_byte_offset
 	/// Stack post:
 	void clearArray(ArrayType const& _type) const;
 	/// Clears the length and data elements of the array referenced on the stack.
-	/// Stack pre: reference
+	/// Stack pre: reference (excludes byte offset)
 	/// Stack post:
 	void clearDynamicArray(ArrayType const& _type) const;
 	/// Changes the size of a dynamic array and clears the tail if it is shortened.
-	/// Stack pre: reference new_length
+	/// Stack pre: reference (excludes byte offset) new_length
 	/// Stack post:
 	void resizeDynamicArray(ArrayType const& _type) const;
 	/// Appends a loop that clears a sequence of storage slots of the given type (excluding end).
@@ -67,11 +67,23 @@ public:
 	void convertLengthToSize(ArrayType const& _arrayType, bool _pad = false) const;
 	/// Retrieves the length (number of elements) of the array ref on the stack. This also
 	/// works for statically-sized arrays.
-	/// Stack pre: reference
+	/// Stack pre: reference (excludes byte offset for dynamic storage arrays)
 	/// Stack post: reference length
 	void retrieveLength(ArrayType const& _arrayType) const;
+	/// Retrieves the value at a specific index. If the location is storage, only retrieves the
+	/// position.
+	/// Stack pre: reference [length] index
+	/// Stack post for storage: slot byte_offset
+	/// Stack post for calldata: value
+	void accessIndex(ArrayType const& _arrayType) const;
 
 private:
+	/// Adds the given number of bytes to a storage byte offset counter and also increments
+	/// the storage offset if adding this number again would increase the counter over 32.
+	/// @param byteOffsetPosition the stack offset of the storage byte offset
+	/// @param storageOffsetPosition the stack offset of the storage slot offset
+	void incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const;
+
 	CompilerContext& m_context;
 };
 
diff --git a/Compiler.cpp b/Compiler.cpp
index 5eeb0c3e..8e263449 100644
--- a/Compiler.cpp
+++ b/Compiler.cpp
@@ -20,12 +20,12 @@
  * Solidity compiler.
  */
 
+#include <libsolidity/Compiler.h>
 #include <algorithm>
 #include <boost/range/adaptor/reversed.hpp>
 #include <libevmcore/Instruction.h>
 #include <libevmcore/Assembly.h>
 #include <libsolidity/AST.h>
-#include <libsolidity/Compiler.h>
 #include <libsolidity/ExpressionCompiler.h>
 #include <libsolidity/CompilerUtils.h>
 
@@ -132,7 +132,7 @@ void Compiler::packIntoContractCreator(ContractDefinition const& _contract, Comp
 
 void Compiler::appendBaseConstructor(FunctionDefinition const& _constructor)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_constructor);
+	CompilerContext::LocationSetter locationSetter(m_context, _constructor);
 	FunctionType constructorType(_constructor);
 	if (!constructorType.getParameterTypes().empty())
 	{
@@ -146,7 +146,7 @@ void Compiler::appendBaseConstructor(FunctionDefinition const& _constructor)
 
 void Compiler::appendConstructor(FunctionDefinition const& _constructor)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_constructor);
+	CompilerContext::LocationSetter locationSetter(m_context, _constructor);
 	// copy constructor arguments from code to memory and then to stack, they are supplied after the actual program
 	unsigned argumentSize = 0;
 	for (ASTPointer<VariableDeclaration> const& var: _constructor.getParameters())
@@ -192,10 +192,12 @@ void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
 	for (auto const& it: interfaceFunctions)
 	{
 		FunctionTypePointer const& functionType = it.second;
+		solAssert(functionType->hasDeclaration(), "");
+		CompilerContext::LocationSetter locationSetter(m_context, functionType->getDeclaration());
 		m_context << callDataUnpackerEntryPoints.at(it.first);
 		eth::AssemblyItem returnTag = m_context.pushNewTag();
 		appendCalldataUnpacker(functionType->getParameterTypes());
-		m_context.appendJumpTo(m_context.getFunctionEntryLabel(it.second->getDeclaration()));
+		m_context.appendJumpTo(m_context.getFunctionEntryLabel(functionType->getDeclaration()));
 		m_context << returnTag;
 		appendReturnValuePacker(functionType->getReturnParameterTypes());
 	}
@@ -226,6 +228,7 @@ void Compiler::appendCalldataUnpacker(TypePointers const& _typeParameters, bool
 				{
 					// Retrieve data start offset by adding length to start offset of previous dynamic type
 					unsigned stackDepth = m_context.getStackHeight() - stackHeightOfPreviousDynamicArgument;
+					solAssert(stackDepth <= 16, "Stack too deep.");
 					m_context << eth::dupInstruction(stackDepth) << eth::dupInstruction(stackDepth);
 					ArrayUtils(m_context).convertLengthToSize(*previousDynamicType, true);
 					m_context << eth::Instruction::ADD;
@@ -271,22 +274,21 @@ void Compiler::appendReturnValuePacker(TypePointers const& _typeParameters)
 
 void Compiler::registerStateVariables(ContractDefinition const& _contract)
 {
-	for (ContractDefinition const* contract: boost::adaptors::reverse(_contract.getLinearizedBaseContracts()))
-		for (ASTPointer<VariableDeclaration> const& variable: contract->getStateVariables())
-			m_context.addStateVariable(*variable);
+	for (auto const& var: ContractType(_contract).getStateVariables())
+		m_context.addStateVariable(*get<0>(var), get<1>(var), get<2>(var));
 }
 
 void Compiler::initializeStateVariables(ContractDefinition const& _contract)
 {
 	for (ASTPointer<VariableDeclaration> const& variable: _contract.getStateVariables())
-		if (variable->getValue())
+		if (variable->getValue() && !variable->isConstant())
 			ExpressionCompiler(m_context, m_optimize).appendStateVariableInitialization(*variable);
 }
 
 bool Compiler::visit(VariableDeclaration const& _variableDeclaration)
 {
 	solAssert(_variableDeclaration.isStateVariable(), "Compiler visit to non-state variable declaration.");
-	CompilerContext::LocationSetter locationSetter(m_context, &_variableDeclaration);
+	CompilerContext::LocationSetter locationSetter(m_context, _variableDeclaration);
 
 	m_context.startFunction(_variableDeclaration);
 	m_breakTags.clear();
@@ -300,7 +302,7 @@ bool Compiler::visit(VariableDeclaration const& _variableDeclaration)
 
 bool Compiler::visit(FunctionDefinition const& _function)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_function);
+	CompilerContext::LocationSetter locationSetter(m_context, _function);
 	//@todo to simplify this, the calling convention could by changed such that
 	// caller puts: [retarg0] ... [retargm] [return address] [arg0] ... [argn]
 	// although note that this reduces the size of the visible stack
@@ -357,6 +359,7 @@ bool Compiler::visit(FunctionDefinition const& _function)
 		stackLayout.push_back(i);
 	stackLayout += vector<int>(c_localVariablesSize, -1);
 
+	solAssert(stackLayout.size() <= 17, "Stack too deep.");
 	while (stackLayout.back() != int(stackLayout.size() - 1))
 		if (stackLayout.back() < 0)
 		{
@@ -376,15 +379,16 @@ bool Compiler::visit(FunctionDefinition const& _function)
 		m_context.removeVariable(*localVariable);
 
 	m_context.adjustStackOffset(-(int)c_returnValuesSize);
+
 	if (!_function.isConstructor())
-		m_context << eth::Instruction::JUMP;
+		m_context.appendJump(eth::AssemblyItem::JumpType::OutOfFunction);
 	return false;
 }
 
 bool Compiler::visit(IfStatement const& _ifStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_ifStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _ifStatement);
 	compileExpression(_ifStatement.getCondition());
 	eth::AssemblyItem trueTag = m_context.appendConditionalJump();
 	if (_ifStatement.getFalseStatement())
@@ -401,7 +405,7 @@ bool Compiler::visit(IfStatement const& _ifStatement)
 bool Compiler::visit(WhileStatement const& _whileStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_whileStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _whileStatement);
 	eth::AssemblyItem loopStart = m_context.newTag();
 	eth::AssemblyItem loopEnd = m_context.newTag();
 	m_continueTags.push_back(loopStart);
@@ -427,7 +431,7 @@ bool Compiler::visit(WhileStatement const& _whileStatement)
 bool Compiler::visit(ForStatement const& _forStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_forStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _forStatement);
 	eth::AssemblyItem loopStart = m_context.newTag();
 	eth::AssemblyItem loopEnd = m_context.newTag();
 	m_continueTags.push_back(loopStart);
@@ -464,7 +468,7 @@ bool Compiler::visit(ForStatement const& _forStatement)
 
 bool Compiler::visit(Continue const& _continueStatement)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_continueStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _continueStatement);
 	if (!m_continueTags.empty())
 		m_context.appendJumpTo(m_continueTags.back());
 	return false;
@@ -472,7 +476,7 @@ bool Compiler::visit(Continue const& _continueStatement)
 
 bool Compiler::visit(Break const& _breakStatement)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_breakStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _breakStatement);
 	if (!m_breakTags.empty())
 		m_context.appendJumpTo(m_breakTags.back());
 	return false;
@@ -480,7 +484,7 @@ bool Compiler::visit(Break const& _breakStatement)
 
 bool Compiler::visit(Return const& _return)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_return);
+	CompilerContext::LocationSetter locationSetter(m_context, _return);
 	//@todo modifications are needed to make this work with functions returning multiple values
 	if (Expression const* expression = _return.getExpression())
 	{
@@ -499,7 +503,7 @@ bool Compiler::visit(Return const& _return)
 bool Compiler::visit(VariableDeclarationStatement const& _variableDeclarationStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_variableDeclarationStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _variableDeclarationStatement);
 	if (Expression const* expression = _variableDeclarationStatement.getExpression())
 	{
 		compileExpression(*expression, _variableDeclarationStatement.getDeclaration().getType());
@@ -512,7 +516,7 @@ bool Compiler::visit(VariableDeclarationStatement const& _variableDeclarationSta
 bool Compiler::visit(ExpressionStatement const& _expressionStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_expressionStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _expressionStatement);
 	Expression const& expression = _expressionStatement.getExpression();
 	compileExpression(expression);
 	CompilerUtils(m_context).popStackElement(*expression.getType());
@@ -523,7 +527,7 @@ bool Compiler::visit(ExpressionStatement const& _expressionStatement)
 bool Compiler::visit(PlaceholderStatement const& _placeholderStatement)
 {
 	StackHeightChecker checker(m_context);
-	CompilerContext::LocationSetter locationSetter(m_context, &_placeholderStatement);
+	CompilerContext::LocationSetter locationSetter(m_context, _placeholderStatement);
 	++m_modifierDepth;
 	appendModifierOrFunctionCode();
 	--m_modifierDepth;
@@ -550,7 +554,7 @@ void Compiler::appendModifierOrFunctionCode()
 		}
 
 		ModifierDefinition const& modifier = m_context.getFunctionModifier(modifierInvocation->getName()->getName());
-		CompilerContext::LocationSetter locationSetter(m_context, &modifier);
+		CompilerContext::LocationSetter locationSetter(m_context, modifier);
 		solAssert(modifier.getParameters().size() == modifierInvocation->getArguments().size(), "");
 		for (unsigned i = 0; i < modifier.getParameters().size(); ++i)
 		{
diff --git a/Compiler.h b/Compiler.h
index 76f16f3a..4b1e1b4d 100644
--- a/Compiler.h
+++ b/Compiler.h
@@ -94,8 +94,8 @@ private:
 	std::vector<eth::AssemblyItem> m_continueTags; ///< tag to jump to for a "continue" statement
 	eth::AssemblyItem m_returnTag; ///< tag to jump to for a "return" statement
 	unsigned m_modifierDepth = 0;
-	FunctionDefinition const* m_currentFunction;
-	unsigned m_stackCleanupForReturn; ///< this number of stack elements need to be removed before jump to m_returnTag
+	FunctionDefinition const* m_currentFunction = nullptr;
+	unsigned m_stackCleanupForReturn = 0; ///< this number of stack elements need to be removed before jump to m_returnTag
 	// arguments for base constructors, filled in derived-to-base order
 	std::map<FunctionDefinition const*, std::vector<ASTPointer<Expression>> const*> m_baseArguments;
 };
diff --git a/CompilerContext.cpp b/CompilerContext.cpp
index b12e0192..0afda136 100644
--- a/CompilerContext.cpp
+++ b/CompilerContext.cpp
@@ -37,15 +37,13 @@ void CompilerContext::addMagicGlobal(MagicVariableDeclaration const& _declaratio
 	m_magicGlobals.insert(&_declaration);
 }
 
-void CompilerContext::addStateVariable(VariableDeclaration const& _declaration)
+void CompilerContext::addStateVariable(
+	VariableDeclaration const& _declaration,
+	u256 const& _storageOffset,
+	unsigned _byteOffset
+)
 {
-	m_stateVariables[&_declaration] = m_stateVariablesSize;
-	bigint newSize = bigint(m_stateVariablesSize) + _declaration.getType()->getStorageSize();
-	if (newSize >= bigint(1) << 256)
-		BOOST_THROW_EXCEPTION(TypeError()
-			<< errinfo_comment("State variable does not fit in storage.")
-			<< errinfo_sourceLocation(_declaration.getLocation()));
-	m_stateVariablesSize = u256(newSize);
+	m_stateVariables[&_declaration] = make_pair(_storageOffset, _byteOffset);
 }
 
 void CompilerContext::startFunction(Declaration const& _function)
@@ -69,7 +67,7 @@ void CompilerContext::removeVariable(VariableDeclaration const& _declaration)
 
 void CompilerContext::addAndInitializeVariable(VariableDeclaration const& _declaration)
 {
-	LocationSetter locationSetter(*this, &_declaration);
+	LocationSetter locationSetter(*this, _declaration);
 	addVariable(_declaration);
 	int const size = _declaration.getType()->getSizeOnStack();
 	for (int i = 0; i < size; ++i)
@@ -174,46 +172,26 @@ unsigned CompilerContext::currentToBaseStackOffset(unsigned _offset) const
 	return m_asm.deposit() - _offset - 1;
 }
 
-u256 CompilerContext::getStorageLocationOfVariable(const Declaration& _declaration) const
+pair<u256, unsigned> CompilerContext::getStorageLocationOfVariable(const Declaration& _declaration) const
 {
 	auto it = m_stateVariables.find(&_declaration);
 	solAssert(it != m_stateVariables.end(), "Variable not found in storage.");
 	return it->second;
 }
 
+CompilerContext& CompilerContext::appendJump(eth::AssemblyItem::JumpType _jumpType)
+{
+	eth::AssemblyItem item(eth::Instruction::JUMP);
+	item.setJumpType(_jumpType);
+	return *this << item;
+}
+
 void CompilerContext::resetVisitedNodes(ASTNode const* _node)
 {
 	stack<ASTNode const*> newStack;
 	newStack.push(_node);
 	std::swap(m_visitedNodes, newStack);
-}
-
-CompilerContext& CompilerContext::operator<<(eth::AssemblyItem const& _item)
-{
-	solAssert(!m_visitedNodes.empty(), "No node on the visited stack");
-	m_asm.append(_item, m_visitedNodes.top()->getLocation());
-	return *this;
-}
-
-CompilerContext& CompilerContext::operator<<(eth::Instruction _instruction)
-{
-	solAssert(!m_visitedNodes.empty(), "No node on the visited stack");
-	m_asm.append(_instruction, m_visitedNodes.top()->getLocation());
-	return *this;
-}
-
-CompilerContext& CompilerContext::operator<<(u256 const& _value)
-{
-	solAssert(!m_visitedNodes.empty(), "No node on the visited stack");
-	m_asm.append(_value, m_visitedNodes.top()->getLocation());
-	return *this;
-}
-
-CompilerContext& CompilerContext::operator<<(bytes const& _data)
-{
-	solAssert(!m_visitedNodes.empty(), "No node on the visited stack");
-	m_asm.append(_data, m_visitedNodes.top()->getLocation());
-	return *this;
+	updateSourceLocation();
 }
 
 vector<ContractDefinition const*>::const_iterator CompilerContext::getSuperContract(ContractDefinition const& _contract) const
@@ -224,5 +202,10 @@ vector<ContractDefinition const*>::const_iterator CompilerContext::getSuperContr
 	return ++it;
 }
 
+void CompilerContext::updateSourceLocation()
+{
+	m_asm.setSourceLocation(m_visitedNodes.empty() ? SourceLocation() : m_visitedNodes.top()->getLocation());
+}
+
 }
 }
diff --git a/CompilerContext.h b/CompilerContext.h
index e42e7c76..87f90d4c 100644
--- a/CompilerContext.h
+++ b/CompilerContext.h
@@ -24,6 +24,7 @@
 
 #include <ostream>
 #include <stack>
+#include <utility>
 #include <libevmcore/Instruction.h>
 #include <libevmcore/Assembly.h>
 #include <libsolidity/ASTForward.h>
@@ -42,7 +43,7 @@ class CompilerContext
 {
 public:
 	void addMagicGlobal(MagicVariableDeclaration const& _declaration);
-	void addStateVariable(VariableDeclaration const& _declaration);
+	void addStateVariable(VariableDeclaration const& _declaration, u256 const& _storageOffset, unsigned _byteOffset);
 	void addVariable(VariableDeclaration const& _declaration, unsigned _offsetToCurrent = 0);
 	void removeVariable(VariableDeclaration const& _declaration);
 	void addAndInitializeVariable(VariableDeclaration const& _declaration);
@@ -82,7 +83,7 @@ public:
 	/// Converts an offset relative to the current stack height to a value that can be used later
 	/// with baseToCurrentStackOffset to point to the same stack element.
 	unsigned currentToBaseStackOffset(unsigned _offset) const;
-	u256 getStorageLocationOfVariable(Declaration const& _declaration) const;
+	std::pair<u256, unsigned> getStorageLocationOfVariable(Declaration const& _declaration) const;
 
 	/// Appends a JUMPI instruction to a new tag and @returns the tag
 	eth::AssemblyItem appendConditionalJump() { return m_asm.appendJumpI().tag(); }
@@ -91,7 +92,7 @@ public:
 	/// Appends a JUMP to a new tag and @returns the tag
 	eth::AssemblyItem appendJumpToNew() { return m_asm.appendJump().tag(); }
 	/// Appends a JUMP to a tag already on the stack
-	CompilerContext&  appendJump() { return *this << eth::Instruction::JUMP; }
+	CompilerContext&  appendJump(eth::AssemblyItem::JumpType _jumpType = eth::AssemblyItem::JumpType::Ordinary);
 	/// Appends a JUMP to a specific tag
 	CompilerContext& appendJumpTo(eth::AssemblyItem const& _tag) { m_asm.appendJump(_tag); return *this; }
 	/// Appends pushing of a new tag and @returns the new tag.
@@ -108,19 +109,19 @@ public:
 	/// Resets the stack of visited nodes with a new stack having only @c _node
 	void resetVisitedNodes(ASTNode const* _node);
 	/// Pops the stack of visited nodes
-	void popVisitedNodes() { m_visitedNodes.pop(); }
+	void popVisitedNodes() { m_visitedNodes.pop(); updateSourceLocation(); }
 	/// Pushes an ASTNode to the stack of visited nodes
-	void pushVisitedNodes(ASTNode const* _node) { m_visitedNodes.push(_node); }
+	void pushVisitedNodes(ASTNode const* _node) { m_visitedNodes.push(_node); updateSourceLocation(); }
 
 	/// Append elements to the current instruction list and adjust @a m_stackOffset.
-	CompilerContext& operator<<(eth::AssemblyItem const& _item);
-	CompilerContext& operator<<(eth::Instruction _instruction);
-	CompilerContext& operator<<(u256 const& _value);
-	CompilerContext& operator<<(bytes const& _data);
+	CompilerContext& operator<<(eth::AssemblyItem const& _item) { m_asm.append(_item); return *this; }
+	CompilerContext& operator<<(eth::Instruction _instruction) { m_asm.append(_instruction); return *this; }
+	CompilerContext& operator<<(u256 const& _value) { m_asm.append(_value); return *this; }
+	CompilerContext& operator<<(bytes const& _data) { m_asm.append(_data); return *this; }
 
 	eth::Assembly const& getAssembly() const { return m_asm; }
 	/// @arg _sourceCodes is the map of input files to source code strings
-	void streamAssembly(std::ostream& _stream, StringMap const& _sourceCodes = StringMap()) const { m_asm.streamRLP(_stream, "", _sourceCodes); }
+	void streamAssembly(std::ostream& _stream, StringMap const& _sourceCodes = StringMap()) const { m_asm.stream(_stream, "", _sourceCodes); }
 
 	bytes getAssembledBytecode(bool _optimize = false) { return m_asm.optimise(_optimize).assemble(); }
 
@@ -130,22 +131,22 @@ public:
 	class LocationSetter: public ScopeGuard
 	{
 	public:
-		LocationSetter(CompilerContext& _compilerContext, ASTNode const* _node):
-			ScopeGuard(std::bind(&CompilerContext::popVisitedNodes, _compilerContext)) { _compilerContext.pushVisitedNodes(_node); }
+		LocationSetter(CompilerContext& _compilerContext, ASTNode const& _node):
+			ScopeGuard([&]{ _compilerContext.popVisitedNodes(); }) { _compilerContext.pushVisitedNodes(&_node); }
 	};
 
 private:
 	std::vector<ContractDefinition const*>::const_iterator getSuperContract(const ContractDefinition &_contract) const;
+	/// Updates source location set in the assembly.
+	void updateSourceLocation();
 
 	eth::Assembly m_asm;
 	/// Magic global variables like msg, tx or this, distinguished by type.
 	std::set<Declaration const*> m_magicGlobals;
 	/// Other already compiled contracts to be used in contract creation calls.
 	std::map<ContractDefinition const*, bytes const*> m_compiledContracts;
-	/// Size of the state variables, offset of next variable to be added.
-	u256 m_stateVariablesSize = 0;
 	/// Storage offsets of state variables
-	std::map<Declaration const*, u256> m_stateVariables;
+	std::map<Declaration const*, std::pair<u256, unsigned>> m_stateVariables;
 	/// Offsets of local variables on the stack (relative to stack base).
 	std::map<Declaration const*, unsigned> m_localVariables;
 	/// Labels pointing to the entry points of functions.
diff --git a/CompilerStack.cpp b/CompilerStack.cpp
index a878bb61..1301bfa5 100644
--- a/CompilerStack.cpp
+++ b/CompilerStack.cpp
@@ -41,14 +41,14 @@ namespace solidity
 {
 
 const map<string, string> StandardSources = map<string, string>{
-	{"coin", R"(import "CoinReg";import "Config";import "configUser";contract coin is configUser{function coin(string3 name, uint denom) {CoinReg(Config(configAddr()).lookup(3)).register(name, denom);}})"},
+	{"coin", R"(import "CoinReg";import "Config";import "configUser";contract coin is configUser{function coin(bytes3 name, uint denom) {CoinReg(Config(configAddr()).lookup(3)).register(name, denom);}})"},
 	{"Coin", R"(contract Coin{function isApprovedFor(address _target,address _proxy)constant returns(bool _r){}function isApproved(address _proxy)constant returns(bool _r){}function sendCoinFrom(address _from,uint256 _val,address _to){}function coinBalanceOf(address _a)constant returns(uint256 _r){}function sendCoin(uint256 _val,address _to){}function coinBalance()constant returns(uint256 _r){}function approve(address _a){}})"},
-	{"CoinReg", R"(contract CoinReg{function count()constant returns(uint256 r){}function info(uint256 i)constant returns(address addr,string3 name,uint256 denom){}function register(string3 name,uint256 denom){}function unregister(){}})"},
+	{"CoinReg", R"(contract CoinReg{function count()constant returns(uint256 r){}function info(uint256 i)constant returns(address addr,bytes3 name,uint256 denom){}function register(bytes3 name,uint256 denom){}function unregister(){}})"},
 	{"configUser", R"(contract configUser{function configAddr()constant returns(address a){ return 0xc6d9d2cd449a754c494264e1809c50e34d64562b;}})"},
 	{"Config", R"(contract Config{function lookup(uint256 service)constant returns(address a){}function kill(){}function unregister(uint256 id){}function register(uint256 id,address service){}})"},
 	{"mortal", R"(import "owned";contract mortal is owned {function kill() { if (msg.sender == owner) suicide(owner); }})"},
-	{"named", R"(import "Config";import "NameReg";import "configUser";contract named is configUser {function named(string32 name) {NameReg(Config(configAddr()).lookup(1)).register(name);}})"},
-	{"NameReg", R"(contract NameReg{function register(string32 name){}function addressOf(string32 name)constant returns(address addr){}function unregister(){}function nameOf(address addr)constant returns(string32 name){}})"},
+	{"named", R"(import "Config";import "NameReg";import "configUser";contract named is configUser {function named(bytes32 name) {NameReg(Config(configAddr()).lookup(1)).register(name);}})"},
+	{"NameReg", R"(contract NameReg{function register(bytes32 name){}function addressOf(bytes32 name)constant returns(address addr){}function unregister(){}function nameOf(address addr)constant returns(bytes32 name){}})"},
 	{"owned", R"(contract owned{function owned(){owner = msg.sender;}modifier onlyowner(){if(msg.sender==owner)_}address owner;})"},
 	{"service", R"(import "Config";import "configUser";contract service is configUser{function service(uint _n){Config(configAddr()).register(_n, this);}})"},
 	{"std", R"(import "owned";import "mortal";import "Config";import "configUser";import "NameReg";import "named";)"}
@@ -138,6 +138,8 @@ void CompilerStack::compile(bool _optimize)
 		for (ASTPointer<ASTNode> const& node: source->ast->getNodes())
 			if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(node.get()))
 			{
+				if (!contract->isFullyImplemented())
+					continue;
 				shared_ptr<Compiler> compiler = make_shared<Compiler>(_optimize);
 				compiler->compileContract(*contract, contractBytecode);
 				Contract& compiledContract = m_contracts[contract->getName()];
diff --git a/CompilerUtils.cpp b/CompilerUtils.cpp
index 8a26b5d1..511254fa 100644
--- a/CompilerUtils.cpp
+++ b/CompilerUtils.cpp
@@ -93,6 +93,7 @@ void CompilerUtils::storeInMemoryDynamic(Type const& _type, bool _padToWordBound
 		else
 		{
 			solAssert(type.getLocation() == ArrayType::Location::Storage, "Memory arrays not yet implemented.");
+			m_context << eth::Instruction::POP; //@todo
 			m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
 			// stack here: memory_offset storage_offset length_bytes
 			// jump to end if length is zero
@@ -138,6 +139,7 @@ void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
 {
 	unsigned const stackPosition = m_context.baseToCurrentStackOffset(m_context.getBaseStackOffsetOfVariable(_variable));
 	unsigned const size = _variable.getType()->getSizeOnStack();
+	solAssert(stackPosition >= size, "Variable size and position mismatch.");
 	// move variable starting from its top end in the stack
 	if (stackPosition - size + 1 > 16)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_variable.getLocation())
@@ -148,8 +150,7 @@ void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
 
 void CompilerUtils::copyToStackTop(unsigned _stackDepth, unsigned _itemSize)
 {
-	if (_stackDepth > 16)
-		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Stack too deep."));
+	solAssert(_stackDepth <= 16, "Stack too deep.");
 	for (unsigned i = 0; i < _itemSize; ++i)
 		m_context << eth::dupInstruction(_stackDepth);
 }
@@ -178,7 +179,7 @@ void CompilerUtils::computeHashStatic(Type const& _type, bool _padToWordBoundari
 unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries)
 {
 	unsigned numBytes = _type.getCalldataEncodedSize(_padToWordBoundaries);
-	bool leftAligned = _type.getCategory() == Type::Category::String;
+	bool leftAligned = _type.getCategory() == Type::Category::FixedBytes;
 	if (numBytes == 0)
 		m_context << eth::Instruction::POP << u256(0);
 	else
@@ -198,11 +199,10 @@ unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCallda
 	return numBytes;
 }
 
-
 unsigned CompilerUtils::prepareMemoryStore(Type const& _type, bool _padToWordBoundaries) const
 {
 	unsigned numBytes = _type.getCalldataEncodedSize(_padToWordBoundaries);
-	bool leftAligned = _type.getCategory() == Type::Category::String;
+	bool leftAligned = _type.getCategory() == Type::Category::FixedBytes;
 	if (numBytes == 0)
 		m_context << eth::Instruction::POP;
 	else
diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index 4be461b2..3ca8de89 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -48,7 +48,7 @@ void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration c
 	if (!_varDecl.getValue())
 		return;
 	solAssert(!!_varDecl.getValue()->getType(), "Type information not available.");
-	CompilerContext::LocationSetter locationSetter(m_context, &_varDecl);
+	CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
 	_varDecl.getValue()->accept(*this);
 	appendTypeConversion(*_varDecl.getValue()->getType(), *_varDecl.getType(), true);
 
@@ -57,7 +57,7 @@ void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration c
 
 void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_varDecl);
+	CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
 	FunctionType accessorType(_varDecl);
 
 	unsigned length = 0;
@@ -67,9 +67,10 @@ void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const&
 		length += CompilerUtils(m_context).storeInMemory(length, *paramType, true);
 
 	// retrieve the position of the variable
-	m_context << m_context.getStorageLocationOfVariable(_varDecl);
-	TypePointer returnType = _varDecl.getType();
+	auto const& location = m_context.getStorageLocationOfVariable(_varDecl);
+	m_context << location.first;
 
+	TypePointer returnType = _varDecl.getType();
 	for (TypePointer const& paramType: paramTypes)
 	{
 		// move offset to memory
@@ -90,9 +91,10 @@ void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const&
 		// struct
 		for (size_t i = 0; i < names.size(); ++i)
 		{
-			m_context << eth::Instruction::DUP1
-					  << structType->getStorageOffsetOfMember(names[i])
-					  << eth::Instruction::ADD;
+			if (types[i]->getCategory() == Type::Category::Mapping)
+				continue;
+			pair<u256, unsigned> const& offsets = structType->getStorageOffsetsOfMember(names[i]);
+			m_context << eth::Instruction::DUP1 << u256(offsets.first) << eth::Instruction::ADD << u256(offsets.second);
 			StorageItem(m_context, *types[i]).retrieveValue(SourceLocation(), true);
 			solAssert(types[i]->getSizeOnStack() == 1, "Returning struct elements with stack size != 1 not yet implemented.");
 			m_context << eth::Instruction::SWAP1;
@@ -104,11 +106,13 @@ void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const&
 	{
 		// simple value
 		solAssert(accessorType.getReturnParameterTypes().size() == 1, "");
+		m_context << u256(location.second);
 		StorageItem(m_context, *returnType).retrieveValue(SourceLocation(), true);
 		retSizeOnStack = returnType->getSizeOnStack();
 	}
 	solAssert(retSizeOnStack <= 15, "Stack too deep.");
-	m_context << eth::dupInstruction(retSizeOnStack + 1) << eth::Instruction::JUMP;
+	m_context << eth::dupInstruction(retSizeOnStack + 1);
+	m_context.appendJump(eth::AssemblyItem::JumpType::OutOfFunction);
 }
 
 void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded)
@@ -122,23 +126,25 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 	Type::Category stackTypeCategory = _typeOnStack.getCategory();
 	Type::Category targetTypeCategory = _targetType.getCategory();
 
-	if (stackTypeCategory == Type::Category::String)
+	switch (stackTypeCategory)
 	{
-		StaticStringType const& typeOnStack = dynamic_cast<StaticStringType const&>(_typeOnStack);
+	case Type::Category::FixedBytes:
+	{
+		FixedBytesType const& typeOnStack = dynamic_cast<FixedBytesType const&>(_typeOnStack);
 		if (targetTypeCategory == Type::Category::Integer)
 		{
-			// conversion from string to hash. no need to clean the high bit
+			// conversion from bytes to integer. no need to clean the high bit
 			// only to shift right because of opposite alignment
 			IntegerType const& targetIntegerType = dynamic_cast<IntegerType const&>(_targetType);
-			solAssert(targetIntegerType.isHash(), "Only conversion between String and Hash is allowed.");
-			solAssert(targetIntegerType.getNumBits() == typeOnStack.getNumBytes() * 8, "The size should be the same.");
 			m_context << (u256(1) << (256 - typeOnStack.getNumBytes() * 8)) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
+			if (targetIntegerType.getNumBits() < typeOnStack.getNumBytes() * 8)
+				appendTypeConversion(IntegerType(typeOnStack.getNumBytes() * 8), _targetType, _cleanupNeeded); 
 		}
 		else
 		{
-			// clear lower-order bytes for conversion to shorter strings - we always clean
-			solAssert(targetTypeCategory == Type::Category::String, "Invalid type conversion requested.");
-			StaticStringType const& targetType = dynamic_cast<StaticStringType const&>(_targetType);
+			// clear lower-order bytes for conversion to shorter bytes - we always clean
+			solAssert(targetTypeCategory == Type::Category::FixedBytes, "Invalid type conversion requested.");
+			FixedBytesType const& targetType = dynamic_cast<FixedBytesType const&>(_targetType);
 			if (targetType.getNumBytes() < typeOnStack.getNumBytes())
 			{
 				if (targetType.getNumBytes() == 0)
@@ -150,22 +156,24 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 			}
 		}
 	}
-	else if (stackTypeCategory == Type::Category::Enum)
-		solAssert(targetTypeCategory == Type::Category::Integer ||
-			targetTypeCategory == Type::Category::Enum, "");
-	else if (stackTypeCategory == Type::Category::Integer ||
-		stackTypeCategory == Type::Category::Contract ||
-		stackTypeCategory == Type::Category::IntegerConstant)
-	{
-		if (targetTypeCategory == Type::Category::String && stackTypeCategory == Type::Category::Integer)
+		break;
+	case Type::Category::Enum:
+		solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Enum, "");
+		break;
+	case Type::Category::Integer:
+	case Type::Category::Contract:
+	case Type::Category::IntegerConstant:
+		if (targetTypeCategory == Type::Category::FixedBytes)
 		{
-			// conversion from hash to string. no need to clean the high bit
+			solAssert(stackTypeCategory == Type::Category::Integer || stackTypeCategory == Type::Category::IntegerConstant,
+				"Invalid conversion to FixedBytesType requested.");
+			// conversion from bytes to string. no need to clean the high bit
 			// only to shift left because of opposite alignment
-			StaticStringType const& targetStringType = dynamic_cast<StaticStringType const&>(_targetType);
-			IntegerType const& typeOnStack = dynamic_cast<IntegerType const&>(_typeOnStack);
-			solAssert(typeOnStack.isHash(), "Only conversion between String and Hash is allowed.");
-			solAssert(typeOnStack.getNumBits() == targetStringType.getNumBytes() * 8, "The size should be the same.");
-			m_context << (u256(1) << (256 - typeOnStack.getNumBits())) << eth::Instruction::MUL;
+			FixedBytesType const& targetBytesType = dynamic_cast<FixedBytesType const&>(_targetType);
+			if (auto typeOnStack = dynamic_cast<IntegerType const*>(&_typeOnStack))
+				if (targetBytesType.getNumBytes() * 8 > typeOnStack->getNumBits())
+					appendHighBitsCleanup(*typeOnStack);
+			m_context << (u256(1) << (256 - targetBytesType.getNumBytes() * 8)) << eth::Instruction::MUL;
 		}
 		else if (targetTypeCategory == Type::Category::Enum)
 			// just clean
@@ -175,7 +183,7 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 			solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Contract, "");
 			IntegerType addressType(0, IntegerType::Modifier::Address);
 			IntegerType const& targetType = targetTypeCategory == Type::Category::Integer
-											? dynamic_cast<IntegerType const&>(_targetType) : addressType;
+				? dynamic_cast<IntegerType const&>(_targetType) : addressType;
 			if (stackTypeCategory == Type::Category::IntegerConstant)
 			{
 				IntegerConstantType const& constType = dynamic_cast<IntegerConstantType const&>(_typeOnStack);
@@ -187,7 +195,7 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 			else
 			{
 				IntegerType const& typeOnStack = stackTypeCategory == Type::Category::Integer
-												? dynamic_cast<IntegerType const&>(_typeOnStack) : addressType;
+					? dynamic_cast<IntegerType const&>(_typeOnStack) : addressType;
 				// Widening: clean up according to source type width
 				// Non-widening and force: clean up according to target type bits
 				if (targetType.getNumBits() > typeOnStack.getNumBits())
@@ -196,15 +204,17 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 					appendHighBitsCleanup(targetType);
 			}
 		}
-	}
-	else if (_typeOnStack != _targetType)
+		break;
+	default:
 		// All other types should not be convertible to non-equal types.
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid type conversion requested."));
+		solAssert(_typeOnStack == _targetType, "Invalid type conversion requested.");
+		break;
+	}
 }
 
 bool ExpressionCompiler::visit(Assignment const& _assignment)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_assignment);
+	CompilerContext::LocationSetter locationSetter(m_context, _assignment);
 	_assignment.getRightHandSide().accept(*this);
 	if (_assignment.getType()->isValueType())
 		appendTypeConversion(*_assignment.getRightHandSide().getType(), *_assignment.getType());
@@ -226,9 +236,12 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 		m_currentLValue->retrieveValue(_assignment.getLocation(), true);
 		appendOrdinaryBinaryOperatorCode(Token::AssignmentToBinaryOp(op), *_assignment.getType());
 		if (lvalueSize > 0)
+		{
+			solAssert(itemSize + lvalueSize <= 16, "Stack too deep.");
 			// value [lvalue_ref] updated_value
 			for (unsigned i = 0; i < itemSize; ++i)
 				m_context << eth::swapInstruction(itemSize + lvalueSize) << eth::Instruction::POP;
+		}
 	}
 	m_currentLValue->storeValue(*_assignment.getRightHandSide().getType(), _assignment.getLocation());
 	m_currentLValue.reset();
@@ -237,7 +250,7 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 
 bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_unaryOperation);
+	CompilerContext::LocationSetter locationSetter(m_context, _unaryOperation);
 	//@todo type checking and creating code for an operator should be in the same place:
 	// the operator should know how to convert itself and to which types it applies, so
 	// put this code together with "Type::acceptsBinary/UnaryOperator" into a class that
@@ -270,23 +283,24 @@ bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
 	case Token::Dec: // -- (pre- or postfix)
 		solAssert(!!m_currentLValue, "LValue not retrieved.");
 		m_currentLValue->retrieveValue(_unaryOperation.getLocation());
-		solAssert(m_currentLValue->sizeOnStack() <= 1, "Not implemented.");
 		if (!_unaryOperation.isPrefixOperation())
 		{
-			if (m_currentLValue->sizeOnStack() == 1)
-				m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2;
-			else
-				m_context << eth::Instruction::DUP1;
+			// store value for later
+			solAssert(_unaryOperation.getType()->getSizeOnStack() == 1, "Stack size != 1 not implemented.");
+			m_context << eth::Instruction::DUP1;
+			if (m_currentLValue->sizeOnStack() > 0)
+				for (unsigned i = 1 + m_currentLValue->sizeOnStack(); i > 0; --i)
+					m_context << eth::swapInstruction(i);
 		}
 		m_context << u256(1);
 		if (_unaryOperation.getOperator() == Token::Inc)
 			m_context << eth::Instruction::ADD;
 		else
-			m_context << eth::Instruction::SWAP1 << eth::Instruction::SUB; // @todo avoid the swap
-		// Stack for prefix: [ref] (*ref)+-1
-		// Stack for postfix: *ref [ref] (*ref)+-1
-		if (m_currentLValue->sizeOnStack() == 1)
-			m_context << eth::Instruction::SWAP1;
+			m_context << eth::Instruction::SWAP1 << eth::Instruction::SUB;
+		// Stack for prefix: [ref...] (*ref)+-1
+		// Stack for postfix: *ref [ref...] (*ref)+-1
+		for (unsigned i = m_currentLValue->sizeOnStack(); i > 0; --i)
+			m_context << eth::swapInstruction(i);
 		m_currentLValue->storeValue(
 			*_unaryOperation.getType(), _unaryOperation.getLocation(),
 			!_unaryOperation.isPrefixOperation());
@@ -307,7 +321,7 @@ bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
 
 bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_binaryOperation);
+	CompilerContext::LocationSetter locationSetter(m_context, _binaryOperation);
 	Expression const& leftExpression = _binaryOperation.getLeftExpression();
 	Expression const& rightExpression = _binaryOperation.getRightExpression();
 	Type const& commonType = _binaryOperation.getCommonType();
@@ -354,7 +368,7 @@ bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
 
 bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_functionCall);
+	CompilerContext::LocationSetter locationSetter(m_context, _functionCall);
 	using Location = FunctionType::Location;
 	if (_functionCall.isTypeConversion())
 	{
@@ -405,7 +419,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 			}
 			_functionCall.getExpression().accept(*this);
 
-			m_context.appendJump();
+			m_context.appendJump(eth::AssemblyItem::JumpType::IntoFunction);
 			m_context << returnLabel;
 
 			unsigned returnParametersSize = CompilerUtils::getSizeOnStack(function.getReturnParameterTypes());
@@ -528,8 +542,11 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 					appendTypeConversion(*arguments[arg - 1]->getType(),
 										 *function.getParameterTypes()[arg - 1], true);
 				}
-			m_context << u256(h256::Arith(dev::sha3(function.getCanonicalSignature(event.getName()))));
-			++numIndexed;
+			if (!event.isAnonymous())
+			{
+				m_context << u256(h256::Arith(dev::sha3(function.externalSignature(event.getName()))));
+				++numIndexed;
+			}
 			solAssert(numIndexed <= 4, "Too many indexed arguments.");
 			// Copy all non-indexed arguments to memory (data)
 			m_context << u256(0);
@@ -550,10 +567,13 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 		case Location::SHA256:
 		case Location::RIPEMD160:
 		{
+			_functionCall.getExpression().accept(*this);
 			static const map<Location, u256> contractAddresses{{Location::ECRecover, 1},
 															   {Location::SHA256, 2},
 															   {Location::RIPEMD160, 3}};
 			m_context << contractAddresses.find(function.getLocation())->second;
+			for (unsigned i = function.getSizeOnStack(); i > 0; --i)
+				m_context << eth::swapInstruction(i);
 			appendExternalFunctionCall(function, arguments, true);
 			break;
 		}
@@ -572,7 +592,7 @@ bool ExpressionCompiler::visit(NewExpression const&)
 
 void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_memberAccess);
+	CompilerContext::LocationSetter locationSetter(m_context, _memberAccess);
 	ASTString const& member = _memberAccess.getMemberName();
 	switch (_memberAccess.getExpression().getType()->getCategory())
 	{
@@ -639,13 +659,18 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 			m_context << eth::Instruction::GASPRICE;
 		else if (member == "data")
 			m_context << u256(0) << eth::Instruction::CALLDATASIZE;
+		else if (member == "sig")
+			m_context << u256(0) << eth::Instruction::CALLDATALOAD
+				<< (u256(0xffffffff) << (256 - 32)) << eth::Instruction::AND;
 		else
 			BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown magic member."));
 		break;
 	case Type::Category::Struct:
 	{
 		StructType const& type = dynamic_cast<StructType const&>(*_memberAccess.getExpression().getType());
-		m_context << type.getStorageOffsetOfMember(member) << eth::Instruction::ADD;
+		m_context << eth::Instruction::POP; // structs always align to new slot
+		pair<u256, unsigned> const& offsets = type.getStorageOffsetsOfMember(member);
+		m_context << offsets.first << eth::Instruction::ADD << u256(offsets.second);
 		setLValueToStorageItem(_memberAccess);
 		break;
 	}
@@ -707,110 +732,43 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 
 bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 {
-	CompilerContext::LocationSetter locationSetter(m_context, &_indexAccess);
+	CompilerContext::LocationSetter locationSetter(m_context, _indexAccess);
 	_indexAccess.getBaseExpression().accept(*this);
 
 	Type const& baseType = *_indexAccess.getBaseExpression().getType();
 	if (baseType.getCategory() == Type::Category::Mapping)
 	{
+		// storage byte offset is ignored for mappings, it should be zero.
+		m_context << eth::Instruction::POP;
+		// stack: storage_base_ref
 		Type const& keyType = *dynamic_cast<MappingType const&>(baseType).getKeyType();
-		m_context << u256(0);
+		m_context << u256(0); // memory position
 		solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
 		appendExpressionCopyToMemory(keyType, *_indexAccess.getIndexExpression());
-		solAssert(baseType.getSizeOnStack() == 1,
-				  "Unexpected: Not exactly one stack slot taken by subscriptable expression.");
 		m_context << eth::Instruction::SWAP1;
 		appendTypeMoveToMemory(IntegerType(256));
 		m_context << u256(0) << eth::Instruction::SHA3;
+		m_context << u256(0);
 		setLValueToStorageItem( _indexAccess);
 	}
 	else if (baseType.getCategory() == Type::Category::Array)
 	{
-		// stack layout: <base_ref> [<length>] <index>
 		ArrayType const& arrayType = dynamic_cast<ArrayType const&>(baseType);
 		solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
-		ArrayType::Location location = arrayType.getLocation();
-		eth::Instruction load =
-			location == ArrayType::Location::Storage ? eth::Instruction::SLOAD :
-			location == ArrayType::Location::Memory ? eth::Instruction::MLOAD :
-			eth::Instruction::CALLDATALOAD;
+
+		// remove storage byte offset
+		if (arrayType.getLocation() == ArrayType::Location::Storage)
+			m_context << eth::Instruction::POP;
 
 		_indexAccess.getIndexExpression()->accept(*this);
-		// retrieve length
-		if (!arrayType.isDynamicallySized())
-			m_context << arrayType.getLength();
-		else if (location == ArrayType::Location::CallData)
-			// length is stored on the stack
-			m_context << eth::Instruction::SWAP1;
-		else
-			m_context << eth::Instruction::DUP2 << load;
-		// stack: <base_ref> <index> <length>
-		// check out-of-bounds access
-		m_context << eth::Instruction::DUP2 << eth::Instruction::LT;
-		eth::AssemblyItem legalAccess = m_context.appendConditionalJump();
-		// out-of-bounds access throws exception (just STOP for now)
-		m_context << eth::Instruction::STOP;
-
-		m_context << legalAccess;
-		// stack: <base_ref> <index>
-		if (arrayType.isByteArray())
-			// byte array is packed differently, especially in storage
-			switch (location)
-			{
-			case ArrayType::Location::Storage:
-				// byte array index storage lvalue on stack (goal):
-				// <ref> <byte_number> = <base_ref + index / 32> <index % 32>
-				m_context << u256(32) << eth::Instruction::SWAP2;
-				CompilerUtils(m_context).computeHashStatic();
-				// stack: 32 index data_ref
-				m_context
-					<< eth::Instruction::DUP3 << eth::Instruction::DUP3
-					<< eth::Instruction::DIV << eth::Instruction::ADD
-				// stack: 32 index (data_ref + index / 32)
-					<< eth::Instruction::SWAP2 << eth::Instruction::SWAP1 << eth::Instruction::MOD;
-				setLValue<StorageByteArrayElement>(_indexAccess);
-				break;
-			case ArrayType::Location::CallData:
-				// no lvalue, just retrieve the value
-				m_context
-					<< eth::Instruction::ADD << eth::Instruction::CALLDATALOAD
-					<< u256(0) << eth::Instruction::BYTE;
-				break;
-			case ArrayType::Location::Memory:
-				solAssert(false, "Memory lvalues not yet implemented.");
-			}
-		else
+		// stack layout: <base_ref> [<length>] <index>
+		ArrayUtils(m_context).accessIndex(arrayType);
+		if (arrayType.getLocation() == ArrayType::Location::Storage)
 		{
-			u256 elementSize =
-				location == ArrayType::Location::Storage ?
-					arrayType.getBaseType()->getStorageSize() :
-					arrayType.getBaseType()->getCalldataEncodedSize();
-			solAssert(elementSize != 0, "Invalid element size.");
-			if (elementSize > 1)
-				m_context << elementSize << eth::Instruction::MUL;
-			if (arrayType.isDynamicallySized())
-			{
-				if (location == ArrayType::Location::Storage)
-				{
-					m_context << eth::Instruction::SWAP1;
-					CompilerUtils(m_context).computeHashStatic();
-				}
-				else if (location == ArrayType::Location::Memory)
-					m_context << u256(32) << eth::Instruction::ADD;
-			}
-			m_context << eth::Instruction::ADD;
-			switch (location)
-			{
-			case ArrayType::Location::CallData:
-				if (arrayType.getBaseType()->isValueType())
-					CompilerUtils(m_context).loadFromMemoryDynamic(*arrayType.getBaseType(), true, true, false);
-				break;
-			case ArrayType::Location::Storage:
+			if (arrayType.isByteArray())
+				setLValue<StorageByteArrayElement>(_indexAccess);
+			else
 				setLValueToStorageItem(_indexAccess);
-				break;
-			case ArrayType::Location::Memory:
-				solAssert(false, "Memory lvalues not yet implemented.");
-			}
 		}
 	}
 	else
@@ -821,18 +779,34 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 
 void ExpressionCompiler::endVisit(Identifier const& _identifier)
 {
+	CompilerContext::LocationSetter locationSetter(m_context, _identifier);
 	Declaration const* declaration = _identifier.getReferencedDeclaration();
 	if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
 	{
-		if (magicVar->getType()->getCategory() == Type::Category::Contract)
+		switch (magicVar->getType()->getCategory())
+		{
+		case Type::Category::Contract:
 			// "this" or "super"
 			if (!dynamic_cast<ContractType const&>(*magicVar->getType()).isSuper())
 				m_context << eth::Instruction::ADDRESS;
+			break;
+		case Type::Category::Integer:
+			// "now"
+			m_context << eth::Instruction::TIMESTAMP;
+			break;
+		default:
+			break;
+		}
 	}
 	else if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
 		m_context << m_context.getVirtualFunctionEntryLabel(*functionDef).pushTag();
-	else if (dynamic_cast<VariableDeclaration const*>(declaration))
-		setLValueFromDeclaration(*declaration, _identifier);
+	else if (auto variable = dynamic_cast<VariableDeclaration const*>(declaration))
+	{
+		if (!variable->isConstant())
+			setLValueFromDeclaration(*declaration, _identifier);
+		else
+			variable->getValue()->accept(*this);
+	}
 	else if (dynamic_cast<ContractDefinition const*>(declaration))
 	{
 		// no-op
@@ -860,11 +834,12 @@ void ExpressionCompiler::endVisit(Identifier const& _identifier)
 
 void ExpressionCompiler::endVisit(Literal const& _literal)
 {
+	CompilerContext::LocationSetter locationSetter(m_context, _literal);
 	switch (_literal.getType()->getCategory())
 	{
 	case Type::Category::IntegerConstant:
 	case Type::Category::Bool:
-	case Type::Category::String:
+	case Type::Category::FixedBytes:
 		m_context << _literal.getType()->literalValue(&_literal);
 		break;
 	default:
@@ -1115,7 +1090,7 @@ void ExpressionCompiler::setLValueFromDeclaration(Declaration const& _declaratio
 	if (m_context.isLocalVariable(&_declaration))
 		setLValue<StackVariable>(_expression, _declaration);
 	else if (m_context.isStateVariable(&_declaration))
-			setLValue<StorageItem>(_expression, _declaration);
+		setLValue<StorageItem>(_expression, _declaration);
 	else
 		BOOST_THROW_EXCEPTION(InternalCompilerError()
 			<< errinfo_sourceLocation(_expression.getLocation())
diff --git a/ExpressionCompiler.h b/ExpressionCompiler.h
index 9cab757e..2577d21b 100644
--- a/ExpressionCompiler.h
+++ b/ExpressionCompiler.h
@@ -42,7 +42,6 @@ class CompilerContext;
 class Type;
 class IntegerType;
 class ArrayType;
-class StaticStringType;
 
 /**
  * Compiler for expressions, i.e. converts an AST tree whose root is an Expression into a stream
@@ -140,7 +139,6 @@ void ExpressionCompiler::setLValue(Expression const& _expression, _Arguments con
 		m_currentLValue = move(lvalue);
 	else
 		lvalue->retrieveValue(_expression.getLocation(), true);
-
 }
 
 }
diff --git a/GlobalContext.cpp b/GlobalContext.cpp
index 60de5105..80cebd76 100644
--- a/GlobalContext.cpp
+++ b/GlobalContext.cpp
@@ -37,26 +37,27 @@ GlobalContext::GlobalContext():
 m_magicVariables(vector<shared_ptr<MagicVariableDeclaration const>>{make_shared<MagicVariableDeclaration>("block", make_shared<MagicType>(MagicType::Kind::Block)),
 					make_shared<MagicVariableDeclaration>("msg", make_shared<MagicType>(MagicType::Kind::Message)),
 					make_shared<MagicVariableDeclaration>("tx", make_shared<MagicType>(MagicType::Kind::Transaction)),
+					make_shared<MagicVariableDeclaration>("now", make_shared<IntegerType>(256)),
 					make_shared<MagicVariableDeclaration>("suicide",
 							make_shared<FunctionType>(strings{"address"}, strings{}, FunctionType::Location::Suicide)),
 					make_shared<MagicVariableDeclaration>("sha3",
-							make_shared<FunctionType>(strings(), strings{"hash"}, FunctionType::Location::SHA3, true)),
+							make_shared<FunctionType>(strings(), strings{"bytes32"}, FunctionType::Location::SHA3, true)),
 					make_shared<MagicVariableDeclaration>("log0",
-							make_shared<FunctionType>(strings{"hash"},strings{}, FunctionType::Location::Log0)),
+							make_shared<FunctionType>(strings{"bytes32"}, strings{}, FunctionType::Location::Log0)),
 					make_shared<MagicVariableDeclaration>("log1",
-							make_shared<FunctionType>(strings{"hash", "hash"},strings{}, FunctionType::Location::Log1)),
+							make_shared<FunctionType>(strings{"bytes32", "bytes32"}, strings{}, FunctionType::Location::Log1)),
 					make_shared<MagicVariableDeclaration>("log2",
-							make_shared<FunctionType>(strings{"hash", "hash", "hash"},strings{}, FunctionType::Location::Log2)),
+							make_shared<FunctionType>(strings{"bytes32", "bytes32", "bytes32"}, strings{}, FunctionType::Location::Log2)),
 					make_shared<MagicVariableDeclaration>("log3",
-							make_shared<FunctionType>(strings{"hash", "hash", "hash", "hash"},strings{}, FunctionType::Location::Log3)),
+							make_shared<FunctionType>(strings{"bytes32", "bytes32", "bytes32", "bytes32"}, strings{}, FunctionType::Location::Log3)),
 					make_shared<MagicVariableDeclaration>("log4",
-							make_shared<FunctionType>(strings{"hash", "hash", "hash", "hash", "hash"},strings{}, FunctionType::Location::Log4)),
+							make_shared<FunctionType>(strings{"bytes32", "bytes32", "bytes32", "bytes32", "bytes32"}, strings{}, FunctionType::Location::Log4)),
 					make_shared<MagicVariableDeclaration>("sha256",
-							make_shared<FunctionType>(strings(), strings{"hash"}, FunctionType::Location::SHA256, true)),
+							make_shared<FunctionType>(strings(), strings{"bytes32"}, FunctionType::Location::SHA256, true)),
 					make_shared<MagicVariableDeclaration>("ecrecover",
-							make_shared<FunctionType>(strings{"hash", "hash8", "hash", "hash"}, strings{"address"}, FunctionType::Location::ECRecover)),
+							make_shared<FunctionType>(strings{"bytes32", "uint8", "bytes32", "bytes32"}, strings{"address"}, FunctionType::Location::ECRecover)),
 					make_shared<MagicVariableDeclaration>("ripemd160",
-							make_shared<FunctionType>(strings(), strings{"hash160"}, FunctionType::Location::RIPEMD160, true))})
+							make_shared<FunctionType>(strings(), strings{"bytes20"}, FunctionType::Location::RIPEMD160, true))})
 {
 }
 
diff --git a/InterfaceHandler.cpp b/InterfaceHandler.cpp
index 99a7db96..aacbbfd7 100644
--- a/InterfaceHandler.cpp
+++ b/InterfaceHandler.cpp
@@ -70,6 +70,7 @@ std::unique_ptr<std::string> InterfaceHandler::getABIInterface(ContractDefinitio
 		Json::Value event;
 		event["type"] = "event";
 		event["name"] = it->getName();
+		event["anonymous"] = it->isAnonymous();
 		Json::Value params(Json::arrayValue);
 		for (auto const& p: it->getParameters())
 		{
@@ -128,7 +129,7 @@ std::unique_ptr<std::string> InterfaceHandler::getUserDocumentation(ContractDefi
 			if (!m_notice.empty())
 			{// since @notice is the only user tag if missing function should not appear
 				user["notice"] = Json::Value(m_notice);
-				methods[it.second->getCanonicalSignature()] = user;
+				methods[it.second->externalSignature()] = user;
 			}
 		}
 	}
@@ -174,8 +175,17 @@ std::unique_ptr<std::string> InterfaceHandler::getDevDocumentation(ContractDefin
 				method["author"] = m_author;
 
 			Json::Value params(Json::objectValue);
+			std::vector<std::string> paramNames = it.second->getParameterNames();
 			for (auto const& pair: m_params)
+			{
+				if (find(paramNames.begin(), paramNames.end(), pair.first) == paramNames.end())
+					// LTODO: mismatching parameter name, throw some form of warning and not just an exception
+					BOOST_THROW_EXCEPTION(
+						DocstringParsingError() <<
+						errinfo_comment("documented parameter \"" + pair.first + "\" not found found in the function")
+					);					
 				params[pair.first] = pair.second;
+			}
 
 			if (!m_params.empty())
 				method["params"] = params;
@@ -184,7 +194,7 @@ std::unique_ptr<std::string> InterfaceHandler::getDevDocumentation(ContractDefin
 				method["return"] = m_return;
 
 			if (!method.empty()) // add the function, only if we have any documentation to add
-				methods[it.second->getCanonicalSignature()] = method;
+				methods[it.second->externalSignature()] = method;
 		}
 	}
 	doc["methods"] = methods;
diff --git a/LValue.cpp b/LValue.cpp
index a036be80..234072bc 100644
--- a/LValue.cpp
+++ b/LValue.cpp
@@ -77,7 +77,8 @@ void StackVariable::setToZero(SourceLocation const& _location, bool) const
 StorageItem::StorageItem(CompilerContext& _compilerContext, Declaration const& _declaration):
 	StorageItem(_compilerContext, *_declaration.getType())
 {
-	m_context << m_context.getStorageLocationOfVariable(_declaration);
+	auto const& location = m_context.getStorageLocationOfVariable(_declaration);
+	m_context << location.first << u256(location.second);
 }
 
 StorageItem::StorageItem(CompilerContext& _compilerContext, Type const& _type):
@@ -86,62 +87,78 @@ StorageItem::StorageItem(CompilerContext& _compilerContext, Type const& _type):
 	if (m_dataType.isValueType())
 	{
 		solAssert(m_dataType.getStorageSize() == m_dataType.getSizeOnStack(), "");
-		solAssert(m_dataType.getStorageSize() <= numeric_limits<unsigned>::max(),
-			"The storage size of " + m_dataType.toString() + " should fit in an unsigned");
-		m_size = unsigned(m_dataType.getStorageSize());
+		solAssert(m_dataType.getStorageSize() == 1, "Invalid storage size.");
 	}
-	else
-		m_size = 0; // unused
 }
 
 void StorageItem::retrieveValue(SourceLocation const&, bool _remove) const
 {
+	// stack: storage_key storage_offset
 	if (!m_dataType.isValueType())
 		return; // no distinction between value and reference for non-value types
 	if (!_remove)
-		m_context << eth::Instruction::DUP1;
-	if (m_size == 1)
-		m_context << eth::Instruction::SLOAD;
+		CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
+	if (m_dataType.getStorageBytes() == 32)
+		m_context << eth::Instruction::POP << eth::Instruction::SLOAD;
 	else
-		for (unsigned i = 0; i < m_size; ++i)
-		{
-			m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP1;
-			if (i + 1 < m_size)
-				m_context << u256(1) << eth::Instruction::ADD;
-			else
-				m_context << eth::Instruction::POP;
-		}
+	{
+		m_context
+			<< eth::Instruction::SWAP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP1
+			<< u256(0x100) << eth::Instruction::EXP << eth::Instruction::SWAP1 << eth::Instruction::DIV;
+		if (m_dataType.getCategory() == Type::Category::FixedBytes)
+			m_context << (u256(0x1) << (256 - 8 * m_dataType.getStorageBytes())) << eth::Instruction::MUL;
+		else
+			m_context << ((u256(0x1) << (8 * m_dataType.getStorageBytes())) - 1) << eth::Instruction::AND;
+	}
 }
 
 void StorageItem::storeValue(Type const& _sourceType, SourceLocation const& _location, bool _move) const
 {
-	// stack layout: value value ... value target_ref
+	// stack: value storage_key storage_offset
 	if (m_dataType.isValueType())
 	{
-		if (!_move) // copy values
+		solAssert(m_dataType.getStorageBytes() <= 32, "Invalid storage bytes size.");
+		solAssert(m_dataType.getStorageBytes() > 0, "Invalid storage bytes size.");
+		if (m_dataType.getStorageBytes() == 32)
 		{
-			if (m_size + 1 > 16)
-				BOOST_THROW_EXCEPTION(CompilerError()
-					<< errinfo_sourceLocation(_location) << errinfo_comment("Stack too deep."));
-			for (unsigned i = 0; i < m_size; ++i)
-				m_context << eth::dupInstruction(m_size + 1) << eth::Instruction::SWAP1;
+			// offset should be zero
+			m_context << eth::Instruction::POP;
+			if (!_move)
+				m_context << eth::Instruction::DUP2 << eth::Instruction::SWAP1;
+			m_context << eth::Instruction::SSTORE;
 		}
-		if (m_size > 1) // store high index value first
-			m_context << u256(m_size - 1) << eth::Instruction::ADD;
-		for (unsigned i = 0; i < m_size; ++i)
+		else
 		{
-			if (i + 1 >= m_size)
-				m_context << eth::Instruction::SSTORE;
-			else
-				// stack here: value value ... value value (target_ref+offset)
-				m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2
-					<< eth::Instruction::SSTORE
-					<< u256(1) << eth::Instruction::SWAP1 << eth::Instruction::SUB;
+			// OR the value into the other values in the storage slot
+			m_context << u256(0x100) << eth::Instruction::EXP;
+			// stack: value storage_ref multiplier
+			// fetch old value
+			m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
+			// stack: value storege_ref multiplier old_full_value
+			// clear bytes in old value
+			m_context
+				<< eth::Instruction::DUP2 << ((u256(1) << (8 * m_dataType.getStorageBytes())) - 1)
+				<< eth::Instruction::MUL;
+			m_context << eth::Instruction::NOT << eth::Instruction::AND;
+			// stack: value storage_ref multiplier cleared_value
+			m_context
+				<< eth::Instruction::SWAP1 << eth::Instruction::DUP4;
+			// stack: value storage_ref cleared_value multiplier value
+			if (m_dataType.getCategory() == Type::Category::FixedBytes)
+				m_context
+					<< (u256(0x1) << (256 - 8 * dynamic_cast<FixedBytesType const&>(m_dataType).getNumBytes()))
+					<< eth::Instruction::SWAP1 << eth::Instruction::DIV;
+			m_context  << eth::Instruction::MUL << eth::Instruction::OR;
+			// stack: value storage_ref updated_value
+			m_context << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
+			if (_move)
+				m_context << eth::Instruction::POP;
 		}
 	}
 	else
 	{
-		solAssert(_sourceType.getCategory() == m_dataType.getCategory(),
+		solAssert(
+			_sourceType.getCategory() == m_dataType.getCategory(),
 			"Wrong type conversation for assignment.");
 		if (m_dataType.getCategory() == Type::Category::Array)
 		{
@@ -149,11 +166,12 @@ void StorageItem::storeValue(Type const& _sourceType, SourceLocation const& _loc
 						dynamic_cast<ArrayType const&>(m_dataType),
 						dynamic_cast<ArrayType const&>(_sourceType));
 			if (_move)
-				m_context << eth::Instruction::POP;
+				CompilerUtils(m_context).popStackElement(_sourceType);
 		}
 		else if (m_dataType.getCategory() == Type::Category::Struct)
 		{
-			// stack layout: source_ref target_ref
+			// stack layout: source_ref source_offset target_ref target_offset
+			// note that we have structs, so offsets should be zero and are ignored
 			auto const& structType = dynamic_cast<StructType const&>(m_dataType);
 			solAssert(structType == _sourceType, "Struct assignment with conversion.");
 			for (auto const& member: structType.getMembers())
@@ -162,26 +180,37 @@ void StorageItem::storeValue(Type const& _sourceType, SourceLocation const& _loc
 				TypePointer const& memberType = member.second;
 				if (memberType->getCategory() == Type::Category::Mapping)
 					continue;
-				m_context << structType.getStorageOffsetOfMember(member.first)
-					<< eth::Instruction::DUP3 << eth::Instruction::DUP2 << eth::Instruction::ADD;
-				// stack: source_ref target_ref member_offset source_member_ref
+				pair<u256, unsigned> const& offsets = structType.getStorageOffsetsOfMember(member.first);
+				m_context
+					<< offsets.first << u256(offsets.second)
+					<< eth::Instruction::DUP6 << eth::Instruction::DUP3
+					<< eth::Instruction::ADD << eth::Instruction::DUP2;
+				// stack: source_ref source_off target_ref target_off member_slot_offset member_byte_offset source_member_ref source_member_off
 				StorageItem(m_context, *memberType).retrieveValue(_location, true);
-				// stack: source_ref target_ref member_offset source_value...
-				m_context << eth::dupInstruction(2 + memberType->getSizeOnStack())
-					<< eth::dupInstruction(2 + memberType->getSizeOnStack()) << eth::Instruction::ADD;
-				// stack: source_ref target_ref member_offset source_value... target_member_ref
+				// stack: source_ref source_off target_ref target_off member_offset source_value...
+				solAssert(4 + memberType->getSizeOnStack() <= 16, "Stack too deep.");
+				m_context
+					<< eth::dupInstruction(4 + memberType->getSizeOnStack())
+					<< eth::dupInstruction(3 + memberType->getSizeOnStack()) << eth::Instruction::ADD
+					<< eth::dupInstruction(2 + memberType->getSizeOnStack());
+				// stack: source_ref source_off target_ref target_off member_slot_offset member_byte_offset source_value... target_member_ref target_member_byte_off
 				StorageItem(m_context, *memberType).storeValue(*memberType, _location, true);
-				m_context << eth::Instruction::POP;
+				m_context << eth::Instruction::POP << eth::Instruction::POP;
 			}
 			if (_move)
-				m_context << eth::Instruction::POP;
+				m_context
+					<< eth::Instruction::POP << eth::Instruction::POP
+					<< eth::Instruction::POP << eth::Instruction::POP;
 			else
-				m_context << eth::Instruction::SWAP1;
-			m_context << eth::Instruction::POP;
+				m_context
+					<< eth::Instruction::SWAP2 << eth::Instruction::POP
+					<< eth::Instruction::SWAP2 << eth::Instruction::POP;
 		}
 		else
-			BOOST_THROW_EXCEPTION(InternalCompilerError()
-				<< errinfo_sourceLocation(_location) << errinfo_comment("Invalid non-value type for assignment."));
+			BOOST_THROW_EXCEPTION(
+				InternalCompilerError()
+					<< errinfo_sourceLocation(_location)
+					<< errinfo_comment("Invalid non-value type for assignment."));
 	}
 }
 
@@ -190,12 +219,13 @@ void StorageItem::setToZero(SourceLocation const&, bool _removeReference) const
 	if (m_dataType.getCategory() == Type::Category::Array)
 	{
 		if (!_removeReference)
-			m_context << eth::Instruction::DUP1;
+			CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
 		ArrayUtils(m_context).clearArray(dynamic_cast<ArrayType const&>(m_dataType));
 	}
 	else if (m_dataType.getCategory() == Type::Category::Struct)
 	{
-		// stack layout: ref
+		// stack layout: storage_key storage_offset
+		// @todo this can be improved for packed types
 		auto const& structType = dynamic_cast<StructType const&>(m_dataType);
 		for (auto const& member: structType.getMembers())
 		{
@@ -203,38 +233,48 @@ void StorageItem::setToZero(SourceLocation const&, bool _removeReference) const
 			TypePointer const& memberType = member.second;
 			if (memberType->getCategory() == Type::Category::Mapping)
 				continue;
-			m_context << structType.getStorageOffsetOfMember(member.first)
-				<< eth::Instruction::DUP2 << eth::Instruction::ADD;
+			pair<u256, unsigned> const& offsets = structType.getStorageOffsetsOfMember(member.first);
+			m_context
+				<< offsets.first << eth::Instruction::DUP3 << eth::Instruction::ADD
+				<< u256(offsets.second);
 			StorageItem(m_context, *memberType).setToZero();
 		}
 		if (_removeReference)
-			m_context << eth::Instruction::POP;
+			m_context << eth::Instruction::POP << eth::Instruction::POP;
 	}
 	else
 	{
 		solAssert(m_dataType.isValueType(), "Clearing of unsupported type requested: " + m_dataType.toString());
-		if (m_size == 0 && _removeReference)
-			m_context << eth::Instruction::POP;
-		else if (m_size == 1)
+		// @todo actually use offset
+		if (!_removeReference)
+			CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
+		if (m_dataType.getStorageBytes() == 32)
+		{
+			// offset should be zero
 			m_context
-				<< u256(0) << (_removeReference ? eth::Instruction::SWAP1 : eth::Instruction::DUP2)
-				<< eth::Instruction::SSTORE;
+				<< eth::Instruction::POP << u256(0)
+				<< eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
+		}
 		else
 		{
-			if (!_removeReference)
-				m_context << eth::Instruction::DUP1;
-			for (unsigned i = 0; i < m_size; ++i)
-				if (i + 1 >= m_size)
-					m_context << u256(0) << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
-				else
-					m_context << u256(0) << eth::Instruction::DUP2 << eth::Instruction::SSTORE
-						<< u256(1) << eth::Instruction::ADD;
+			m_context << u256(0x100) << eth::Instruction::EXP;
+			// stack: storage_ref multiplier
+			// fetch old value
+			m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
+			// stack: storege_ref multiplier old_full_value
+			// clear bytes in old value
+			m_context
+				<< eth::Instruction::SWAP1 << ((u256(1) << (8 * m_dataType.getStorageBytes())) - 1)
+				<< eth::Instruction::MUL;
+			m_context << eth::Instruction::NOT << eth::Instruction::AND;
+			// stack: storage_ref cleared_value
+			m_context << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
 		}
 	}
 }
 
 /// Used in StorageByteArrayElement
-static IntegerType byteType(8, IntegerType::Modifier::Hash);
+static FixedBytesType byteType(1);
 
 StorageByteArrayElement::StorageByteArrayElement(CompilerContext& _compilerContext):
 	LValue(_compilerContext, byteType)
@@ -250,6 +290,7 @@ void StorageByteArrayElement::retrieveValue(SourceLocation const&, bool _remove)
 	else
 		m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD
 			<< eth::Instruction::DUP2 << eth::Instruction::BYTE;
+	m_context << (u256(1) << (256 - 8)) << eth::Instruction::MUL;
 }
 
 void StorageByteArrayElement::storeValue(Type const&, SourceLocation const&, bool _move) const
@@ -265,8 +306,9 @@ void StorageByteArrayElement::storeValue(Type const&, SourceLocation const&, boo
 	m_context << eth::Instruction::DUP2 << u256(0xff) << eth::Instruction::MUL
 		<< eth::Instruction::NOT << eth::Instruction::AND;
 	// stack: value ref (1<<(32-byte_number)) old_full_value_with_cleared_byte
-	m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP4 << eth::Instruction::MUL
-		<< eth::Instruction::OR;
+	m_context << eth::Instruction::SWAP1;
+	m_context << (u256(1) << (256 - 8)) << eth::Instruction::DUP5 << eth::Instruction::DIV
+		<< eth::Instruction::MUL << eth::Instruction::OR;
 	// stack: value ref new_full_value
 	m_context << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
 	if (_move)
@@ -297,6 +339,8 @@ StorageArrayLength::StorageArrayLength(CompilerContext& _compilerContext, const
 	m_arrayType(_arrayType)
 {
 	solAssert(m_arrayType.isDynamicallySized(), "");
+	// storage byte offset must be zero
+	m_context << eth::Instruction::POP;
 }
 
 void StorageArrayLength::retrieveValue(SourceLocation const&, bool _remove) const
diff --git a/LValue.h b/LValue.h
index c57c80e3..ad622516 100644
--- a/LValue.h
+++ b/LValue.h
@@ -98,7 +98,9 @@ private:
 };
 
 /**
- * Reference to some item in storage. The (starting) position of the item is stored on the stack.
+ * Reference to some item in storage. On the stack this is <storage key> <offset_inside_value>,
+ * where 0 <= offset_inside_value < 32 and an offset of i means that the value is multiplied
+ * by 2**i before storing it.
  */
 class StorageItem: public LValue
 {
@@ -107,6 +109,7 @@ public:
 	StorageItem(CompilerContext& _compilerContext, Declaration const& _declaration);
 	/// Constructs the LValue and assumes that the storage reference is already on the stack.
 	StorageItem(CompilerContext& _compilerContext, Type const& _type);
+	virtual unsigned sizeOnStack() const { return 2; }
 	virtual void retrieveValue(SourceLocation const& _location, bool _remove = false) const override;
 	virtual void storeValue(
 		Type const& _sourceType,
@@ -117,11 +120,6 @@ public:
 		SourceLocation const& _location = SourceLocation(),
 		bool _removeReference = true
 	) const override;
-
-private:
-	/// Number of stack elements occupied by the value (not the reference).
-	/// Only used for value types.
-	unsigned m_size;
 };
 
 /**
diff --git a/Parser.cpp b/Parser.cpp
index 44d11159..5c7676df 100644
--- a/Parser.cpp
+++ b/Parser.cpp
@@ -164,8 +164,17 @@ ASTPointer<ContractDefinition> Parser::parseContractDefinition()
 	}
 	nodeFactory.markEndPosition();
 	expectToken(Token::RBrace);
-	return nodeFactory.createNode<ContractDefinition>(name, docString, baseContracts, structs, enums,
-													  stateVariables, functions, modifiers, events);
+	return nodeFactory.createNode<ContractDefinition>(
+		name,
+		docString,
+		baseContracts,
+		structs,
+		enums,
+		stateVariables,
+		functions,
+		modifiers,
+		events
+	);
 }
 
 ASTPointer<InheritanceSpecifier> Parser::parseInheritanceSpecifier()
@@ -247,8 +256,15 @@ ASTPointer<FunctionDefinition> Parser::parseFunctionDefinition(ASTString const*
 	}
 	else
 		returnParameters = createEmptyParameterList();
-	ASTPointer<Block> block = parseBlock();
-	nodeFactory.setEndPositionFromNode(block);
+	ASTPointer<Block> block = ASTPointer<Block>();
+	nodeFactory.markEndPosition();
+	if (m_scanner->getCurrentToken() != Token::Semicolon)
+	{
+		block = parseBlock();
+		nodeFactory.setEndPositionFromNode(block);
+	}
+	else
+		m_scanner->next(); // just consume the ';'
 	bool const c_isConstructor = (_contractName && *name == *_contractName);
 	return nodeFactory.createNode<FunctionDefinition>(name, visibility, c_isConstructor, docstring,
 													  parameters, isDeclaredConst, modifiers,
@@ -317,6 +333,7 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 			nodeFactory.setEndPositionFromNode(type);
 	}
 	bool isIndexed = false;
+	bool isDeclaredConst = false;
 	ASTPointer<ASTString> identifier;
 	Token::Value token = m_scanner->getCurrentToken();
 	Declaration::Visibility visibility(Declaration::Visibility::Default);
@@ -327,7 +344,13 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 		isIndexed = true;
 		m_scanner->next();
 	}
+	if (token == Token::Const)
+	{
+		isDeclaredConst = true;
+		m_scanner->next();
+	}
 	nodeFactory.markEndPosition();
+
 	if (_options.allowEmptyName && m_scanner->getCurrentToken() != Token::Identifier)
 	{
 		identifier = make_shared<ASTString>("");
@@ -348,7 +371,7 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 	}
 	return nodeFactory.createNode<VariableDeclaration>(type, identifier, value,
 									visibility, _options.isStateVariable,
-									isIndexed);
+									isIndexed, isDeclaredConst);
 }
 
 ASTPointer<ModifierDefinition> Parser::parseModifierDefinition()
@@ -387,9 +410,15 @@ ASTPointer<EventDefinition> Parser::parseEventDefinition()
 		parameters = parseParameterList(true, true);
 	else
 		parameters = createEmptyParameterList();
+	bool anonymous = false;
+	if (m_scanner->getCurrentToken() == Token::Anonymous)
+	{
+		anonymous = true;
+		m_scanner->next();
+	}
 	nodeFactory.markEndPosition();
 	expectToken(Token::Semicolon);
-	return nodeFactory.createNode<EventDefinition>(name, docstring, parameters);
+	return nodeFactory.createNode<EventDefinition>(name, docstring, parameters, anonymous);
 }
 
 ASTPointer<ModifierInvocation> Parser::parseModifierInvocation()
@@ -913,6 +942,7 @@ Parser::LookAheadInfo Parser::peekStatementType() const
 	// In all other cases, we have an expression statement.
 	Token::Value token(m_scanner->getCurrentToken());
 	bool mightBeTypeName = (Token::isElementaryTypeName(token) || token == Token::Identifier);
+
 	if (token == Token::Mapping || token == Token::Var ||
 			(mightBeTypeName && m_scanner->peekNextToken() == Token::Identifier))
 		return LookAheadInfo::VariableDeclarationStatement;
diff --git a/Parser.h b/Parser.h
index 87eb2f8f..08c47c25 100644
--- a/Parser.h
+++ b/Parser.h
@@ -34,6 +34,8 @@ class Scanner;
 class Parser
 {
 public:
+	Parser() {}
+
 	ASTPointer<SourceUnit> parse(std::shared_ptr<Scanner> const& _scanner);
 	std::shared_ptr<std::string const> const& getSourceName() const;
 
@@ -64,8 +66,7 @@ private:
 	ASTPointer<StructDefinition> parseStructDefinition();
 	ASTPointer<EnumDefinition> parseEnumDefinition();
 	ASTPointer<EnumValue> parseEnumValue();
-	ASTPointer<VariableDeclaration> parseVariableDeclaration(
-		VarDeclParserOptions const& _options = VarDeclParserOptions(),
+	ASTPointer<VariableDeclaration> parseVariableDeclaration(VarDeclParserOptions const& _options = VarDeclParserOptions(),
 		ASTPointer<TypeName> const& _lookAheadArrayType = ASTPointer<TypeName>());
 	ASTPointer<ModifierDefinition> parseModifierDefinition();
 	ASTPointer<EventDefinition> parseEventDefinition();
diff --git a/Token.h b/Token.h
index 85979b56..1435dcc5 100644
--- a/Token.h
+++ b/Token.h
@@ -143,8 +143,8 @@ namespace solidity
 	\
 	/* Keywords */                                                     \
 	K(Break, "break", 0)                                               \
-	K(Case, "case", 0)                                                 \
 	K(Const, "constant", 0)                                            \
+	K(Anonymous, "anonymous", 0)                                       \
 	K(Continue, "continue", 0)                                         \
 	K(Contract, "contract", 0)                                         \
 	K(Default, "default", 0)                                           \
@@ -167,7 +167,6 @@ namespace solidity
 	K(Return, "return", 0)                                             \
 	K(Returns, "returns", 0)                                           \
 	K(Struct, "struct", 0)                                             \
-	K(Switch, "switch", 0)                                             \
 	K(Var, "var", 0)                                                   \
 	K(While, "while", 0)                                               \
 	K(Enum, "enum", 0)                                                 \
@@ -252,77 +251,43 @@ namespace solidity
 	K(UInt240, "uint240", 0)                                           \
 	K(UInt248, "uint248", 0)                                           \
 	K(UInt256, "uint256", 0)                                           \
-	K(Hash, "hash", 0)                                                 \
-	K(Hash8, "hash8", 0)                                               \
-	K(Hash16, "hash16", 0)                                             \
-	K(Hash24, "hash24", 0)                                             \
-	K(Hash32, "hash32", 0)                                             \
-	K(Hash40, "hash40", 0)                                             \
-	K(Hash48, "hash48", 0)                                             \
-	K(Hash56, "hash56", 0)                                             \
-	K(Hash64, "hash64", 0)                                             \
-	K(Hash72, "hash72", 0)                                             \
-	K(Hash80, "hash80", 0)                                             \
-	K(Hash88, "hash88", 0)                                             \
-	K(Hash96, "hash96", 0)                                             \
-	K(Hash104, "hash104", 0)                                           \
-	K(Hash112, "hash112", 0)                                           \
-	K(Hash120, "hash120", 0)                                           \
-	K(Hash128, "hash128", 0)                                           \
-	K(Hash136, "hash136", 0)                                           \
-	K(Hash144, "hash144", 0)                                           \
-	K(Hash152, "hash152", 0)                                           \
-	K(Hash160, "hash160", 0)                                           \
-	K(Hash168, "hash168", 0)                                           \
-	K(Hash176, "hash178", 0)                                           \
-	K(Hash184, "hash184", 0)                                           \
-	K(Hash192, "hash192", 0)                                           \
-	K(Hash200, "hash200", 0)                                           \
-	K(Hash208, "hash208", 0)                                           \
-	K(Hash216, "hash216", 0)                                           \
-	K(Hash224, "hash224", 0)                                           \
-	K(Hash232, "hash232", 0)                                           \
-	K(Hash240, "hash240", 0)                                           \
-	K(Hash248, "hash248", 0)                                           \
-	K(Hash256, "hash256", 0)                                           \
+	K(Bytes0, "bytes0", 0)                                             \
+	K(Bytes1, "bytes1", 0)                                             \
+	K(Bytes2, "bytes2", 0)                                             \
+	K(Bytes3, "bytes3", 0)                                             \
+	K(Bytes4, "bytes4", 0)                                             \
+	K(Bytes5, "bytes5", 0)                                             \
+	K(Bytes6, "bytes6", 0)                                             \
+	K(Bytes7, "bytes7", 0)                                             \
+	K(Bytes8, "bytes8", 0)                                             \
+	K(Bytes9, "bytes9", 0)                                             \
+	K(Bytes10, "bytes10", 0)                                           \
+	K(Bytes11, "bytes11", 0)                                           \
+	K(Bytes12, "bytes12", 0)                                           \
+	K(Bytes13, "bytes13", 0)                                           \
+	K(Bytes14, "bytes14", 0)                                           \
+	K(Bytes15, "bytes15", 0)                                           \
+	K(Bytes16, "bytes16", 0)                                           \
+	K(Bytes17, "bytes17", 0)                                           \
+	K(Bytes18, "bytes18", 0)                                           \
+	K(Bytes19, "bytes19", 0)                                           \
+	K(Bytes20, "bytes20", 0)                                           \
+	K(Bytes21, "bytes21", 0)                                           \
+	K(Bytes22, "bytes22", 0)                                           \
+	K(Bytes23, "bytes23", 0)                                           \
+	K(Bytes24, "bytes24", 0)                                           \
+	K(Bytes25, "bytes25", 0)                                           \
+	K(Bytes26, "bytes26", 0)                                           \
+	K(Bytes27, "bytes27", 0)                                           \
+	K(Bytes28, "bytes28", 0)                                           \
+	K(Bytes29, "bytes29", 0)                                           \
+	K(Bytes30, "bytes30", 0)                                           \
+	K(Bytes31, "bytes31", 0)                                           \
+	K(Bytes32, "bytes32", 0)                                           \
+	K(Bytes, "bytes", 0)                                               \
+	K(Byte, "byte", 0)                                                 \
 	K(Address, "address", 0)                                           \
 	K(Bool, "bool", 0)                                                 \
-	K(Bytes, "bytes", 0)                                               \
-	K(StringType, "string", 0)                                         \
-	K(String0, "string0", 0)                                           \
-	K(String1, "string1", 0)                                           \
-	K(String2, "string2", 0)                                           \
-	K(String3, "string3", 0)                                           \
-	K(String4, "string4", 0)                                           \
-	K(String5, "string5", 0)                                           \
-	K(String6, "string6", 0)                                           \
-	K(String7, "string7", 0)                                           \
-	K(String8, "string8", 0)                                           \
-	K(String9, "string9", 0)                                           \
-	K(String10, "string10", 0)                                         \
-	K(String11, "string11", 0)                                         \
-	K(String12, "string12", 0)                                         \
-	K(String13, "string13", 0)                                         \
-	K(String14, "string14", 0)                                         \
-	K(String15, "string15", 0)                                         \
-	K(String16, "string16", 0)                                         \
-	K(String17, "string17", 0)                                         \
-	K(String18, "string18", 0)                                         \
-	K(String19, "string19", 0)                                         \
-	K(String20, "string20", 0)                                         \
-	K(String21, "string21", 0)                                         \
-	K(String22, "string22", 0)                                         \
-	K(String23, "string23", 0)                                         \
-	K(String24, "string24", 0)                                         \
-	K(String25, "string25", 0)                                         \
-	K(String26, "string26", 0)                                         \
-	K(String27, "string27", 0)                                         \
-	K(String28, "string28", 0)                                         \
-	K(String29, "string29", 0)                                         \
-	K(String30, "string30", 0)                                         \
-	K(String31, "string31", 0)                                         \
-	K(String32, "string32", 0)                                         \
-	K(Text, "text", 0)                                                 \
 	K(Real, "real", 0)                                                 \
 	K(UReal, "ureal", 0)                                               \
 	T(TypesEnd, NULL, 0) /* used as type enum end marker */            \
@@ -338,6 +303,16 @@ namespace solidity
 	/* Identifiers (not keywords or future reserved words). */         \
 	T(Identifier, NULL, 0)                                             \
 	\
+	/* Keywords reserved for future. use*/                             \
+	T(String, "string", 0)                                             \
+	K(Case, "case", 0)                                                 \
+	K(Switch, "switch", 0)                                             \
+	K(Throw, "throw", 0)                                               \
+	K(Try, "try", 0)                                                   \
+	K(Catch, "catch", 0)                                               \
+	K(Using, "using", 0)                                               \
+	K(Type, "type", 0)                                                 \
+	K(TypeOf, "typeof", 0)                                             \
 	/* Illegal token - not able to scan. */                            \
 	T(Illegal, "ILLEGAL", 0)                                           \
 	\
diff --git a/Types.cpp b/Types.cpp
index 454d79d9..78649cc9 100644
--- a/Types.cpp
+++ b/Types.cpp
@@ -20,14 +20,14 @@
  * Solidity data types
  */
 
+#include <libsolidity/Types.h>
+#include <limits>
+#include <boost/range/adaptor/reversed.hpp>
 #include <libdevcore/CommonIO.h>
 #include <libdevcore/CommonData.h>
 #include <libsolidity/Utils.h>
-#include <libsolidity/Types.h>
 #include <libsolidity/AST.h>
 
-#include <limits>
-
 using namespace std;
 
 namespace dev
@@ -35,28 +35,113 @@ namespace dev
 namespace solidity
 {
 
+void StorageOffsets::computeOffsets(TypePointers const& _types)
+{
+	bigint slotOffset = 0;
+	unsigned byteOffset = 0;
+	map<size_t, pair<u256, unsigned>> offsets;
+	for (size_t i = 0; i < _types.size(); ++i)
+	{
+		TypePointer const& type = _types[i];
+		if (!type->canBeStored())
+			continue;
+		if (byteOffset + type->getStorageBytes() > 32)
+		{
+			// would overflow, go to next slot
+			++slotOffset;
+			byteOffset = 0;
+		}
+		if (slotOffset >= bigint(1) << 256)
+			BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Object too large for storage."));
+		offsets[i] = make_pair(u256(slotOffset), byteOffset);
+		solAssert(type->getStorageSize() >= 1, "Invalid storage size.");
+		if (type->getStorageSize() == 1 && byteOffset + type->getStorageBytes() <= 32)
+			byteOffset += type->getStorageBytes();
+		else
+		{
+			slotOffset += type->getStorageSize();
+			byteOffset = 0;
+		}
+	}
+	if (byteOffset > 0)
+		++slotOffset;
+	if (slotOffset >= bigint(1) << 256)
+		BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Object too large for storage."));
+	m_storageSize = u256(slotOffset);
+	swap(m_offsets, offsets);
+}
+
+pair<u256, unsigned> const* StorageOffsets::getOffset(size_t _index) const
+{
+	if (m_offsets.count(_index))
+		return &m_offsets.at(_index);
+	else
+		return nullptr;
+}
+
+MemberList& MemberList::operator=(MemberList&& _other)
+{
+	m_memberTypes = std::move(_other.m_memberTypes);
+	m_storageOffsets = std::move(_other.m_storageOffsets);
+	return *this;
+}
+
+std::pair<u256, unsigned> const* MemberList::getMemberStorageOffset(string const& _name) const
+{
+	if (!m_storageOffsets)
+	{
+		TypePointers memberTypes;
+		memberTypes.reserve(m_memberTypes.size());
+		for (auto const& nameAndType: m_memberTypes)
+			memberTypes.push_back(nameAndType.second);
+		m_storageOffsets.reset(new StorageOffsets());
+		m_storageOffsets->computeOffsets(memberTypes);
+	}
+	for (size_t index = 0; index < m_memberTypes.size(); ++index)
+		if (m_memberTypes[index].first == _name)
+			return m_storageOffsets->getOffset(index);
+	return nullptr;
+}
+
+u256 const& MemberList::getStorageSize() const
+{
+	// trigger lazy computation
+	getMemberStorageOffset("");
+	return m_storageOffsets->getStorageSize();
+}
+
 TypePointer Type::fromElementaryTypeName(Token::Value _typeToken)
 {
-	solAssert(Token::isElementaryTypeName(_typeToken), "Elementary type name expected.");
+	char const* tokenCstr = Token::toString(_typeToken);
+	solAssert(Token::isElementaryTypeName(_typeToken),
+		"Expected an elementary type name but got " + ((tokenCstr) ? std::string(Token::toString(_typeToken)) : ""));
 
-	if (Token::Int <= _typeToken && _typeToken <= Token::Hash256)
+	if (Token::Int <= _typeToken && _typeToken <= Token::Bytes32)
 	{
 		int offset = _typeToken - Token::Int;
 		int bytes = offset % 33;
-		if (bytes == 0)
+		if (bytes == 0 && _typeToken != Token::Bytes0)
 			bytes = 32;
 		int modifier = offset / 33;
-		return make_shared<IntegerType>(bytes * 8,
-										modifier == 0 ? IntegerType::Modifier::Signed :
-										modifier == 1 ? IntegerType::Modifier::Unsigned :
-										IntegerType::Modifier::Hash);
+		switch(modifier)
+		{
+		case 0:
+			return make_shared<IntegerType>(bytes * 8, IntegerType::Modifier::Signed);
+		case 1:
+			return make_shared<IntegerType>(bytes * 8, IntegerType::Modifier::Unsigned);
+		case 2:
+			return make_shared<FixedBytesType>(bytes);
+		default:
+			solAssert(false, "Unexpected modifier value. Should never happen");
+			return TypePointer();
+		}
 	}
+	else if (_typeToken == Token::Byte)
+		return make_shared<FixedBytesType>(1);
 	else if (_typeToken == Token::Address)
 		return make_shared<IntegerType>(0, IntegerType::Modifier::Address);
 	else if (_typeToken == Token::Bool)
 		return make_shared<BoolType>();
-	else if (Token::String0 <= _typeToken && _typeToken <= Token::String32)
-		return make_shared<StaticStringType>(int(_typeToken) - int(Token::String0));
 	else if (_typeToken == Token::Bytes)
 		return make_shared<ArrayType>(ArrayType::Location::Storage);
 	else
@@ -99,6 +184,8 @@ TypePointer Type::fromArrayTypeName(TypeName& _baseTypeName, Expression* _length
 	TypePointer baseType = _baseTypeName.toType();
 	if (!baseType)
 		BOOST_THROW_EXCEPTION(_baseTypeName.createTypeError("Invalid type name."));
+	if (baseType->getStorageBytes() == 0)
+		BOOST_THROW_EXCEPTION(_baseTypeName.createTypeError("Illegal base type of storage size zero for array."));
 	if (_length)
 	{
 		if (!_length->getType())
@@ -123,7 +210,7 @@ TypePointer Type::forLiteral(Literal const& _literal)
 		return make_shared<IntegerConstantType>(_literal);
 	case Token::StringLiteral:
 		//@todo put larger strings into dynamic strings
-		return StaticStringType::smallestTypeForLiteral(_literal.getValue());
+		return FixedBytesType::smallestTypeForLiteral(_literal.getValue());
 	default:
 		return shared_ptr<Type>();
 	}
@@ -139,7 +226,7 @@ TypePointer Type::commonType(TypePointer const& _a, TypePointer const& _b)
 		return TypePointer();
 }
 
-const MemberList Type::EmptyMemberList = MemberList();
+const MemberList Type::EmptyMemberList;
 
 IntegerType::IntegerType(int _bits, IntegerType::Modifier _modifier):
 	m_bits(_bits), m_modifier(_modifier)
@@ -159,8 +246,6 @@ bool IntegerType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 		return false;
 	if (isAddress())
 		return convertTo.isAddress();
-	else if (isHash())
-		return convertTo.isHash();
 	else if (isSigned())
 		return convertTo.isSigned();
 	else
@@ -169,14 +254,10 @@ bool IntegerType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 
 bool IntegerType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 {
-	if (_convertTo.getCategory() == Category::String)
-	{
-		StaticStringType const& convertTo = dynamic_cast<StaticStringType const&>(_convertTo);
-		return isHash() && (m_bits == convertTo.getNumBytes() * 8);
-	}
 	return _convertTo.getCategory() == getCategory() ||
-		   _convertTo.getCategory() == Category::Contract ||
-		   _convertTo.getCategory() == Category::Enum;
+		_convertTo.getCategory() == Category::Contract ||
+		_convertTo.getCategory() == Category::Enum ||
+		_convertTo.getCategory() == Category::FixedBytes;
 }
 
 TypePointer IntegerType::unaryOperatorResult(Token::Value _operator) const
@@ -187,16 +268,10 @@ TypePointer IntegerType::unaryOperatorResult(Token::Value _operator) const
 	// no further unary operators for addresses
 	else if (isAddress())
 		return TypePointer();
-	// "~" is ok for all other types
-	else if (_operator == Token::BitNot)
-		return shared_from_this();
-	// nothing else for hashes
-	else if (isHash())
-		return TypePointer();
-	// for non-hash integers, we allow +, -, ++ and --
+	// for non-address integers, we allow +, -, ++ and --
 	else if (_operator == Token::Add || _operator == Token::Sub ||
 			_operator == Token::Inc || _operator == Token::Dec ||
-			_operator == Token::After)
+			_operator == Token::After || _operator == Token::BitNot)
 		return shared_from_this();
 	else
 		return TypePointer();
@@ -214,7 +289,7 @@ string IntegerType::toString() const
 {
 	if (isAddress())
 		return "address";
-	string prefix = isHash() ? "hash" : (isSigned() ? "int" : "uint");
+	string prefix = isSigned() ? "int" : "uint";
 	return prefix + dev::toString(m_bits);
 }
 
@@ -230,20 +305,18 @@ TypePointer IntegerType::binaryOperatorResult(Token::Value _operator, TypePointe
 	// All integer types can be compared
 	if (Token::isCompareOp(_operator))
 		return commonType;
-
-	// Nothing else can be done with addresses, but hashes can receive bit operators
+	// Nothing else can be done with addresses
 	if (commonType->isAddress())
 		return TypePointer();
-	else if (commonType->isHash() && !Token::isBitOp(_operator))
-		return TypePointer();
-	else
-		return commonType;
+
+	return commonType;
 }
 
-const MemberList IntegerType::AddressMemberList =
-	MemberList({{"balance", make_shared<IntegerType >(256)},
-				{"call", make_shared<FunctionType>(strings(), strings(), FunctionType::Location::Bare, true)},
-				{"send", make_shared<FunctionType>(strings{"uint"}, strings{}, FunctionType::Location::Send)}});
+const MemberList IntegerType::AddressMemberList({
+	{"balance", make_shared<IntegerType >(256)},
+	{"call", make_shared<FunctionType>(strings(), strings(), FunctionType::Location::Bare, true)},
+	{"send", make_shared<FunctionType>(strings{"uint"}, strings{}, FunctionType::Location::Send)}
+});
 
 IntegerConstantType::IntegerConstantType(Literal const& _literal)
 {
@@ -284,8 +357,17 @@ IntegerConstantType::IntegerConstantType(Literal const& _literal)
 
 bool IntegerConstantType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 {
-	TypePointer integerType = getIntegerType();
-	return integerType && integerType->isImplicitlyConvertibleTo(_convertTo);
+	shared_ptr<IntegerType const> integerType = getIntegerType();
+	if (!integerType)
+		return false;
+
+	if (_convertTo.getCategory() == Category::FixedBytes)
+	{
+		FixedBytesType const& convertTo = dynamic_cast<FixedBytesType const&>(_convertTo);
+		return convertTo.getNumBytes() * 8 >= integerType->getNumBits();
+	}
+
+	return integerType->isImplicitlyConvertibleTo(_convertTo);
 }
 
 bool IntegerConstantType::isExplicitlyConvertibleTo(Type const& _convertTo) const
@@ -433,50 +515,67 @@ shared_ptr<IntegerType const> IntegerConstantType::getIntegerType() const
 												 : IntegerType::Modifier::Unsigned);
 }
 
-shared_ptr<StaticStringType> StaticStringType::smallestTypeForLiteral(string const& _literal)
+shared_ptr<FixedBytesType> FixedBytesType::smallestTypeForLiteral(string const& _literal)
 {
 	if (_literal.length() <= 32)
-		return make_shared<StaticStringType>(_literal.length());
-	return shared_ptr<StaticStringType>();
+		return make_shared<FixedBytesType>(_literal.length());
+	return shared_ptr<FixedBytesType>();
 }
 
-StaticStringType::StaticStringType(int _bytes): m_bytes(_bytes)
+FixedBytesType::FixedBytesType(int _bytes): m_bytes(_bytes)
 {
 	solAssert(m_bytes >= 0 && m_bytes <= 32,
-			  "Invalid byte number for static string type: " + dev::toString(m_bytes));
+			  "Invalid byte number for fixed bytes type: " + dev::toString(m_bytes));
 }
 
-bool StaticStringType::isImplicitlyConvertibleTo(Type const& _convertTo) const
+bool FixedBytesType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 {
 	if (_convertTo.getCategory() != getCategory())
 		return false;
-	StaticStringType const& convertTo = dynamic_cast<StaticStringType const&>(_convertTo);
+	FixedBytesType const& convertTo = dynamic_cast<FixedBytesType const&>(_convertTo);
 	return convertTo.m_bytes >= m_bytes;
 }
 
-bool StaticStringType::isExplicitlyConvertibleTo(Type const& _convertTo) const
+bool FixedBytesType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 {
-	if (_convertTo.getCategory() == getCategory())
-		return true;
-	if (_convertTo.getCategory() == Category::Integer)
-	{
-		IntegerType const& convertTo = dynamic_cast<IntegerType const&>(_convertTo);
-		if (convertTo.isHash() && (m_bytes * 8 == convertTo.getNumBits()))
-			return true;
-	}
+	return _convertTo.getCategory() == Category::Integer ||
+		_convertTo.getCategory() == Category::Contract ||
+		_convertTo.getCategory() == getCategory();
+}
 
-	return false;
+TypePointer FixedBytesType::unaryOperatorResult(Token::Value _operator) const
+{
+	// "delete" and "~" is okay for FixedBytesType
+	if (_operator == Token::Delete)
+		return make_shared<VoidType>();
+	else if (_operator == Token::BitNot)
+		return shared_from_this();
+
+	return TypePointer();
+}
+
+TypePointer FixedBytesType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
+{
+	auto commonType = dynamic_pointer_cast<FixedBytesType const>(Type::commonType(shared_from_this(), _other));
+	if (!commonType)
+		return TypePointer();
+
+	// FixedBytes can be compared and have bitwise operators applied to them
+	if (Token::isCompareOp(_operator) || Token::isBitOp(_operator))
+		return commonType;
+
+	return TypePointer();
 }
 
-bool StaticStringType::operator==(Type const& _other) const
+bool FixedBytesType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())
 		return false;
-	StaticStringType const& other = dynamic_cast<StaticStringType const&>(_other);
+	FixedBytesType const& other = dynamic_cast<FixedBytesType const&>(_other);
 	return other.m_bytes == m_bytes;
 }
 
-u256 StaticStringType::literalValue(const Literal* _literal) const
+u256 FixedBytesType::literalValue(const Literal* _literal) const
 {
 	solAssert(_literal, "");
 	u256 value = 0;
@@ -603,13 +702,21 @@ u256 ArrayType::getStorageSize() const
 {
 	if (isDynamicallySized())
 		return 1;
-	else
+
+	bigint size;
+	unsigned baseBytes = getBaseType()->getStorageBytes();
+	if (baseBytes == 0)
+		size = 1;
+	else if (baseBytes < 32)
 	{
-		bigint size = bigint(getLength()) * getBaseType()->getStorageSize();
-		if (size >= bigint(1) << 256)
-			BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Array too large for storage."));
-		return max<u256>(1, u256(size));
+		unsigned itemsPerSlot = 32 / baseBytes;
+		size = (bigint(getLength()) + (itemsPerSlot - 1)) / itemsPerSlot;
 	}
+	else
+		size = bigint(getLength()) * getBaseType()->getStorageSize();
+	if (size >= bigint(1) << 256)
+		BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Array too large for storage."));
+	return max<u256>(1, u256(size));
 }
 
 unsigned ArrayType::getSizeOnStack() const
@@ -617,6 +724,9 @@ unsigned ArrayType::getSizeOnStack() const
 	if (m_location == Location::CallData)
 		// offset [length] (stack top)
 		return 1 + (isDynamicallySized() ? 1 : 0);
+	else if (m_location == Location::Storage)
+		// storage_key storage_offset
+		return 2;
 	else
 		// offset
 		return 1;
@@ -632,6 +742,23 @@ string ArrayType::toString() const
 	return ret + "]";
 }
 
+TypePointer ArrayType::externalType() const
+{
+	if (m_location != Location::CallData)
+		return TypePointer();
+	if (m_isByteArray)
+		return shared_from_this();
+	if (!m_baseType->externalType())
+		return TypePointer();
+	if (m_baseType->getCategory() == Category::Array && m_baseType->isDynamicallySized())
+		return TypePointer();
+
+	if (isDynamicallySized())
+		return std::make_shared<ArrayType>(Location::CallData, m_baseType->externalType());
+	else
+		return std::make_shared<ArrayType>(Location::CallData, m_baseType->externalType(), m_length);
+}
+
 shared_ptr<ArrayType> ArrayType::copyForLocation(ArrayType::Location _location) const
 {
 	auto copy = make_shared<ArrayType>(_location);
@@ -645,7 +772,7 @@ shared_ptr<ArrayType> ArrayType::copyForLocation(ArrayType::Location _location)
 	return copy;
 }
 
-const MemberList ArrayType::s_arrayTypeMemberList = MemberList({{"length", make_shared<IntegerType>(256)}});
+const MemberList ArrayType::s_arrayTypeMemberList({{"length", make_shared<IntegerType>(256)}});
 
 bool ContractType::operator==(Type const& _other) const
 {
@@ -706,6 +833,26 @@ u256 ContractType::getFunctionIdentifier(string const& _functionName) const
 	return Invalid256;
 }
 
+vector<tuple<VariableDeclaration const*, u256, unsigned>> ContractType::getStateVariables() const
+{
+	vector<VariableDeclaration const*> variables;
+	for (ContractDefinition const* contract: boost::adaptors::reverse(m_contract.getLinearizedBaseContracts()))
+		for (ASTPointer<VariableDeclaration> const& variable: contract->getStateVariables())
+			if (!variable->isConstant())
+				variables.push_back(variable.get());
+	TypePointers types;
+	for (auto variable: variables)
+		types.push_back(variable->getType());
+	StorageOffsets offsets;
+	offsets.computeOffsets(types);
+
+	vector<tuple<VariableDeclaration const*, u256, unsigned>> variablesAndOffsets;
+	for (size_t index = 0; index < variables.size(); ++index)
+		if (auto const* offset = offsets.getOffset(index))
+			variablesAndOffsets.push_back(make_tuple(variables[index], offset->first, offset->second));
+	return variablesAndOffsets;
+}
+
 TypePointer StructType::unaryOperatorResult(Token::Value _operator) const
 {
 	return _operator == Token::Delete ? make_shared<VoidType>() : TypePointer();
@@ -721,12 +868,7 @@ bool StructType::operator==(Type const& _other) const
 
 u256 StructType::getStorageSize() const
 {
-	bigint size = 0;
-	for (pair<string, TypePointer> const& member: getMembers())
-		size += member.second->getStorageSize();
-	if (size >= bigint(1) << 256)
-		BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Struct too large for storage."));
-	return max<u256>(1, u256(size));
+	return max<u256>(1, getMembers().getStorageSize());
 }
 
 bool StructType::canLiveOutsideStorage() const
@@ -755,17 +897,11 @@ MemberList const& StructType::getMembers() const
 	return *m_members;
 }
 
-u256 StructType::getStorageOffsetOfMember(string const& _name) const
+pair<u256, unsigned> const& StructType::getStorageOffsetsOfMember(string const& _name) const
 {
-	//@todo cache member offset?
-	u256 offset;
-	for (ASTPointer<VariableDeclaration> const& variable: m_struct.getMembers())
-	{
-		if (variable->getName() == _name)
-			return offset;
-		offset += variable->getType()->getStorageSize();
-	}
-	BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage offset of non-existing member requested."));
+	auto const* offsets = getMembers().getMemberStorageOffset(_name);
+	solAssert(offsets, "Storage offset of non-existing member requested.");
+	return *offsets;
 }
 
 TypePointer EnumType::unaryOperatorResult(Token::Value _operator) const
@@ -781,6 +917,15 @@ bool EnumType::operator==(Type const& _other) const
 	return other.m_enum == m_enum;
 }
 
+unsigned EnumType::getStorageBytes() const
+{
+	size_t elements = m_enum.getMembers().size();
+	if (elements <= 1)
+		return 1;
+	else
+		return dev::bytesRequired(elements - 1);
+}
+
 string EnumType::toString() const
 {
 	return string("enum ") + m_enum.getName();
@@ -925,6 +1070,13 @@ string FunctionType::toString() const
 	return name + ")";
 }
 
+u256 FunctionType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable function type requested."));
+}
+
 unsigned FunctionType::getSizeOnStack() const
 {
 	Location location = m_location;
@@ -946,6 +1098,26 @@ unsigned FunctionType::getSizeOnStack() const
 	return size;
 }
 
+TypePointer FunctionType::externalType() const
+{
+	TypePointers paramTypes;
+	TypePointers retParamTypes;
+
+	for (auto type: m_parameterTypes)
+	{
+		if (!type->externalType())
+			return TypePointer();
+		paramTypes.push_back(type->externalType());
+	}
+	for (auto type: m_returnParameterTypes)
+	{
+		if (!type->externalType())
+			return TypePointer();
+		retParamTypes.push_back(type->externalType());
+	}
+	return make_shared<FunctionType>(paramTypes, retParamTypes, m_location, m_arbitraryParameters);
+}
+
 MemberList const& FunctionType::getMembers() const
 {
 	switch (m_location)
@@ -975,7 +1147,7 @@ MemberList const& FunctionType::getMembers() const
 	}
 }
 
-string FunctionType::getCanonicalSignature(std::string const& _name) const
+string FunctionType::externalSignature(std::string const& _name) const
 {
 	std::string funcName = _name;
 	if (_name == "")
@@ -985,8 +1157,12 @@ string FunctionType::getCanonicalSignature(std::string const& _name) const
 	}
 	string ret = funcName + "(";
 
-	for (auto it = m_parameterTypes.cbegin(); it != m_parameterTypes.cend(); ++it)
-		ret += (*it)->toString() + (it + 1 == m_parameterTypes.cend() ? "" : ",");
+	TypePointers externalParameterTypes = dynamic_cast<FunctionType const&>(*externalType()).getParameterTypes();
+	for (auto it = externalParameterTypes.cbegin(); it != externalParameterTypes.cend(); ++it)
+	{
+		solAssert(!!(*it), "Parameter should have external type");
+		ret += (*it)->toString() + (it + 1 == externalParameterTypes.cend() ? "" : ",");
+	}
 
 	return ret + ")";
 }
@@ -1047,6 +1223,13 @@ string MappingType::toString() const
 	return "mapping(" + getKeyType()->toString() + " => " + getValueType()->toString() + ")";
 }
 
+u256 VoidType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable void type requested."));
+}
+
 bool TypeType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())
@@ -1055,6 +1238,13 @@ bool TypeType::operator==(Type const& _other) const
 	return *getActualType() == *other.getActualType();
 }
 
+u256 TypeType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable type type requested."));
+}
+
 MemberList const& TypeType::getMembers() const
 {
 	// We need to lazy-initialize it because of recursive references.
@@ -1092,6 +1282,13 @@ ModifierType::ModifierType(const ModifierDefinition& _modifier)
 	swap(params, m_parameterTypes);
 }
 
+u256 ModifierType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable type type requested."));
+}
+
 bool ModifierType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())
@@ -1122,22 +1319,29 @@ MagicType::MagicType(MagicType::Kind _kind):
 	switch (m_kind)
 	{
 	case Kind::Block:
-		m_members = MemberList({{"coinbase", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
-								{"timestamp", make_shared<IntegerType>(256)},
-								{"blockhash", make_shared<FunctionType>(strings{"uint"}, strings{"hash"}, FunctionType::Location::BlockHash)},
-								{"difficulty", make_shared<IntegerType>(256)},
-								{"number", make_shared<IntegerType>(256)},
-								{"gaslimit", make_shared<IntegerType>(256)}});
+		m_members = move(MemberList({
+			{"coinbase", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
+			{"timestamp", make_shared<IntegerType>(256)},
+			{"blockhash", make_shared<FunctionType>(strings{"uint"}, strings{"bytes32"}, FunctionType::Location::BlockHash)},
+			{"difficulty", make_shared<IntegerType>(256)},
+			{"number", make_shared<IntegerType>(256)},
+			{"gaslimit", make_shared<IntegerType>(256)}
+		}));
 		break;
 	case Kind::Message:
-		m_members = MemberList({{"sender", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
-								{"gas", make_shared<IntegerType>(256)},
-								{"value", make_shared<IntegerType>(256)},
-								{"data", make_shared<ArrayType>(ArrayType::Location::CallData)}});
+		m_members = move(MemberList({
+			{"sender", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
+			{"gas", make_shared<IntegerType>(256)},
+			{"value", make_shared<IntegerType>(256)},
+			{"data", make_shared<ArrayType>(ArrayType::Location::CallData)},
+			{"sig", make_shared<FixedBytesType>(4)}
+		}));
 		break;
 	case Kind::Transaction:
-		m_members = MemberList({{"origin", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
-								{"gasprice", make_shared<IntegerType>(256)}});
+		m_members = move(MemberList({
+			{"origin", make_shared<IntegerType>(0, IntegerType::Modifier::Address)},
+			{"gasprice", make_shared<IntegerType>(256)}
+		}));
 		break;
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown kind of magic."));
diff --git a/Types.h b/Types.h
index b19f7540..5fa09f69 100644
--- a/Types.h
+++ b/Types.h
@@ -43,6 +43,26 @@ using TypePointer = std::shared_ptr<Type const>;
 using FunctionTypePointer = std::shared_ptr<FunctionType const>;
 using TypePointers = std::vector<TypePointer>;
 
+
+/**
+ * Helper class to compute storage offsets of members of structs and contracts.
+ */
+class StorageOffsets
+{
+public:
+	/// Resets the StorageOffsets objects and determines the position in storage for each
+	/// of the elements of @a _types.
+	void computeOffsets(TypePointers const& _types);
+	/// @returns the offset of the given member, might be null if the member is not part of storage.
+	std::pair<u256, unsigned> const* getOffset(size_t _index) const;
+	/// @returns the total number of slots occupied by all members.
+	u256 const& getStorageSize() const { return m_storageSize; }
+
+private:
+	u256 m_storageSize;
+	std::map<size_t, std::pair<u256, unsigned>> m_offsets;
+};
+
 /**
  * List of members of a type.
  */
@@ -53,6 +73,7 @@ public:
 
 	MemberList() {}
 	explicit MemberList(MemberMap const& _members): m_memberTypes(_members) {}
+	MemberList& operator=(MemberList&& _other);
 	TypePointer getMemberType(std::string const& _name) const
 	{
 		for (auto const& it: m_memberTypes)
@@ -60,12 +81,18 @@ public:
 				return it.second;
 		return TypePointer();
 	}
+	/// @returns the offset of the given member in storage slots and bytes inside a slot or
+	/// a nullptr if the member is not part of storage.
+	std::pair<u256, unsigned> const* getMemberStorageOffset(std::string const& _name) const;
+	/// @returns the number of storage slots occupied by the members.
+	u256 const& getStorageSize() const;
 
 	MemberMap::const_iterator begin() const { return m_memberTypes.begin(); }
 	MemberMap::const_iterator end() const { return m_memberTypes.end(); }
 
 private:
 	MemberMap m_memberTypes;
+	mutable std::unique_ptr<StorageOffsets> m_storageOffsets;
 };
 
 /**
@@ -77,12 +104,12 @@ public:
 	enum class Category
 	{
 		Integer, IntegerConstant, Bool, Real, Array,
-		String, Contract, Struct, Function, OverloadedFunctions, Enum,
+		FixedBytes, Contract, Struct, Function, OverloadedFunctions, Enum,
 		Mapping, Void, TypeType, Modifier, Magic
 	};
 
-	///@{
-	///@name Factory functions
+	/// @{
+	/// @name Factory functions
 	/// Factory functions that convert an AST @ref TypeName to a Type.
 	static TypePointer fromElementaryTypeName(Token::Value _typeToken);
 	static TypePointer fromElementaryTypeName(std::string const& _name);
@@ -97,6 +124,8 @@ public:
 	/// @returns a pointer to _a or _b if the other is implicitly convertible to it or nullptr otherwise
 	static TypePointer commonType(TypePointer const& _a, TypePointer const& _b);
 
+	/// Calculates the
+
 	virtual Category getCategory() const = 0;
 	virtual bool isImplicitlyConvertibleTo(Type const& _other) const { return *this == _other; }
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const
@@ -126,9 +155,15 @@ public:
 	unsigned getCalldataEncodedSize() const { return getCalldataEncodedSize(true); }
 	/// @returns true if the type is dynamically encoded in calldata
 	virtual bool isDynamicallySized() const { return false; }
-	/// @returns number of bytes required to hold this value in storage.
+	/// @returns the number of storage slots required to hold this value in storage.
 	/// For dynamically "allocated" types, it returns the size of the statically allocated head,
 	virtual u256 getStorageSize() const { return 1; }
+	/// Multiple small types can be packed into a single storage slot. If such a packing is possible
+	/// this function @returns the size in bytes smaller than 32. Data is moved to the next slot if
+	/// it does not fit.
+	/// In order to avoid computation at runtime of whether such moving is necessary, structs and
+	/// array data (not each element) always start a new slot.
+	virtual unsigned getStorageBytes() const { return 32; }
 	/// Returns true if the type can be stored in storage.
 	virtual bool canBeStored() const { return true; }
 	/// Returns false if the type cannot live outside the storage, i.e. if it includes some mapping.
@@ -152,20 +187,24 @@ public:
 																		 "for type without literals."));
 	}
 
+	/// @returns a type suitable for outside of Solidity, i.e. for contract types it returns address.
+	/// If there is no such type, returns an empty shared pointer.
+	virtual TypePointer externalType() const { return TypePointer(); }
+
 protected:
 	/// Convenience object used when returning an empty member list.
 	static const MemberList EmptyMemberList;
 };
 
 /**
- * Any kind of integer type including hash and address.
+ * Any kind of integer type (signed, unsigned, address).
  */
 class IntegerType: public Type
 {
 public:
 	enum class Modifier
 	{
-		Unsigned, Signed, Hash, Address
+		Unsigned, Signed, Address
 	};
 	virtual Category getCategory() const override { return Category::Integer; }
 
@@ -179,14 +218,16 @@ public:
 	virtual bool operator==(Type const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : m_bits / 8; }
+	virtual unsigned getStorageBytes() const override { return m_bits / 8; }
 	virtual bool isValueType() const override { return true; }
 
-	virtual MemberList const& getMembers() const { return isAddress() ? AddressMemberList : EmptyMemberList; }
+	virtual MemberList const& getMembers() const override { return isAddress() ? AddressMemberList : EmptyMemberList; }
 
 	virtual std::string toString() const override;
 
+	virtual TypePointer externalType() const override { return shared_from_this(); }
+
 	int getNumBits() const { return m_bits; }
-	bool isHash() const { return m_modifier == Modifier::Hash || m_modifier == Modifier::Address; }
 	bool isAddress() const { return m_modifier == Modifier::Address; }
 	bool isSigned() const { return m_modifier == Modifier::Signed; }
 
@@ -232,28 +273,32 @@ private:
 };
 
 /**
- * String type with fixed length, up to 32 bytes.
+ * Bytes type with fixed length of up to 32 bytes.
  */
-class StaticStringType: public Type
+class FixedBytesType: public Type
 {
 public:
-	virtual Category getCategory() const override { return Category::String; }
+	virtual Category getCategory() const override { return Category::FixedBytes; }
 
-	/// @returns the smallest string type for the given literal or an empty pointer
+	/// @returns the smallest bytes type for the given literal or an empty pointer
 	/// if no type fits.
-	static std::shared_ptr<StaticStringType> smallestTypeForLiteral(std::string const& _literal);
+	static std::shared_ptr<FixedBytesType> smallestTypeForLiteral(std::string const& _literal);
 
-	explicit StaticStringType(int _bytes);
+	explicit FixedBytesType(int _bytes);
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual bool operator==(Type const& _other) const override;
+	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
+	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize(bool _padded) const override { return _padded && m_bytes > 0 ? 32 : m_bytes; }
+	virtual unsigned getStorageBytes() const override { return m_bytes; }
 	virtual bool isValueType() const override { return true; }
 
-	virtual std::string toString() const override { return "string" + dev::toString(m_bytes); }
+	virtual std::string toString() const override { return "bytes" + dev::toString(m_bytes); }
 	virtual u256 literalValue(Literal const* _literal) const override;
+	virtual TypePointer externalType() const override { return shared_from_this(); }
 
 	int getNumBytes() const { return m_bytes; }
 
@@ -273,16 +318,21 @@ public:
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
 	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
-	virtual unsigned getCalldataEncodedSize(bool _padded) const { return _padded ? 32 : 1; }
+	virtual unsigned getCalldataEncodedSize(bool _padded) const override{ return _padded ? 32 : 1; }
+	virtual unsigned getStorageBytes() const override { return 1; }
 	virtual bool isValueType() const override { return true; }
 
 	virtual std::string toString() const override { return "bool"; }
 	virtual u256 literalValue(Literal const* _literal) const override;
+	virtual TypePointer externalType() const override { return shared_from_this(); }
 };
 
 /**
  * The type of an array. The flavours are byte array (bytes), statically- (<type>[<length>])
  * and dynamically-sized array (<type>[]).
+ * In storage, all arrays are packed tightly (as long as more than one elementary type fits in
+ * one slot). Dynamically sized arrays (including byte arrays) start with their size as a uint and
+ * thus start on their own slot.
  */
 class ArrayType: public Type
 {
@@ -293,13 +343,22 @@ public:
 
 	/// Constructor for a byte array ("bytes")
 	explicit ArrayType(Location _location):
-		m_location(_location), m_isByteArray(true), m_baseType(std::make_shared<IntegerType>(8)) {}
+		m_location(_location),
+		m_isByteArray(true),
+		m_baseType(std::make_shared<FixedBytesType>(8))
+	{}
 	/// Constructor for a dynamically sized array type ("type[]")
 	ArrayType(Location _location, const TypePointer &_baseType):
-		m_location(_location), m_baseType(_baseType) {}
+		m_location(_location),
+		m_baseType(_baseType)
+	{}
 	/// Constructor for a fixed-size array type ("type[20]")
 	ArrayType(Location _location, const TypePointer &_baseType, u256 const& _length):
-		m_location(_location), m_baseType(_baseType), m_hasDynamicLength(false), m_length(_length) {}
+		m_location(_location),
+		m_baseType(_baseType),
+		m_hasDynamicLength(false),
+		m_length(_length)
+	{}
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
@@ -310,6 +369,7 @@ public:
 	virtual unsigned getSizeOnStack() const override;
 	virtual std::string toString() const override;
 	virtual MemberList const& getMembers() const override { return s_arrayTypeMemberList; }
+	virtual TypePointer externalType() const override;
 
 	Location getLocation() const { return m_location; }
 	bool isByteArray() const { return m_isByteArray; }
@@ -344,10 +404,12 @@ public:
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
 	virtual bool operator==(Type const& _other) const override;
+	virtual unsigned getStorageBytes() const override { return 20; }
 	virtual bool isValueType() const override { return true; }
 	virtual std::string toString() const override;
 
 	virtual MemberList const& getMembers() const override;
+	virtual TypePointer externalType() const override { return std::make_shared<IntegerType>(160, IntegerType::Modifier::Address); }
 
 	bool isSuper() const { return m_super; }
 	ContractDefinition const& getContractDefinition() const { return m_contract; }
@@ -360,6 +422,10 @@ public:
 	/// not exist.
 	u256 getFunctionIdentifier(std::string const& _functionName) const;
 
+	/// @returns a list of all state variables (including inherited) of the contract and their
+	/// offsets in storage.
+	std::vector<std::tuple<VariableDeclaration const*, u256, unsigned>> getStateVariables() const;
+
 private:
 	ContractDefinition const& m_contract;
 	/// If true, it is the "super" type of the current contract, i.e. it contains only inherited
@@ -383,12 +449,12 @@ public:
 	virtual bool operator==(Type const& _other) const override;
 	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override;
-	virtual unsigned getSizeOnStack() const override { return 1; /*@todo*/ }
+	virtual unsigned getSizeOnStack() const override { return 2; }
 	virtual std::string toString() const override;
 
 	virtual MemberList const& getMembers() const override;
 
-	u256 getStorageOffsetOfMember(std::string const& _name) const;
+	std::pair<u256, unsigned> const& getStorageOffsetsOfMember(std::string const& _name) const;
 
 private:
 	StructDefinition const& m_struct;
@@ -407,10 +473,12 @@ public:
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
 	virtual bool operator==(Type const& _other) const override;
 	virtual unsigned getSizeOnStack() const override { return 1; }
+	virtual unsigned getStorageBytes() const override;
 	virtual std::string toString() const override;
 	virtual bool isValueType() const override { return true; }
 
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
+	virtual TypePointer externalType() const override { return std::make_shared<IntegerType>(8 * int(getStorageBytes())); }
 
 	EnumDefinition const& getEnumDefinition() const { return m_enum; }
 	/// @returns the value that the string has in the Enum
@@ -443,6 +511,11 @@ public:
 						  Bare };
 
 	virtual Category getCategory() const override { return Category::Function; }
+
+	/// @returns TypePointer of a new FunctionType object. All input/return parameters are an appropriate external types of input/return parameters of current function.
+	/// Returns an empty shared pointer if one of the input/return parameters does not have an externaltype.
+	virtual TypePointer externalType() const override;
+
 	explicit FunctionType(FunctionDefinition const& _function, bool _isInternal = true);
 	explicit FunctionType(VariableDeclaration const& _varDecl);
 	explicit FunctionType(EventDefinition const& _event);
@@ -476,16 +549,16 @@ public:
 	virtual bool operator==(Type const& _other) const override;
 	virtual std::string toString() const override;
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable function type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override;
 	virtual MemberList const& getMembers() const override;
 
 	Location const& getLocation() const { return m_location; }
-	/// @returns the canonical signature of this function type given the function name
+	/// @returns the external signature of this function type given the function name
 	/// If @a _name is not provided (empty string) then the @c m_declaration member of the
 	/// function type is used
-	std::string getCanonicalSignature(std::string const& _name = "") const;
+	std::string externalSignature(std::string const& _name = "") const;
 	Declaration const& getDeclaration() const
 	{
 		solAssert(m_declaration, "Requested declaration from a FunctionType that has none");
@@ -515,7 +588,7 @@ private:
 	std::vector<std::string> m_parameterNames;
 	std::vector<std::string> m_returnParameterNames;
 	Location const m_location;
-	/// true iff the function takes an arbitrary number of arguments of arbitrary types
+	/// true if the function takes an arbitrary number of arguments of arbitrary types
 	bool const m_arbitraryParameters = false;
 	bool const m_gasSet = false; ///< true iff the gas value to be used is on the stack
 	bool const m_valueSet = false; ///< true iff the value to be sent is on the stack
@@ -540,6 +613,7 @@ private:
 
 /**
  * The type of a mapping, there is one distinct type per key/value type pair.
+ * Mappings always occupy their own storage slot, but do not actually use it.
  */
 class MappingType: public Type
 {
@@ -550,6 +624,7 @@ public:
 
 	virtual bool operator==(Type const& _other) const override;
 	virtual std::string toString() const override;
+	virtual unsigned getSizeOnStack() const override { return 2; }
 	virtual bool canLiveOutsideStorage() const override { return false; }
 
 	TypePointer const& getKeyType() const { return m_keyType; }
@@ -573,7 +648,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual std::string toString() const override { return "void"; }
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable void type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 };
@@ -593,7 +668,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual bool operator==(Type const& _other) const override;
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable type type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 	virtual std::string toString() const override { return "type(" + m_actualType->toString() + ")"; }
@@ -619,7 +694,7 @@ public:
 
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable type type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 	virtual bool operator==(Type const& _other) const override;
diff --git a/Utils.h b/Utils.h
index 1411f66b..05c5fa6f 100644
--- a/Utils.h
+++ b/Utils.h
@@ -22,34 +22,9 @@
 
 #pragma once
 
-#include <string>
-#include <libsolidity/Exceptions.h>
-
-namespace dev
-{
-namespace solidity
-{
+#include <libdevcore/Assertions.h>
 
 /// Assertion that throws an InternalCompilerError containing the given description if it is not met.
 #define solAssert(CONDITION, DESCRIPTION) \
-	::dev::solidity::solAssertAux(CONDITION, DESCRIPTION, __LINE__, __FILE__, ETH_FUNC)
-
-inline void solAssertAux(bool _condition, std::string const& _errorDescription, unsigned _line,
-						 char const* _file, char const* _function)
-{
-	if (!_condition)
-		::boost::throw_exception( InternalCompilerError()
-				<< errinfo_comment(_errorDescription)
-				<< ::boost::throw_function(_function)
-				<< ::boost::throw_file(_file)
-				<< ::boost::throw_line(_line));
-}
-
-inline void solAssertAux(void const* _pointer, std::string const& _errorDescription, unsigned _line,
-						 char const* _file, char const* _function)
-{
-	solAssertAux(_pointer != nullptr, _errorDescription, _line, _file, _function);
-}
+	assertThrow(CONDITION, ::dev::solidity::InternalCompilerError, DESCRIPTION)
 
-}
-}