Merge branch 'sol_integerConstants' of https://github.com/chriseth/cpp-ethereum into chriseth-sol_integerConstants

6 files changed, 323 insertions, 164 deletions

diff --git a/AST.cpp b/AST.cpp
index 04771106..79ac314c 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -173,7 +173,15 @@ void VariableDefinition::checkTypeRequirements()
 		{
 			// no type declared and no previous assignment, infer the type
 			m_value->checkTypeRequirements();
-			m_variable->setType(m_value->getType());
+			TypePointer type = m_value->getType();
+			if (type->getCategory() == Type::Category::INTEGER_CONSTANT)
+			{
+				auto intType = dynamic_pointer_cast<IntegerConstantType const>(type)->getIntegerType();
+				if (!intType)
+					BOOST_THROW_EXCEPTION(m_value->createTypeError("Invalid integer constant " + type->toString()));
+				type = intType;
+			}
+			m_variable->setType(type);
 		}
 	}
 }
@@ -192,16 +200,22 @@ void Assignment::checkTypeRequirements()
 	{
 		// compound assignment
 		m_rightHandSide->checkTypeRequirements();
-		TypePointer resultType = Type::binaryOperatorResult(Token::AssignmentToBinaryOp(m_assigmentOperator),
-															m_type, m_rightHandSide->getType());
+		TypePointer resultType = m_type->binaryOperatorResult(Token::AssignmentToBinaryOp(m_assigmentOperator),
+															  m_rightHandSide->getType());
 		if (!resultType || *resultType != *m_type)
-			BOOST_THROW_EXCEPTION(createTypeError("Operator not compatible with type."));
+			BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_assigmentOperator)) +
+												  " not compatible with types " +
+												  m_type->toString() + " and " +
+												  m_rightHandSide->getType()->toString()));
 	}
 }
 
 void ExpressionStatement::checkTypeRequirements()
 {
 	m_expression->checkTypeRequirements();
+	if (m_expression->getType()->getCategory() == Type::Category::INTEGER_CONSTANT)
+		if (!dynamic_pointer_cast<IntegerConstantType const>(m_expression->getType())->getIntegerType())
+			BOOST_THROW_EXCEPTION(m_expression->createTypeError("Invalid integer constant."));
 }
 
 void Expression::expectType(Type const& _expectedType)
@@ -227,8 +241,8 @@ void UnaryOperation::checkTypeRequirements()
 	m_subExpression->checkTypeRequirements();
 	if (m_operator == Token::Value::INC || m_operator == Token::Value::DEC || m_operator == Token::Value::DELETE)
 		m_subExpression->requireLValue();
-	m_type = m_subExpression->getType();
-	if (!m_type->acceptsUnaryOperator(m_operator))
+	m_type = m_subExpression->getType()->unaryOperatorResult(m_operator);
+	if (!m_type)
 		BOOST_THROW_EXCEPTION(createTypeError("Unary operator not compatible with type."));
 }
 
@@ -236,7 +250,7 @@ void BinaryOperation::checkTypeRequirements()
 {
 	m_left->checkTypeRequirements();
 	m_right->checkTypeRequirements();
-	m_commonType = Type::binaryOperatorResult(m_operator, m_left->getType(), m_right->getType());
+	m_commonType = m_left->getType()->binaryOperatorResult(m_operator, m_right->getType());
 	if (!m_commonType)
 		BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_operator)) +
 											  " not compatible with types " +
@@ -300,7 +314,7 @@ void NewExpression::checkTypeRequirements()
 	m_contract = dynamic_cast<ContractDefinition const*>(m_contractName->getReferencedDeclaration());
 	if (!m_contract)
 		BOOST_THROW_EXCEPTION(createTypeError("Identifier is not a contract."));
-	shared_ptr<ContractType const> type = make_shared<ContractType const>(*m_contract);
+	shared_ptr<ContractType const> type = make_shared<ContractType>(*m_contract);
 	m_type = type;
 	TypePointers const& parameterTypes = type->getConstructorType()->getParameterTypes();
 	if (parameterTypes.size() != m_arguments.size())
@@ -351,7 +365,7 @@ void Identifier::checkTypeRequirements()
 	if (structDef)
 	{
 		// note that we do not have a struct type here
-		m_type = make_shared<TypeType const>(make_shared<StructType const>(*structDef));
+		m_type = make_shared<TypeType>(make_shared<StructType>(*structDef));
 		return;
 	}
 	FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(m_referencedDeclaration);
@@ -360,13 +374,13 @@ void Identifier::checkTypeRequirements()
 		// a function reference is not a TypeType, because calling a TypeType converts to the type.
 		// Calling a function (e.g. function(12), otherContract.function(34)) does not do a type
 		// conversion.
-		m_type = make_shared<FunctionType const>(*functionDef);
+		m_type = make_shared<FunctionType>(*functionDef);
 		return;
 	}
 	ContractDefinition const* contractDef = dynamic_cast<ContractDefinition const*>(m_referencedDeclaration);
 	if (contractDef)
 	{
-		m_type = make_shared<TypeType const>(make_shared<ContractType>(*contractDef));
+		m_type = make_shared<TypeType>(make_shared<ContractType>(*contractDef));
 		return;
 	}
 	MagicVariableDeclaration const* magicVariable = dynamic_cast<MagicVariableDeclaration const*>(m_referencedDeclaration);
@@ -380,14 +394,14 @@ void Identifier::checkTypeRequirements()
 
 void ElementaryTypeNameExpression::checkTypeRequirements()
 {
-	m_type = make_shared<TypeType const>(Type::fromElementaryTypeName(m_typeToken));
+	m_type = make_shared<TypeType>(Type::fromElementaryTypeName(m_typeToken));
 }
 
 void Literal::checkTypeRequirements()
 {
 	m_type = Type::forLiteral(*this);
 	if (!m_type)
-		BOOST_THROW_EXCEPTION(createTypeError("Literal value too large."));
+		BOOST_THROW_EXCEPTION(createTypeError("Invalid literal value."));
 }
 
 }
diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index ec66b69a..8e8f492e 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -71,12 +71,20 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 	return false;
 }
 
-void ExpressionCompiler::endVisit(UnaryOperation const& _unaryOperation)
+bool ExpressionCompiler::visit(UnaryOperation const& _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
 	// represents the operator
+	if (_unaryOperation.getType()->getCategory() == Type::Category::INTEGER_CONSTANT)
+	{
+		m_context << _unaryOperation.getType()->literalValue(nullptr);
+		return false;
+	}
+
+	_unaryOperation.getSubExpression().accept(*this);
+
 	switch (_unaryOperation.getOperator())
 	{
 	case Token::NOT: // !
@@ -128,6 +136,7 @@ void ExpressionCompiler::endVisit(UnaryOperation const& _unaryOperation)
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid unary operator: " +
 																		 string(Token::toString(_unaryOperation.getOperator()))));
 	}
+	return false;
 }
 
 bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
@@ -139,17 +148,19 @@ bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
 
 	if (op == Token::AND || op == Token::OR) // special case: short-circuiting
 		appendAndOrOperatorCode(_binaryOperation);
+	else if (commonType.getCategory() == Type::Category::INTEGER_CONSTANT)
+		m_context << commonType.literalValue(nullptr);
 	else
 	{
-		bool cleanupNeeded = false;
-		if (commonType.getCategory() == Type::Category::INTEGER)
-			if (Token::isCompareOp(op) || op == Token::DIV || op == Token::MOD)
-				cleanupNeeded = true;
+		bool cleanupNeeded = commonType.getCategory() == Type::Category::INTEGER &&
+								(Token::isCompareOp(op) || op == Token::DIV || op == Token::MOD);
 
 		// for commutative operators, push the literal as late as possible to allow improved optimization
-		//@todo this has to be extended for literal expressions
-		bool swap = (m_optimize && Token::isCommutativeOp(op) && dynamic_cast<Literal const*>(&rightExpression)
-					 && !dynamic_cast<Literal const*>(&leftExpression));
+		auto isLiteral = [](Expression const& _e)
+		{
+			return dynamic_cast<Literal const*>(&_e) || _e.getType()->getCategory() == Type::Category::INTEGER_CONSTANT;
+		};
+		bool swap = m_optimize && Token::isCommutativeOp(op) && isLiteral(rightExpression) && !isLiteral(leftExpression);
 		if (swap)
 		{
 			leftExpression.accept(*this);
@@ -478,10 +489,10 @@ void ExpressionCompiler::endVisit(Literal const& _literal)
 {
 	switch (_literal.getType()->getCategory())
 	{
-	case Type::Category::INTEGER:
+	case Type::Category::INTEGER_CONSTANT:
 	case Type::Category::BOOL:
 	case Type::Category::STRING:
-		m_context << _literal.getType()->literalValue(_literal);
+		m_context << _literal.getType()->literalValue(&_literal);
 		break;
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Only integer, boolean and string literals implemented for now."));
@@ -617,9 +628,16 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 
 	if (_typeOnStack == _targetType && !_cleanupNeeded)
 		return;
-	if (_typeOnStack.getCategory() == Type::Category::INTEGER)
+	Type::Category stackTypeCategory = _typeOnStack.getCategory();
+	Type::Category targetTypeCategory = _targetType.getCategory();
+	if (stackTypeCategory == Type::Category::INTEGER)
+	{
+		solAssert(targetTypeCategory == Type::Category::INTEGER || targetTypeCategory == Type::Category::CONTRACT, "");
 		appendHighBitsCleanup(dynamic_cast<IntegerType const&>(_typeOnStack));
-	else if (_typeOnStack.getCategory() == Type::Category::STRING)
+	}
+	else if (stackTypeCategory == Type::Category::INTEGER_CONSTANT)
+		solAssert(targetTypeCategory == Type::Category::INTEGER || targetTypeCategory == Type::Category::CONTRACT, "");
+	else if (stackTypeCategory == Type::Category::STRING)
 	{
 		// nothing to do, strings are high-order-bit-aligned
 		//@todo clear lower-order bytes if we allow explicit conversion to shorter strings
diff --git a/ExpressionCompiler.h b/ExpressionCompiler.h
index e39bcddb..abd7f775 100644
--- a/ExpressionCompiler.h
+++ b/ExpressionCompiler.h
@@ -58,7 +58,7 @@ private:
 		m_optimize(_optimize), m_context(_compilerContext), m_currentLValue(m_context) {}
 
 	virtual bool visit(Assignment const& _assignment) override;
-	virtual void endVisit(UnaryOperation const& _unaryOperation) override;
+	virtual bool visit(UnaryOperation const& _unaryOperation) override;
 	virtual bool visit(BinaryOperation const& _binaryOperation) override;
 	virtual bool visit(FunctionCall const& _functionCall) override;
 	virtual bool visit(NewExpression const& _newExpression) override;
diff --git a/Scanner.cpp b/Scanner.cpp
index 6433b526..6e3d04bc 100644
--- a/Scanner.cpp
+++ b/Scanner.cpp
@@ -455,7 +455,7 @@ void Scanner::scanToken()
 				token = Token::ADD;
 			break;
 		case '-':
-			// - -- -= Number
+			// - -- -=
 			advance();
 			if (m_char == '-')
 			{
@@ -464,8 +464,6 @@ void Scanner::scanToken()
 			}
 			else if (m_char == '=')
 				token = selectToken(Token::ASSIGN_SUB);
-			else if (m_char == '.' || isDecimalDigit(m_char))
-				token = scanNumber('-');
 			else
 				token = Token::SUB;
 			break;
@@ -650,8 +648,7 @@ Token::Value Scanner::scanNumber(char _charSeen)
 	}
 	else
 	{
-		if (_charSeen == '-')
-			addLiteralChar('-');
+		solAssert(_charSeen == 0, "");
 		// if the first character is '0' we must check for octals and hex
 		if (m_char == '0')
 		{
diff --git a/Types.cpp b/Types.cpp
index 7a81b65f..dcfc704a 100644
--- a/Types.cpp
+++ b/Types.cpp
@@ -44,17 +44,17 @@ shared_ptr<Type const> Type::fromElementaryTypeName(Token::Value _typeToken)
 		if (bytes == 0)
 			bytes = 32;
 		int modifier = offset / 33;
-		return make_shared<IntegerType const>(bytes * 8,
+		return make_shared<IntegerType>(bytes * 8,
 										modifier == 0 ? IntegerType::Modifier::SIGNED :
 										modifier == 1 ? IntegerType::Modifier::UNSIGNED :
 										IntegerType::Modifier::HASH);
 	}
 	else if (_typeToken == Token::ADDRESS)
-		return make_shared<IntegerType const>(0, IntegerType::Modifier::ADDRESS);
+		return make_shared<IntegerType>(0, IntegerType::Modifier::ADDRESS);
 	else if (_typeToken == Token::BOOL)
-		return make_shared<BoolType const>();
+		return make_shared<BoolType>();
 	else if (Token::STRING0 <= _typeToken && _typeToken <= Token::STRING32)
-		return make_shared<StaticStringType const>(int(_typeToken) - int(Token::STRING0));
+		return make_shared<StaticStringType>(int(_typeToken) - int(Token::STRING0));
 	else
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unable to convert elementary typename " +
 																		 std::string(Token::toString(_typeToken)) + " to type."));
@@ -64,11 +64,11 @@ shared_ptr<Type const> Type::fromUserDefinedTypeName(UserDefinedTypeName const&
 {
 	Declaration const* declaration = _typeName.getReferencedDeclaration();
 	if (StructDefinition const* structDef = dynamic_cast<StructDefinition const*>(declaration))
-		return make_shared<StructType const>(*structDef);
+		return make_shared<StructType>(*structDef);
 	else if (FunctionDefinition const* function = dynamic_cast<FunctionDefinition const*>(declaration))
-		return make_shared<FunctionType const>(*function);
+		return make_shared<FunctionType>(*function);
 	else if (ContractDefinition const* contract = dynamic_cast<ContractDefinition const*>(declaration))
-		return make_shared<ContractType const>(*contract);
+		return make_shared<ContractType>(*contract);
 	return shared_ptr<Type const>();
 }
 
@@ -80,7 +80,7 @@ shared_ptr<Type const> Type::fromMapping(Mapping const& _typeName)
 	shared_ptr<Type const> valueType = _typeName.getValueType().toType();
 	if (!valueType)
 		BOOST_THROW_EXCEPTION(_typeName.getValueType().createTypeError("Invalid type name"));
-	return make_shared<MappingType const>(keyType, valueType);
+	return make_shared<MappingType>(keyType, valueType);
 }
 
 shared_ptr<Type const> Type::forLiteral(Literal const& _literal)
@@ -89,14 +89,14 @@ shared_ptr<Type const> Type::forLiteral(Literal const& _literal)
 	{
 	case Token::TRUE_LITERAL:
 	case Token::FALSE_LITERAL:
-		return make_shared<BoolType const>();
+		return make_shared<BoolType>();
 	case Token::NUMBER:
-		return IntegerType::smallestTypeForLiteral(_literal.getValue());
+		return IntegerConstantType::fromLiteral(_literal.getValue());
 	case Token::STRING_LITERAL:
 		//@todo put larger strings into dynamic strings
 		return StaticStringType::smallestTypeForLiteral(_literal.getValue());
 	default:
-		return shared_ptr<Type const>();
+		return shared_ptr<Type>();
 	}
 }
 
@@ -112,19 +112,6 @@ TypePointer Type::commonType(TypePointer const& _a, TypePointer const& _b)
 
 const MemberList Type::EmptyMemberList = MemberList();
 
-shared_ptr<IntegerType const> IntegerType::smallestTypeForLiteral(string const& _literal)
-{
-	bigint value(_literal);
-	bool isSigned = value < 0 || (!_literal.empty() && _literal.front() == '-');
-	if (isSigned)
-		// convert to positive number of same bit requirements
-		value = ((-value) - 1) << 1;
-	unsigned bytes = max(bytesRequired(value), 1u);
-	if (bytes > 32)
-		return shared_ptr<IntegerType const>();
-	return make_shared<IntegerType const>(bytes * 8, isSigned ? Modifier::SIGNED : Modifier::UNSIGNED);
-}
-
 IntegerType::IntegerType(int _bits, IntegerType::Modifier _modifier):
 	m_bits(_bits), m_modifier(_modifier)
 {
@@ -156,18 +143,26 @@ bool IntegerType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 	return _convertTo.getCategory() == getCategory() || _convertTo.getCategory() == Category::CONTRACT;
 }
 
-bool IntegerType::acceptsUnaryOperator(Token::Value _operator) const
+TypePointer IntegerType::unaryOperatorResult(Token::Value _operator) const
 {
+	// "delete" is ok for all integer types
 	if (_operator == Token::DELETE)
-		return true;
-	if (isAddress())
-		return false;
-	if (_operator == Token::BIT_NOT)
-		return true;
-	if (isHash())
-		return false;
-	return _operator == Token::ADD || _operator == Token::SUB ||
-		   _operator == Token::INC || _operator == Token::DEC;
+		return shared_from_this();
+	// no further unary operators for addresses
+	else if (isAddress())
+		return TypePointer();
+	// "~" is ok for all other types
+	else if (_operator == Token::BIT_NOT)
+		return shared_from_this();
+	// nothing else for hashes
+	else if (isHash())
+		return TypePointer();
+	// for non-hash integers, we allow +, -, ++ and --
+	else if (_operator == Token::ADD || _operator == Token::SUB ||
+			_operator == Token::INC || _operator == Token::DEC)
+		return shared_from_this();
+	else
+		return TypePointer();
 }
 
 bool IntegerType::operator==(Type const& _other) const
@@ -186,17 +181,11 @@ string IntegerType::toString() const
 	return prefix + dev::toString(m_bits);
 }
 
-u256 IntegerType::literalValue(Literal const& _literal) const
-{
-	bigint value(_literal.getValue());
-	return u256(value);
-}
-
-TypePointer IntegerType::binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const
+TypePointer IntegerType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
 {
-	if (getCategory() != _other->getCategory())
+	if (_other->getCategory() != Category::INTEGER_CONSTANT && _other->getCategory() != getCategory())
 		return TypePointer();
-	auto commonType = dynamic_pointer_cast<IntegerType const>(Type::commonType(_this, _other));
+	auto commonType = dynamic_pointer_cast<IntegerType const>(Type::commonType(shared_from_this(), _other));
 
 	if (!commonType)
 		return TypePointer();
@@ -216,17 +205,152 @@ TypePointer IntegerType::binaryOperatorResultImpl(Token::Value _operator, TypePo
 
 const MemberList IntegerType::AddressMemberList =
 	MemberList({{"balance",
-					make_shared<IntegerType const>(256)},
+					make_shared<IntegerType >(256)},
 				{"callstring32",
-					make_shared<FunctionType const>(TypePointers({make_shared<StaticStringType const>(32)}),
-													TypePointers(), FunctionType::Location::BARE)},
+					make_shared<FunctionType>(TypePointers({make_shared<StaticStringType>(32)}),
+											  TypePointers(), FunctionType::Location::BARE)},
 				{"callstring32string32",
-					make_shared<FunctionType const>(TypePointers({make_shared<StaticStringType const>(32),
-																  make_shared<StaticStringType const>(32)}),
-													TypePointers(), FunctionType::Location::BARE)},
+					make_shared<FunctionType>(TypePointers({make_shared<StaticStringType>(32),
+															make_shared<StaticStringType>(32)}),
+											  TypePointers(), FunctionType::Location::BARE)},
 				{"send",
-					make_shared<FunctionType const>(TypePointers({make_shared<IntegerType const>(256)}),
-													TypePointers(), FunctionType::Location::SEND)}});
+					make_shared<FunctionType>(TypePointers({make_shared<IntegerType>(256)}),
+											  TypePointers(), FunctionType::Location::SEND)}});
+
+shared_ptr<IntegerConstantType const> IntegerConstantType::fromLiteral(string const& _literal)
+{
+	return make_shared<IntegerConstantType>(bigint(_literal));
+}
+
+bool IntegerConstantType::isImplicitlyConvertibleTo(Type const& _convertTo) const
+{
+	TypePointer integerType = getIntegerType();
+	return integerType && integerType->isImplicitlyConvertibleTo(_convertTo);
+}
+
+bool IntegerConstantType::isExplicitlyConvertibleTo(Type const& _convertTo) const
+{
+	TypePointer integerType = getIntegerType();
+	return integerType && integerType->isExplicitlyConvertibleTo(_convertTo);
+}
+
+TypePointer IntegerConstantType::unaryOperatorResult(Token::Value _operator) const
+{
+	bigint value;
+	switch (_operator)
+	{
+	case Token::BIT_NOT:
+		value = ~m_value;
+		break;
+	case Token::ADD:
+		value = m_value;
+		break;
+	case Token::SUB:
+		value = -m_value;
+		break;
+	default:
+		return TypePointer();
+	}
+	return make_shared<IntegerConstantType>(value);
+}
+
+TypePointer IntegerConstantType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
+{
+	if (_other->getCategory() == Category::INTEGER)
+	{
+		shared_ptr<IntegerType const> integerType = getIntegerType();
+		if (!integerType)
+			return TypePointer();
+		return integerType->binaryOperatorResult(_operator, _other);
+	}
+	else if (_other->getCategory() != getCategory())
+		return TypePointer();
+
+	IntegerConstantType const& other = dynamic_cast<IntegerConstantType const&>(*_other);
+	if (Token::isCompareOp(_operator))
+	{
+		shared_ptr<IntegerType const> thisIntegerType = getIntegerType();
+		shared_ptr<IntegerType const> otherIntegerType = other.getIntegerType();
+		if (!thisIntegerType || !otherIntegerType)
+			return TypePointer();
+		return thisIntegerType->binaryOperatorResult(_operator, otherIntegerType);
+	}
+	else
+	{
+		bigint value;
+		switch (_operator)
+		{
+		case Token::BIT_OR:
+			value = m_value | other.m_value;
+			break;
+		case Token::BIT_XOR:
+			value = m_value ^ other.m_value;
+			break;
+		case Token::BIT_AND:
+			value = m_value & other.m_value;
+			break;
+		case Token::ADD:
+			value = m_value + other.m_value;
+			break;
+		case Token::SUB:
+			value = m_value - other.m_value;
+			break;
+		case Token::MUL:
+			value = m_value * other.m_value;
+			break;
+		case Token::DIV:
+			if (other.m_value == 0)
+				return TypePointer();
+			value = m_value / other.m_value;
+			break;
+		case Token::MOD:
+			if (other.m_value == 0)
+				return TypePointer();
+			value = m_value % other.m_value;
+			break;
+		default:
+			return TypePointer();
+		}
+		return make_shared<IntegerConstantType>(value);
+	}
+}
+
+bool IntegerConstantType::operator==(Type const& _other) const
+{
+	if (_other.getCategory() != getCategory())
+		return false;
+	return m_value == dynamic_cast<IntegerConstantType const&>(_other).m_value;
+}
+
+string IntegerConstantType::toString() const
+{
+	return "int_const " + m_value.str();
+}
+
+u256 IntegerConstantType::literalValue(Literal const*) const
+{
+	// we ignore the literal and hope that the type was correctly determined
+	solAssert(m_value <= u256(-1), "Integer constant too large.");
+	solAssert(m_value >= -(bigint(1) << 255), "Integer constant too small.");
+	if (m_value >= 0)
+		return u256(m_value);
+	else
+		return s2u(s256(m_value));
+}
+
+shared_ptr<IntegerType const> IntegerConstantType::getIntegerType() const
+{
+	bigint value = m_value;
+	bool negative = (value < 0);
+	if (negative) // convert to positive number of same bit requirements
+		value = ((-value) - 1) << 1;
+	if (value > u256(-1))
+		return shared_ptr<IntegerType const>();
+	else
+		return make_shared<IntegerType>(max(bytesRequired(value), 1u) * 8,
+										negative ? IntegerType::Modifier::SIGNED
+												 : IntegerType::Modifier::UNSIGNED);
+}
 
 shared_ptr<StaticStringType> StaticStringType::smallestTypeForLiteral(string const& _literal)
 {
@@ -257,12 +381,13 @@ bool StaticStringType::operator==(Type const& _other) const
 	return other.m_bytes == m_bytes;
 }
 
-u256 StaticStringType::literalValue(const Literal& _literal) const
+u256 StaticStringType::literalValue(const Literal* _literal) const
 {
+	solAssert(_literal, "");
 	u256 value = 0;
-	for (char c: _literal.getValue())
+	for (char c: _literal->getValue())
 		value = (value << 8) | byte(c);
-	return value << ((32 - _literal.getValue().length()) * 8);
+	return value << ((32 - _literal->getValue().length()) * 8);
 }
 
 bool BoolType::isExplicitlyConvertibleTo(Type const& _convertTo) const
@@ -278,22 +403,23 @@ bool BoolType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 	return isImplicitlyConvertibleTo(_convertTo);
 }
 
-u256 BoolType::literalValue(Literal const& _literal) const
+u256 BoolType::literalValue(Literal const* _literal) const
 {
-	if (_literal.getToken() == Token::TRUE_LITERAL)
+	solAssert(_literal, "");
+	if (_literal->getToken() == Token::TRUE_LITERAL)
 		return u256(1);
-	else if (_literal.getToken() == Token::FALSE_LITERAL)
+	else if (_literal->getToken() == Token::FALSE_LITERAL)
 		return u256(0);
 	else
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Bool type constructed from non-boolean literal."));
 }
 
-TypePointer BoolType::binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const
+TypePointer BoolType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
 {
 	if (getCategory() != _other->getCategory())
 		return TypePointer();
 	if (Token::isCompareOp(_operator) || _operator == Token::AND || _operator == Token::OR)
-		return _this;
+		return _other;
 	else
 		return TypePointer();
 }
@@ -347,9 +473,9 @@ shared_ptr<FunctionType const> const& ContractType::getConstructorType() const
 	{
 		FunctionDefinition const* constructor = m_contract.getConstructor();
 		if (constructor)
-			m_constructorType = make_shared<FunctionType const>(*constructor);
+			m_constructorType = make_shared<FunctionType>(*constructor);
 		else
-			m_constructorType = make_shared<FunctionType const>(TypePointers(), TypePointers());
+			m_constructorType = make_shared<FunctionType>(TypePointers(), TypePointers());
 	}
 	return m_constructorType;
 }
@@ -521,21 +647,21 @@ MagicType::MagicType(MagicType::Kind _kind):
 	switch (m_kind)
 	{
 	case Kind::BLOCK:
-		m_members = MemberList({{"coinbase", make_shared<IntegerType const>(0, IntegerType::Modifier::ADDRESS)},
-								{"timestamp", make_shared<IntegerType const>(256)},
-								{"prevhash", make_shared<IntegerType const>(256, IntegerType::Modifier::HASH)},
-								{"difficulty", make_shared<IntegerType const>(256)},
-								{"number", make_shared<IntegerType const>(256)},
-								{"gaslimit", make_shared<IntegerType const>(256)}});
+		m_members = MemberList({{"coinbase", make_shared<IntegerType>(0, IntegerType::Modifier::ADDRESS)},
+								{"timestamp", make_shared<IntegerType >(256)},
+								{"prevhash", make_shared<IntegerType>(256, IntegerType::Modifier::HASH)},
+								{"difficulty", make_shared<IntegerType>(256)},
+								{"number", make_shared<IntegerType>(256)},
+								{"gaslimit", make_shared<IntegerType>(256)}});
 		break;
 	case Kind::MSG:
-		m_members = MemberList({{"sender", make_shared<IntegerType const>(0, IntegerType::Modifier::ADDRESS)},
-								{"gas", make_shared<IntegerType const>(256)},
-								{"value", make_shared<IntegerType const>(256)}});
+		m_members = MemberList({{"sender", make_shared<IntegerType>(0, IntegerType::Modifier::ADDRESS)},
+								{"gas", make_shared<IntegerType>(256)},
+								{"value", make_shared<IntegerType>(256)}});
 		break;
 	case Kind::TX:
-		m_members = MemberList({{"origin", make_shared<IntegerType const>(0, IntegerType::Modifier::ADDRESS)},
-								{"gasprice", make_shared<IntegerType const>(256)}});
+		m_members = 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 b25d5d89..828c53b9 100644
--- a/Types.h
+++ b/Types.h
@@ -70,12 +70,12 @@ private:
 /**
  * Abstract base class that forms the root of the type hierarchy.
  */
-class Type: private boost::noncopyable
+class Type: private boost::noncopyable, public std::enable_shared_from_this<Type>
 {
 public:
 	enum class Category
 	{
-		INTEGER, BOOL, REAL, STRING, CONTRACT, STRUCT, FUNCTION, MAPPING, VOID, TYPE, MAGIC
+		INTEGER, INTEGER_CONSTANT, BOOL, REAL, STRING, CONTRACT, STRUCT, FUNCTION, MAPPING, VOID, TYPE, MAGIC
 	};
 
 	///@{
@@ -92,12 +92,6 @@ public:
 	static TypePointer forLiteral(Literal const& _literal);
 	/// @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);
-	/// @returns the resulting type of applying the given operator or an empty pointer if this is not possible.
-	/// The default implementation allows comparison operators if a common type exists
-	static TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _a, TypePointer const& _b)
-	{
-		return _a->binaryOperatorResultImpl(_operator, _a, _b);
-	}
 
 	virtual Category getCategory() const = 0;
 	virtual bool isImplicitlyConvertibleTo(Type const& _other) const { return *this == _other; }
@@ -105,7 +99,17 @@ public:
 	{
 		return isImplicitlyConvertibleTo(_convertTo);
 	}
-	virtual bool acceptsUnaryOperator(Token::Value) const { return false; }
+	/// @returns the resulting type of applying the given unary operator or an empty pointer if
+	/// this is not possible.
+	/// The default implementation does not allow any unary operator.
+	virtual TypePointer unaryOperatorResult(Token::Value) const { return TypePointer(); }
+	/// @returns the resulting type of applying the given binary operator or an empty pointer if
+	/// this is not possible.
+	/// The default implementation allows comparison operators if a common type exists
+	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
+	{
+		return Token::isCompareOp(_operator) ? commonType(shared_from_this(), _other) : TypePointer();
+	}
 
 	virtual bool operator==(Type const& _other) const { return getCategory() == _other.getCategory(); }
 	virtual bool operator!=(Type const& _other) const { return !this->operator ==(_other); }
@@ -131,18 +135,13 @@ public:
 	TypePointer getMemberType(std::string const& _name) const { return getMembers().getMemberType(_name); }
 
 	virtual std::string toString() const = 0;
-	virtual u256 literalValue(Literal const&) const
+	virtual u256 literalValue(Literal const*) const
 	{
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Literal value requested "
 																		  "for type without literals."));
 	}
 
 protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _a, TypePointer const& _b) const
-	{
-		return Token::isCompareOp(_operator) ? commonType(_a, _b) : TypePointer();
-	}
-
 	/// Convenience object used when returning an empty member list.
 	static const MemberList EmptyMemberList;
 };
@@ -159,15 +158,12 @@ public:
 	};
 	virtual Category getCategory() const override { return Category::INTEGER; }
 
-	/// @returns the smallest integer type for the given literal or an empty pointer
-	/// if no type fits.
-	static std::shared_ptr<IntegerType const> smallestTypeForLiteral(std::string const& _literal);
-
 	explicit IntegerType(int _bits, Modifier _modifier = Modifier::UNSIGNED);
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
-	virtual bool acceptsUnaryOperator(Token::Value _operator) const override;
+	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
+	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
 	virtual bool operator==(Type const& _other) const override;
 
@@ -177,16 +173,12 @@ public:
 	virtual MemberList const& getMembers() const { return isAddress() ? AddressMemberList : EmptyMemberList; }
 
 	virtual std::string toString() const override;
-	virtual u256 literalValue(Literal const& _literal) const override;
 
 	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; }
 	int isSigned() const { return m_modifier == Modifier::SIGNED; }
 
-protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override;
-
 private:
 	int m_bits;
 	Modifier m_modifier;
@@ -194,6 +186,40 @@ private:
 };
 
 /**
+ * Integer constants either literals or computed. Example expressions: 2, 2+10, ~10.
+ * There is one distinct type per value.
+ */
+class IntegerConstantType: public Type
+{
+public:
+	virtual Category getCategory() const override { return Category::INTEGER_CONSTANT; }
+
+	static std::shared_ptr<IntegerConstantType const> fromLiteral(std::string const& _literal);
+
+	explicit IntegerConstantType(bigint _value): m_value(_value) {}
+
+	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
+	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
+	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
+	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
+
+	virtual bool operator==(Type const& _other) const override;
+
+	virtual bool canBeStored() const override { return false; }
+	virtual bool canLiveOutsideStorage() const override { return false; }
+	virtual unsigned getSizeOnStack() const override { return 1; }
+
+	virtual std::string toString() const override;
+	virtual u256 literalValue(Literal const* _literal) const override;
+
+	/// @returns the smallest integer type that can hold the value or an empty pointer if not possible.
+	std::shared_ptr<IntegerType const> getIntegerType() const;
+
+private:
+	bigint m_value;
+};
+
+/**
  * String type with fixed length, up to 32 bytes.
  */
 class StaticStringType: public Type
@@ -214,7 +240,7 @@ public:
 	virtual bool isValueType() const override { return true; }
 
 	virtual std::string toString() const override { return "string" + dev::toString(m_bytes); }
-	virtual u256 literalValue(Literal const& _literal) const override;
+	virtual u256 literalValue(Literal const* _literal) const override;
 
 	int getNumBytes() const { return m_bytes; }
 
@@ -231,19 +257,17 @@ public:
 	BoolType() {}
 	virtual Category getCategory() const { return Category::BOOL; }
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
-	virtual bool acceptsUnaryOperator(Token::Value _operator) const override
+	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override
 	{
-		return _operator == Token::NOT || _operator == Token::DELETE;
+		return (_operator == Token::NOT || _operator == Token::DELETE) ? shared_from_this() : TypePointer();
 	}
+	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize() const { 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;
-
-protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override;
+	virtual u256 literalValue(Literal const* _literal) const override;
 };
 
 /**
@@ -285,9 +309,9 @@ class StructType: public Type
 public:
 	virtual Category getCategory() const override { return Category::STRUCT; }
 	StructType(StructDefinition const& _struct): m_struct(_struct) {}
-	virtual bool acceptsUnaryOperator(Token::Value _operator) const override
+	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override
 	{
-		return _operator == Token::DELETE;
+		return _operator == Token::DELETE ? shared_from_this() : TypePointer();
 	}
 
 	virtual bool operator==(Type const& _other) const override;
@@ -378,20 +402,12 @@ public:
 	virtual Category getCategory() const override { return Category::VOID; }
 	VoidType() {}
 
+	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 bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
-
-protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override
-	{
-		(void)_operator;
-		(void)_this;
-		(void)_other;
-		return TypePointer();
-	}
 };
 
 /**
@@ -403,24 +419,15 @@ class TypeType: public Type
 public:
 	virtual Category getCategory() const override { return Category::TYPE; }
 	TypeType(TypePointer const& _actualType): m_actualType(_actualType) {}
-
 	TypePointer const& getActualType() const { return m_actualType; }
 
+	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 bool canLiveOutsideStorage() const override { return false; }
 	virtual std::string toString() const override { return "type(" + m_actualType->toString() + ")"; }
 
-protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override
-	{
-		(void)_operator;
-		(void)_this;
-		(void)_other;
-		return TypePointer();
-	}
-
 private:
 	TypePointer m_actualType;
 };
@@ -437,6 +444,12 @@ public:
 	virtual Category getCategory() const override { return Category::MAGIC; }
 
 	MagicType(Kind _kind);
+
+	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override
+	{
+		return TypePointer();
+	}
+
 	virtual bool operator==(Type const& _other) const;
 	virtual bool canBeStored() const override { return false; }
 	virtual bool canLiveOutsideStorage() const override { return true; }
@@ -445,15 +458,6 @@ public:
 
 	virtual std::string toString() const override;
 
-protected:
-	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override
-	{
-		(void)_operator;
-		(void)_this;
-		(void)_other;
-		return TypePointer();
-	}
-
 private:
 	Kind m_kind;