Merge pull request #667 from chriseth/sol_moreFlexibleBinaryOps

Possibility for binary operators to yield types different from their operands'.

AST.cpp

@@ -180,12 +180,18 @@ void Assignment::checkTypeRequirements()
 	//@todo later, assignments to structs might be possible, but not to mappings
 	if (!m_leftHandSide->getType()->isValueType() && !m_leftHandSide->isLocalLValue())
 		BOOST_THROW_EXCEPTION(createTypeError("Assignment to non-local non-value lvalue."));
-	m_rightHandSide->expectType(*m_leftHandSide->getType());
 	m_type = m_leftHandSide->getType();
-	if (m_assigmentOperator != Token::ASSIGN)
+	if (m_assigmentOperator == Token::ASSIGN)
+		m_rightHandSide->expectType(*m_type);
+	else
+	{
 		// compound assignment
-		if (!m_type->acceptsBinaryOperator(Token::AssignmentToBinaryOp(m_assigmentOperator)))
+		m_rightHandSide->checkTypeRequirements();
+		TypePointer resultType = Type::binaryOperatorResult(Token::AssignmentToBinaryOp(m_assigmentOperator),
+															m_type, m_rightHandSide->getType());
+		if (!resultType || *resultType != *m_type)
 			BOOST_THROW_EXCEPTION(createTypeError("Operator not compatible with type."));
+	}
 }
 
 void ExpressionStatement::checkTypeRequirements()
@@ -225,24 +231,13 @@ void BinaryOperation::checkTypeRequirements()
 {
 	m_left->checkTypeRequirements();
 	m_right->checkTypeRequirements();
-	if (m_right->getType()->isImplicitlyConvertibleTo(*m_left->getType()))
+	m_commonType = Type::binaryOperatorResult(m_operator, m_left->getType(), m_right->getType());
-		m_commonType = m_left->getType();
+	if (!m_commonType)
-	else if (m_left->getType()->isImplicitlyConvertibleTo(*m_right->getType()))
+		BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_operator)) +
-		m_commonType = m_right->getType();
+											  " not compatible with types " +
-	else
+											  m_left->getType()->toString() + " and " +
-		BOOST_THROW_EXCEPTION(createTypeError("No common type found in binary operation: " +
-											  m_left->getType()->toString() + " vs. " +
 											  m_right->getType()->toString()));
-	if (Token::isCompareOp(m_operator))
+	m_type = Token::isCompareOp(m_operator) ? make_shared<BoolType>() : m_commonType;
-		m_type = make_shared<BoolType>();
-	else
-	{
-		m_type = m_commonType;
-		if (!m_commonType->acceptsBinaryOperator(m_operator))
-			BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_operator)) +
-												  " not compatible with type " +
-												  m_commonType->toString()));
-	}
 }
 
 void FunctionCall::checkTypeRequirements()

Types.cpp

@@ -100,6 +100,16 @@ shared_ptr<Type const> Type::forLiteral(Literal const& _literal)
 	}
 }
 
+TypePointer Type::commonType(TypePointer const& _a, TypePointer const& _b)
+{
+	if (_b->isImplicitlyConvertibleTo(*_a))
+		return _a;
+	else if (_a->isImplicitlyConvertibleTo(*_b))
+		return _b;
+	else
+		return TypePointer();
+}
+
 const MemberList Type::EmptyMemberList = MemberList();
 
 shared_ptr<IntegerType const> IntegerType::smallestTypeForLiteral(string const& _literal)
@@ -146,16 +156,6 @@ bool IntegerType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 	return _convertTo.getCategory() == getCategory() || _convertTo.getCategory() == Category::CONTRACT;
 }
 
-bool IntegerType::acceptsBinaryOperator(Token::Value _operator) const
-{
-	if (isAddress())
-		return Token::isCompareOp(_operator);
-	else if (isHash())
-		return Token::isCompareOp(_operator) || Token::isBitOp(_operator);
-	else
-		return true;
-}
-
 bool IntegerType::acceptsUnaryOperator(Token::Value _operator) const
 {
 	if (_operator == Token::DELETE)
@@ -192,6 +192,28 @@ u256 IntegerType::literalValue(Literal const& _literal) const
 	return u256(value);
 }
 
+TypePointer IntegerType::binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const
+{
+	if (getCategory() != _other->getCategory())
+		return TypePointer();
+	auto commonType = dynamic_pointer_cast<IntegerType const>(Type::commonType(_this, _other));
+
+	if (!commonType)
+		return TypePointer();
+
+	// 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
+	if (commonType->isAddress())
+		return TypePointer();
+	else if (commonType->isHash() && !Token::isBitOp(_operator))
+		return TypePointer();
+	else
+		return commonType;
+}
+
 const MemberList IntegerType::AddressMemberList =
 	MemberList({{"balance",
 					make_shared<IntegerType const>(256)},
@@ -266,6 +288,16 @@ u256 BoolType::literalValue(Literal const& _literal) const
 		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
+{
+	if (getCategory() != _other->getCategory())
+		return TypePointer();
+	if (Token::isCompareOp(_operator) || _operator == Token::AND || _operator == Token::OR)
+		return _this;
+	else
+		return TypePointer();
+}
+
 bool ContractType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 {
 	if (isImplicitlyConvertibleTo(_convertTo))

Types.h

@@ -81,15 +81,23 @@ public:
 	///@{
 	///@name Factory functions
 	/// Factory functions that convert an AST @ref TypeName to a Type.
-	static std::shared_ptr<Type const> fromElementaryTypeName(Token::Value _typeToken);
+	static TypePointer fromElementaryTypeName(Token::Value _typeToken);
-	static std::shared_ptr<Type const> fromUserDefinedTypeName(UserDefinedTypeName const& _typeName);
+	static TypePointer fromUserDefinedTypeName(UserDefinedTypeName const& _typeName);
-	static std::shared_ptr<Type const> fromMapping(Mapping const& _typeName);
+	static TypePointer fromMapping(Mapping const& _typeName);
-	static std::shared_ptr<Type const> fromFunction(FunctionDefinition const& _function);
+	static TypePointer fromFunction(FunctionDefinition const& _function);
 	/// @}
 
 	/// Auto-detect the proper type for a literal. @returns an empty pointer if the literal does
 	/// not fit any type.
-	static std::shared_ptr<Type const> forLiteral(Literal const& _literal);
+	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; }
@@ -97,7 +105,6 @@ public:
 	{
 		return isImplicitlyConvertibleTo(_convertTo);
 	}
-	virtual bool acceptsBinaryOperator(Token::Value) const { return false; }
 	virtual bool acceptsUnaryOperator(Token::Value) const { return false; }
 
 	virtual bool operator==(Type const& _other) const { return getCategory() == _other.getCategory(); }
@@ -131,6 +138,11 @@ public:
 	}
 
 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;
 };
@@ -155,7 +167,6 @@ public:
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
-	virtual bool acceptsBinaryOperator(Token::Value _operator) const override;
 	virtual bool acceptsUnaryOperator(Token::Value _operator) const override;
 
 	virtual bool operator==(Type const& _other) const override;
@@ -173,6 +184,9 @@ public:
 	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;
@@ -217,10 +231,6 @@ public:
 	BoolType() {}
 	virtual Category getCategory() const { return Category::BOOL; }
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
-	virtual bool acceptsBinaryOperator(Token::Value _operator) const override
-	{
-		return _operator == Token::AND || _operator == Token::OR;
-	}
 	virtual bool acceptsUnaryOperator(Token::Value _operator) const override
 	{
 		return _operator == Token::NOT || _operator == Token::DELETE;
@@ -231,6 +241,9 @@ public:
 
 	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;
 };
 
 /**
@@ -369,6 +382,12 @@ public:
 	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
+	{
+		return TypePointer();
+	}
 };
 
 /**
@@ -389,6 +408,12 @@ public:
 	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
+	{
+		return TypePointer();
+	}
+
 private:
 	TypePointer m_actualType;
 };
@@ -413,6 +438,12 @@ public:
 
 	virtual std::string toString() const override;
 
+protected:
+	virtual TypePointer binaryOperatorResultImpl(Token::Value _operator, TypePointer const& _this, TypePointer const& _other) const override
+	{
+		return TypePointer();
+	}
+
 private:
 	Kind m_kind;