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

1 files changed, 15 insertions, 20 deletions

diff --git a/AST.cpp b/AST.cpp
index 1fa6d8f6..c7d617b4 100644
--- a/AST.cpp
+++ b/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 = m_left->getType();
-	else if (m_left->getType()->isImplicitlyConvertibleTo(*m_right->getType()))
-		m_commonType = m_right->getType();
-	else
-		BOOST_THROW_EXCEPTION(createTypeError("No common type found in binary operation: " +
-											  m_left->getType()->toString() + " vs. " +
+	m_commonType = Type::binaryOperatorResult(m_operator, m_left->getType(), m_right->getType());
+	if (!m_commonType)
+		BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_operator)) +
+											  " not compatible with types " +
+											  m_left->getType()->toString() + " and " +
 											  m_right->getType()->toString()));
-	if (Token::isCompareOp(m_operator))
-		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()));
-	}
+	m_type = Token::isCompareOp(m_operator) ? make_shared<BoolType>() : m_commonType;
 }
 
 void FunctionCall::checkTypeRequirements()