diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 483faae4c..24b8cbfb8 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -349,6 +349,10 @@ bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
 	case Token::Inc: // ++ (pre- or postfix)
 	case Token::Dec: // -- (pre- or postfix)
 		solAssert(!!m_currentLValue, "LValue not retrieved.");
+		solUnimplementedAssert(
+			_unaryOperation.annotation().type->category() != Type::Category::FixedPoint,
+			"Not yet implemented - FixedPointType."
+		);
 		m_currentLValue->retrieveValue(_unaryOperation.location());
 		if (!_unaryOperation.isPrefixOperation())
 		{
@@ -1647,12 +1651,12 @@ void ExpressionCompiler::appendOrdinaryBinaryOperatorCode(Token::Value _operator
 
 void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Type const& _type)
 {
-	IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
-	bool const c_isSigned = type.isSigned();
-
 	if (_type.category() == Type::Category::FixedPoint)
 		solUnimplemented("Not yet implemented - FixedPointType.");
 
+	IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
+	bool const c_isSigned = type.isSigned();
+
 	switch (_operator)
 	{
 	case Token::Add: