protected virtual Expression ResolveEnumOperator(ParseContext ec, Expression expr)
{
var underlyingType = Enum.GetUnderlyingType(expr.Type);
var bestExpr = ResolvePrimitivePredefinedType(ec, EmptyCastExpression.Create(expr, underlyingType));
if (bestExpr == null)
{
return(null);
}
Operand = bestExpr;
Type = expr.Type;
return(EmptyCastExpression.Create(this, Type));
}
Expression LiftResult(ParseContext ec, Expression res_expr)
{
TypeExpression lifted_type;
//
// Avoid double conversion
//
if (left_unwrap == null || left_null_lifted || !TypeManager.IsEqual(left_unwrap.Type, Left.Type) || (left_unwrap != null && right_null_lifted))
{
lifted_type = new NullableTypeExpression(Left.Type, Span);
lifted_type = lifted_type.ResolveAsTypeTerminal(ec, false);
if (lifted_type == null)
{
return(null);
}
if (Left is CastExpression)
{
((CastExpression)Left).DestinationType = new TypeExpression(lifted_type.Type);
}
else
{
Left = EmptyCastExpression.Create(Left, lifted_type.Type);
}
}
if (right_unwrap == null || right_null_lifted || !TypeManager.IsEqual(right_unwrap.Type, Right.Type) || (right_unwrap != null && left_null_lifted))
{
lifted_type = new NullableTypeExpression(Right.Type, Span);
lifted_type = lifted_type.ResolveAsTypeTerminal(ec, false);
if (lifted_type == null)
{
return(null);
}
if (Right is CastExpression)
{
((CastExpression)Right).DestinationType = new TypeExpression(lifted_type.Type);
}
else
{
Right = EmptyCastExpression.Create(Right, lifted_type.Type);
}
}
if (!Operator.IsComparison())
{
lifted_type = new NullableTypeExpression(res_expr.Type, Span);
lifted_type = lifted_type.ResolveAsTypeTerminal(ec, false);
if (lifted_type == null)
{
return(null);
}
wrap_ctor = new NullableInfo(lifted_type.Type).Constructor;
ResultType = res_expr.Type = lifted_type.Type;
}
if (left_null_lifted)
{
Left = LiftedNullExpression.Create(Right.Type, Left.Span);
if (Operator.IsArithmetic() || Operator.IsShift() || Operator.IsBitwise())
{
return(LiftedNullExpression.CreateFromExpression(ec, res_expr));
}
//
// Value types and null comparison
//
if (right_unwrap == null || Operator.IsRelational())
{
return(CreateNullConstant(ec, right_orig).Resolve(ec));
}
}
if (right_null_lifted)
{
Right = LiftedNullExpression.Create(Left.Type, Right.Span);
if (Operator.IsArithmetic() || Operator.IsShift() || Operator.IsBitwise())
{
return(LiftedNullExpression.CreateFromExpression(ec, res_expr));
}
//
// Value types and null comparison
//
if (left_unwrap == null || Operator.IsRelational())
{
return(CreateNullConstant(ec, left_orig).Resolve(ec));
}
}
return(res_expr);
}