public static Constant CreateFromExpression (ResolveContext rc, Expression e)
{
if (!rc.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
rc.Report.Warning (458, 2, e.Location, "The result of the expression is always `null' of type `{0}'",
e.Type.GetSignatureForError ());
}
return ReducedExpression.Create (Create (e.Type, e.Location), e);
}