Notice (2018-05-24): bugzilla.xamarin.com is now in
Please join us on
Visual Studio Developer Community and in the
Mono organizations on
GitHub to continue tracking issues. Bugzilla will remain
available for reference in read-only mode. We will continue to work
on open Bugzilla bugs, copy them to the new locations
as needed for follow-up, and add the new items under Related
Our sincere thanks to everyone who has contributed on this bug
tracker over the years. Thanks also for your understanding as we
make these adjustments and improvements for the future.
Please create a new report on
GitHub or Developer Community with
your current version information, steps to reproduce, and relevant error
messages or log files if you are hitting an issue that looks similar to
this resolved bug and you do not yet see a matching new report.
The following code is compiled by mcs and throws an InvalidProgramException when run:
static class Program
static void Bug<T>(Func<T> func)
static void Main()
Bug(() => 123);
csc from VS2015 on the other hand returns error "CS0023: Operator '?' cannot be applied to operand of type 'T'" unless there is a constraint on T.
Reproduced both on Ubuntu with mono 184.108.40.206 and FreeBSD with mono 220.127.116.11.
Fixed in master and 4.5 preview