bug#23053: 25.0.92; error in cc-mode when editing C# file with a generic class inheritance

[Ingo Lohmar]

On Fri, Mar 18 2016 22:33 (+0100), Jostein Kjønigsen wrote:

> While the error is encountered in csharp-mode (which is a non-official
> Emacs-package) I think it's worth nothing that this didn't use to cause
> errors in the past.
>
> I've run this test-case against the "regular" Windows build 24.5.1,
> using latest csharp-mode package and it runs fine. Trying latest Emacs
> from git master on Ubuntu I can reproduce this error systematically
> using the exact same version of csharp-mode.
>
> In my opinion that makes this an Emacs-bug.
>
> Whatever changes was done with cc-mode, it seems they're not fully
> compatible with all derived modes out there. It might be worth reaching
> out to other known third-party mode-developers basing their work on
> cc-mode to see if they too have issues with the recent changes in git
> master?

It is quite daring to call out an Emacs bug when you only encounter a
problem in "random" 3rd-party code :)

I have used csharp-mode before --- unless something has dramatically
changed in the last 3 months, it is essentially unmaintained.

Also, and I hope this does not sound too harsh, the csharp-mode code has
its fair share of problems to begin with.  For example, it uses faces
and cc-mode variables in ways that they are not intended for.
Therefore, it is plagued by more or less subtle font-lock and
indentation bugs.  It has severe performance problems.  It has not been
updated to deal w/ recent C# additions.  It is also fairly bloated,
adding "features" only remotely related to editing C# code.

About a year ago, I started to strip down the code to the bare
essentials and tried to make it more robust and play nicely with the
cc-mode machinery.  While this worked.. hmmm.. ok for the most part, I
have hesitated to put any of that code out in the open, as some of the
above problems remain unsolved.  My take-away was that cc-mode is a big
and complex beast as it stands, and I am not too eager to dive into all
its details.  If nobody else is doing the dirty work, chances to
properly support C# in *this* framework are pretty slim, I guess.

My hope is that the open-sourced Roslyn framework that is now used in
Omnisharp (haven't tested it) could also be used to do the whole
font-lock/indentation thing, such that we would not have to try to fit
C# into the cc-mode shape.