Implement interface code fix

[dungpa]

Move the feature from VFPT:

[vasily-kirichenko]

Fantastic :)

[vasily-kirichenko]

It does not add the closing curly brace:

[vasily-kirichenko]

BTW, the preview is particular useful for this feature :)

[smoothdeveloper]

Regarding performance, will there be a way to disable the features that the user deem not useful like in VFPT?

I'm concerned that having all the features in VS but no way to disable those might lead to bigger performance concerns, I know some F# users don't install VFPT because of this.

[vasily-kirichenko]

@smoothdeveloper that were not the features that makes VS slower with VFPT enabled. It was FCS itself. Now we have FCS in VS built-in and its older duplicate has gone. Enabling / disabling features like the one implemented in this PR does not affect performance.

[smoothdeveloper]

@vasily-kirichenko thanks, figured that separate FCS was hurting a lot as well, looking forward to try that new version soon :)

[cartermp]

In general you'll have slow performance on very large files (a few thousand lines), which is something we're definitely going to address after VS RTM release. Can't afford the time to do it now, but it's a priority. I've noticed that if files stay under 1k lines, it's pretty fast and definitely usable.

[vasily-kirichenko]

@smoothdeveloper having that said, we are definitely planning to add a setting dialog, like we had in VFPT, see #2111 (comment)

[saul]

This looks great @dungpa :)

Only thing to note is that the "Implement Interface Explicitly" should be in normal sentence case for consistency with the other code fixes (i.e. "Implement interface explicitly"). Also maybe the verbose option should be more clear - I can't tell without looking at the preview what it does. I also think that that "Stub missing interface methods" reads better.

[dungpa]

@saul Thanks. I renamed the labels to "Implement interface explicitly" (meaning having type annotations on arguments and return types) and "Implement interface explicitly without type annotation".

@vasily-kirichenko That part has never been done in VFPT. I will have a look at implementing it.

[KevinRansom]

This is great.

I noticed that: if I format the first line like this, I get no lollipop fixer?

Whereas when I format it on a separate line the fixer appears:

Is that intentional?

Kevin

[dsyme]

Perhaps FSharp.Core should contain

let nyi () = raise (NotImplementedException())

However we could only use that in codegen if the appropriate version of FSharp.Core was referenced

[KevinRansom]

@dsyme I don't think so ... the purpose of the nyi is a reminder to the developer to add code here.

[KevinRansom]

LGTM