Add ability to ignore particular build warnings

[smudge202]

There is currently no way to suppress specified compiler warnings akin the Build tab of old project properties.

http://puu.sh/hCNDe/6314b5a5ef.png

Issue first raised here: dotnet/aspnetcore#564

[muratg]

This is a good idea. Let's try it in beta 6.

[Eilon]

Moving this out of backlog so we can reconsider.

[bricelam]

I prototyped something in bricelam:nowarn, but it's probably not the design you're looking for...

Format would be

{    
  "compilationOptions": {
    "noWarn": ["CS618", "CS1591"]
  }
}

[muratg]

I actually like @bricelam's design and implementation. cc: @davidfowl

If we decide to go with it, I'd like Brice to add some tests :)

[davidfowl]

Is it just suppressions? Do we want to expose this enum:

ReportDiagnostic.XX

[smudge202]

Just suppressions as @bricelam implemented looks ideal. Can always improve the model with fanciness later. Suppression is much closer to need.

[Eilon]

I think just suppressions like /nowarn:X would be awesome for v1.

Could we just take @bricelam 's code as a PR?

BTW after doing this also need to send a PR to SchemaStore to add the new option to the project.json schema: https://github.com/SchemaStore/schemastore/blob/master/src/schemas/json/project.json

[bricelam]

I'll add some tests and send an official PR.

[davidfowl]

@bricelam Lets do it

[muratg]

This issue was moved to dotnet/cli#576