When XML doc generation is off, namespaces used by crefs are treated as unused

[davkean]

When XML doc generation is off, namespaces used by crefs are greyed out indicating that are they are unused:

I'm also offered to remove using System despite it actually being used by the cref.

I'm not sure if this by design or not (or rather a fallout of how this was designed), but this seems incorrect, especially as the colorizer appears to be processing them (if we're not processing them, why we run the colorizer over them?).

[gafter]

We should probably disable reporting unused usings when we are not processing doc comments.

[sharwell]

Duplicate of #2773.

Do note that this refactoring will cause a compile error once you switch to a configuration that generates XML docs (which is typically what you do in a release build).

• It is a compile warning, not error
• You can (and should) enable XML documentation output for all builds or incorrect syntax can sneak into your release builds. We actually have a new warning to catch this: New rule proposal: Documentation output should be enabled DotNetAnalyzers/StyleCopAnalyzers#1053

[jnm2]

If removing the using breaks a cref, it should not be suggested. Please fix.

Currently this results in bouncing back and forth between ReSharper complaining that you should add the using for the XML documentation and Roslyn complaining that you should remove it. It's a bad user experience.

If the only correct solution is truly to enable XML doc generation, then please stop suggesting removal of the using and start suggesting enabling XML documentation output.

This may be a moonshot, but in an ideal world, I think I should be able to leave XML documentation output off and still have all the syntax checking as though it was on, minus the warning about publicly visible types missing comments.

[gafter]

@jnm2 discussion has moved to #2773

[jnm2]

@gafter Thanks. Moved the comment.