ErrorSquiggles only appears in open files

[lh123]

ErrorSquiggles disappears when the file is closed.

I think ErrorSquiggle should be kept when the file is closed.

[bobbrow]

This is how VSCode works with other languages too. We could consider adding a setting to leave the squiggles around, but we'd need to see more upvotes before doing this work.

[sean-mcmanus]

Is there a reason you would want error squiggles to still show for closed files? Are these closed files header files that belong to the currently open translation unit?

[lh123]

This is how VSCode works with other languages too. We could consider adding a setting to leave the squiggles around, but we'd need to see more upvotes before doing this work.

1. typescript lsp
   ErrorSquiggles still shows after the file is closed.
   
2. vscode-clangd
   ErrorSquiggles still shows after the file is closed.
   

[lh123]

Is there a reason you would want error squiggles to still show for closed files?

This will let me know if other files have errors.
Without this feature, I have to recompile the project to know the errors in other files.

Are these closed files header files that belong to the currently open translation unit?

No. But even in the same translation unit, ErrorSquiggles will not be displayed in the closed file.

[sean-mcmanus]

Okay, that's news to me -- VS Code's json squiggler stops showing the errors when the file is closed, so maybe that's what I was thinking of. Visual Studio also stops showing IntelliSense errors when the file is closed (I filed a bug on VS 2 years ago and they closed it as "By Design", not sure of the reasoning behind that design).

This looks like a 1 line change if we want to do this, plus any test case changes. Probably won't be till March/April though.

[lh123]

I hope this feature is implemented because it is implemented in most "LSP".

[bobbrow]

I'm fairly certain TypeScript used to clear the problems when the file closed. This is news to me. When we do this work, we would enable it behind a C_Cpp.persistProblemsForClosedFiles or some such setting. It would default to false.