Roslyn: Intellisense cannot be shown when the caret is between two dots

[jnm2]

In VS 2019 Preview 1.1 (and I think 1), when you backspace and retype a dot but there's another dot ahead of the caret, VS doesn't show intellisense anymore. Alt+Right also stops working while the caret is between the two dots.

Sometimes I see a very brief flash of a tiny light-colored square over the editor when intellisense fails to show, like a window opening and closing immediately.

VS2019:

VS2017:

I'm typing nonsense for demo purposes in the file I had open, but the same thing happens everywhere.

I've tripped over it several times a day every day I've been using the preview. I assume ranges had something to do with this, and I tried to reconcile myself to it for the past month on that basis, but I just can't deal with it. I hope this change wasn't intentional. This is a common thing for me to do when refactoring, fixing changed names after things move, etc.

[CyrusNajmabadi]

This should be fixed. It's lkely a supression for .. is causing this. However, that suppression should happen on the second dot, not the first.

[ivanbasov]

It seems this is caused by support of ranges like 1..10. I talked to the compiler team. They confirmed that two dots in "this..ToString()" are parsed as RangeExpression. Then, CreateContextWorker in CSharpSyntaxContext called from a completion provider does set proper flags to the context while locating on dots. It seems we should correct the context while located on the first dot of the range expression.

[CyrusNajmabadi]

FWIW, i am hitting this all the time now and it's driving me nuts :)

[ivanbasov]

@CyrusNajmabadi , totally agree. Should be a high priority.