Suggestions fail to show up in switch statement when accessing enum member

[mehlian]

Environment

• OS and Version: Windows 10
• VS Code Version: 1.108.2
• C/C++ Extension Version: 1.32.2
• If using SSH remote, specify OS of remote machine: none

Bug Summary and Steps to Reproduce

Bug Summary:
Suggestions popup fails to show up when editor cursor is between ::: chars.

Steps to reproduce:

1. Paste code (file.hpp):

enum class MyEnum
{
    None,
    One,
};

void func(MyEnum myEnum)
{
    switch (myEnum)
    {
    case MyEnum:::                       // <- problem here
        break;
    
    default:
        break;
    }
}

2. Move editor's cursor between 3 colon chars (like this: ::|: ) and press CTRL+SPACE to trigger suggestions popup.
3. No suggestions info shows up
4. Make space between 3 colon chars (like this :: : ) and try again to press CTRL+SPACE when cursor is after 2 colon chars and space - suggestions show up

Expected behavior:
Suggestions popup show up after pressing CTRL+SPACE when editor's cursor is after 2 colon chars regardless of what char comes after.

Configuration and Logs

none

Other Extensions

No response

Additional context

No response

[sean-mcmanus]

@mehlian During normal typing it's not an issue. Getting completion to work between an invalid triple ::: might be an issue with how our tokens are parsed for the completions. Are you sure you really want us to track this as a bug? I think it would be hard to justify us working on this fix given much higher priority issues we're working on, but maybe we could throw Copilot at it later on. I would guess we could have lots of other corner case invalid token completion cases in addition to this -- we haven't gotten many user complaints about it though.

[mehlian]

This does not work well with snippets. When using 'switch' snipped whole switch statement code block is created and user can use TAB key to navigate placeholders.

    switch (expression)
    {
    case constant expression:
        /* code */
        break;
    
    default:
        break;
    }

As you can see 'case constant expression:' already have ':' at the end and when user wants to type in enum member then 'constant expression' placeholder is removed and we end up with ::: situation.

[sean-mcmanus]

@mehlian Okay, that makes sense. Also, the bug doesn't repro in VS, which means it's happening our non-shared layer and most likely easily fixable (i.e. via Copilot).