In D131295#3935759, @Trass3r wrote:

Yeah quite complex: https://godbolt.org/z/8T5Pqadro

In D131295#3935027, @Trass3r wrote:

Thanks, it seems to fix the base case, but I still see multiple lenses when I add

template <int V>
int Foo<V>::foo()
{
    return 0;
}

In D131295#3933381, @Trass3r wrote:

One remaining issue is multiple lenses for template code like

template <int V>
int i = 0;

template int i<0>;
template int i<1>;
template int i<2>;

template <int V>
struct Foo {
    int foo(); // I see 3 codelenses here
};

template struct Foo<0>;
template struct Foo<1>;

int main()
{
    // return Foo<0>().foo() + Foo<1>().foo();
    // return i<0> + i<1> + i<2>;
}

Well, multiple lenses occured due to https://github.com/lightmelodies/llvm-project/blob/codelens/clang-tools-extra/clangd/FindSymbols.cpp#L500
And can be fixed by https://github.com/lightmelodies/llvm-project/blob/codelens/clang-tools-extra/clangd/CodeLens.cpp#L69

In D96751#2571563, @sammccall wrote:

Fantastic, thank you!

In D96751#2571346, @sammccall wrote:

Nice! This looks good to land as-is, I just have some suggestions where we may want to mark behavior to revisit later, and some places where we could trim the tests a bit.

Do you have commit access, or want me to land this for you? (I'd need an address for the commit)

Better printing for C++ constructor and destructor. Remove unnecessary test cases.

Change behavior of template and add unit tests.

Thanks for your response. Yes decl is too verbose in many cases. In fact I have tried another concise version, but I can not decide which one is better. Unit test in FindSymbolsTests.cpp is also done, but I would like upload them after we reach an agreement on what behavior is prefered.

I have also considered these problems, and here is some points of my view.
Latency
Consider llvm-project itself, textDocument/codeLens can be done in <500ms generally and <100ms if collect hierarchy is disabled in my notebook. Latency is significant in some rare case like Type.h which has too complex hierarchy relations. Meanwhile, vscode is smart to remember previous codelens's positions so the text rendering will not look too weird during long-time request. In fact, the biggest performance issue I find is that building AST when open a new file costs too much time, which makes textDocument/codeLens quite slow, as well as other action such as textDocument/documentSymbols. That's why I modified ClangdLSPServer.cpp to keep AST for recent closed files.

In D91930#2411338, @kadircet wrote:

Thanks a lot for working on improving clangd!

Can you also give a high-level overview of what kind of functionality you are providing here? Looks like there's a lot going on here, and it would be nice to know what you are attempting to do, rather than inferring that from the code. It would also help future travellers, as they can just read the description rather than going through the whole patch.