signatureHelp doesn't work for similar parameters

[oblitum]

Result from CocInfo
Run :CocInfo command and paste the content below.

## versions

vim version: NVIM v0.3.1
node version: v11.4.0
coc.nvim version: 0.0.39
term: tmux-256color
platform: linux

## Error messages

## Output channel: prettier

Describe the bug
A clear and concise description of what the bug is.

Two issues identified when prototypes have parameters without names:

1. completion suggestions for prototypes won't get refreshed on remotion of parameter names, only when names are changed
   • signatureHelp gets refreshed though
2. "JumpPlaceholder" signatureHelp only works when parameters have name
   • using autocmd User CocJumpPlaceholder call CocActionAsync('showSignatureHelp')

To Reproduce
Steps to reproduce the behavior:

1. ccls configuration
2. See video

Screenshots
If applicable, add screenshots to help explain your problem.

• https://i.imgur.com/IJiZ2E7.mp4

[chemzqm]

completion suggestions for prototypes won't get refreshed on remotion of parameter names, only when names are changed.

It's just what returns by ccls, should be from cache of ccls.

"JumpPlaceholder" only works when parameters have name

The autocmd triggered as expected, you can try it with other command, ccls doesn't give correct active param (always 0), but clangd does.

[oblitum]

Ops, ok, sorry, I was betting this was some regex matching issue on parameters without name.

cc @MaskRay

[oblitum]

The autocmd triggered as expected, you can try it with other command, ccls doesn't give correct active param (always 0), but clangd does.

Hi @chemzqm, I just tried clangd (same configuration as the wiki), and it provides the same behavior as in the video for the part of not highlighting current parameter (it does refresh the signature correctly though).

[oblitum]

This gif is simpler for showing that issue because it doesn't involve snippet usage:

[chemzqm]

Just tried with clangd and ccls, they both work as expected for me.

[oblitum]

I was thinking whether it's a clang version issue, I'm on 7.0.0 (official numbering, not Apple Clang one).

[oblitum]

clangd

Server seems to be responding correctly:

• coc-clangd-signaturehelp.log

On file open:

void foo(int, int) {}

int main() {
}

On end of session:

void foo(int, int) {}

int main() {
    foo(4,
}

[oblitum]

• These changes had no effect:

  • 2e93b1f#diff-4b0287e58feb91e5735437c5854f2a15

• Issue is possibly due to assuming parameter strings can't repeat, then just indexing the first occurrence:

  • coc.nvim/src/handler/index.ts

    Line 623 in 2e93b1f

    let idx = ms ? ms.index : after.indexOf(active.label)

• Proof it's not related to parameters being unnamed:
  

[MaskRay]

It is one of my complaints https://github.com/MaskRay/ccls/wiki/LSP

textDocument/signatureHelp: the position of ParameterInformation::label is unspecified: it is difficult to highlight ParameterInformation::label in SignatureInformation::label

[oblitum]

With just the following, it indeed requires some extra logic on client's side:

[Trace - 11:19:20 PM] Received response 'textDocument/signatureHelp - (4)' in 6ms.
Result: {
    "activeParameter": 1,
    "activeSignature": 0,
    "signatures": [
        {
            "label": "foo(int, int) -> void",
            "parameters": [
                {
                    "label": "int"
                },
                {
                    "label": "int"
                }
            ]
        }
    ]
}