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tessl/npm-coc-nvim

tessl install tessl/npm-coc-nvim@0.0.0

LSP based intellisense engine for neovim & vim8.

Diagnostics [Basic]

Complexity: Basic | Category: Intelligence

Common Tasks: View errors | Navigate diagnostics | Toggle display | Filter by severity

View, navigate, and manage diagnostics (errors, warnings, hints, and information) from language servers.

Common Tasks
Commands
Key Mappings
CocAction API
Utility Functions
Buffer Variables
Global Variables
Autocmd Events
Highlight Groups
Configuration
Usage Examples
Error Handling
Troubleshooting
See Also

Common Tasks

Navigate to Next Diagnostic

nmap <silent> ]g <Plug>(coc-diagnostic-next)

Jump to next diagnostic of any severity.

Navigate to Next Error Only

nmap <silent> ]e <Plug>(coc-diagnostic-next-error)

Jump to next error, skipping warnings and hints.

Show Diagnostic Info

nmap <silent> <leader>d <Plug>(coc-diagnostic-info)

Display diagnostic message at cursor in float window.

Open Diagnostic List

:CocDiagnostics

Show all diagnostics in location list window.

Commands

:CocDiagnostics

:CocDiagnostics [height]

Open all diagnostics in a location list window.

Parameters:

height: Optional window height in lines

Example:

:CocDiagnostics
:CocDiagnostics 15

Key Mappings

<Plug>(coc-diagnostic-info)

<Plug>(coc-diagnostic-info)

Show diagnostic message at cursor position in a float window.

Example:

nmap <silent> <leader>di <Plug>(coc-diagnostic-info)

<Plug>(coc-diagnostic-next)

<Plug>(coc-diagnostic-next)

Jump to next diagnostic of any severity.

Example:

nmap <silent> ]g <Plug>(coc-diagnostic-next)

<Plug>(coc-diagnostic-prev)

<Plug>(coc-diagnostic-prev)

Jump to previous diagnostic of any severity.

Example:

nmap <silent> [g <Plug>(coc-diagnostic-prev)

<Plug>(coc-diagnostic-next-error)

<Plug>(coc-diagnostic-next-error)

Jump to next error diagnostic (skip warnings, info, hints).

Example:

nmap <silent> ]e <Plug>(coc-diagnostic-next-error)

<Plug>(coc-diagnostic-prev-error)

<Plug>(coc-diagnostic-prev-error)

Jump to previous error diagnostic.

Example:

nmap <silent> [e <Plug>(coc-diagnostic-prev-error)

CocAction API

diagnosticInfo

CocAction('diagnosticInfo')
" Returns: void

Show diagnostic information at cursor in a float window.

Example:

nnoremap <silent> K :call CocAction('diagnosticInfo')<CR>

diagnosticNext

CocAction('diagnosticNext', [severity])

Jump to next diagnostic, optionally filtered by severity.

Parameters:

severity: Optional severity level ('error', 'warning', 'information', 'hint')

Example:

" Jump to next diagnostic of any severity
call CocAction('diagnosticNext')

" Jump to next error only
call CocAction('diagnosticNext', 'error')

diagnosticPrevious

CocAction('diagnosticPrevious', [severity])

Jump to previous diagnostic, optionally filtered by severity.

Parameters:

severity: Optional severity level

Example:

call CocAction('diagnosticPrevious')
call CocAction('diagnosticPrevious', 'warning')

diagnosticList

CocAction('diagnosticList')
" Returns: list

Get all diagnostics for all buffers.

Returns: List of diagnostic objects with properties:

file: File path
lnum: Line number (1-based)
col: Column number (1-based)
severity: Severity string
message: Diagnostic message
source: Diagnostic source

Example:

let diagnostics = CocAction('diagnosticList')
echo 'Total diagnostics: ' . len(diagnostics)

for diag in diagnostics
  echo diag.file . ':' . diag.lnum . ' [' . diag.severity . '] ' . diag.message
endfor

diagnosticToggle

CocAction('diagnosticToggle', [enable])

Toggle diagnostics display globally.

Parameters:

enable: Optional boolean to explicitly enable/disable

Example:

" Toggle diagnostics
call CocAction('diagnosticToggle')

" Explicitly disable
call CocAction('diagnosticToggle', v:false)

" Explicitly enable
call CocAction('diagnosticToggle', v:true)

diagnosticToggleBuffer

CocAction('diagnosticToggleBuffer', bufnr)

Toggle diagnostics for a specific buffer.

Parameters:

bufnr: Buffer number

Example:

" Toggle for current buffer
call CocAction('diagnosticToggleBuffer', bufnr('%'))

diagnosticPreview

CocAction('diagnosticPreview')

Preview diagnostic at cursor in a floating window with full details.

Example:

nnoremap <silent> <leader>dp :call CocAction('diagnosticPreview')<CR>

diagnosticRefresh

CocAction('diagnosticRefresh', [bufnr])

Force refresh diagnostics, optionally for a specific buffer.

Parameters:

bufnr: Optional buffer number

Example:

" Refresh current buffer
call CocAction('diagnosticRefresh')

" Refresh specific buffer
call CocAction('diagnosticRefresh', bufnr('%'))

Utility Functions

coc#util#diagnostic_info()

coc#util#diagnostic_info(bufnr, checkInsert)
" Returns: dictionary

Get diagnostic counts for a buffer.

Parameters:

bufnr: Buffer number
checkInsert: Check if in insert mode

Returns: Dictionary with keys:

error: Error count
warning: Warning count
information: Info count
hint: Hint count

Example:

let info = coc#util#diagnostic_info(bufnr('%'), 0)
echo 'Errors: ' . info.error . ', Warnings: ' . info.warning

coc#util#check_refresh()

coc#util#check_refresh(bufnr)
" Returns: boolean

Check if diagnostics need refresh for a buffer.

Parameters:

bufnr: Buffer number

Returns: 1 if refresh needed, 0 otherwise.

Buffer Variables

b:coc_diagnostic_disable

let b:coc_diagnostic_disable = 1

Disable diagnostics for the current buffer.

Type: Number Default: 0

Example:

" Disable diagnostics for log files
autocmd BufEnter *.log let b:coc_diagnostic_disable = 1

b:coc_diagnostic_info

b:coc_diagnostic_info

Read-only variable containing diagnostic counts for the buffer.

Type: Dictionary (read-only) Structure:

error: Number of errors
warning: Number of warnings
information: Number of info diagnostics
hint: Number of hints

Example:

if exists('b:coc_diagnostic_info')
  let errors = b:coc_diagnostic_info.error
  echo 'Buffer has ' . errors . ' errors'
endif

Global Variables

g:coc_status_error_sign

let g:coc_status_error_sign = 'E'

Sign text for errors in statusline.

Type: String Default: 'E'

Example:

let g:coc_status_error_sign = '✗'

g:coc_status_warning_sign

let g:coc_status_warning_sign = 'W'

Sign text for warnings in statusline.

Type: String Default: 'W'

Example:

let g:coc_status_warning_sign = '⚠'

Autocmd Events

User CocDiagnosticChange

autocmd User CocDiagnosticChange {command}

Triggered when diagnostics are updated for any buffer.

Example:

autocmd User CocDiagnosticChange call UpdateStatusLine()

function! UpdateStatusLine() abort
  let info = get(b:, 'coc_diagnostic_info', {})
  let errors = get(info, 'error', 0)
  let warnings = get(info, 'warning', 0)
  echo 'Diagnostics: E' . errors . ' W' . warnings
endfunction

Highlight Groups

Diagnostic Signs

" Highlight groups for sign column
CocErrorSign
CocWarningSign
CocInfoSign
CocHintSign

Example:

highlight CocErrorSign ctermfg=Red guifg=#ff0000
highlight CocWarningSign ctermfg=Yellow guifg=#ffcc00
highlight CocInfoSign ctermfg=Blue guifg=#00aaff
highlight CocHintSign ctermfg=Cyan guifg=#00ffaa

Diagnostic Virtual Text

" Highlight groups for virtual text
CocErrorVirtualText
CocWarningVirtualText
CocInfoVirtualText
CocHintVirtualText

Diagnostic Highlights

" Highlight groups for code ranges
CocErrorHighlight
CocWarningHighlight
CocInfoHighlight
CocHintHighlight
CocDeprecatedHighlight
CocUnusedHighlight

Diagnostic Lines

" Highlight groups for entire lines
CocErrorLine
CocWarningLine
CocInfoLine
CocHintLine

Diagnostics in Float Windows

" Highlight groups for floating windows
CocErrorFloat
CocWarningFloat
CocInfoFloat
CocHintFloat

Configuration

Common diagnostic settings in coc-settings.json:

{
  "diagnostic.enable": true,
  "diagnostic.enableSign": true,
  "diagnostic.enableHighlightLineNumber": true,
  "diagnostic.refreshOnInsertMode": false,
  "diagnostic.checkCurrentLine": true,
  "diagnostic.virtualText": false,
  "diagnostic.virtualTextCurrentLineOnly": true,
  "diagnostic.virtualTextPrefix": " ❯❯❯ ",
  "diagnostic.errorSign": "✗",
  "diagnostic.warningSign": "⚠",
  "diagnostic.infoSign": "ℹ",
  "diagnostic.hintSign": "➤",
  "diagnostic.locationlistUpdate": true,
  "diagnostic.messageTarget": "float",
  "diagnostic.messageDelay": 250,
  "diagnostic.maxWindowHeight": 20,
  "diagnostic.maxWindowWidth": 80
}

Usage Examples

Basic Navigation

" Navigate diagnostics
nmap <silent> [g <Plug>(coc-diagnostic-prev)
nmap <silent> ]g <Plug>(coc-diagnostic-next)

" Navigate errors only
nmap <silent> [e <Plug>(coc-diagnostic-prev-error)
nmap <silent> ]e <Plug>(coc-diagnostic-next-error)

" Show diagnostic info
nmap <silent> <leader>d <Plug>(coc-diagnostic-info)

Diagnostic List Display

" Show all diagnostics in location list
nnoremap <silent> <leader>dl :CocDiagnostics<CR>

" Custom diagnostic list function
function! ShowDiagnosticList() abort
  let diagnostics = CocAction('diagnosticList')

  if len(diagnostics) == 0
    echo "No diagnostics found"
    return
  endif

  " Group by severity
  let errors = []
  let warnings = []
  let info = []

  for diag in diagnostics
    if diag.severity == 'Error'
      call add(errors, diag)
    elseif diag.severity == 'Warning'
      call add(warnings, diag)
    else
      call add(info, diag)
    endif
  endfor

  echo "Errors: " . len(errors)
  echo "Warnings: " . len(warnings)
  echo "Info: " . len(info)
endfunction

command! DiagnosticSummary call ShowDiagnosticList()

Toggle Diagnostics

" Toggle diagnostics globally
nnoremap <silent> <leader>dt :call CocAction('diagnosticToggle')<CR>

" Toggle for current buffer
nnoremap <silent> <leader>db :call CocAction('diagnosticToggleBuffer', bufnr('%'))<CR>

" Disable for specific filetypes
autocmd FileType markdown,text let b:coc_diagnostic_disable = 1

Statusline Integration

" Show diagnostic info in statusline
function! StatusDiagnostic() abort
  let info = get(b:, 'coc_diagnostic_info', {})
  if empty(info) | return '' | endif
  let msgs = []
  if get(info, 'error', 0)
    call add(msgs, g:coc_status_error_sign . info.error)
  endif
  if get(info, 'warning', 0)
    call add(msgs, g:coc_status_warning_sign . info.warning)
  endif
  return join(msgs, ' ')
endfunction

set statusline+=%{StatusDiagnostic()}

Auto-Open Diagnostic Float

" Show diagnostic info on cursor hold
autocmd CursorHold * silent call CocActionAsync('diagnosticInfo')

" Set update time for faster response
set updatetime=300

Filter Diagnostics by Severity

function! ShowErrorsOnly() abort
  let all_diags = CocAction('diagnosticList')
  let errors = filter(all_diags, 'v:val.severity == "Error"')

  if len(errors) == 0
    echo "No errors found"
    return
  endif

  for err in errors
    echo err.file . ':' . err.lnum . ' - ' . err.message
  endfor
endfunction

command! CocErrors call ShowErrorsOnly()

Diagnostic Statistics

function! DiagnosticStats() abort
  let all_diagnostics = CocAction('diagnosticList')
  let stats = {'Error': 0, 'Warning': 0, 'Information': 0, 'Hint': 0}
  let by_file = {}

  for diag in all_diagnostics
    let stats[diag.severity] += 1

    if !has_key(by_file, diag.file)
      let by_file[diag.file] = 0
    endif
    let by_file[diag.file] += 1
  endfor

  echo "=== Diagnostic Statistics ==="
  echo "Errors: " . stats.Error
  echo "Warnings: " . stats.Warning
  echo "Info: " . stats.Information
  echo "Hints: " . stats.Hint
  echo "Total: " . len(all_diagnostics)
  echo "\nFiles with issues: " . len(by_file)
endfunction

command! DiagStats call DiagnosticStats()

Cycle Through Severity Levels

let g:diagnostic_severity_index = 0
let g:diagnostic_severities = ['error', 'warning', 'information', 'hint']

function! CycleDiagnosticSeverity() abort
  let g:diagnostic_severity_index = (g:diagnostic_severity_index + 1) % len(g:diagnostic_severities)
  let severity = g:diagnostic_severities[g:diagnostic_severity_index]
  echo "Jumping to: " . severity
  call CocAction('diagnosticNext', severity)
endfunction

nnoremap <silent> <leader>dn :call CycleDiagnosticSeverity()<CR>

Custom Diagnostic Signs

" Customize sign appearance
let g:coc_user_config = {
  \ 'diagnostic.errorSign': '✗',
  \ 'diagnostic.warningSign': '⚠',
  \ 'diagnostic.infoSign': 'ℹ',
  \ 'diagnostic.hintSign': '➤'
  \ }

" Customize sign highlight colors
highlight CocErrorSign ctermfg=Red guifg=#e06c75
highlight CocWarningSign ctermfg=Yellow guifg=#e5c07b
highlight CocInfoSign ctermfg=Blue guifg=#61afef
highlight CocHintSign ctermfg=Cyan guifg=#56b6c2

Refresh Diagnostics Manually

" Refresh diagnostics for current buffer
nnoremap <silent> <leader>dr :call CocAction('diagnosticRefresh')<CR>

" Auto-refresh on save
autocmd BufWritePost * call CocAction('diagnosticRefresh')

Error Handling

Diagnostics Not Showing

Problem: Diagnostics don't appear even though there are errors in the code.

Solutions:

" Check if diagnostics are enabled
:CocCommand workspace.showOutput

" Verify diagnostic settings
echo coc#util#get_config('diagnostic.enable')

" Check buffer-specific disable
if get(b:, 'coc_diagnostic_disable', 0)
  echo "Diagnostics disabled for this buffer"
endif

" Manually refresh
call CocAction('diagnosticRefresh')

Language Server Not Providing Diagnostics

Problem: Language server is running but not reporting diagnostics.

Solutions:

" Check LSP connection
:CocInfo

" Restart language server
:CocRestart

" Check language server configuration
:CocConfig

" Verify file is saved (some servers only diagnose saved files)
:w

Troubleshooting

Too many diagnostic messages

Problem: Diagnostic messages are overwhelming or distracting.

Solutions:

Filter by severity: nmap ]e <Plug>(coc-diagnostic-next-error) (errors only)
Disable virtual text: "diagnostic.virtualText": false
Increase message delay: "diagnostic.messageDelay": 500
Show only on current line: "diagnostic.virtualTextCurrentLineOnly": true

Diagnostics lag or slow performance

Problem: Diagnostic updates cause editor to slow down.

Solutions:

Disable in insert mode: "diagnostic.refreshOnInsertMode": false
Increase refresh delay: "diagnostic.refreshAfterSave": true

Disable for large files:

autocmd BufEnter * if line('$') > 5000 | let b:coc_diagnostic_disable = 1 | endif

Diagnostic signs not visible

Problem: Sign column doesn't show diagnostic indicators.

Solutions:

Enable signs: "diagnostic.enableSign": true
Check sign column is visible: :set signcolumn=yes

Verify highlight groups are defined:

highlight CocErrorSign ctermfg=Red guifg=#ff0000
highlight CocWarningSign ctermfg=Yellow guifg=#ffcc00

False positive diagnostics

Problem: Diagnostics report errors that aren't actually errors.

Solutions:

Update language server: :CocUpdate
Check workspace configuration: :CocLocalConfig
Add to ignore patterns in language server config
Restart coc.nvim: :CocRestart

Diagnostics don't update after fixing

Problem: After fixing code, diagnostics still show old errors.

Solutions:

Save file: :w (many servers require save)
Manual refresh: call CocAction('diagnosticRefresh')
Check auto-save settings: "diagnostic.refreshAfterSave": true
Restart if stuck: :CocRestart

Version

tessl/npm-coc-nvim

diagnostics.md.css-3qkkll{font-size:var(--chakra-font-sizes-sm);font-weight:var(--chakra-font-weights-normal);color:var(--chakra-colors-gray-300);}docs/intelligence/

Diagnostics [Basic]

Table of Contents

Common Tasks

Navigate to Next Diagnostic

Navigate to Next Error Only

Show Diagnostic Info

Open Diagnostic List

Commands

:CocDiagnostics

Key Mappings

<Plug>(coc-diagnostic-info)

<Plug>(coc-diagnostic-next)

<Plug>(coc-diagnostic-prev)

<Plug>(coc-diagnostic-next-error)

<Plug>(coc-diagnostic-prev-error)

CocAction API

diagnosticInfo

diagnosticNext

diagnosticPrevious

diagnosticList

diagnosticToggle

diagnosticToggleBuffer

diagnosticPreview

diagnosticRefresh

Utility Functions

coc#util#diagnostic_info()

coc#util#check_refresh()

Buffer Variables

b:coc_diagnostic_disable

b:coc_diagnostic_info

Global Variables

g:coc_status_error_sign

g:coc_status_warning_sign

Autocmd Events

User CocDiagnosticChange

Highlight Groups

Diagnostic Signs

Diagnostic Virtual Text

Diagnostic Highlights

Diagnostic Lines

Diagnostics in Float Windows

Configuration

Usage Examples

Basic Navigation

Diagnostic List Display

Toggle Diagnostics

Statusline Integration

Auto-Open Diagnostic Float

Filter Diagnostics by Severity

Diagnostic Statistics

Cycle Through Severity Levels

Custom Diagnostic Signs

Refresh Diagnostics Manually

Error Handling

Diagnostics Not Showing

Language Server Not Providing Diagnostics

Troubleshooting

Too many diagnostic messages

Diagnostics lag or slow performance

Diagnostic signs not visible

False positive diagnostics

Diagnostics don't update after fixing

See Also

diagnostics.mddocs/intelligence/