LSP: highlight groups test, doc

runtime/doc/lsp.txt

@@ -57,24 +57,39 @@ use of |v:lua| to call Lua from Vimscript): >
   autocmd Filetype python setlocal omnifunc=v:lua.vim.lsp.omnifunc
 
 
-FAQ ~
+================================================================================
+FAQ                                                     *lsp-faq*
 
-> How to force-reload LSP?
-
-Stop all clients, then reload the buffer. >
+- Q: How to force-reload LSP?
+  A: Stop all clients, then reload the buffer. >
 
   :lua vim.lsp.stop_all_clients()
   :edit
 
-> Why isn't completion working?
-
-In the buffer where you want to use LSP, check that 'omnifunc' is set to
-"v:lua.vim.lsp.omnifunc": >
+- Q: Why isn't completion working?
+  A: In the buffer where you want to use LSP, check that 'omnifunc' is set to
+  "v:lua.vim.lsp.omnifunc": >
 
   :verbose set omnifunc?
 
-Some other plugin may be overriding the option. To avoid that, you could set
-the option in an |after-directory| ftplugin, e.g. "after/ftplugin/python.vim".
+<  Some other plugin may be overriding the option. To avoid that, you could
+  set the option in an |after-directory| ftplugin, e.g.
+  "after/ftplugin/python.vim".
+
+================================================================================
+LSP HIGHLIGHT                                           *lsp-highlight*
+
+When LSP is activated these highlight groups are defined:
+
+  LspDiagnosticsError
+  LspDiagnosticsHint
+  LspDiagnosticsInformation
+  LspDiagnosticsUnderline
+  LspDiagnosticsUnderlineError
+  LspDiagnosticsUnderlineHint
+  LspDiagnosticsUnderlineInformation
+  LspDiagnosticsUnderlineWarning
+  LspDiagnosticsWarning
 
 ================================================================================
 LSP API                                                 *lsp-api*

runtime/lua/vim/lsp/util.lua

@@ -549,7 +549,9 @@ do
   local underline_highlight_name = "LspDiagnosticsUnderline"
   vim.cmd(string.format("highlight default %s gui=underline cterm=underline", underline_highlight_name))
   for kind, _ in pairs(protocol.DiagnosticSeverity) do
-    vim.cmd(string.format("highlight default link %s%s %s", underline_highlight_name, kind, underline_highlight_name))
+    if type(kind) == 'string' then
+      vim.cmd(string.format("highlight default link %s%s %s", underline_highlight_name, kind, underline_highlight_name))
+    end
   end
 
   local severity_highlights = {}

test/functional/plugin/lsp_spec.lua

@@ -1,6 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 
 local clear = helpers.clear
+local buf_lines = helpers.buf_lines
 local dedent = helpers.dedent
 local exec_lua = helpers.exec_lua
 local eq = helpers.eq
@@ -709,14 +710,9 @@ describe('LSP', function()
   end)
 end)
 
-describe('LSP util', function()
+describe('LSP', function()
   before_each(function()
     clear()
-    insert(dedent([[
-      First line of text
-      Second line of text
-      Third line of text
-      Fourth line of text]]))
   end)
 
   local function make_edit(y_0, x_0, y_1, x_1, text)
@@ -729,8 +725,29 @@ describe('LSP util', function()
     }
   end
 
+  it('highlight groups', function()
+    eq({'LspDiagnosticsError',
+        'LspDiagnosticsHint',
+        'LspDiagnosticsInformation',
+        'LspDiagnosticsUnderline',
+        'LspDiagnosticsUnderlineError',
+        'LspDiagnosticsUnderlineHint',
+        'LspDiagnosticsUnderlineInformation',
+        'LspDiagnosticsUnderlineWarning',
+        'LspDiagnosticsWarning',
+      },
+      exec_lua([[require'vim.lsp'; return vim.fn.getcompletion('Lsp', 'highlight')]]))
+  end)
+
   describe('apply_edits', function()
-    it('should apply simple edits', function()
+    before_each(function()
+      insert(dedent([[
+        First line of text
+        Second line of text
+        Third line of text
+        Fourth line of text]]))
+    end)
+    it('applies apply simple edits', function()
       local edits = {
         make_edit(0, 0, 0, 0, {"123"});
         make_edit(1, 0, 1, 1, {"2"});
@@ -744,8 +761,7 @@ describe('LSP util', function()
         'Fourth line of text';
       }, buf_lines(1))
     end)
-
-    it('should apply complex edits', function()
+    it('applies complex edits', function()
       local edits = {
         make_edit(0, 0, 0, 0, {"", "12"});
         make_edit(0, 0, 0, 0, {"3", "foo"});