fix(diagnostic): remove useless highlight links (#15683)

These links were actually defined backwards: the highlight groups
actually being used for display are the new "Diagnostic*" groups, so
linking the old "LspDiagnostics*" groups to these does absolutely
nothing, since there is nothing actually being highlighted with the
LspDiagnostics* groups.

These links were made in an attempt to preserve backward compatibility
with existing colorschemes. We could reverse the links to maintain this
preservation, but then that disallows us from actually defining default
values for the new highlight groups.

Instead, just remove the links and be done with the old LspDiagnostics*
highlight groups.

This is not technically a breaking change: the breaking change already
happened in #15585, but this PR just makes that explicit.

1 files changed, 0 insertions, 28 deletions

diff --git a/test/functional/plugin/lsp/diagnostic_spec.lua b/test/functional/plugin/lsp/diagnostic_spec.lua
index 2a6d7de634..353de667ea 100644
--- a/test/functional/plugin/lsp/diagnostic_spec.lua
+++ b/test/functional/plugin/lsp/diagnostic_spec.lua
@@ -1,6 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
 
-local command = helpers.command
 local clear = helpers.clear
 local exec_lua = helpers.exec_lua
 local eq = helpers.eq
@@ -945,31 +944,4 @@ describe('vim.lsp.diagnostic', function()
       assert(loc_list[1].lnum < loc_list[2].lnum)
     end)
   end)
-
-  it('highlight groups', function()
-    command('runtime plugin/diagnostic.vim')
-    eq({
-      'LspDiagnosticsDefaultError',
-      'LspDiagnosticsDefaultHint',
-      'LspDiagnosticsDefaultInformation',
-      'LspDiagnosticsDefaultWarning',
-      'LspDiagnosticsFloatingError',
-      'LspDiagnosticsFloatingHint',
-      'LspDiagnosticsFloatingInformation',
-      'LspDiagnosticsFloatingWarning',
-      'LspDiagnosticsSignError',
-      'LspDiagnosticsSignHint',
-      'LspDiagnosticsSignInformation',
-      'LspDiagnosticsSignWarning',
-      'LspDiagnosticsUnderlineError',
-      'LspDiagnosticsUnderlineHint',
-      'LspDiagnosticsUnderlineInformation',
-      'LspDiagnosticsUnderlineWarning',
-      'LspDiagnosticsVirtualTextError',
-      'LspDiagnosticsVirtualTextHint',
-      'LspDiagnosticsVirtualTextInformation',
-      'LspDiagnosticsVirtualTextWarning',
-    }, exec_lua([[return vim.fn.getcompletion('Lsp', 'highlight')]]))
-  end)
-
 end)