feat(lsp)!: replace snippet parser by lpeg grammar

5 files changed, 118 insertions, 668 deletions

diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index db0c7b4407..3c20e52155 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -68,6 +68,10 @@ The following changes may require adaptations in user config or plugins.
 • Float window support hide and show by setting `hide` on `nvim_open_win` and
   `nvim_win_set_config`.
 
+• |vim.lsp.util.parse_snippet()| will now strictly follow the snippet grammar
+  defined by LSP, and hence previously parsed snippets might now be considered
+  invalid input.
+
 ==============================================================================
 NEW FEATURES                                                    *news-features*
 
diff --git a/runtime/lua/vim/lsp/_snippet.lua b/runtime/lua/vim/lsp/_snippet.lua
deleted file mode 100644
index e7ada5415f..0000000000
--- a/runtime/lua/vim/lsp/_snippet.lua
+++ /dev/null
@@ -1,500 +0,0 @@
-local P = {}
-
----Take characters until the target characters (The escape sequence is '\' + char)
----@param targets string[] The character list for stop consuming text.
----@param specials string[] If the character isn't contained in targets/specials, '\' will be left.
-P.take_until = function(targets, specials)
-  targets = targets or {}
-  specials = specials or {}
-
-  return function(input, pos)
-    local new_pos = pos
-    local raw = {}
-    local esc = {}
-    while new_pos <= #input do
-      local c = string.sub(input, new_pos, new_pos)
-      if c == '\\' then
-        table.insert(raw, '\\')
-        new_pos = new_pos + 1
-        c = string.sub(input, new_pos, new_pos)
-        if not vim.list_contains(targets, c) and not vim.list_contains(specials, c) then
-          table.insert(esc, '\\')
-        end
-        table.insert(raw, c)
-        table.insert(esc, c)
-        new_pos = new_pos + 1
-      else
-        if vim.list_contains(targets, c) then
-          break
-        end
-        table.insert(raw, c)
-        table.insert(esc, c)
-        new_pos = new_pos + 1
-      end
-    end
-
-    if new_pos == pos then
-      return P.unmatch(pos)
-    end
-
-    return {
-      parsed = true,
-      value = {
-        raw = table.concat(raw, ''),
-        esc = table.concat(esc, ''),
-      },
-      pos = new_pos,
-    }
-  end
-end
-
-P.unmatch = function(pos)
-  return {
-    parsed = false,
-    value = nil,
-    pos = pos,
-  }
-end
-
-P.map = function(parser, map)
-  return function(input, pos)
-    local result = parser(input, pos)
-    if result.parsed then
-      return {
-        parsed = true,
-        value = map(result.value),
-        pos = result.pos,
-      }
-    end
-    return P.unmatch(pos)
-  end
-end
-
-P.lazy = function(factory)
-  return function(input, pos)
-    return factory()(input, pos)
-  end
-end
-
-P.token = function(token)
-  return function(input, pos)
-    local maybe_token = string.sub(input, pos, pos + #token - 1)
-    if token == maybe_token then
-      return {
-        parsed = true,
-        value = maybe_token,
-        pos = pos + #token,
-      }
-    end
-    return P.unmatch(pos)
-  end
-end
-
-P.pattern = function(p)
-  return function(input, pos)
-    local maybe_match = string.match(string.sub(input, pos), '^' .. p)
-    if maybe_match then
-      return {
-        parsed = true,
-        value = maybe_match,
-        pos = pos + #maybe_match,
-      }
-    end
-    return P.unmatch(pos)
-  end
-end
-
-P.many = function(parser)
-  return function(input, pos)
-    local values = {}
-    local new_pos = pos
-    while new_pos <= #input do
-      local result = parser(input, new_pos)
-      if not result.parsed then
-        break
-      end
-      table.insert(values, result.value)
-      new_pos = result.pos
-    end
-    if #values > 0 then
-      return {
-        parsed = true,
-        value = values,
-        pos = new_pos,
-      }
-    end
-    return P.unmatch(pos)
-  end
-end
-
-P.any = function(...)
-  local parsers = { ... }
-  return function(input, pos)
-    for _, parser in ipairs(parsers) do
-      local result = parser(input, pos)
-      if result.parsed then
-        return result
-      end
-    end
-    return P.unmatch(pos)
-  end
-end
-
-P.opt = function(parser)
-  return function(input, pos)
-    local result = parser(input, pos)
-    return {
-      parsed = true,
-      value = result.value,
-      pos = result.pos,
-    }
-  end
-end
-
-P.seq = function(...)
-  local parsers = { ... }
-  return function(input, pos)
-    local values = {}
-    local new_pos = pos
-    for i, parser in ipairs(parsers) do
-      local result = parser(input, new_pos)
-      if result.parsed then
-        values[i] = result.value
-        new_pos = result.pos
-      else
-        return P.unmatch(pos)
-      end
-    end
-    return {
-      parsed = true,
-      value = values,
-      pos = new_pos,
-    }
-  end
-end
-
-local Node = {}
-
-Node.Type = {
-  SNIPPET = 0,
-  TABSTOP = 1,
-  PLACEHOLDER = 2,
-  VARIABLE = 3,
-  CHOICE = 4,
-  TRANSFORM = 5,
-  FORMAT = 6,
-  TEXT = 7,
-}
-
-function Node:__tostring()
-  local insert_text = {}
-  if self.type == Node.Type.SNIPPET then
-    for _, c in ipairs(self.children) do
-      table.insert(insert_text, tostring(c))
-    end
-  elseif self.type == Node.Type.CHOICE then
-    table.insert(insert_text, self.items[1])
-  elseif self.type == Node.Type.PLACEHOLDER then
-    for _, c in ipairs(self.children or {}) do
-      table.insert(insert_text, tostring(c))
-    end
-  elseif self.type == Node.Type.TEXT then
-    table.insert(insert_text, self.esc)
-  end
-  return table.concat(insert_text, '')
-end
-
---@see https://code.visualstudio.com/docs/editor/userdefinedsnippets#_grammar
-
-local S = {}
-S.dollar = P.token('$')
-S.open = P.token('{')
-S.close = P.token('}')
-S.colon = P.token(':')
-S.slash = P.token('/')
-S.comma = P.token(',')
-S.pipe = P.token('|')
-S.plus = P.token('+')
-S.minus = P.token('-')
-S.question = P.token('?')
-S.int = P.map(P.pattern('[0-9]+'), function(value)
-  return tonumber(value, 10)
-end)
-S.var = P.pattern('[%a_][%w_]+')
-S.text = function(targets, specials)
-  return P.map(P.take_until(targets, specials), function(value)
-    return setmetatable({
-      type = Node.Type.TEXT,
-      raw = value.raw,
-      esc = value.esc,
-    }, Node)
-  end)
-end
-
-S.toplevel = P.lazy(function()
-  return P.any(S.placeholder, S.tabstop, S.variable, S.choice)
-end)
-
-S.format = P.any(
-  P.map(P.seq(S.dollar, S.int), function(values)
-    return setmetatable({
-      type = Node.Type.FORMAT,
-      capture_index = values[2],
-    }, Node)
-  end),
-  P.map(P.seq(S.dollar, S.open, S.int, S.close), function(values)
-    return setmetatable({
-      type = Node.Type.FORMAT,
-      capture_index = values[3],
-    }, Node)
-  end),
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.int,
-      S.colon,
-      S.slash,
-      P.any(
-        P.token('upcase'),
-        P.token('downcase'),
-        P.token('capitalize'),
-        P.token('camelcase'),
-        P.token('pascalcase')
-      ),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.FORMAT,
-        capture_index = values[3],
-        modifier = values[6],
-      }, Node)
-    end
-  ),
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.int,
-      S.colon,
-      P.seq(
-        S.question,
-        P.opt(P.take_until({ ':' }, { '\\' })),
-        S.colon,
-        P.opt(P.take_until({ '}' }, { '\\' }))
-      ),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.FORMAT,
-        capture_index = values[3],
-        if_text = values[5][2] and values[5][2].esc or '',
-        else_text = values[5][4] and values[5][4].esc or '',
-      }, Node)
-    end
-  ),
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.int,
-      S.colon,
-      P.seq(S.plus, P.opt(P.take_until({ '}' }, { '\\' }))),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.FORMAT,
-        capture_index = values[3],
-        if_text = values[5][2] and values[5][2].esc or '',
-        else_text = '',
-      }, Node)
-    end
-  ),
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.int,
-      S.colon,
-      S.minus,
-      P.opt(P.take_until({ '}' }, { '\\' })),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.FORMAT,
-        capture_index = values[3],
-        if_text = '',
-        else_text = values[6] and values[6].esc or '',
-      }, Node)
-    end
-  ),
-  P.map(
-    P.seq(S.dollar, S.open, S.int, S.colon, P.opt(P.take_until({ '}' }, { '\\' })), S.close),
-    function(values)
-      return setmetatable({
-        type = Node.Type.FORMAT,
-        capture_index = values[3],
-        if_text = '',
-        else_text = values[5] and values[5].esc or '',
-      }, Node)
-    end
-  )
-)
-
-S.transform = P.map(
-  P.seq(
-    S.slash,
-    P.take_until({ '/' }, { '\\' }),
-    S.slash,
-    P.many(P.any(S.format, S.text({ '$', '/' }, { '\\' }))),
-    S.slash,
-    P.opt(P.pattern('[ig]+'))
-  ),
-  function(values)
-    return setmetatable({
-      type = Node.Type.TRANSFORM,
-      pattern = values[2].raw,
-      format = values[4],
-      option = values[6],
-    }, Node)
-  end
-)
-
-S.tabstop = P.any(
-  P.map(P.seq(S.dollar, S.int), function(values)
-    return setmetatable({
-      type = Node.Type.TABSTOP,
-      tabstop = values[2],
-    }, Node)
-  end),
-  P.map(P.seq(S.dollar, S.open, S.int, S.close), function(values)
-    return setmetatable({
-      type = Node.Type.TABSTOP,
-      tabstop = values[3],
-    }, Node)
-  end),
-  P.map(P.seq(S.dollar, S.open, S.int, S.transform, S.close), function(values)
-    return setmetatable({
-      type = Node.Type.TABSTOP,
-      tabstop = values[3],
-      transform = values[4],
-    }, Node)
-  end)
-)
-
-S.placeholder = P.any(
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.int,
-      S.colon,
-      P.opt(P.many(P.any(S.toplevel, S.text({ '$', '}' }, { '\\' })))),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.PLACEHOLDER,
-        tabstop = values[3],
-        -- insert empty text if opt did not match.
-        children = values[5] or {
-          setmetatable({
-            type = Node.Type.TEXT,
-            raw = '',
-            esc = '',
-          }, Node),
-        },
-      }, Node)
-    end
-  )
-)
-
-S.choice = P.map(
-  P.seq(
-    S.dollar,
-    S.open,
-    S.int,
-    S.pipe,
-    P.many(P.map(P.seq(S.text({ ',', '|' }), P.opt(S.comma)), function(values)
-      return values[1].esc
-    end)),
-    S.pipe,
-    S.close
-  ),
-  function(values)
-    return setmetatable({
-      type = Node.Type.CHOICE,
-      tabstop = values[3],
-      items = values[5],
-    }, Node)
-  end
-)
-
-S.variable = P.any(
-  P.map(P.seq(S.dollar, S.var), function(values)
-    return setmetatable({
-      type = Node.Type.VARIABLE,
-      name = values[2],
-    }, Node)
-  end),
-  P.map(P.seq(S.dollar, S.open, S.var, S.close), function(values)
-    return setmetatable({
-      type = Node.Type.VARIABLE,
-      name = values[3],
-    }, Node)
-  end),
-  P.map(P.seq(S.dollar, S.open, S.var, S.transform, S.close), function(values)
-    return setmetatable({
-      type = Node.Type.VARIABLE,
-      name = values[3],
-      transform = values[4],
-    }, Node)
-  end),
-  P.map(
-    P.seq(
-      S.dollar,
-      S.open,
-      S.var,
-      S.colon,
-      P.many(P.any(S.toplevel, S.text({ '$', '}' }, { '\\' }))),
-      S.close
-    ),
-    function(values)
-      return setmetatable({
-        type = Node.Type.VARIABLE,
-        name = values[3],
-        children = values[5],
-      }, Node)
-    end
-  )
-)
-
-S.snippet = P.map(P.many(P.any(S.toplevel, S.text({ '$' }, { '}', '\\' }))), function(values)
-  return setmetatable({
-    type = Node.Type.SNIPPET,
-    children = values,
-  }, Node)
-end)
-
-local M = {}
-
----The snippet node type enum
----@types table<string, integer>
-M.NodeType = Node.Type
-
----Parse snippet string and returns the AST
----@param input string
----@return table
-function M.parse(input)
-  local result = S.snippet(input, 1)
-  if not result.parsed then
-    error('snippet parsing failed.')
-  end
-  return result.value
-end
-
-return M
diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index 51ed87219c..a4c8959b99 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -1,5 +1,5 @@
 local protocol = require('vim.lsp.protocol')
-local snippet = require('vim.lsp._snippet')
+local snippet = require('vim.lsp._snippet_grammar')
 local validate = vim.validate
 local api = vim.api
 local list_extend = vim.list_extend
@@ -610,12 +610,41 @@ end
 ---@return string parsed snippet
 function M.parse_snippet(input)
   local ok, parsed = pcall(function()
-    return tostring(snippet.parse(input))
+    return snippet.parse(input)
   end)
   if not ok then
     return input
   end
-  return parsed
+
+  --- @param node vim.snippet.Node<any>
+  --- @return string
+  local function node_to_string(node)
+    local insert_text = {}
+    if node.type == snippet.NodeType.Snippet then
+      for _, child in
+        ipairs((node.data --[[@as vim.snippet.SnippetData]]).children)
+      do
+        table.insert(insert_text, node_to_string(child))
+      end
+    elseif node.type == snippet.NodeType.Choice then
+      table.insert(insert_text, (node.data --[[@as vim.snippet.ChoiceData]]).values[1])
+    elseif node.type == snippet.NodeType.Placeholder then
+      table.insert(
+        insert_text,
+        node_to_string((node.data --[[@as vim.snippet.PlaceholderData]]).value)
+      )
+    elseif node.type == snippet.NodeType.Text then
+      table.insert(
+        insert_text,
+        node
+          .data --[[@as vim.snippet.TextData]]
+          .text
+      )
+    end
+    return table.concat(insert_text)
+  end
+
+  return node_to_string(parsed)
 end
 
 --- Sorts by CompletionItem.sortText.
diff --git a/test/functional/plugin/lsp/snippet_spec.lua b/test/functional/plugin/lsp/snippet_spec.lua
index 7903885420..13df861b91 100644
--- a/test/functional/plugin/lsp/snippet_spec.lua
+++ b/test/functional/plugin/lsp/snippet_spec.lua
@@ -1,130 +1,70 @@
 local helpers = require('test.functional.helpers')(after_each)
-local snippet = require('vim.lsp._snippet')
+local snippet = require('vim.lsp._snippet_grammar')
 
 local eq = helpers.eq
 local exec_lua = helpers.exec_lua
 
-describe('vim.lsp._snippet', function()
+describe('vim.lsp._snippet_grammar', function()
   before_each(helpers.clear)
   after_each(helpers.clear)
 
   local parse = function(...)
-    return exec_lua('return require("vim.lsp._snippet").parse(...)', ...)
+    local res = exec_lua('return require("vim.lsp._snippet_grammar").parse(...)', ...)
+    return res.data.children
   end
 
-  it('should parse only text', function()
+  it('parses only text', function()
     eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
-        {
-          type = snippet.NodeType.TEXT,
-          raw = 'TE\\$\\}XT',
-          esc = 'TE$}XT',
-        },
-      },
+      { type = snippet.NodeType.Text, data = { text = 'TE$}XT' } },
     }, parse('TE\\$\\}XT'))
   end)
 
-  it('should parse tabstop', function()
+  it('parses tabstops', function()
     eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
-        {
-          type = snippet.NodeType.TABSTOP,
-          tabstop = 1,
-        },
-        {
-          type = snippet.NodeType.TABSTOP,
-          tabstop = 2,
-        },
-      },
+      { type = snippet.NodeType.Tabstop, data = { tabstop = 1 } },
+      { type = snippet.NodeType.Tabstop, data = { tabstop = 2 } },
     }, parse('$1${2}'))
   end)
 
-  it('should parse placeholders', function()
+  it('parses nested placeholders', function()
     eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
-        {
-          type = snippet.NodeType.PLACEHOLDER,
+      {
+        type = snippet.NodeType.Placeholder,
+        data = {
           tabstop = 1,
-          children = {
-            {
-              type = snippet.NodeType.PLACEHOLDER,
+          value = {
+            type = snippet.NodeType.Placeholder,
+            data = {
               tabstop = 2,
-              children = {
-                {
-                  type = snippet.NodeType.TEXT,
-                  raw = 'TE\\$\\}XT',
-                  esc = 'TE$}XT',
-                },
-                {
-                  type = snippet.NodeType.TABSTOP,
-                  tabstop = 3,
-                },
-                {
-                  type = snippet.NodeType.TABSTOP,
-                  tabstop = 1,
-                  transform = {
-                    type = snippet.NodeType.TRANSFORM,
-                    pattern = 'regex',
-                    option = 'i',
-                    format = {
-                      {
-                        type = snippet.NodeType.FORMAT,
-                        capture_index = 1,
-                        modifier = 'upcase',
-                      },
-                    },
-                  },
-                },
-                {
-                  type = snippet.NodeType.TEXT,
-                  raw = 'TE\\$\\}XT',
-                  esc = 'TE$}XT',
-                },
-              },
+              value = { type = snippet.NodeType.Tabstop, data = { tabstop = 3 } },
             },
           },
         },
       },
-    }, parse('${1:${2:TE\\$\\}XT$3${1/regex/${1:/upcase}/i}TE\\$\\}XT}}'))
+    }, parse('${1:${2:${3}}}'))
   end)
 
-  it('should parse variables', function()
+  it('parses variables', function()
     eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
-        {
-          type = snippet.NodeType.VARIABLE,
-          name = 'VAR',
-        },
-        {
-          type = snippet.NodeType.VARIABLE,
+      { type = snippet.NodeType.Variable, data = { name = 'VAR' } },
+      { type = snippet.NodeType.Variable, data = { name = 'VAR' } },
+      {
+        type = snippet.NodeType.Variable,
+        data = {
           name = 'VAR',
+          default = { type = snippet.NodeType.Tabstop, data = { tabstop = 1 } },
         },
-        {
-          type = snippet.NodeType.VARIABLE,
+      },
+      {
+        type = snippet.NodeType.Variable,
+        data = {
           name = 'VAR',
-          children = {
+          regex = 'regex',
+          options = '',
+          format = {
             {
-              type = snippet.NodeType.TABSTOP,
-              tabstop = 1,
-            },
-          },
-        },
-        {
-          type = snippet.NodeType.VARIABLE,
-          name = 'VAR',
-          transform = {
-            type = snippet.NodeType.TRANSFORM,
-            pattern = 'regex',
-            format = {
-              {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                modifier = 'upcase',
-              },
+              type = snippet.NodeType.Format,
+              data = { capture = 1, modifier = 'upcase' },
             },
           },
         },
@@ -132,105 +72,82 @@ describe('vim.lsp._snippet', function()
     }, parse('$VAR${VAR}${VAR:$1}${VAR/regex/${1:/upcase}/}'))
   end)
 
-  it('should parse choice', function()
+  it('parses choice', function()
     eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
-        {
-          type = snippet.NodeType.CHOICE,
-          tabstop = 1,
-          items = {
-            ',',
-            '|',
-          },
-        },
+      {
+        type = snippet.NodeType.Choice,
+        data = { tabstop = 1, values = { ',', '|' } },
       },
     }, parse('${1|\\,,\\||}'))
   end)
 
-  it('should parse format', function()
-    eq({
-      type = snippet.NodeType.SNIPPET,
-      children = {
+  it('parses format', function()
+    eq(
+      {
         {
-          type = snippet.NodeType.VARIABLE,
-          name = 'VAR',
-          transform = {
-            type = snippet.NodeType.TRANSFORM,
-            pattern = 'regex',
+          type = snippet.NodeType.Variable,
+          data = {
+            name = 'VAR',
+            regex = 'regex',
+            options = '',
             format = {
               {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                modifier = 'upcase',
+                type = snippet.NodeType.Format,
+                data = { capture = 1, modifier = 'upcase' },
               },
               {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                if_text = 'if_text',
-                else_text = '',
+                type = snippet.NodeType.Format,
+                data = { capture = 1, if_text = 'if_text' },
               },
               {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                if_text = '',
-                else_text = 'else_text',
+                type = snippet.NodeType.Format,
+                data = { capture = 1, else_text = 'else_text' },
               },
               {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                else_text = 'else_text',
-                if_text = 'if_text',
+                type = snippet.NodeType.Format,
+                data = { capture = 1, if_text = 'if_text', else_text = 'else_text' },
               },
               {
-                type = snippet.NodeType.FORMAT,
-                capture_index = 1,
-                if_text = '',
-                else_text = 'else_text',
+                type = snippet.NodeType.Format,
+                data = { capture = 1, else_text = 'else_text' },
               },
             },
           },
         },
       },
-    }, parse('${VAR/regex/${1:/upcase}${1:+if_text}${1:-else_text}${1:?if_text:else_text}${1:else_text}/}'))
+      parse(
+        '${VAR/regex/${1:/upcase}${1:+if_text}${1:-else_text}${1:?if_text:else_text}${1:else_text}/}'
+      )
+    )
   end)
 
-  it('should parse empty strings', function()
+  it('parses empty strings', function()
     eq({
-      children = {
-        {
-          children = { {
-            esc = '',
-            raw = '',
-            type = 7,
-          } },
+      {
+        type = snippet.NodeType.Placeholder,
+        data = {
           tabstop = 1,
-          type = 2,
-        },
-        {
-          esc = ' ',
-          raw = ' ',
-          type = 7,
+          value = { type = snippet.NodeType.Text, data = { text = '' } },
         },
-        {
+      },
+      {
+        type = snippet.NodeType.Text,
+        data = { text = ' ' },
+      },
+      {
+        type = snippet.NodeType.Variable,
+        data = {
           name = 'VAR',
-          transform = {
-            format = {
-              {
-                capture_index = 1,
-                else_text = '',
-                if_text = '',
-                type = 6,
-              },
+          regex = 'erg',
+          format = {
+            {
+              type = snippet.NodeType.Format,
+              data = { capture = 1, if_text = '' },
             },
-            option = 'g',
-            pattern = 'erg',
-            type = 5,
           },
-          type = 3,
+          options = 'g',
         },
       },
-      type = 0,
-    }, parse('${1:} ${VAR/erg/${1:?:}/g}'))
+    }, parse('${1:} ${VAR/erg/${1:+}/g}'))
   end)
 end)
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index ef08860f10..73e05d8d11 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -2301,7 +2301,7 @@ describe('LSP', function()
         { label='foocar', sortText="g", insertText='foodar', insertTextFormat=2, textEdit={newText='foobar(${1:place holder}, ${2:more ...holder{\\}})'} },
         { label='foocar', sortText="h", insertText='foodar(${1:var1} typ1, ${2:var2} *typ2) {$0\\}', insertTextFormat=2, textEdit={} },
         -- nested snippet tokens
-        { label='foocar', sortText="i", insertText='foodar(${1:var1 ${2|typ2,typ3|} ${3:tail}}) {$0\\}', insertTextFormat=2, textEdit={} },
+        { label='foocar', sortText="i", insertText='foodar(${1:${2|typ1,typ2|}}) {$0\\}', insertTextFormat=2, textEdit={} },
         -- braced tabstop
         { label='foocar', sortText="j", insertText='foodar()${0}', insertTextFormat=2, textEdit={} },
         -- plain text
@@ -2317,7 +2317,7 @@ describe('LSP', function()
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foobar', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="f", textEdit={newText='foobar'} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foobar(place holder, more ...holder{})', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="g", insertText='foodar', insertTextFormat=2, textEdit={newText='foobar(${1:place holder}, ${2:more ...holder{\\}})'} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foodar(var1 typ1, var2 *typ2) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="h", insertText='foodar(${1:var1} typ1, ${2:var2} *typ2) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
-        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foodar(var1 typ2 tail) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="i", insertText='foodar(${1:var1 ${2|typ2,typ3|} ${3:tail}}) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
+        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foodar(typ1) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="i", insertText='foodar(${1:${2|typ1,typ2|}}) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foodar()', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="j", insertText='foodar()${0}', insertTextFormat=2, textEdit={} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, kind = 'Unknown', menu = '', word = 'foodar(${1:var1})', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="k", insertText='foodar(${1:var1})', insertTextFormat=1, textEdit={} } } } } },
       }