Replace parser/surround-context with the toxic2 tolerant parser

.dialyzer_ignore.exs

@@ -24,8 +24,7 @@
   {"lib/elixir_sense/core/compiler/fn.ex", :pattern_match},
   {"lib/elixir_sense/core/normalized/macro/env.ex", :pattern_match},
 
-  # 2. Pre-existing peripheral logic (vendored tokenizer/parser, normalized helpers)
-  {"lib/elixir_sense/core/normalized/tokenizer.ex", :contract_supertype},
-  {"lib/elixir_sense/core/normalized/tokenizer.ex", :pattern_match},
-  {"lib/elixir_sense/core/parser.ex", :guard_fail}
+  # 3. Completion engine ported wholesale from elixir-ls (commit 98e983d). The unreachable `:error`
+  #    clauses in expand_dot_path/expand_aliases are upstream-faithful defensive fallbacks.
+  {"lib/elixir_sense/providers/completion/completion_engine.ex", :pattern_match}
 ]

.github/workflows/ci.yml

@@ -69,7 +69,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Same matrix as mix_test (Linux). See above for compatibility notes.
+        # Same matrix as mix_test (Linux).
         include:
           - elixir: 1.16.x
             otp: 26.x

lib/elixir_sense.ex

@@ -49,7 +49,7 @@ defmodule ElixirSense do
       ...> end
       ...> '''
       iex> ElixirSense.string_to_quoted(code, 1)
-      {:ok, {:defmodule, [do: [line: 1, column: 11], end: [line: 2, column: 1], line: 1, column: 1], [[do: {:__block__, [], []}]]}}
+      {:ok, {:defmodule, [do: [line: 1, column: 11], end: [line: 2, column: 1], line: 1, column: 1], [[do: {:__block__, [line: 1, column: 11], []}]]}}
   """
   @spec string_to_quoted(
           String.t(),

lib/elixir_sense/core/compiler.ex

@@ -1771,6 +1771,21 @@ defmodule ElixirSense.Core.Compiler do
     {Enum.reverse(ast), %{state | protocol: nil}, env}
   end
 
+  defp expand_macro(
+         meta,
+         Kernel,
+         :defmodule,
+         [alias, {:__cursor__, _, cursor_args} = cursor],
+         callback,
+         state,
+         env
+       )
+       when is_list(cursor_args) do
+    # tolerant parsers may produce a cursor in place of the do block
+    # expand as if the cursor was the module body
+    expand_macro(meta, Kernel, :defmodule, [alias, [do: cursor]], callback, state, env)
+  end
+
   defp expand_macro(
          meta,
          Kernel,

lib/elixir_sense/core/metadata.ex

@@ -74,16 +74,6 @@ defmodule ElixirSense.Core.Metadata do
     }
   end
 
-  if Version.match?(System.version(), "< 1.18.0-dev") do
-    def container_cursor_to_quoted_options(_trailing_fragment) do
-      [columns: true, token_metadata: true]
-    end
-  else
-    def container_cursor_to_quoted_options(trailing_fragment) do
-      [columns: true, token_metadata: true, trailing_fragment: trailing_fragment]
-    end
-  end
-
   def get_cursor_env(
         metadata,
         position,
@@ -95,57 +85,17 @@ defmodule ElixirSense.Core.Metadata do
         {line, column},
         surround
       ) do
-    {{prefix, needle, suffix}, source_with_cursor} =
-      case surround do
-        {{begin_line, begin_column}, {end_line, end_column}} ->
-          [prefix, needle, suffix] =
-            ElixirSense.Core.Source.split_at(metadata.source, [
-              {begin_line, begin_column},
-              {end_line, end_column}
-            ])
-
-          source_with_cursor = prefix <> "__cursor__(#{needle})" <> suffix
-
-          {{prefix, needle, suffix}, source_with_cursor}
-
-        nil ->
-          [prefix, suffix] =
-            ElixirSense.Core.Source.split_at(metadata.source, [
-              {line, column}
-            ])
-
-          source_with_cursor = prefix <> "__cursor__()" <> suffix
-
-          {{prefix, "", suffix}, source_with_cursor}
-      end
-
-    {meta, cursor_env} =
-      case Code.string_to_quoted(source_with_cursor,
-             columns: true,
-             token_metadata: true,
-             emit_warnings: false
-           ) do
-        {:ok, ast} ->
-          MetadataBuilder.build(ast).cursor_env || {[], nil}
-
-        _ ->
-          {[], nil}
-      end
-
-    {_meta, cursor_env} =
-      if cursor_env != nil do
-        {meta, cursor_env}
-      else
-        # IO.puts(prefix <> "|")
-        options = container_cursor_to_quoted_options(needle <> suffix)
-
-        case Code.Fragment.container_cursor_to_quoted(prefix, options) do
-          {:ok, ast} ->
-            MetadataBuilder.build(ast).cursor_env || {[], nil}
-
-          _ ->
-            {[], nil}
-        end
+    # the cursor environment is derived by marking the AST node at the cursor
+    # (located via toxic2's source ranges) - a separate parse from the one that
+    # produced `metadata`, so the marker never pollutes the calls/vars/references
+    # metadata. A `surround` range means the caller is navigating an existing
+    # symbol (definition/hover/references), so we keep that token in the tree.
+    opts = if surround == nil, do: [], else: [preserve_token: true]
+
+    cursor_env =
+      case ElixirSense.Core.Parser.cursor_env(metadata.source, {line, column}, opts) do
+        {_meta, env} -> env
+        nil -> nil
       end
 
     if cursor_env != nil do