Use stacktrace in mix compiled diagnostics on elixir 1.15

remove special handling for token missing error
the hint line is extracted elsewhere and populates related info

Author: lukaszsamson

apps/language_server/lib/language_server/diagnostics.ex

@@ -46,12 +46,20 @@ defmodule ElixirLS.LanguageServer.Diagnostics do
 
       %__MODULE__{normalized | message: message, file: file, position: position}
     else
-      {type, file, position, stacktrace} =
+      {_type, file, position, stacktrace} =
         extract_message_info(diagnostic.message, root_path)
 
+      {file, position} =
+        get_file_and_position_with_stacktrace_fallback(
+          {file || diagnostic.file, position || diagnostic.position},
+          Map.get(diagnostic, :stacktrace, []),
+          root_path,
+          mixfile
+        )
+
       normalized
       |> maybe_update_file(file, mixfile)
-      |> maybe_update_position(type, position, stacktrace)
+      |> maybe_update_position(position, stacktrace)
     end
   end
 
@@ -85,21 +93,7 @@ defmodule ElixirLS.LanguageServer.Diagnostics do
     end
   end
 
-  defp maybe_update_position(diagnostic, "TokenMissingError", position, stacktrace) do
-    case extract_line_from_missing_hint(diagnostic.message) do
-      line when is_integer(line) and line > 0 ->
-        %{diagnostic | position: line}
-
-      _ ->
-        do_maybe_update_position(diagnostic, position, stacktrace)
-    end
-  end
-
-  defp maybe_update_position(diagnostic, _type, position, stacktrace) do
-    do_maybe_update_position(diagnostic, position, stacktrace)
-  end
-
-  defp do_maybe_update_position(diagnostic, position, stacktrace) do
+  defp maybe_update_position(diagnostic, position, stacktrace) do
     cond do
       position != nil ->
         %{diagnostic | position: position}
@@ -191,16 +185,6 @@ defmodule ElixirLS.LanguageServer.Diagnostics do
     false
   end
 
-  defp extract_line_from_missing_hint(message) do
-    case Regex.run(
-           ~r/starting at line (\d+)\)/u,
-           message
-         ) do
-      [_, line] -> String.to_integer(line)
-      _ -> nil
-    end
-  end
-
   defp extract_line_from_stacktrace(file, stacktrace) do
     Enum.find_value(stacktrace, fn stack_item ->
       with [_, _, file_relative, line] <-

apps/language_server/test/diagnostics_test.exs

@@ -143,29 +143,6 @@ defmodule ElixirLS.LanguageServer.DiagnosticsTest do
         assert diagnostic.position == 13
       end
 
-      test "if position is nil and error is TokenMissingError, try to retrieve from the hint" do
-        root_path = Path.join(__DIR__, "fixtures/token_missing_error")
-        file = Path.join(root_path, "lib/has_error.ex")
-        position = nil
-
-        message = """
-        ** (TokenMissingError) lib/has_error.ex:16:1: missing terminator: end (for "do" starting at line 1)
-
-            HINT: it looks like the "do" on line 6 does not have a matching "end"
-
-            (elixir 1.12.1) lib/kernel/parallel_compiler.ex:319: anonymous fn/4 in Kernel.ParallelCompiler.spawn_workers/7
-        """
-
-        diagnostic =
-          build_diagnostic(message, file, position)
-          |> Diagnostics.from_mix_task_compiler_diagnostic(
-            Path.join(root_path, "mix.exs"),
-            root_path
-          )
-
-        assert diagnostic.position == 1
-      end
-
       defp build_diagnostic(message, file, position) do
         %Mix.Task.Compiler.Diagnostic{
           compiler_name: "Elixir",