Dialyzer improvements (#422)

* avoid another pass over enumerable

* avoid expand_references on the same modules if they are used in more than 1 app

avoid getting path from module when path is already known

* add always started otp apps to plt

before they were included indirectly as elixir app deps
not all modules from those apps were analyzed

* prefer consolidated protocol beams

* avoid unnecessary passes over map

* run formatter

* avoid another iterations

Author: lukaszsamson

apps/language_server/lib/language_server/dialyzer.ex

@@ -210,11 +210,21 @@ defmodule ElixirLS.LanguageServer.Dialyzer do
   defp update_stale(md5, removed_files, file_changes, timestamp) do
     prev_paths = Map.keys(md5) |> MapSet.new()
 
+    # FIXME: Private API
+    consolidation_path = Mix.Project.consolidation_path()
+
+    consolidated_protocol_beams =
+      for path <- Path.join(consolidation_path, "*.beam") |> Path.wildcard(),
+          into: MapSet.new(),
+          do: Path.basename(path)
+
     # FIXME: Private API
     all_paths =
-      Mix.Utils.extract_files([Mix.Project.build_path()], [:beam])
-      |> Enum.map(&Path.relative_to_cwd(&1))
-      |> MapSet.new()
+      for path <- Mix.Utils.extract_files([Mix.Project.build_path()], [:beam]),
+          Path.basename(path) not in consolidated_protocol_beams or
+            Path.dirname(path) == consolidation_path,
+          into: MapSet.new(),
+          do: Path.relative_to_cwd(path)
 
     removed =
       prev_paths
@@ -373,13 +383,13 @@ defmodule ElixirLS.LanguageServer.Dialyzer do
         mod_deps = update_mod_deps(mod_deps, new_mod_deps, removed_modules)
         warnings = add_warnings(warnings, raw_warnings)
 
+        md5 = Map.drop(md5, removed_files)
+
         md5 =
           for {file, {_, hash}} <- file_changes, into: md5 do
             {file, hash}
           end
 
-        md5 = remove_files(md5, removed_files)
-
         {active_plt, mod_deps, md5, warnings}
       end)
 
@@ -392,14 +402,11 @@ defmodule ElixirLS.LanguageServer.Dialyzer do
   end
 
   defp update_mod_deps(mod_deps, new_mod_deps, removed_modules) do
-    mod_deps
-    |> Map.merge(new_mod_deps)
-    |> Map.drop(removed_modules)
-    |> Map.new(fn {mod, deps} -> {mod, deps -- removed_modules} end)
-  end
-
-  defp remove_files(md5, removed_files) do
-    Map.drop(md5, removed_files)
+    for {mod, deps} <- mod_deps,
+        mod not in removed_modules,
+        into: new_mod_deps do
+      {mod, deps -- removed_modules}
+    end
   end
 
   defp add_warnings(warnings, raw_warnings) do

apps/language_server/lib/language_server/dialyzer/manifest.ex

@@ -115,23 +115,31 @@ defmodule ElixirLS.LanguageServer.Dialyzer.Manifest do
     Path.join([Mix.Utils.mix_home(), "elixir-ls-#{otp_vsn()}_elixir-#{System.version()}"])
   end
 
-  @elixir_apps [:elixir, :eex, :ex_unit, :iex, :logger, :mix]
+  @elixir_apps [:elixir, :ex_unit, :mix, :iex, :logger, :eex]
+  @erlang_apps [:erts, :kernel, :stdlib, :compiler]
 
   defp build_elixir_plt() do
     JsonRpc.show_message(
       :info,
       "Building core Dialyzer Elixir PLT. This will take a few minutes (often 15+) and can be disabled in the settings."
     )
 
+    modules_to_paths =
+      for app <- @erlang_apps ++ @elixir_apps,
+          path <- Path.join([Application.app_dir(app), "**/*.beam"]) |> Path.wildcard(),
+          into: %{},
+          do: {pathname_to_module(path), path |> String.to_charlist()}
+
+    modules =
+      modules_to_paths
+      |> Map.keys()
+      |> expand_references
+
     files =
-      Enum.flat_map(@elixir_apps, fn app ->
-        Path.join([Application.app_dir(app), "**/*.beam"])
-        |> Path.wildcard()
-        |> Enum.map(&pathname_to_module/1)
-        |> expand_references()
-        |> Enum.map(&Utils.get_beam_file/1)
-        |> Enum.filter(&is_list/1)
-      end)
+      for mod <- modules,
+          path = modules_to_paths[mod] || Utils.get_beam_file(mod),
+          is_list(path),
+          do: path
 
     File.mkdir_p!(Path.dirname(elixir_plt_path()))
 

apps/language_server/lib/language_server/dialyzer/utils.ex

@@ -25,7 +25,7 @@ defmodule ElixirLS.LanguageServer.Dialyzer.Utils do
     String.to_atom(Path.basename(path, ".beam"))
   end
 
-  def expand_references(modules, exclude \\ [], result \\ MapSet.new())
+  def expand_references(modules, exclude \\ MapSet.new(), result \\ MapSet.new())
 
   def expand_references([], _, result) do
     result
@@ -60,8 +60,7 @@ defmodule ElixirLS.LanguageServer.Dialyzer.Utils do
           forms
         )
 
-      modules = for {:call, _, {:remote, _, {:atom, _, module}, _}, _} <- calls, do: module
-      Enum.uniq(modules)
+      for {:call, _, {:remote, _, {:atom, _, module}, _}, _} <- calls, uniq: true, do: module
     rescue
       _ -> []
     catch