From 3731b6a3f688cb646dfa770e7fcf8181ee3fc891 Mon Sep 17 00:00:00 2001
From: Lukasz Samson <lukaszsamson@gmail.com>
Date: Thu, 29 Aug 2024 23:23:41 +0200
Subject: [PATCH] correctly handle var versioning

---
 lib/elixir_sense/core/compiler.ex         |  7 +++---
 lib/elixir_sense/core/metadata_builder.ex | 27 ++++++++++-------------
 lib/elixir_sense/core/state.ex            | 17 +++++++++++---
 3 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/lib/elixir_sense/core/compiler.ex b/lib/elixir_sense/core/compiler.ex
index 2679b218..e882b487 100644
--- a/lib/elixir_sense/core/compiler.ex
+++ b/lib/elixir_sense/core/compiler.ex
@@ -1499,8 +1499,6 @@ defmodule ElixirSense.Core.Compiler do
       |> new_vars_scope
       |> new_attributes_scope
 
-    # TODO magic with ElixirEnv instead of new_vars_scope?
-
     {state, _env} = maybe_add_protocol_behaviour(state, %{env | module: full})
 
     {_result, state, e_env} = expand(block, state, %{env | module: full})
@@ -1535,9 +1533,10 @@ defmodule ElixirSense.Core.Compiler do
       end)
 
     # restore vars from outer scope
+    # restore version counter
     state = state
       |> apply_optional_callbacks(%{env | module: full})
-      |> remove_vars_scope(state_orig)
+      |> remove_vars_scope(state_orig, true)
       |> remove_attributes_scope
       |> remove_module
 
@@ -1633,6 +1632,8 @@ defmodule ElixirSense.Core.Compiler do
     {_e_args, state, env_for_expand} =
       expand_args(args, %{state | prematch: {%{}, 0, :none}}, %{env_for_expand | context: :match})
 
+    # TODO expand defaults
+
     {e_guard, state, env_for_expand} =
       __MODULE__.Clauses.guard(
         guards,
diff --git a/lib/elixir_sense/core/metadata_builder.ex b/lib/elixir_sense/core/metadata_builder.ex
index 38ddec59..b8d94ee4 100644
--- a/lib/elixir_sense/core/metadata_builder.ex
+++ b/lib/elixir_sense/core/metadata_builder.ex
@@ -14,24 +14,21 @@ defmodule ElixirSense.Core.MetadataBuilder do
   """
   @spec build(Macro.t(), nil | {pos_integer, pos_integer}) :: State.t()
   def build(ast, cursor_position \\ nil) do
-    {_ast, state, _env} =
-      Compiler.expand(
-        ast,
-        %State{
-          cursor_position: cursor_position,
-          prematch:
-            if Version.match?(System.version(), ">= 1.15.0-dev") do
-              Code.get_compiler_option(:on_undefined_variable)
-            else
-              :warn
-            end
-        },
-        Compiler.env()
-      )
+    state_orig = %State{
+      cursor_position: cursor_position,
+      prematch:
+        if Version.match?(System.version(), ">= 1.15.0-dev") do
+          Code.get_compiler_option(:on_undefined_variable)
+        else
+          :warn
+        end
+    }
+
+    {_ast, state, _env} =Compiler.expand(ast, state_orig, Compiler.env())
 
     state
     |> remove_attributes_scope
-    |> remove_vars_scope(%{vars: {%{}, false}})
+    |> remove_vars_scope(state_orig)
     |> remove_module
   end
 
diff --git a/lib/elixir_sense/core/state.ex b/lib/elixir_sense/core/state.ex
index d9a4811c..a593d33a 100644
--- a/lib/elixir_sense/core/state.ex
+++ b/lib/elixir_sense/core/state.ex
@@ -810,6 +810,7 @@ defmodule ElixirSense.Core.State do
         scope_id_count: scope_id,
         vars_info: [%{} | state.vars_info],
         # elixir_ex entries
+        # each def starts versioning from 0
         unused: 0,
         vars: {%{}, false}
     }
@@ -819,9 +820,9 @@ defmodule ElixirSense.Core.State do
     %__MODULE__{state | attributes: [[] | state.attributes], scope_attributes: [[]]}
   end
 
-  def remove_vars_scope(%__MODULE__{} = state, %{vars: vars}) do
+  def remove_vars_scope(%__MODULE__{} = state, %{vars: vars, unused: unused}, restore_version_counter \\ false) do
     state = maybe_move_vars_to_outer_scope(state)
-    %__MODULE__{
+    state = %__MODULE__{
       state
       | scope_ids: tl(state.scope_ids),
         vars_info: tl(state.vars_info),
@@ -829,9 +830,18 @@ defmodule ElixirSense.Core.State do
         # restore elixir_ex fields
         vars: vars
     }
+
+    if restore_version_counter do
+      # this is used by defmodule as module body does not affect outside versioning
+      %__MODULE__{
+        state
+        | unused: unused
+      }
+    else
+      state
+    end
   end
 
-  # TODO should we restore unused?
   def remove_func_vars_scope(%__MODULE__{} = state, %{vars: vars, unused: unused}) do
     %__MODULE__{
       state
@@ -840,6 +850,7 @@ defmodule ElixirSense.Core.State do
         vars_info_per_scope_id: update_vars_info_per_scope_id(state),
         # restore elixir_ex fields
         vars: vars,
+        # restore versioning
         unused: unused
     }
   end