Revert alias shadowing warning due to false positives (#13568)

* Revert "Fix false positive with nested shadowed alias (#13564)"

This reverts commit 8dc94db.

* Revert "Warn on unused shadowed aliases (#13550)"

This reverts commit d1b3063.

Author: sabiwara

lib/elixir/lib/kernel/lexical_tracker.ex

@@ -40,8 +40,8 @@ defmodule Kernel.LexicalTracker do
   end
 
   @doc false
-  def add_alias(pid, module, meta, warn, function?) when is_atom(module) do
-    :gen_server.cast(pid, {:add_alias, module, meta, warn, function?})
+  def add_alias(pid, module, meta, warn) when is_atom(module) do
+    :gen_server.cast(pid, {:add_alias, module, meta, warn})
   end
 
   @doc false
@@ -123,14 +123,7 @@ defmodule Kernel.LexicalTracker do
 
   @doc false
   def handle_call(:unused_aliases, _from, state) do
-    unused_aliases =
-      Enum.map(state.aliases, fn
-        {{:shadowed, module}, meta} -> {module, meta}
-        {module, meta} when is_atom(module) -> {module, meta}
-      end)
-      |> Enum.sort()
-
-    {:reply, unused_aliases, state}
+    {:reply, Enum.sort(state.aliases), state}
   end
 
   def handle_call(:unused_imports, _from, state) do
@@ -225,18 +218,8 @@ defmodule Kernel.LexicalTracker do
     end
   end
 
-  def handle_cast({:add_alias, module, meta, warn, function?}, state) do
+  def handle_cast({:add_alias, module, meta, warn}, state) do
     if warn do
-      state =
-        case state do
-          # we only track shadowed unused aliases at the top-level
-          %{aliases: %{^module => meta}} when not function? ->
-            put_in(state.aliases[{:shadowed, module}], meta)
-
-          _ ->
-            state
-        end
-
       {:noreply, put_in(state.aliases[module], meta)}
     else
       {:noreply, state}

lib/elixir/lib/macro/env.ex

@@ -447,7 +447,7 @@ defmodule Macro.Env do
 
   ## Examples
 
-      iex> alias List, as: MyList, warn: false
+      iex> alias List, as: MyList
       iex> Macro.Env.expand_alias(__ENV__, [], [:MyList])
       {:alias, List}
       iex> Macro.Env.expand_alias(__ENV__, [], [:MyList, :Nested])
@@ -456,7 +456,7 @@ defmodule Macro.Env do
   If there is no alias or the alias starts with `Elixir.`
   (which disables aliasing), then `:error` is returned:
 
-      iex> alias List, as: MyList, warn: false
+      iex> alias List, as: MyList
       iex> Macro.Env.expand_alias(__ENV__, [], [:Elixir, MyList])
       :error
       iex> Macro.Env.expand_alias(__ENV__, [], [:AnotherList])

lib/elixir/src/elixir_lexical.erl

@@ -40,8 +40,8 @@ trace({import, Meta, Module, Opts}, #{lexical_tracker := Pid}) ->
 
   ?tracker:add_import(Pid, Module, Only, Meta, Imported and should_warn(Meta, Opts)),
   ok;
-trace({alias, Meta, _Old, New, Opts}, #{lexical_tracker := Pid, function := Function}) ->
-  ?tracker:add_alias(Pid, New, Meta, should_warn(Meta, Opts), Function /= nil),
+trace({alias, Meta, _Old, New, Opts}, #{lexical_tracker := Pid}) ->
+  ?tracker:add_alias(Pid, New, Meta, should_warn(Meta, Opts)),
   ok;
 trace({alias_expansion, _Meta, Lookup, _Result}, #{lexical_tracker := Pid}) ->
   ?tracker:alias_dispatch(Pid, Lookup),

lib/elixir/test/elixir/kernel/alias_test.exs

@@ -34,12 +34,6 @@ defmodule Kernel.AliasTest do
     assert Billing == :"Elixir.MyApp.Billing"
   end
 
-  test "overriding parent alias with child alias" do
-    alias MyApp.Billing
-    alias Billing.Billing
-    assert Billing == :"Elixir.MyApp.Billing.Billing"
-  end
-
   test "lexical" do
     if true_fun() do
       alias OMG, as: List, warn: false

lib/elixir/test/elixir/kernel/lexical_tracker_test.exs

@@ -52,7 +52,7 @@ defmodule Kernel.LexicalTrackerTest do
   end
 
   test "can add aliases", config do
-    D.add_alias(config[:pid], String, 1, true, false)
+    D.add_alias(config[:pid], String, 1, true)
     D.alias_dispatch(config[:pid], String)
     assert D.references(config[:pid]) == {[], [], [], []}
   end
@@ -93,18 +93,18 @@ defmodule Kernel.LexicalTrackerTest do
   end
 
   test "unused aliases", config do
-    D.add_alias(config[:pid], String, 1, true, false)
+    D.add_alias(config[:pid], String, 1, true)
     assert D.collect_unused_aliases(config[:pid]) == [{String, 1}]
   end
 
   test "used aliases are not unused", config do
-    D.add_alias(config[:pid], String, 1, true, false)
+    D.add_alias(config[:pid], String, 1, true)
     D.alias_dispatch(config[:pid], String)
     assert D.collect_unused_aliases(config[:pid]) == []
   end
 
   test "aliases with no warn are not unused", config do
-    D.add_alias(config[:pid], String, 1, false, false)
+    D.add_alias(config[:pid], String, 1, false)
     assert D.collect_unused_aliases(config[:pid]) == []
   end
 

lib/elixir/test/elixir/kernel/warning_test.exs

@@ -894,39 +894,6 @@ defmodule Kernel.WarningTest do
     purge(Sample)
   end
 
-  test "unused alias due to shadowing" do
-    assert_warn_compile(
-      ["nofile:2:3", "unused alias Baz"],
-      """
-      defmodule Sample do
-        alias Foo.Baz
-        alias Bar.Baz
-
-        def baz, do: Baz
-      end
-      """
-    )
-  after
-    purge(Sample)
-  end
-
-  test "does not warn when shadowing alias in nested block" do
-    assert capture_compile("""
-           defmodule Sample do
-             alias Foo.Baz
-
-             def foo do
-               alias Bar.Baz
-               Baz
-             end
-
-             def baz, do: Baz
-           end
-           """) == ""
-  after
-    purge(Sample)
-  end
-
   test "unused inside dynamic module" do
     import List, only: [flatten: 1], warn: false