Do not add runtime dependencies to remotes in typespecs, closes #10406

lib/elixir/lib/kernel/typespec.ex

@@ -643,10 +643,7 @@ defmodule Kernel.Typespec do
   end
 
   defp typespec({:__aliases__, _, _} = alias, vars, caller, state) do
-    # We set a function name to avoid tracking
-    # aliases in typespecs as compile time dependencies.
-    atom = Macro.expand(alias, %{caller | function: {:typespec, 0}})
-    typespec(atom, vars, caller, state)
+    typespec(expand_remote(alias, caller), vars, caller, state)
   end
 
   # Handle funs
@@ -734,9 +731,7 @@ defmodule Kernel.Typespec do
 
   # Handle remote calls
   defp typespec({{:., meta, [remote, name]}, _, args} = orig, vars, caller, state) do
-    # We set a function name to avoid tracking
-    # aliases in typespecs as compile time dependencies.
-    remote = Macro.expand(remote, %{caller | function: {:typespec, 0}})
+    remote = expand_remote(remote, caller)
 
     cond do
       not is_atom(remote) ->
@@ -907,6 +902,25 @@ defmodule Kernel.Typespec do
 
   ## Helpers
 
+  # This is a backport of Macro.expand/2 because we want to expand
+  # aliases but we don't them to become compile-time references.
+  defp expand_remote({:__aliases__, _, _} = alias, env) do
+    case :elixir_aliases.expand(alias, env) do
+      receiver when is_atom(receiver) ->
+        receiver
+
+      aliases ->
+        aliases = :lists.map(&Macro.expand_once(&1, env), aliases)
+
+        case :lists.all(&is_atom/1, aliases) do
+          true -> :elixir_aliases.concat(aliases)
+          false -> alias
+        end
+    end
+  end
+
+  defp expand_remote(other, env), do: Macro.expand(other, env)
+
   defp compile_error(caller, desc) do
     raise CompileError, file: caller.file, line: caller.line, description: desc
   end

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

@@ -109,20 +109,26 @@ defmodule Kernel.LexicalTrackerTest do
   end
 
   test "does not tag aliases nor types" do
-    {{compile, _exports, runtime, _}, _binding} =
-      Code.eval_string("""
-      defmodule Kernel.LexicalTrackerTest.AliasTypespecs do
-        alias Foo.Bar, as: Bar, warn: false
-        @type bar :: Foo.Bar.t
-        @opaque bar2 :: Foo.Bar.t
-        @typep bar3 :: Foo.Bar.t
-        @callback foo :: Foo.Bar.t
-        @macrocallback foo2(Foo.Bar.t) :: Foo.Bar.t
-        @spec foo(bar3) :: Foo.Bar.t
-        def foo(_), do: :bar
-        Kernel.LexicalTracker.references(__ENV__.lexical_tracker)
-      end |> elem(3)
-      """)
+    Code.eval_string("""
+    defmodule Kernel.LexicalTrackerTest.AliasTypespecs do
+      alias Foo.Bar, as: Bar, warn: false
+      @type bar :: Foo.Bar | Foo.Bar.t
+      @opaque bar2 :: Foo.Bar.t
+      @typep bar3 :: Foo.Bar.t
+      @callback foo :: Foo.Bar.t
+      @macrocallback foo2(Foo.Bar.t) :: Foo.Bar.t
+      @spec foo(bar3) :: Foo.Bar.t
+      def foo(_), do: :ok
+
+      # References from specs are processed only late
+      @after_compile __MODULE__
+      def __after_compile__(env, _) do
+        send(self(), {:references, Kernel.LexicalTracker.references(env.lexical_tracker)})
+      end
+    end
+    """)
+
+    assert_received {:references, {compile, _exports, runtime, _}}
 
     refute Elixir.Bar in runtime
     refute Elixir.Bar in compile