 
       [xref_manifest] = Mix.Tasks.Compile.Xref.manifests()
 
-      assert_no_warn fn ->
+      assert_no_warn(fn ->
         assert Mix.Tasks.Compile.Xref.run([]) == {:noop, []}
-        refute File.exists? xref_manifest
-      end
+        refute File.exists?(xref_manifest)
+      end)
     end
   end
 

    in_fixture "no_mixfile", fn ->
      write_no_func()

      assert_warn_no_func fn ->
        assert Mix.Tasks.Compile.Elixir.run([]) == {:ok, []}
        file = Path.absname("lib/a.ex")
        assert {:noop, [%Mix.Task.Compiler.Diagnostic{
          compiler_name: "Xref",
          file: ^file,
          message: "function B.no_func/0 is undefined or private",
          position: 2,
          severity: :warning
        }]} = Mix.Tasks.Compile.Xref.run([])
      end

      [manifest] = Mix.Tasks.Compile.Elixir.manifests()
      future = {{2020, 1, 1}, {0, 0, 0}}

Code.require_file("../../test_helper.exs", __DIR__)

defmodule Mix.Tasks.Compile.XrefTest do
  use MixTest.Case
