diff --git a/lib/mix/tasks/espec.ex b/lib/mix/tasks/espec.ex
index 13fb555..fb4d8b6 100644
--- a/lib/mix/tasks/espec.ex
+++ b/lib/mix/tasks/espec.ex
@@ -300,6 +300,7 @@ defmodule Mix.Tasks.Espec do
     shared_spec_files
     |> Enum.each(&Code.require_file/1)
 
-    Kernel.ParallelCompiler.compile(spec_files -- shared_spec_files, parallel_require_callbacks)
+    opts = Keyword.put(parallel_require_callbacks, :return_diagnostics, true)
+    Kernel.ParallelCompiler.compile(spec_files -- shared_spec_files, opts)
   end
 end