Fix crash when capturing ambiguous import

Author: lukaszsamson

lib/elixir/src/elixir_dispatch.erl

@@ -77,7 +77,7 @@ import_function(Meta, Name, Arity, E) ->
       false;
     {import, Receiver} ->
       require_function(Meta, Receiver, Name, Arity, E);
-    {ambiguous, Ambiguous} ->
+    {ambiguous, _} = Ambiguous ->
       elixir_errors:file_error(Meta, E, ?MODULE, {import, Ambiguous, Name, Arity});
     false ->
       case elixir_import:special_form(Name, Arity) of

lib/elixir/test/elixir/kernel/errors_test.exs

@@ -634,6 +634,16 @@ defmodule Kernel.ErrorsTest do
       end
       """
     )
+
+    assert_compile_error(
+      ["nofile:3:17", "function exit/1 imported from both :erlang and Kernel, call is ambiguous"],
+      ~c"""
+      defmodule Kernel.ErrorsTest.FunctionImportConflict do
+        import :erlang, only: [exit: 1], warn: false
+        def foo, do: &exit/1
+      end
+      """
+    )
   end
 
   test "ensure valid import :only option" do