Ensure compilation works for a variable named super, closes #9390

Author: José Valim

lib/elixir/src/elixir_erl_pass.erl

@@ -69,7 +69,7 @@ translate({'__CALLER__', Meta, Atom}, S) when is_atom(Atom) ->
 translate({'__STACKTRACE__', Meta, Atom}, S = #elixir_erl{stacktrace={Var, _}}) when is_atom(Atom) ->
   {{var, ?ann(Meta), Var}, S#elixir_erl{stacktrace={Var, true}}};
 
-translate({'super', Meta, Args}, S) ->
+translate({'super', Meta, Args}, S) when is_list(Args) ->
   %% In the expanded AST, super is used to invoke a function
   %% in the current module originated from a default clause
   %% or a super call.

lib/elixir/test/elixir/kernel/overridable_test.exs

@@ -254,6 +254,11 @@ defmodule Kernel.OverridableTest do
     assert Overridable.capture_super_macro(5) == [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
   end
 
+  test "super as a variable" do
+    super = :ok
+    assert super == :ok
+  end
+
   test "overridable with many clauses" do
     assert Overridable.many_clauses(0) == 11
     assert Overridable.many_clauses(1) == 13