dialyzer: fix crash with nominal types

Fix #9131

lib/dialyzer/src/erl_types.erl

@@ -2148,6 +2148,8 @@ t_sup_aux(?nominal(LHS_Name, ?nominal(LHS_InnerName, _)=LHS_Inner)=LHS,
       ?nominal(RHS_Name, Sup);
     ?nominal(RHS_InnerName = LHS_Name, _)=Sup ->
       ?nominal(LHS_Name, Sup);
+    ?nominal(_,_)=Sup ->
+      Sup;
     ?nominal_set(_, ?none) when LHS_Name < RHS_Name ->
       ?nominal_set([LHS, RHS], ?none);
     ?nominal_set(_, ?none) ->

lib/dialyzer/test/opaque_SUITE_data/src/union/union_nested_nominal.erl

@@ -0,0 +1,26 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2024. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+
+-module(nested_nominal).
+-nominal i1() :: i2() | integer().
+-opaque i2() :: i3().
+-nominal i3() :: {i1() | i2()}.
+-export_type([i2/0]).
+
+%% Expected: should not crash