From a8f585426f47ecf533b787464aef424857791ba2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 28 Aug 2023 13:54:16 +0200
Subject: [PATCH] dialyzer: Handle definition of type product/0

Analyzing a module that defines the type `product/0` could crash
Dialyzer. This bug was introduced in 4d08fc95830b650d.

Fixes #7584
---
 lib/dialyzer/src/dialyzer_utils.erl                 |  7 +++++++
 .../test/small_SUITE_data/src/test_product_app.erl  | 13 +++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 lib/dialyzer/test/small_SUITE_data/src/test_product_app.erl

diff --git a/lib/dialyzer/src/dialyzer_utils.erl b/lib/dialyzer/src/dialyzer_utils.erl
index b920d22b309b..4df458c7b658 100644
--- a/lib/dialyzer/src/dialyzer_utils.erl
+++ b/lib/dialyzer/src/dialyzer_utils.erl
@@ -581,6 +581,13 @@ massage_forms([H | T], Defs) ->
 massage_forms([], _Defs) ->
   [].
 
+massage_type({type, Loc, 'fun',
+              [{type, ArgsLoc, product, ArgTypes}, Ret0]},
+             Defs) ->
+  %% We must make sure that we keep the built-in `product` type here.
+  Args = {type, ArgsLoc, product, massage_type_list(ArgTypes, Defs)},
+  Ret = massage_type(Ret0, Defs),
+  {type, Loc, 'fun', [Args, Ret]};
 massage_type({type, Loc, Name, Args0}, Defs) when is_list(Args0) ->
   case sets:is_element({Name, length(Args0)}, Defs) of
     true ->
diff --git a/lib/dialyzer/test/small_SUITE_data/src/test_product_app.erl b/lib/dialyzer/test/small_SUITE_data/src/test_product_app.erl
new file mode 100644
index 000000000000..2115c62a1b38
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/test_product_app.erl
@@ -0,0 +1,13 @@
+-module(test_product_app).
+-export([zero/0, one/1]).
+
+-type mfa() :: integer().
+-type product() :: binary().
+
+-spec zero() -> any().
+zero() ->
+    ok.
+
+-spec one(mfa()) -> mfa().
+one(I) when is_integer(I) ->
+    I * 42.