From a37d0a27979641d953ffa318e660e659bf9bbaf8 Mon Sep 17 00:00:00 2001
From: Nelson Vides <nelson.vides@erlang-solutions.com>
Date: Wed, 23 Oct 2019 12:20:17 +0200
Subject: [PATCH 1/2] Normalize annotated types

---
 src/typechecker.erl                             |  7 +++++++
 .../should_pass/annotated_types_problems.erl    |  9 ---------
 .../should_pass/pattern_ann_type.erl            | 13 -------------
 test/should_pass/ann_types.erl                  | 17 ++++++++++++++++-
 test/should_pass/user_types.erl                 |  4 +++-
 5 files changed, 26 insertions(+), 24 deletions(-)
 delete mode 100644 test/known_problems/should_pass/annotated_types_problems.erl
 delete mode 100644 test/known_problems/should_pass/pattern_ann_type.erl

diff --git a/src/typechecker.erl b/src/typechecker.erl
index 0d54efff..e00f4f66 100644
--- a/src/typechecker.erl
+++ b/src/typechecker.erl
@@ -587,6 +587,13 @@ normalize({type, _, union, Tys}, TEnv) ->
         [T] -> T;
         Ts  -> type(union, Ts)
     end;
+normalize({ann_type, _, _} = Type, TEnv) ->
+    Types = flatten_type(Type, TEnv),
+    case merge_union_types(Types, TEnv) of
+        []  -> type(none);
+        [T] -> T;
+        Ts  -> type(union, Ts)
+    end;
 normalize({user_type, P, Name, Args} = Type, TEnv) ->
     case typelib:get_module_from_annotation(P) of
         {ok, Module} ->
diff --git a/test/known_problems/should_pass/annotated_types_problems.erl b/test/known_problems/should_pass/annotated_types_problems.erl
deleted file mode 100644
index 682511d6..00000000
--- a/test/known_problems/should_pass/annotated_types_problems.erl
+++ /dev/null
@@ -1,9 +0,0 @@
--module(annotated_types_problems).
-
--export([named_record_arg/1]).
-
--record(r, {}).
--type r() :: #r{}.
-
--spec named_record_arg(R :: r()) -> {ok, R}.
-named_record_arg(#r{} = R) -> {ok, R}.
diff --git a/test/known_problems/should_pass/pattern_ann_type.erl b/test/known_problems/should_pass/pattern_ann_type.erl
deleted file mode 100644
index c9888730..00000000
--- a/test/known_problems/should_pass/pattern_ann_type.erl
+++ /dev/null
@@ -1,13 +0,0 @@
--module(pattern_ann_type).
-
--export([f/1]).
-
--type mytuple() :: tuple().
-
-%% The problem is that a user_type/remote_type is encapsulated in an
-%% ann_type. The type is not normalized if annotated and
-%% `expect_tuple_type/2` cannot handle user/remote types.
-%% Type check passes if Pat annotation is removed.
--spec f(Pat :: mytuple()) -> ok.
-f({}) ->
-    ok.
diff --git a/test/should_pass/ann_types.erl b/test/should_pass/ann_types.erl
index fe0e8bfb..a71ca74b 100644
--- a/test/should_pass/ann_types.erl
+++ b/test/should_pass/ann_types.erl
@@ -1,7 +1,7 @@
 %%% @doc Test module for annotated types
 -module(ann_types).
 
--export([f/2]).
+-export([f/2, g/2, h/1, annotated_named_record_arg/1, remote_named_record_arg/1]).
 
 -spec f(A :: atom(), integer()) -> {A :: term(), B :: number()}.
 f(A, B) ->
@@ -10,3 +10,18 @@ f(A, B) ->
 -spec g(A :: atom(), Map :: map()) -> NewMap :: map().
 g(A, Map) ->
     Map#{ A => any }.
+
+-type mytuple() :: tuple().
+-spec h(Pat :: mytuple()) -> ok.
+h({}) ->
+    ok.
+
+-record(r, {}).
+-type r() :: #r{}.
+-spec annotated_named_record_arg(R :: r()) -> {ok, R :: r()}.
+annotated_named_record_arg(#r{} = R) -> {ok, R}.
+
+-spec remote_named_record_arg(R :: user_types:my_empty_record()) ->
+    {ok, R :: user_types:my_empty_record()}.
+remote_named_record_arg(#r{} = R) -> {ok, R}.
+
diff --git a/test/should_pass/user_types.erl b/test/should_pass/user_types.erl
index 738a4f6c..579b66ad 100644
--- a/test/should_pass/user_types.erl
+++ b/test/should_pass/user_types.erl
@@ -3,8 +3,10 @@
 -export([f/1]).
 
 %% these exported types are used in remote_types module
--export_type([my_tuple/0, my_list/0, my_union/0, my_opaque/0]).
+-export_type([my_tuple/0, my_list/0, my_union/0, my_opaque/0, my_empty_record/0]).
 
+-record(r, {}).
+-type my_empty_record() :: #r{}.
 -type my_atom() :: atom().
 -type my_tuple() :: {my_atom(), integer()}.
 -type my_list() :: list(my_atom()).

From bc5c68811c487df7871f78bcbd9ab676fcc4c3b3 Mon Sep 17 00:00:00 2001
From: Nelson Vides <nelson.vides@erlang-solutions.com>
Date: Tue, 31 Dec 2019 18:04:40 +0000
Subject: [PATCH 2/2] Parse ann_type in place

---
 src/typechecker.erl | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/src/typechecker.erl b/src/typechecker.erl
index e00f4f66..83c75c0f 100644
--- a/src/typechecker.erl
+++ b/src/typechecker.erl
@@ -587,13 +587,8 @@ normalize({type, _, union, Tys}, TEnv) ->
         [T] -> T;
         Ts  -> type(union, Ts)
     end;
-normalize({ann_type, _, _} = Type, TEnv) ->
-    Types = flatten_type(Type, TEnv),
-    case merge_union_types(Types, TEnv) of
-        []  -> type(none);
-        [T] -> T;
-        Ts  -> type(union, Ts)
-    end;
+normalize({ann_type, _Ann, [_Var, Type]}, TEnv) ->
+    normalize(Type, TEnv);
 normalize({user_type, P, Name, Args} = Type, TEnv) ->
     case typelib:get_module_from_annotation(P) of
         {ok, Module} ->