Merge branch 'kostis/dialyzer_R16B02_fixes/OTP-11374' into maint

* kostis/dialyzer_R16B02_fixes/OTP-11374:
  Fix crash when using remote types in the tail of list types
  Adopt a convention about unknown modules
  No reason for calls to unknown modules
  Use the modern version of is_subtype
  Adopt a convention about unknown modules
  Fix a comment
  Add some more comments about what the test does

9 files changed, 55 insertions, 34 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/trec b/lib/dialyzer/test/small_SUITE_data/results/trec
index 01ccc63761..b95df1e6ef 100644
--- a/lib/dialyzer/test/small_SUITE_data/results/trec
+++ b/lib/dialyzer/test/small_SUITE_data/results/trec
@@ -1,7 +1,7 @@
 
-trec.erl:26: Function test/0 has no local return
-trec.erl:27: The call trec:mk_foo_loc(42,any()) will never return since it differs in the 1st argument from the success typing arguments: ('undefined',atom())
-trec.erl:29: Function mk_foo_loc/2 has no local return
-trec.erl:30: Record construction violates the declared type for #foo{} since variable A cannot be of type atom()
-trec.erl:36: Function mk_foo_exp/2 has no local return
-trec.erl:37: Record construction violates the declared type for #foo{} since variable A cannot be of type atom()
+trec.erl:28: Function test/0 has no local return
+trec.erl:29: The call trec:mk_foo_loc(42,any()) will never return since it differs in the 1st argument from the success typing arguments: ('undefined',atom())
+trec.erl:31: Function mk_foo_loc/2 has no local return
+trec.erl:32: Record construction violates the declared type for #foo{} since variable A cannot be of type atom()
+trec.erl:38: Function mk_foo_exp/2 has no local return
+trec.erl:39: Record construction violates the declared type for #foo{} since variable A cannot be of type atom()
diff --git a/lib/dialyzer/test/small_SUITE_data/src/appmon_place.erl b/lib/dialyzer/test/small_SUITE_data/src/appmon_place.erl
index 60ffbe818f..ddb97796fb 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/appmon_place.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/appmon_place.erl
@@ -1,6 +1,6 @@
 %%---------------------------------------------------------------------
 %% This is added as a test because it was giving a false positive
-%% (function move/4 will nevr be called) due to the strange use of
+%% (function move/4 will never be called) due to the strange use of
 %% self-recursive fun construction in placex/3.
 %%
 %% The analysis was getting confused that the foldl call will never
diff --git a/lib/dialyzer/test/small_SUITE_data/src/contract3.erl b/lib/dialyzer/test/small_SUITE_data/src/contract3.erl
index 5b0bee9694..a6ce91882e 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/contract3.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/contract3.erl
@@ -18,16 +18,23 @@ t(X, Y, Z) ->
         (atom()|list()) -> atom().
 
 t1(X) ->
-  foo:bar(X).
+  f(X).
 
 -spec t2(atom(), integer()) -> integer();
         (atom(), list()) -> atom().
 
 t2(X, Y) ->
-  foo:bar(X, Y).
+  g(X, Y).
 
 -spec t3(atom(), integer(), list()) -> integer();
         (X, integer(), list()) -> X.
 
 t3(X, Y, Z) ->
   X.
+
+%% dummy functions below
+
+f(X) -> X.
+
+g(X, Y) when is_atom(X), is_integer(Y) -> Y;
+g(X, Y) when is_atom(X), is_list(Y) -> X.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/empty_list_infimum.erl b/lib/dialyzer/test/small_SUITE_data/src/empty_list_infimum.erl
index b58fa732cb..3acc5ca065 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/empty_list_infimum.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/empty_list_infimum.erl
@@ -1,6 +1,6 @@
 %%
-%% The Original Code is RabbitMQ.
-%%
+%% This is stripped down code from RabbitMQ. It is used to report an
+%% invalid type specification for function list_vhost_permissions/1.
 %% The Initial Developer of the Original Code is VMware, Inc.
 %%
 
@@ -38,7 +38,7 @@ vhost_perms_info_keys() ->
 -spec list_vhost_permissions(vhost()) -> infos().
 
 list_vhost_permissions(VHostPath) ->
-    list_permissions(vhost_perms_info_keys(), rabbit_foo:some_list()).
+    list_permissions(vhost_perms_info_keys(), some_mod:some_function()).
 
 filter_props(Keys, Props) ->
     [T || T = {K, _} <- Props, lists:member(K, Keys)].
diff --git a/lib/dialyzer/test/small_SUITE_data/src/gencall.erl b/lib/dialyzer/test/small_SUITE_data/src/gencall.erl
index d2875c9df1..762be55007 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/gencall.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/gencall.erl
@@ -7,6 +7,6 @@
 f() ->
   gen_server:call(1,2,3),
   ets:lookup(1,2,3),
-  gencall2:foo(),
+  some_mod:some_function(),
   gencall:foo(),
   gen_server:handle_cast(1,2).
diff --git a/lib/dialyzer/test/small_SUITE_data/src/maybe_improper.erl b/lib/dialyzer/test/small_SUITE_data/src/maybe_improper.erl
index 1743d81493..6d2a35b7c8 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/maybe_improper.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/maybe_improper.erl
@@ -1,7 +1,18 @@
+%%%========================================================================
+%%% Tests handling of maybe improper lists
+%%%========================================================================
 -module(maybe_improper).
 
--export([s/1]).
+-export([s/1, t/0]).
 
 -spec s(maybe_improper_list(X,Y)) -> {[X], maybe_improper_list(X,Y)}.
-s(A) ->
-    lists:split(2,A).
+s(L) ->
+    lists:split(2, L).
+
+%% Having a remote type in the 'tail' of the list crashed dialyzer.
+%% The problem was fixed for R16B03.
+-type t_mil() :: maybe_improper_list(integer(), orddict:orddict()).
+
+-spec t() -> t_mil().
+t() ->
+    [42 | []].
diff --git a/lib/dialyzer/test/small_SUITE_data/src/overloaded1.erl b/lib/dialyzer/test/small_SUITE_data/src/overloaded1.erl
index 0af4f7446f..074a93e2fe 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/overloaded1.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/overloaded1.erl
@@ -1,5 +1,5 @@
 %%-----------------------------------------------------------------------------
-%% Test that tests overloaded contratcs.
+%% Test that tests overloaded contracts.
 %% In December 2008 it works as far as intersection types are concerned (test1)
 %% However, it does NOT work as far as type variables are concerned (test2)
 %%-----------------------------------------------------------------------------
@@ -16,13 +16,13 @@ test2() ->
 
 -type mod() :: atom().
 
--spec foo(ATM, list()) -> {'ok', ATM} | {'error', _} when is_subtype(ATM, mod())
-       ; (MFA, list()) -> {'ok', MFA} | {'error', _} when is_subtype(MFA, mfa()).
+-spec foo(ATM, list()) -> {'ok', ATM} | {'error', _} when ATM :: mod()
+       ; (MFA, list()) -> {'ok', MFA} | {'error', _} when MFA :: mfa().
 
 foo(F, _) when is_atom(F) ->
   case atom_to_list(F) of
-      [42|_] -> {ok, F};
-      _Other -> {error, mod:bar(F)}
+    [42|_] -> {ok, F};
+    _Other -> {error, some_mod:some_function()}
   end;
 foo({M,F,A}, _) ->
   case A =:= 0 of
diff --git a/lib/dialyzer/test/small_SUITE_data/src/trec.erl b/lib/dialyzer/test/small_SUITE_data/src/trec.erl
index ba50c3b401..06706162c1 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/trec.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/trec.erl
@@ -18,20 +18,22 @@
 %%      ('undefined',atom())
 %%   3. Function mk_foo_loc/2 has no local return
 %%
-%% Arguably, the second warning is not what most users have in mind
-%% when they wrote the type declarations in the 'foo' record, so no
-%% doubt they'll find it confusing. But note that it is also inconsistent!
-%% How come there is a success typing for a function that has no local return?
+%% Arguably, the second warning is not what most users have in mind when
+%% they wrote the type declarations in the 'foo' record, so no doubt
+%% they'll find it confusing. But note that it is also quite confusing!
+%% Many users may be wondering: How come there is a success typing for a
+%% function that has no local return? Running typer on this module
+%% reveals a success typing for this function that is interesting indeed.
 %%
 test() ->
-   mk_foo_loc(42, bar:f()).
+   mk_foo_loc(42, some_mod:some_function()).
 
 mk_foo_loc(A, B) ->
     #foo{a = A, b = [A,B]}.
 
 %%
-%% For this function we currently get "has no local return" but we get
-%% no reason; I want us to get a reason.
+%% For this function we used to get a "has no local return" warning
+%% but we got no reason. This has now been fixed.
 %%
 mk_foo_exp(A, B) when is_integer(A) ->
     #foo{a = A, b = [A,B]}.
diff --git a/lib/hipe/cerl/erl_types.erl b/lib/hipe/cerl/erl_types.erl
index d1243b2325..d7d8a878c5 100644
--- a/lib/hipe/cerl/erl_types.erl
+++ b/lib/hipe/cerl/erl_types.erl
@@ -671,8 +671,9 @@ t_solve_remote(?function(Domain, Range), ET, R, C) ->
   {RT2, RR2} = t_solve_remote(Range, ET, R, C),
   {?function(RT1, RT2), RR1 ++ RR2};
 t_solve_remote(?list(Types, Term, Size), ET, R, C) ->
-  {RT, RR} = t_solve_remote(Types, ET, R, C),
-  {?list(RT, Term, Size), RR};
+  {RT1, RR1} = t_solve_remote(Types, ET, R, C),
+  {RT2, RR2} = t_solve_remote(Term, ET, R, C),
+  {?list(RT1, RT2, Size), RR1 ++ RR2};
 t_solve_remote(?product(Types), ET, R, C) ->
   {RL, RR} = list_solve_remote(Types, ET, R, C),
   {?product(RL), RR};
@@ -1349,8 +1350,8 @@ t_maybe_improper_list() ->
 t_maybe_improper_list(_Content, ?unit) -> ?none;
 t_maybe_improper_list(?unit, _Termination) -> ?none;
 t_maybe_improper_list(Content, Termination) ->
-  %% Safety check
-  true = t_is_subtype(t_nil(), Termination),
+  %% Safety check: would be nice to have but does not work with remote types
+  %% true = t_is_subtype(t_nil(), Termination),
   ?list(Content, Termination, ?unknown_qual).
 
 -spec t_is_maybe_improper_list(erl_type()) -> boolean().
@@ -1365,8 +1366,8 @@ t_is_maybe_improper_list(_) -> false.
 %% t_improper_list(?unit, _Termination) -> ?none;
 %% t_improper_list(_Content, ?unit) -> ?none;
 %% t_improper_list(Content, Termination) ->
-%%   %% Safety check
-%%   false = t_is_subtype(t_nil(), Termination),
+%%   %% Safety check: would be nice to have but does not work with remote types
+%%   %% false = t_is_subtype(t_nil(), Termination),
 %%   ?list(Content, Termination, ?any).  
 
 -spec lift_list_to_pos_empty(erl_type()) -> erl_type().