Merge branch 'aronisstav/dialyzer/external_funs/OTP-11826'

* aronisstav/dialyzer/external_funs/OTP-11826:
  Dialyzer now plays nicely with funs that come as "external" arguments

4 files changed, 123 insertions, 24 deletions

diff --git a/lib/dialyzer/src/dialyzer_dataflow.erl b/lib/dialyzer/src/dialyzer_dataflow.erl
index 692684cd99..e0873b17f8 100644
--- a/lib/dialyzer/src/dialyzer_dataflow.erl
+++ b/lib/dialyzer/src/dialyzer_dataflow.erl
@@ -363,20 +363,24 @@ traverse_list([], Map, State, Acc) ->
 handle_apply(Tree, Map, State) ->
   Args = cerl:apply_args(Tree),
   Op = cerl:apply_op(Tree),
-  {State1, Map1, ArgTypes} = traverse_list(Args, Map, State),
-  {State2, Map2, OpType} = traverse(Op, Map1, State1),
+  {State0, Map1, ArgTypes} = traverse_list(Args, Map, State),
+  {State1, Map2, OpType} = traverse(Op, Map1, State0),
   case any_none(ArgTypes) of
     true ->
-      {State2, Map2, t_none()};
+      {State1, Map2, t_none()};
     false ->
-      {CallSitesKnown, FunList} =
-	case state__lookup_call_site(Tree, State2) of
-	  error -> {false, []};
-	  {ok, [external]} -> {false, []};
-	  {ok, List} -> {true, List}
+      FunList =
+	case state__lookup_call_site(Tree, State) of
+	  error -> [external]; %% so that we go directly in the fallback
+	  {ok, List} -> List
 	end,
-      case CallSitesKnown of
-	false ->
+      FunInfoList = [{local, state__fun_info(Fun, State)} || Fun <- FunList],
+      case
+        handle_apply_or_call(FunInfoList, Args, ArgTypes, Map2, Tree, State1)
+      of
+	{had_external, State2} ->
+	  %% Fallback: use whatever info we collected from traversing the op
+	  %% instead of the result that has been generalized to t_any().
 	  Arity = length(Args),
 	  OpType1 = t_inf(OpType, t_fun(Arity, t_any())),
 	  case t_is_none(OpType1) of
@@ -408,25 +412,23 @@ handle_apply(Tree, Map, State) ->
 		  {State2, enter_type(Op, OpType1, Map3), Range}
 	      end
 	  end;
-	true ->
-	  FunInfoList = [{local, state__fun_info(Fun, State)}
-			 || Fun <- FunList],
-	  handle_apply_or_call(FunInfoList, Args, ArgTypes, Map2, Tree, State1)
+	Normal -> Normal
       end
   end.
 
 handle_apply_or_call(FunInfoList, Args, ArgTypes, Map, Tree, State) ->
   None = t_none(),
   handle_apply_or_call(FunInfoList, Args, ArgTypes, Map, Tree, State,
-		       [None || _ <- ArgTypes], None).
+		       [None || _ <- ArgTypes], None, false).
 
 handle_apply_or_call([{local, external}|Left], Args, ArgTypes, Map, Tree, State,
-		     _AccArgTypes, _AccRet) ->
+		     _AccArgTypes, _AccRet, _HadExternal) ->
   handle_apply_or_call(Left, Args, ArgTypes, Map, Tree, State,
-		       ArgTypes, t_any());
+		       ArgTypes, t_any(), true);
 handle_apply_or_call([{TypeOfApply, {Fun, Sig, Contr, LocalRet}}|Left],
 		     Args, ArgTypes, Map, Tree,
-                     #state{opaques = Opaques} = State, AccArgTypes, AccRet) ->
+                     #state{opaques = Opaques} = State,
+                     AccArgTypes, AccRet, HadExternal) ->
   Any = t_any(),
   AnyArgs = [Any || _ <- Args],
   GenSig = {AnyArgs, fun(_) -> t_any() end},
@@ -573,11 +575,16 @@ handle_apply_or_call([{TypeOfApply, {Fun, Sig, Contr, LocalRet}}|Left],
   NewAccRet = t_sup(AccRet, TotalRet),
   ?debug("NewAccRet: ~s\n", [t_to_string(NewAccRet)]),
   handle_apply_or_call(Left, Args, ArgTypes, Map, Tree,
-		       State3, NewAccArgTypes, NewAccRet);
+		       State3, NewAccArgTypes, NewAccRet, HadExternal);
 handle_apply_or_call([], Args, _ArgTypes, Map, _Tree, State,
-		     AccArgTypes, AccRet) ->
-  NewMap = enter_type_lists(Args, AccArgTypes, Map),
-  {State, NewMap, AccRet}.
+		     AccArgTypes, AccRet, HadExternal) ->
+  case HadExternal of
+    false ->
+      NewMap = enter_type_lists(Args, AccArgTypes, Map),
+      {State, NewMap, AccRet};
+    true ->
+      {had_external, State}
+  end.
 
 apply_fail_reason(FailedSig, FailedBif, FailedContract) ->
   if
diff --git a/lib/dialyzer/src/dialyzer_dep.erl b/lib/dialyzer/src/dialyzer_dep.erl
index e3ece144c9..572e60278d 100644
--- a/lib/dialyzer/src/dialyzer_dep.erl
+++ b/lib/dialyzer/src/dialyzer_dep.erl
@@ -124,8 +124,10 @@ traverse(Tree, Out, State, CurrentFun) ->
 	    TmpState = state__add_deps(Label, O1, State),
 	    state__add_deps(CurrentFun, O2,TmpState)
 	end,
-      {BodyFuns, State2} = traverse(Body, Out, State1, 
-				    cerl_trees:get_label(Tree)),
+      Vars = cerl:fun_vars(Tree),
+      Out1 = bind_single(Vars, output(set__singleton(external)), Out),
+      {BodyFuns, State2} =
+        traverse(Body, Out1, State1, cerl_trees:get_label(Tree)),
       {output(set__singleton(Label)), state__add_esc(BodyFuns, State2)};
     'let' ->
       Vars = cerl:let_vars(Tree),
diff --git a/lib/dialyzer/test/small_SUITE_data/results/funs_from_outside b/lib/dialyzer/test/small_SUITE_data/results/funs_from_outside
new file mode 100644
index 0000000000..3e597ef1bc
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/funs_from_outside
@@ -0,0 +1,7 @@
+
+funs_from_outside.erl:18: The pattern 'error' can never match the type {'ok','nothing' | 'something'}
+funs_from_outside.erl:32: Function run2/2 has no local return
+funs_from_outside.erl:35: Function testb/3 has no local return
+funs_from_outside.erl:41: The pattern 'error' can never match the type {'ok','nothing' | 'something'}
+funs_from_outside.erl:78: Function test2/1 has no local return
+funs_from_outside.erl:83: The pattern 'error' can never match the type 'ok'
diff --git a/lib/dialyzer/test/small_SUITE_data/src/funs_from_outside.erl b/lib/dialyzer/test/small_SUITE_data/src/funs_from_outside.erl
new file mode 100644
index 0000000000..f4cbf31160
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/funs_from_outside.erl
@@ -0,0 +1,83 @@
+-module(funs_from_outside).

+

+-export([run1/2, run2/2, run3/2]).

+-export([test1/1, test2/1]).

+

+%%------------------------------------------------------------------------------

+

+run1(X, Y) ->

+    testa(fun do_something/1, X, Y).

+

+testa(Fun, X, Y) ->

+    F = case even(X) of

+	    true -> Fun;

+	    false -> fun do_nothing/1

+	end,

+    case F(Y) of

+	{ok, _} -> ok;

+	error -> error

+    end.

+

+do_nothing(_) -> {ok, nothing}.

+

+do_something(_) -> {ok, something}.

+

+even(X) ->

+    X rem 2 =:= 0.

+

+%%------------------------------------------------------------------------------

+

+%% Duplicating code since we are monovariant...

+

+run2(X, Y) ->

+    testb(fun do_something/1, X, Y).

+

+testb(Fun, X, Y) ->

+    F = case even(X) of

+	    true -> Fun;

+	    false -> fun do_nothing/1

+	end,

+    case F(Y) of

+	error -> error

+    end.

+

+%%------------------------------------------------------------------------------

+

+%% Duplicating code since we are monovariant...

+

+run3(X, Y) ->

+    testc(fun do_something_2/1, X, Y).

+

+testc(Fun, X, Y) ->

+    F = case even(X) of

+	    true -> Fun;

+	    false -> fun do_nothing/1

+	end,

+    case F(Y) of

+	{ok, _} -> ok;

+        %% This pattern can match. 

+	error -> error

+    end.

+

+do_something_2(foo) -> {ok, something};

+do_something_2(_) -> error.

+

+%%------------------------------------------------------------------------------

+

+test1(Fun) ->

+    F = case get(test1) of

+            test1_t -> Fun;

+            test1_f -> fun fok/0

+        end,

+    error = F().

+

+fok() -> ok.

+

+%%------------------------------------------------------------------------------

+

+test2(Fun) ->

+    F = case get(test1) of

+            test1_t -> fun fok/0;

+            test1_f -> fun fok/0

+        end,

+    error = F().