Merge branch 'hb/optional_callbacks/OTP-11861'

* hb/optional_callbacks/OTP-11861:
  [edoc] Handle optional behaviour callbacks
  [syntax_tools] Let erl_syntax:concrete() accept the F/A syntax
  Introduce the attribute -optional_callbacks in the context of behaviours

13 files changed, 430 insertions, 75 deletions

diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 39cc03cf7a..5deddf6bd1 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -130,6 +130,8 @@ value_option(Flag, Default, On, OnVal, Off, OffVal, Opts) ->
                    :: dict:dict(mfa(), line()),
                callbacks = dict:new()           %Callback types
                    :: dict:dict(mfa(), line()),
+               optional_callbacks = dict:new()  %Optional callbacks
+                   :: dict:dict(mfa(), line()),
                types = dict:new()               %Type definitions
                    :: dict:dict(ta(), #typeinfo{}),
                exp_types=gb_sets:empty()        %Exported types
@@ -313,13 +315,20 @@ format_error({undefined_behaviour,Behaviour}) ->
     io_lib:format("behaviour ~w undefined", [Behaviour]);
 format_error({undefined_behaviour_callbacks,Behaviour}) ->
     io_lib:format("behaviour ~w callback functions are undefined",
-                  [Behaviour]);
+		  [Behaviour]);
 format_error({ill_defined_behaviour_callbacks,Behaviour}) ->
     io_lib:format("behaviour ~w callback functions erroneously defined",
 		  [Behaviour]);
+format_error({ill_defined_optional_callbacks,Behaviour}) ->
+    io_lib:format("behaviour ~w optional callback functions erroneously defined",
+		  [Behaviour]);
 format_error({behaviour_info, {_M,F,A}}) ->
     io_lib:format("cannot define callback attibute for ~w/~w when "
                   "behaviour_info is defined",[F,A]);
+format_error({redefine_optional_callback, {F, A}}) ->
+    io_lib:format("optional callback ~w/~w duplicated", [F, A]);
+format_error({undefined_callback, {_M, F, A}}) ->
+    io_lib:format("callback ~w/~w is undefined", [F, A]);
 %% --- types and specs ---
 format_error({singleton_typevar, Name}) ->
     io_lib:format("type variable ~w is only used once (is unbound)", [Name]);
@@ -727,6 +736,8 @@ attribute_state({attribute,L,spec,{Fun,Types}}, St) ->
     spec_decl(L, Fun, Types, St);
 attribute_state({attribute,L,callback,{Fun,Types}}, St) ->
     callback_decl(L, Fun, Types, St);
+attribute_state({attribute,L,optional_callbacks,Es}, St) ->
+    optional_callbacks(L, Es, St);
 attribute_state({attribute,L,on_load,Val}, St) ->
     on_load(L, Val, St);
 attribute_state({attribute,_L,_Other,_Val}, St) -> % Ignore others
@@ -834,57 +845,73 @@ check_behaviour(St0) ->
 %%  Check behaviours for existence and defined functions.
 
 behaviour_check(Bs, St0) ->
-    {AllBfs,St1} = all_behaviour_callbacks(Bs, [], St0),
-    St = behaviour_missing_callbacks(AllBfs, St1),
+    {AllBfs0, St1} = all_behaviour_callbacks(Bs, [], St0),
+    St = behaviour_missing_callbacks(AllBfs0, St1),
+    Exports = exports(St0),
+    F = fun(Bfs, OBfs) ->
+                [B || B <- Bfs,
+                      not lists:member(B, OBfs)
+                      orelse gb_sets:is_member(B, Exports)]
+        end,
+    %% After fixing missing callbacks new warnings may be emitted.
+    AllBfs = [{Item,F(Bfs0, OBfs0)} || {Item,Bfs0,OBfs0} <- AllBfs0],
     behaviour_conflicting(AllBfs, St).
 
 all_behaviour_callbacks([{Line,B}|Bs], Acc, St0) ->
-    {Bfs0,St} = behaviour_callbacks(Line, B, St0),
-    all_behaviour_callbacks(Bs, [{{Line,B},Bfs0}|Acc], St);
+    {Bfs0,OBfs0,St} = behaviour_callbacks(Line, B, St0),
+    all_behaviour_callbacks(Bs, [{{Line,B},Bfs0,OBfs0}|Acc], St);
 all_behaviour_callbacks([], Acc, St) -> {reverse(Acc),St}.
 
 behaviour_callbacks(Line, B, St0) ->
     try B:behaviour_info(callbacks) of
-        Funcs when is_list(Funcs) ->
-            All = all(fun({FuncName, Arity}) ->
-                              is_atom(FuncName) andalso is_integer(Arity);
-			 ({FuncName, Arity, Spec}) ->
-			      is_atom(FuncName) andalso is_integer(Arity)
-				  andalso is_list(Spec);
-                         (_Other) ->
-                              false
-                      end,
-                      Funcs),
-	    MaybeRemoveSpec = fun({_F,_A}=FA) -> FA;
-				 ({F,A,_S}) -> {F,A};
-				 (Other) -> Other
-			      end,
-            if
-                All =:= true ->
-                    {[MaybeRemoveSpec(F) || F <- Funcs], St0};
+        undefined ->
+            St1 = add_warning(Line, {undefined_behaviour_callbacks, B}, St0),
+            {[], [], St1};
+        Funcs ->
+            case is_fa_list(Funcs) of
                 true ->
+                    try B:behaviour_info(optional_callbacks) of
+                        undefined ->
+                            {Funcs, [], St0};
+                        OptFuncs ->
+                            %% OptFuncs should always be OK thanks to
+                            %% sys_pre_expand.
+                            case is_fa_list(OptFuncs) of
+                                true ->
+                                    {Funcs, OptFuncs, St0};
+                                false ->
+                                    W = {ill_defined_optional_callbacks, B},
+                                    St1 = add_warning(Line, W, St0),
+                                    {Funcs, [], St1}
+                            end
+                    catch
+                        _:_ ->
+                            {Funcs, [], St0}
+                    end;
+                false ->
                     St1 = add_warning(Line,
-                                      {ill_defined_behaviour_callbacks,B},
+                                      {ill_defined_behaviour_callbacks, B},
                                       St0),
-                    {[], St1}
-            end;
-        undefined ->
-            St1 = add_warning(Line, {undefined_behaviour_callbacks,B}, St0),
-            {[], St1};
-        _Other ->
-            St1 = add_warning(Line, {ill_defined_behaviour_callbacks,B}, St0),
-            {[], St1}
+                    {[], [], St1}
+            end
     catch
         _:_ ->
-            St1 = add_warning(Line, {undefined_behaviour,B}, St0),
-            {[], St1}
+            St1 = add_warning(Line, {undefined_behaviour, B}, St0),
+            {[], [], St1}
     end.
 
-behaviour_missing_callbacks([{{Line,B},Bfs}|T], St0) ->
+behaviour_missing_callbacks([{{Line,B},Bfs0,OBfs}|T], St0) ->
+    Bfs = ordsets:subtract(ordsets:from_list(Bfs0), ordsets:from_list(OBfs)),
     Exports = gb_sets:to_list(exports(St0)),
-    Missing = ordsets:subtract(ordsets:from_list(Bfs), Exports),
+    Missing = ordsets:subtract(Bfs, Exports),
     St = foldl(fun (F, S0) ->
-		       add_warning(Line, {undefined_behaviour_func,F,B}, S0)
+                       case is_fa(F) of
+                           true ->
+                               M = {undefined_behaviour_func,F,B},
+                               add_warning(Line, M, S0);
+                           false ->
+                               S0 % ill_defined_behaviour_callbacks
+                       end
 	       end, St0, Missing),
     behaviour_missing_callbacks(T, St);
 behaviour_missing_callbacks([], St) -> St.
@@ -1127,19 +1154,29 @@ check_unused_records(Forms, St0) ->
     end.
 
 check_callback_information(#lint{callbacks = Callbacks,
-				 defined = Defined} = State) ->
-    case gb_sets:is_member({behaviour_info,1}, Defined) of
-	false -> State;
+                                 optional_callbacks = OptionalCbs,
+				 defined = Defined} = St0) ->
+    OptFun = fun({MFA, Line}, St) ->
+                     case dict:is_key(MFA, Callbacks) of
+                         true ->
+                             St;
+                         false ->
+                             add_error(Line, {undefined_callback, MFA}, St)
+                     end
+             end,
+    St1 = lists:foldl(OptFun, St0, dict:to_list(OptionalCbs)),
+    case gb_sets:is_member({behaviour_info, 1}, Defined) of
+	false -> St1;
 	true ->
 	    case dict:size(Callbacks) of
-		0 -> State;
+		0 -> St1;
 		_ ->
 		    CallbacksList = dict:to_list(Callbacks),
 		    FoldL =
-			fun({Fa,Line},St) ->
+			fun({Fa, Line}, St) ->
 				add_error(Line, {behaviour_info, Fa}, St)
 			end,
-		    lists:foldl(FoldL, State, CallbacksList)
+		    lists:foldl(FoldL, St1, CallbacksList)
 	    end
     end.
 
@@ -2927,6 +2964,39 @@ callback_decl(Line, MFA0, TypeSpecs,
 	false -> check_specs(TypeSpecs, Arity, St1)
     end.
 
+%% optional_callbacks(Line, FAs, State) -> State.
+
+optional_callbacks(Line, Term, St0) ->
+    try true = is_fa_list(Term), Term of
+        FAs ->
+            optional_cbs(Line, FAs, St0)
+    catch
+        _:_ ->
+            St0 % ignore others
+    end.
+
+optional_cbs(_Line, [], St) ->
+    St;
+optional_cbs(Line, [{F,A}|FAs], St0) ->
+    #lint{optional_callbacks = OptionalCbs, module = Mod} = St0,
+    MFA = {Mod, F, A},
+    St1 = St0#lint{optional_callbacks = dict:store(MFA, Line, OptionalCbs)},
+    St2 = case dict:is_key(MFA, OptionalCbs) of
+              true ->
+                  add_error(Line, {redefine_optional_callback, {F,A}}, St1);
+              false ->
+                  St1
+          end,
+    optional_cbs(Line, FAs, St2).
+
+is_fa_list([E|L]) -> is_fa(E) andalso is_fa_list(L);
+is_fa_list([]) -> true;
+is_fa_list(_) -> false.
+
+is_fa({FuncName, Arity})
+  when is_atom(FuncName), is_integer(Arity), Arity >= 0 -> true;
+is_fa(_) -> false.
+
 check_specs([FunType|Left], Arity, St0) ->
     {FunType1, CTypes} =
 	case FunType of
diff --git a/lib/stdlib/src/erl_pp.erl b/lib/stdlib/src/erl_pp.erl
index 82bc2c1460..788dbb40b6 100644
--- a/lib/stdlib/src/erl_pp.erl
+++ b/lib/stdlib/src/erl_pp.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -232,13 +232,21 @@ lattribute(import, Name, _Opts, _State) when is_list(Name) ->
     attr("import", [{var,0,pname(Name)}]);
 lattribute(import, {From,Falist}, _Opts, _State) ->
     attr("import",[{var,0,pname(From)},falist(Falist)]);
+lattribute(optional_callbacks, Falist, Opts, _State) ->
+    ArgL = try falist(Falist)
+           catch _:_ -> abstract(Falist, Opts)
+           end,
+    call({var,0,"-optional_callbacks"}, [ArgL], 0, options(none));
 lattribute(file, {Name,Line}, _Opts, State) ->
     attr("file", [{var,0,(State#pp.string_fun)(Name)},{integer,0,Line}]);
 lattribute(record, {Name,Is}, Opts, _State) ->
     Nl = leaf(format("-record(~w,", [Name])),
     [{first,Nl,record_fields(Is, Opts)},$)];
-lattribute(Name, Arg, #options{encoding = Encoding}, _State) ->
-    attr(write(Name), [erl_parse:abstract(Arg, [{encoding,Encoding}])]).
+lattribute(Name, Arg, Options, _State) ->
+    attr(write(Name), [abstract(Arg, Options)]).
+
+abstract(Arg, #options{encoding = Encoding}) ->
+    erl_parse:abstract(Arg, [{encoding,Encoding}]).
 
 typeattr(Tag, {TypeName,Type,Args}, _Opts) ->
     {first,leaf("-"++atom_to_list(Tag)++" "),
diff --git a/lib/stdlib/src/gen_event.erl b/lib/stdlib/src/gen_event.erl
index d39dd89d3a..bb0ff46268 100644
--- a/lib/stdlib/src/gen_event.erl
+++ b/lib/stdlib/src/gen_event.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -101,6 +101,14 @@
 -callback code_change(OldVsn :: (term() | {down, term()}),
                       State :: term(), Extra :: term()) ->
     {ok, NewState :: term()}.
+-callback format_status(Opt, StatusData) -> Status when
+      Opt :: 'normal' | 'terminate',
+      StatusData :: [PDict | State],
+      PDict :: [{Key :: term(), Value :: term()}],
+      State :: term(),
+      Status :: term().
+
+-optional_callbacks([format_status/2]).
 
 %%---------------------------------------------------------------------------
 
diff --git a/lib/stdlib/src/gen_fsm.erl b/lib/stdlib/src/gen_fsm.erl
index e914f7d0b2..56137cde13 100644
--- a/lib/stdlib/src/gen_fsm.erl
+++ b/lib/stdlib/src/gen_fsm.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -160,6 +160,14 @@
 -callback code_change(OldVsn :: term() | {down, term()}, StateName :: atom(),
 		      StateData :: term(), Extra :: term()) ->
     {ok, NextStateName :: atom(), NewStateData :: term()}.
+-callback format_status(Opt, StatusData) -> Status when
+      Opt :: 'normal' | 'terminate',
+      StatusData :: [PDict | State],
+      PDict :: [{Key :: term(), Value :: term()}],
+      State :: term(),
+      Status :: term().
+
+-optional_callbacks([format_status/2]).
 
 %%% ---------------------------------------------------
 %%% Starts a generic state machine.
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index 202a931fae..22acdf10b7 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -137,6 +137,15 @@
 -callback code_change(OldVsn :: (term() | {down, term()}), State :: term(),
                       Extra :: term()) ->
     {ok, NewState :: term()} | {error, Reason :: term()}.
+-callback format_status(Opt, StatusData) -> Status when
+      Opt :: 'normal' | 'terminate',
+      StatusData :: [PDict | State],
+      PDict :: [{Key :: term(), Value :: term()}],
+      State :: term(),
+      Status :: term().
+
+-optional_callbacks([format_status/2]).
+
 
 %%%  -----------------------------------------------------------------
 %%% Starts a generic server.
diff --git a/lib/stdlib/test/erl_internal_SUITE.erl b/lib/stdlib/test/erl_internal_SUITE.erl
index b6b3c004ea..197a7a33eb 100644
--- a/lib/stdlib/test/erl_internal_SUITE.erl
+++ b/lib/stdlib/test/erl_internal_SUITE.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1999-2011. All Rights Reserved.
+%% Copyright Ericsson AB 1999-2014. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -51,7 +51,7 @@ end_per_group(_GroupName, Config) ->
 -define(default_timeout, ?t:minutes(2)).
 
 init_per_testcase(_Case, Config) ->
-    ?line Dog = test_server:timetrap(?default_timeout),
+    Dog = test_server:timetrap(?default_timeout),
     [{watchdog, Dog}|Config].
 
 end_per_testcase(_Case, Config) ->
@@ -63,27 +63,50 @@ behav(suite) -> [];
 behav(doc) ->
     ["Check that the behaviour callbacks are correctly defined"];
 behav(_) ->
-    ?line check_behav_list([{start,2}, {stop,1}], 
-			   application:behaviour_info(callbacks)),
-    ?line check_behav_list([{init,1}, {handle_call,3}, {handle_cast,2},
-			    {handle_info,2}, {terminate,2}, {code_change,3}],
-			   gen_server:behaviour_info(callbacks)),
-    ?line check_behav_list([{init,1}, {handle_event,3}, {handle_sync_event,4},
-			    {handle_info,3}, {terminate,3}, {code_change,4}],
-			   gen_fsm:behaviour_info(callbacks)),
-    ?line check_behav_list([{init,1}, {handle_event,2}, {handle_call,2},
-			    {handle_info,2}, {terminate,2}, {code_change,3}],
-			   gen_event:behaviour_info(callbacks)),
-    ?line check_behav_list( [{init,1}, {terminate,2}], 
-			   supervisor_bridge:behaviour_info(callbacks)),
-    ?line check_behav_list([{init,1}],
-			   supervisor:behaviour_info(callbacks)),
-    ok.
+    Modules = [application, gen_server, gen_fsm, gen_event,
+               supervisor_bridge, supervisor],
+    lists:foreach(fun check_behav/1, Modules).
+
+check_behav(Module) ->
+    Callbacks = callbacks(Module),
+    Optional = optional_callbacks(Module),
+    check_behav_list(Callbacks, Module:behaviour_info(callbacks)),
+    check_behav_list(Optional, Module:behaviour_info(optional_callbacks)).
 
 check_behav_list([], []) -> ok;
 check_behav_list([L | L1], L2) ->
-    ?line true = lists:member(L, L2),
-    ?line L3 = lists:delete(L, L2),
+    true = lists:member(L, L2),
+    L3 = lists:delete(L, L2),
     check_behav_list(L1, L3).
 
-
+callbacks(application) ->
+    [{start,2}, {stop,1}];
+callbacks(gen_server) ->
+    [{init,1}, {handle_call,3}, {handle_cast,2},
+     {handle_info,2}, {terminate,2}, {code_change,3},
+     {format_status,2}];
+callbacks(gen_fsm) ->
+    [{init,1}, {handle_event,3}, {handle_sync_event,4},
+     {handle_info,3}, {terminate,3}, {code_change,4},
+     {format_status,2}];
+callbacks(gen_event) ->
+    [{init,1}, {handle_event,2}, {handle_call,2},
+     {handle_info,2}, {terminate,2}, {code_change,3},
+     {format_status,2}];
+callbacks(supervisor_bridge) ->
+    [{init,1}, {terminate,2}];
+callbacks(supervisor) ->
+    [{init,1}].
+
+optional_callbacks(application) ->
+    [];
+optional_callbacks(gen_server) ->
+    [{format_status,2}];
+optional_callbacks(gen_fsm) ->
+    [{format_status,2}];
+optional_callbacks(gen_event) ->
+    [{format_status,2}];
+optional_callbacks(supervisor_bridge) ->
+    [];
+optional_callbacks(supervisor) ->
+    [].
diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl
index ea61b2082b..5506d3d166 100644
--- a/lib/stdlib/test/erl_lint_SUITE.erl
+++ b/lib/stdlib/test/erl_lint_SUITE.erl
@@ -55,7 +55,7 @@
           otp_11772/1, otp_11771/1, otp_11872/1,
           export_all/1,
 	  bif_clash/1,
-	  behaviour_basic/1, behaviour_multiple/1,
+	  behaviour_basic/1, behaviour_multiple/1, otp_11861/1,
 	  otp_7550/1,
 	  otp_8051/1,
 	  format_warn/1,
@@ -89,7 +89,7 @@ all() ->
      otp_5362, otp_5371, otp_7227, otp_5494, otp_5644,
      otp_5878, otp_5917, otp_6585, otp_6885, otp_10436, otp_11254,
      otp_11772, otp_11771, otp_11872, export_all,
-     bif_clash, behaviour_basic, behaviour_multiple,
+     bif_clash, behaviour_basic, behaviour_multiple, otp_11861,
      otp_7550, otp_8051, format_warn, {group, on_load},
      too_many_arguments, basic_errors, bin_syntax_errors, predef,
      maps, maps_type].
@@ -3080,6 +3080,193 @@ behaviour_multiple(Config) when is_list(Config) ->
     ?line [] = run(Config, Ts),
     ok.
 
+otp_11861(doc) ->
+    "OTP-11861. behaviour_info() and -callback.";
+otp_11861(suite) -> [];
+otp_11861(Conf) when is_list(Conf) ->
+    CallbackFiles = [callback1, callback2, callback3,
+                     bad_behaviour1, bad_behaviour2],
+    lists:foreach(fun(M) ->
+                          F = filename:join(?datadir, M),
+                          Opts = [{outdir,?privdir}, return],
+                          {ok, M, []} = compile:file(F, Opts)
+                  end, CallbackFiles),
+    CodePath = code:get_path(),
+    true = code:add_path(?privdir),
+    Ts = [{otp_11861_1,
+           <<"
+              -export([b1/1]).
+              -behaviour(callback1).
+              -behaviour(callback2).
+
+              -spec b1(atom()) -> integer().
+              b1(A) when is_atom(A)->
+                  3.
+             ">>,
+           [],
+           %% b2/1 is optional in both modules
+           {warnings,[{4,erl_lint,
+                       {conflicting_behaviours,{b1,1},callback2,3,callback1}}]}},
+          {otp_11861_2,
+           <<"
+              -export([b2/1]).
+              -behaviour(callback1).
+              -behaviour(callback2).
+
+              -spec b2(integer()) -> atom().
+              b2(I) when is_integer(I)->
+                  a.
+             ">>,
+           [],
+           %% b2/1 is optional in callback2, but not in callback1
+           {warnings,[{3,erl_lint,{undefined_behaviour_func,{b1,1},callback1}},
+                      {4,erl_lint,
+                       {conflicting_behaviours,{b2,1},callback2,3,callback1}}]}},
+          {otp_11861_3,
+           <<"
+              -callback b(_) -> atom().
+              -optional_callbacks({b1,1}). % non-existing and ignored
+             ">>,
+           [],
+           []},
+          {otp_11861_4,
+           <<"
+              -callback b(_) -> atom().
+              -optional_callbacks([{b1,1}]). % non-existing
+             ">>,
+           [],
+           %% No behaviour-info(), but callback.
+           {errors,[{3,erl_lint,{undefined_callback,{lint_test,b1,1}}}],[]}},
+          {otp_11861_5,
+           <<"
+              -optional_callbacks([{b1,1}]). % non-existing
+             ">>,
+           [],
+           %% No behaviour-info() and no callback: warning anyway
+           {errors,[{2,erl_lint,{undefined_callback,{lint_test,b1,1}}}],[]}},
+          {otp_11861_6,
+           <<"
+              -optional_callbacks([b1/1]). % non-existing
+              behaviour_info(callbacks) -> [{b1,1}].
+             ">>,
+           [],
+           %% behaviour-info() and no callback: warning anyway
+           {errors,[{2,erl_lint,{undefined_callback,{lint_test,b1,1}}}],[]}},
+          {otp_11861_7,
+           <<"
+              -optional_callbacks([b1/1]). % non-existing
+              -callback b(_) -> atom().
+              behaviour_info(callbacks) -> [{b1,1}].
+             ">>,
+           [],
+           %% behaviour-info() callback: warning
+           {errors,[{2,erl_lint,{undefined_callback,{lint_test,b1,1}}},
+                    {3,erl_lint,{behaviour_info,{lint_test,b,1}}}],
+            []}},
+          {otp_11861_8,
+           <<"
+              -callback b(_) -> atom().
+              -optional_callbacks([b/1, {b, 1}]).
+             ">>,
+           [],
+           {errors,[{3,erl_lint,{redefine_optional_callback,{b,1}}}],[]}},
+          {otp_11861_9,
+           <<"
+              -behaviour(gen_server).
+              -export([handle_call/3,handle_cast/2,handle_info/2,
+                       code_change/3, init/1, terminate/2]).
+              handle_call(_, _, _) -> ok.
+              handle_cast(_, _) -> ok.
+              handle_info(_, _) -> ok.
+              code_change(_, _, _) -> ok.
+              init(_) -> ok.
+              terminate(_, _) -> ok.
+             ">>,
+           [],
+           []},
+          {otp_11861_9,
+           <<"
+              -behaviour(gen_server).
+              -export([handle_call/3,handle_cast/2,handle_info/2,
+                       code_change/3, init/1, terminate/2, format_status/2]).
+              handle_call(_, _, _) -> ok.
+              handle_cast(_, _) -> ok.
+              handle_info(_, _) -> ok.
+              code_change(_, _, _) -> ok.
+              init(_) -> ok.
+              terminate(_, _) -> ok.
+              format_status(_, _) -> ok. % optional callback
+             ">>,
+           [],
+           %% Nothing...
+           []},
+          {otp_11861_10,
+           <<"
+              -optional_callbacks([{b1,1,bad}]). % badly formed and ignored
+              behaviour_info(callbacks) -> [{b1,1}].
+             ">>,
+           [],
+           []},
+          {otp_11861_11,
+           <<"
+              -behaviour(bad_behaviour1).
+             ">>,
+           [],
+           {warnings,[{2,erl_lint,
+                       {ill_defined_behaviour_callbacks,bad_behaviour1}}]}},
+          {otp_11861_12,
+           <<"
+              -behaviour(non_existing_behaviour).
+             ">>,
+           [],
+           {warnings,[{2,erl_lint,
+                       {undefined_behaviour,non_existing_behaviour}}]}},
+          {otp_11861_13,
+           <<"
+              -behaviour(bad_behaviour_none).
+             ">>,
+           [],
+           {warnings,[{2,erl_lint,{undefined_behaviour,bad_behaviour_none}}]}},
+          {otp_11861_14,
+           <<"
+              -callback b(_) -> atom().
+             ">>,
+           [],
+           []},
+          {otp_11861_15,
+           <<"
+              -optional_callbacks([{b1,1,bad}]). % badly formed
+              -callback b(_) -> atom().
+             ">>,
+           [],
+           []},
+          {otp_11861_16,
+           <<"
+              -callback b(_) -> atom().
+              -callback b(_) -> atom().
+             ">>,
+           [],
+           {errors,[{3,erl_lint,{redefine_callback,{lint_test,b,1}}}],[]}},
+          {otp_11861_17,
+           <<"
+              -behaviour(bad_behaviour2).
+             ">>,
+           [],
+           {warnings,[{2,erl_lint,{undefined_behaviour_callbacks,
+                                   bad_behaviour2}}]}},
+          {otp_11861_18,
+           <<"
+              -export([f1/1]).
+              -behaviour(callback3).
+              f1(_) -> ok.
+             ">>,
+           [],
+           []}
+	 ],
+    ?line [] = run(Conf, Ts),
+    true = code:set_path(CodePath),
+    ok.
+
 otp_7550(doc) ->
     "Test that the new utf8/utf16/utf32 types do not allow size or unit specifiers.";
 otp_7550(Config) when is_list(Config) ->
diff --git a/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour1.erl b/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour1.erl
new file mode 100644
index 0000000000..230f4b4519
--- /dev/null
+++ b/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour1.erl
@@ -0,0 +1,6 @@
+-module(bad_behaviour1).
+
+-export([behaviour_info/1]).
+
+behaviour_info(callbacks) ->
+    [{a,1,bad}].
diff --git a/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour2.erl b/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour2.erl
new file mode 100644
index 0000000000..bb755ce18b
--- /dev/null
+++ b/lib/stdlib/test/erl_lint_SUITE_data/bad_behaviour2.erl
@@ -0,0 +1,6 @@
+-module(bad_behaviour2).
+
+-export([behaviour_info/1]).
+
+behaviour_info(callbacks) ->
+    undefined.
diff --git a/lib/stdlib/test/erl_lint_SUITE_data/callback1.erl b/lib/stdlib/test/erl_lint_SUITE_data/callback1.erl
new file mode 100644
index 0000000000..3cc5b51879
--- /dev/null
+++ b/lib/stdlib/test/erl_lint_SUITE_data/callback1.erl
@@ -0,0 +1,6 @@
+-module(callback1).
+
+-callback b1(I :: integer()) -> atom().
+-callback b2(A :: atom()) -> integer().
+
+-optional_callbacks([{b2,1}]).
diff --git a/lib/stdlib/test/erl_lint_SUITE_data/callback2.erl b/lib/stdlib/test/erl_lint_SUITE_data/callback2.erl
new file mode 100644
index 0000000000..211cf9f115
--- /dev/null
+++ b/lib/stdlib/test/erl_lint_SUITE_data/callback2.erl
@@ -0,0 +1,6 @@
+-module(callback2).
+
+-callback b1(I :: integer()) -> atom().
+-callback b2(A :: atom()) -> integer().
+
+-optional_callbacks([b1/1, b2/1]).
diff --git a/lib/stdlib/test/erl_lint_SUITE_data/callback3.erl b/lib/stdlib/test/erl_lint_SUITE_data/callback3.erl
new file mode 100644
index 0000000000..97b3ecb860
--- /dev/null
+++ b/lib/stdlib/test/erl_lint_SUITE_data/callback3.erl
@@ -0,0 +1,8 @@
+-module(callback3).
+
+-export([behaviour_info/1]).
+
+behaviour_info(callbacks) ->
+    [{f1, 1}];
+behaviour_info(_) ->
+    undefined.
diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl
index babf3a49eb..d0892c6d79 100644
--- a/lib/stdlib/test/erl_pp_SUITE.erl
+++ b/lib/stdlib/test/erl_pp_SUITE.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2006-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2006-2014. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -50,7 +50,7 @@
 
 	  otp_6321/1, otp_6911/1, otp_6914/1, otp_8150/1, otp_8238/1,
 	  otp_8473/1, otp_8522/1, otp_8567/1, otp_8664/1, otp_9147/1,
-          otp_10302/1, otp_10820/1, otp_11100/1]).
+          otp_10302/1, otp_10820/1, otp_11100/1, otp_11861/1]).
 
 %% Internal export.
 -export([ehook/6]).
@@ -83,7 +83,7 @@ groups() ->
      {tickets, [],
       [otp_6321, otp_6911, otp_6914, otp_8150, otp_8238,
        otp_8473, otp_8522, otp_8567, otp_8664, otp_9147,
-       otp_10302, otp_10820, otp_11100]}].
+       otp_10302, otp_10820, otp_11100, otp_11861]}].
 
 init_per_suite(Config) ->
     Config.
@@ -1204,8 +1204,18 @@ otp_11100(Config) when is_list(Config) ->
              []}}),
     ok.
 
+otp_11861(doc) ->
+    "OTP-11861. behaviour_info() and -callback.";
+otp_11861(suite) -> [];
+otp_11861(Config) when is_list(Config) ->
+    "-optional_callbacks([bar/0]).\n" =
+        pf({attribute,3,optional_callbacks,[{bar,0}]}),
+    "-optional_callbacks([{bar,1,bad}]).\n" =
+        pf({attribute,4,optional_callbacks,[{bar,1,bad}]}),
+    ok.
+
 pf(Form) ->
-    lists:flatten(erl_pp:form(Form,none)).
+    lists:flatten(erl_pp:form(Form, none)).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%