Merge branch 'hb/stdlib/remove_old_type_syntax/OTP-11879'

* hb/stdlib/remove_old_type_syntax/OTP-11879:
  stdlib: Add a comment about is_subtype(_, _) constraints
  hipe: Use '::' for constraints
  debugger: Use '::' for constraints
  doc: Remove 'is_subtype' from Types and Function Specifications
  dialyzer: Print constraints using the '::' syntax
  stdlib: Remove undocumented function specification syntax

13 files changed, 82 insertions, 78 deletions

diff --git a/lib/debugger/src/dbg_iload.erl b/lib/debugger/src/dbg_iload.erl
index 7746a06fcb..369b456524 100644
--- a/lib/debugger/src/dbg_iload.erl
+++ b/lib/debugger/src/dbg_iload.erl
@@ -39,7 +39,7 @@
 %% dbg_iserver. We are suspended until the module has been loaded.
 %%--------------------------------------------------------------------
 -spec load_mod(Mod, file:filename(), binary(), ets:tid()) ->
-        {'ok', Mod} when is_subtype(Mod, atom()).
+        {'ok', Mod} when Mod :: atom().
 
 load_mod(Mod, File, Binary, Db) ->
     Flag = process_flag(trap_exit, true),
diff --git a/lib/dialyzer/src/dialyzer_contracts.erl b/lib/dialyzer/src/dialyzer_contracts.erl
index 7251de8b10..83b3ef72f2 100644
--- a/lib/dialyzer/src/dialyzer_contracts.erl
+++ b/lib/dialyzer/src/dialyzer_contracts.erl
@@ -126,13 +126,19 @@ butlast([H|T]) -> [H|butlast(T)].
 
 constraints_to_string([]) ->
   "";
-constraints_to_string([{type, _, constraint, [{atom, _, What}, Types]}]) ->
-  atom_to_list(What) ++ "(" ++
-    sequence([erl_types:t_form_to_string(T) || T <- Types], ",") ++ ")";
 constraints_to_string([{type, _, constraint, [{atom, _, What}, Types]}|Rest]) ->
-  atom_to_list(What) ++ "(" ++
-    sequence([erl_types:t_form_to_string(T) || T <- Types], ",")
-    ++ "), " ++ constraints_to_string(Rest).
+  S = constraint_to_string(What, Types),
+  case Rest of
+    [] -> S;
+    _ -> S ++ ", " ++ constraints_to_string(Rest)
+  end.
+
+constraint_to_string(is_subtype, [{var, _, Var}, T]) ->
+  atom_to_list(Var) ++ " :: " ++ erl_types:t_form_to_string(T);
+constraint_to_string(What, Types) ->
+  atom_to_list(What) ++ "("
+    ++ sequence([erl_types:t_form_to_string(T) || T <- Types], ",")
+    ++ ")".
 
 sequence([], _Delimiter) -> "";
 sequence([H], _Delimiter) -> H;
diff --git a/lib/dialyzer/test/r9c_SUITE_data/results/mnesia b/lib/dialyzer/test/r9c_SUITE_data/results/mnesia
index 1dc5a105bf..220b18ca7a 100644
--- a/lib/dialyzer/test/r9c_SUITE_data/results/mnesia
+++ b/lib/dialyzer/test/r9c_SUITE_data/results/mnesia
@@ -6,7 +6,7 @@ mnesia_bup.erl:111: The created fun has no local return
 mnesia_bup.erl:574: Function fallback_receiver/2 has no local return
 mnesia_bup.erl:967: Function uninstall_fallback_master/2 has no local return
 mnesia_checkpoint.erl:1014: The variable Error can never match since previous clauses completely covered the type {'ok',#checkpoint_args{nodes::[any()],retainers::[any(),...]}}
-mnesia_checkpoint.erl:894: The call sys:handle_system_msg(Msg::any(),From::any(),'no_parent','mnesia_checkpoint',[],Cp::#checkpoint_args{}) breaks the contract (Msg,From,Parent,Module,Debug,Misc) -> no_return() when is_subtype(Msg,term()), is_subtype(From,{pid(),Tag::_}), is_subtype(Parent,pid()), is_subtype(Module,module()), is_subtype(Debug,[dbg_opt()]), is_subtype(Misc,term())
+mnesia_checkpoint.erl:894: The call sys:handle_system_msg(Msg::any(),From::any(),'no_parent','mnesia_checkpoint',[],Cp::#checkpoint_args{}) breaks the contract (Msg,From,Parent,Module,Debug,Misc) -> no_return() when Msg :: term(), From :: {pid(),Tag::_}, Parent :: pid(), Module :: module(), Debug :: [dbg_opt()], Misc :: term()
 mnesia_controller.erl:1666: The variable Tab can never match since previous clauses completely covered the type [any()]
 mnesia_controller.erl:1679: The pattern {'stop', Reason, Reply, State2} can never match the type {'noreply',_} | {'reply',_,_} | {'stop','shutdown',#state{}}
 mnesia_controller.erl:1685: The pattern {'noreply', State2, _Timeout} can never match the type {'reply',_,_}
diff --git a/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes
index a9fbfb6068..d2a3ebb766 100644
--- a/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes
+++ b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes
@@ -1,15 +1,15 @@
 
-contracts_with_subtypes.erl:106: The call contracts_with_subtypes:rec_arg({'a','b'}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,{'a',A} | {'b',B}), is_subtype(A,'a' | {'b',B}), is_subtype(B,'b' | {'a',A})
-contracts_with_subtypes.erl:107: The call contracts_with_subtypes:rec_arg({'b','a'}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,{'a',A} | {'b',B}), is_subtype(A,'a' | {'b',B}), is_subtype(B,'b' | {'a',A})
-contracts_with_subtypes.erl:109: The call contracts_with_subtypes:rec_arg({'b',{'a','b'}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,{'a',A} | {'b',B}), is_subtype(A,'a' | {'b',B}), is_subtype(B,'b' | {'a',A})
-contracts_with_subtypes.erl:135: The call contracts_with_subtypes:rec2({'a','b'}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:136: The call contracts_with_subtypes:rec2({'b','a'}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:137: The call contracts_with_subtypes:rec2({'a',{'b','a'}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:138: The call contracts_with_subtypes:rec2({'b',{'a','b'}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:139: The call contracts_with_subtypes:rec2({'a',{'b',{'a','b'}}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:140: The call contracts_with_subtypes:rec2({'b',{'a',{'b','a'}}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:141: The call contracts_with_subtypes:rec2({'a',{'b',{'a',{'b','a'}}}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
-contracts_with_subtypes.erl:142: The call contracts_with_subtypes:rec2({'b',{'a',{'b',{'a','b'}}}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,ab())
+contracts_with_subtypes.erl:106: The call contracts_with_subtypes:rec_arg({'a','b'}) breaks the contract (Arg) -> 'ok' when Arg :: {'a',A} | {'b',B}, A :: 'a' | {'b',B}, B :: 'b' | {'a',A}
+contracts_with_subtypes.erl:107: The call contracts_with_subtypes:rec_arg({'b','a'}) breaks the contract (Arg) -> 'ok' when Arg :: {'a',A} | {'b',B}, A :: 'a' | {'b',B}, B :: 'b' | {'a',A}
+contracts_with_subtypes.erl:109: The call contracts_with_subtypes:rec_arg({'b',{'a','b'}}) breaks the contract (Arg) -> 'ok' when Arg :: {'a',A} | {'b',B}, A :: 'a' | {'b',B}, B :: 'b' | {'a',A}
+contracts_with_subtypes.erl:135: The call contracts_with_subtypes:rec2({'a','b'}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:136: The call contracts_with_subtypes:rec2({'b','a'}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:137: The call contracts_with_subtypes:rec2({'a',{'b','a'}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:138: The call contracts_with_subtypes:rec2({'b',{'a','b'}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:139: The call contracts_with_subtypes:rec2({'a',{'b',{'a','b'}}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:140: The call contracts_with_subtypes:rec2({'b',{'a',{'b','a'}}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:141: The call contracts_with_subtypes:rec2({'a',{'b',{'a',{'b','a'}}}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
+contracts_with_subtypes.erl:142: The call contracts_with_subtypes:rec2({'b',{'a',{'b',{'a','b'}}}}) breaks the contract (Arg) -> 'ok' when Arg :: ab()
 contracts_with_subtypes.erl:175: The pattern 1 can never match the type string()
 contracts_with_subtypes.erl:178: The pattern 'alpha' can never match the type {'ok',_} | {'ok',_,string()}
 contracts_with_subtypes.erl:180: The pattern 42 can never match the type {'ok',_} | {'ok',_,string()}
@@ -24,13 +24,13 @@ contracts_with_subtypes.erl:23: Invalid type specification for function contract
 contracts_with_subtypes.erl:240: The pattern {'ok', 42} can never match the type {'ok',_,string()}
 contracts_with_subtypes.erl:241: The pattern 42 can never match the type {'ok',_,string()}
 contracts_with_subtypes.erl:267: Function flat_ets_new_t/0 has no local return
-contracts_with_subtypes.erl:268: The call contracts_with_subtypes:flat_ets_new(12,[]) breaks the contract (Name,Options) -> atom() when is_subtype(Name,atom()), is_subtype(Options,[Option]), is_subtype(Option,'set' | 'ordered_set' | 'bag' | 'duplicate_bag' | 'public' | 'protected' | 'private' | 'named_table' | {'keypos',integer()} | {'heir',pid(),term()} | {'heir','none'} | {'write_concurrency',boolean()} | {'read_concurrency',boolean()} | 'compressed')
+contracts_with_subtypes.erl:268: The call contracts_with_subtypes:flat_ets_new(12,[]) breaks the contract (Name,Options) -> atom() when Name :: atom(), Options :: [Option], Option :: 'set' | 'ordered_set' | 'bag' | 'duplicate_bag' | 'public' | 'protected' | 'private' | 'named_table' | {'keypos',integer()} | {'heir',pid(),term()} | {'heir','none'} | {'write_concurrency',boolean()} | {'read_concurrency',boolean()} | 'compressed'
 contracts_with_subtypes.erl:294: Function factored_ets_new_t/0 has no local return
-contracts_with_subtypes.erl:295: The call contracts_with_subtypes:factored_ets_new(12,[]) breaks the contract (Name,Options) -> atom() when is_subtype(Name,atom()), is_subtype(Options,[Option]), is_subtype(Option,Type | Access | 'named_table' | {'keypos',Pos} | {'heir',Pid::pid(),HeirData} | {'heir','none'} | Tweaks), is_subtype(Type,type()), is_subtype(Access,access()), is_subtype(Tweaks,{'write_concurrency',boolean()} | {'read_concurrency',boolean()} | 'compressed'), is_subtype(Pos,pos_integer()), is_subtype(HeirData,term())
-contracts_with_subtypes.erl:77: The call contracts_with_subtypes:foo1(5) breaks the contract (Arg1) -> Res when is_subtype(Arg1,atom()), is_subtype(Res,atom())
-contracts_with_subtypes.erl:78: The call contracts_with_subtypes:foo2(5) breaks the contract (Arg1) -> Res when is_subtype(Arg1,Arg2), is_subtype(Arg2,atom()), is_subtype(Res,atom())
-contracts_with_subtypes.erl:79: The call contracts_with_subtypes:foo3(5) breaks the contract (Arg1) -> Res when is_subtype(Arg2,atom()), is_subtype(Arg1,Arg2), is_subtype(Res,atom())
+contracts_with_subtypes.erl:295: The call contracts_with_subtypes:factored_ets_new(12,[]) breaks the contract (Name,Options) -> atom() when Name :: atom(), Options :: [Option], Option :: Type | Access | 'named_table' | {'keypos',Pos} | {'heir',Pid::pid(),HeirData} | {'heir','none'} | Tweaks, Type :: type(), Access :: access(), Tweaks :: {'write_concurrency',boolean()} | {'read_concurrency',boolean()} | 'compressed', Pos :: pos_integer(), HeirData :: term()
+contracts_with_subtypes.erl:77: The call contracts_with_subtypes:foo1(5) breaks the contract (Arg1) -> Res when Arg1 :: atom(), Res :: atom()
+contracts_with_subtypes.erl:78: The call contracts_with_subtypes:foo2(5) breaks the contract (Arg1) -> Res when Arg1 :: Arg2, Arg2 :: atom(), Res :: atom()
+contracts_with_subtypes.erl:79: The call contracts_with_subtypes:foo3(5) breaks the contract (Arg1) -> Res when Arg2 :: atom(), Arg1 :: Arg2, Res :: atom()
 contracts_with_subtypes.erl:7: Invalid type specification for function contracts_with_subtypes:extract/0. The success typing is () -> 'something'
-contracts_with_subtypes.erl:80: The call contracts_with_subtypes:foo4(5) breaks the contract (Type) -> Type when is_subtype(Type,atom())
+contracts_with_subtypes.erl:80: The call contracts_with_subtypes:foo4(5) breaks the contract (Type) -> Type when Type :: atom()
 contracts_with_subtypes.erl:81: The call contracts_with_subtypes:foo5(5) breaks the contract (Type::atom()) -> Type::atom()
-contracts_with_subtypes.erl:82: The call contracts_with_subtypes:foo6(5) breaks the contract (Type) -> Type when is_subtype(Type,atom())
+contracts_with_subtypes.erl:82: The call contracts_with_subtypes:foo6(5) breaks the contract (Type) -> Type when Type :: atom()
diff --git a/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes2 b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes2
index 9f5433a13d..1a8aeb13d0 100644
--- a/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes2
+++ b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes2
@@ -1,3 +1,3 @@
 
 contracts_with_subtypes2.erl:18: Function t/0 has no local return
-contracts_with_subtypes2.erl:19: The call contracts_with_subtypes2:t({'a',{'b',{'c',{'d',{'e',{'g',3}}}}}}) breaks the contract (Arg) -> 'ok' when is_subtype(Arg,{'a',A}), is_subtype(A,{'b',B}), is_subtype(B,{'c',C}), is_subtype(C,{'d',D}), is_subtype(D,{'e',E}), is_subtype(E,{'f',_})
+contracts_with_subtypes2.erl:19: The call contracts_with_subtypes2:t({'a',{'b',{'c',{'d',{'e',{'g',3}}}}}}) breaks the contract (Arg) -> 'ok' when Arg :: {'a',A}, A :: {'b',B}, B :: {'c',C}, C :: {'d',D}, D :: {'e',E}, E :: {'f',_}
diff --git a/lib/dialyzer/test/small_SUITE_data/results/pretty_bitstring b/lib/dialyzer/test/small_SUITE_data/results/pretty_bitstring
index 0ad6eee766..e148e5cf22 100644
--- a/lib/dialyzer/test/small_SUITE_data/results/pretty_bitstring
+++ b/lib/dialyzer/test/small_SUITE_data/results/pretty_bitstring
@@ -1,3 +1,3 @@
 
 pretty_bitstring.erl:7: Function t/0 has no local return
-pretty_bitstring.erl:8: The call binary:copy(#{#<1>(8, 1, 'integer', ['unsigned', 'big']), #<2>(8, 1, 'integer', ['unsigned', 'big']), #<3>(3, 1, 'integer', ['unsigned', 'big'])}#,2) breaks the contract (Subject,N) -> binary() when is_subtype(Subject,binary()), is_subtype(N,non_neg_integer())
+pretty_bitstring.erl:8: The call binary:copy(#{#<1>(8, 1, 'integer', ['unsigned', 'big']), #<2>(8, 1, 'integer', ['unsigned', 'big']), #<3>(3, 1, 'integer', ['unsigned', 'big'])}#,2) breaks the contract (Subject,N) -> binary() when Subject :: binary(), N :: non_neg_integer()
diff --git a/lib/dialyzer/test/user_SUITE_data/results/wsp_pdu b/lib/dialyzer/test/user_SUITE_data/results/wsp_pdu
index d1f8f4caf2..626e677524 100644
--- a/lib/dialyzer/test/user_SUITE_data/results/wsp_pdu
+++ b/lib/dialyzer/test/user_SUITE_data/results/wsp_pdu
@@ -6,7 +6,7 @@ wsp_pdu.erl:2403: The call wsp_pdu:d_date(Data1::binary()) will never return sin
 wsp_pdu.erl:2406: Guard test is_integer(Sec::{[byte()] | byte() | {'long',binary()} | {'short',binary()},binary()}) can never succeed
 wsp_pdu.erl:2408: The pattern {'short', Data2} can never match the type {[byte()] | byte() | {'long',binary()} | {'short',binary()},binary()}
 wsp_pdu.erl:2755: Function parse_push_flag/1 has no local return
-wsp_pdu.erl:2756: The call erlang:integer_to_list(Value::[any()]) breaks the contract (Integer) -> string() when is_subtype(Integer,integer())
+wsp_pdu.erl:2756: The call erlang:integer_to_list(Value::[any()]) breaks the contract (Integer) -> string() when Integer :: integer()
 wsp_pdu.erl:2875: The call wsp_pdu:d_text_string(Data::byte()) will never return since it differs in the 1st argument from the success typing arguments: (binary())
 wsp_pdu.erl:2976: The call wsp_pdu:d_q_value(QData::byte()) will never return since it differs in the 1st argument from the success typing arguments: (<<_:8,_:_*8>>)
 wsp_pdu.erl:3336: The call wsp_pdu:encode_typed_field(Ver::any(),'Q-value',ParamValue::any()) will never return since it differs in the 2nd argument from the success typing arguments: (any(),'Constrained-encoding' | 'Date-value' | 'No-value' | 'Short-integer' | 'Text-string' | 'Text-value' | 'Well-known-charset',any())
diff --git a/lib/hipe/icode/hipe_icode.erl b/lib/hipe/icode/hipe_icode.erl
index 9692eebb10..07d230491d 100644
--- a/lib/hipe/icode/hipe_icode.erl
+++ b/lib/hipe/icode/hipe_icode.erl
@@ -1376,12 +1376,12 @@ remove_constants(L) ->
 %% Substitution: replace occurrences of X by Y if {X,Y} is in the
 %%   Subst_list.
 
--spec subst([{_,_}], I) -> I when is_subtype(I, icode_instr()).
+-spec subst([{_,_}], I) -> I when I :: icode_instr().
 
 subst(Subst, I) ->
   subst_defines(Subst, subst_uses(Subst, I)).
 
--spec subst_uses([{_,_}], I) -> I when is_subtype(I, icode_instr()).
+-spec subst_uses([{_,_}], I) -> I when I :: icode_instr().
 
 subst_uses(Subst, I) ->
   case I of
@@ -1405,7 +1405,7 @@ subst_uses(Subst, I) ->
     #icode_label{} -> I
   end.
 
--spec subst_defines([{_,_}], I) -> I when is_subtype(I, icode_instr()).
+-spec subst_defines([{_,_}], I) -> I when I :: icode_instr().
 
 subst_defines(Subst, I) ->
   case I of
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 4a4019b8bd..3ce6abe752 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -373,9 +373,9 @@ format_error({spec_fun_undefined, {F, A}}) ->
 format_error({missing_spec, {F,A}}) ->
     io_lib:format("missing specification for function ~w/~w", [F, A]);
 format_error(spec_wrong_arity) ->
-    "spec has the wrong arity";
+    "spec has wrong arity";
 format_error(callback_wrong_arity) ->
-    "callback has the wrong arity";
+    "callback has wrong arity";
 format_error({deprecated_builtin_type, {Name, Arity},
               Replacement, Rel}) ->
     UseS = case Replacement of
@@ -2878,7 +2878,7 @@ spec_decl(Line, MFA0, TypeSpecs, St0 = #lint{specs = Specs, module = Mod}) ->
     St1 = St0#lint{specs = dict:store(MFA, Line, Specs)},
     case dict:is_key(MFA, Specs) of
 	true -> add_error(Line, {redefine_spec, MFA0}, St1);
-	false -> check_specs(TypeSpecs, Arity, St1)
+	false -> check_specs(TypeSpecs, spec_wrong_arity, Arity, St1)
     end.
 
 %% callback_decl(Line, Fun, Types, State) -> State.
@@ -2892,7 +2892,8 @@ callback_decl(Line, MFA0, TypeSpecs,
             St1 = St0#lint{callbacks = dict:store(MFA, Line, Callbacks)},
             case dict:is_key(MFA, Callbacks) of
                 true -> add_error(Line, {redefine_callback, MFA0}, St1);
-                false -> check_specs(TypeSpecs, Arity, St1)
+                false -> check_specs(TypeSpecs, callback_wrong_arity,
+                                     Arity, St1)
             end
     end.
 
@@ -2929,7 +2930,7 @@ is_fa({FuncName, Arity})
   when is_atom(FuncName), is_integer(Arity), Arity >= 0 -> true;
 is_fa(_) -> false.
 
-check_specs([FunType|Left], Arity, St0) ->
+check_specs([FunType|Left], ETag, Arity, St0) ->
     {FunType1, CTypes} =
 	case FunType of
 	    {type, _, bounded_fun, [FT = {type, _, 'fun', _}, Cs]} ->
@@ -2937,18 +2938,16 @@ check_specs([FunType|Left], Arity, St0) ->
 		{FT, lists:append(Types0)};
 	    {type, _, 'fun', _} = FT -> {FT, []}
 	end,
-    SpecArity =
-	case FunType1 of
-	    {type, L, 'fun', [any, _]} -> any;
-	    {type, L, 'fun', [{type, _, product, D}, _]} -> length(D)
-	end,
+    {type, L, 'fun', [{type, _, product, D}, _]} = FunType1,
+    SpecArity = length(D),
     St1 = case Arity =:= SpecArity of
 	      true -> St0;
-	      false -> add_error(L, spec_wrong_arity, St0)
+	      false -> %% Cannot happen if called from the compiler.
+                  add_error(L, ETag, St0)
 	  end,
     St2 = check_type({type, nowarn(), product, [FunType1|CTypes]}, St1),
-    check_specs(Left, Arity, St2);
-check_specs([], _Arity, St) ->
+    check_specs(Left, ETag, Arity, St2);
+check_specs([], _ETag, _Arity, St) ->
     St.
 
 nowarn() ->
diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl
index ae42a8f0b1..e07ab2efc2 100644
--- a/lib/stdlib/src/erl_parse.yrl
+++ b/lib/stdlib/src/erl_parse.yrl
@@ -85,10 +85,6 @@ type_spec -> '(' spec_fun type_sigs ')' : {'$2', '$3'}.
 
 spec_fun ->                           atom : '$1'.
 spec_fun ->                  atom ':' atom : {'$1', '$3'}.
-%% The following two are retained only for backwards compatibility;
-%% they are not part of the EEP syntax and should be removed.
-spec_fun ->          atom '/' integer '::' : {'$1', '$3'}.
-spec_fun -> atom ':' atom '/' integer '::' : {'$1', '$3', '$5'}.
 
 typed_attr_val -> expr ',' typed_record_fields : {typed_record, '$1', '$3'}.
 typed_attr_val -> expr '::' top_type           : {type_def, '$1', '$3'}.
@@ -634,14 +630,8 @@ build_type_spec({Kind,Aa}, {SpecFun, TypeSpecs})
 	    {atom, _, Fun} ->
 		{Fun, find_arity_from_specs(TypeSpecs)};
 	    {{atom,_, Mod}, {atom,_, Fun}} ->
-		{Mod,Fun,find_arity_from_specs(TypeSpecs)};
-	    {{atom, _, Fun}, {integer, _, Arity}} ->
-		%% Old style spec. Allow this for now.
-		{Fun,Arity};
-	    {{atom,_, Mod}, {atom, _, Fun}, {integer, _, Arity}} ->
-		%% Old style spec. Allow this for now.
-		{Mod,Fun,Arity}
-	    end,
+		{Mod,Fun,find_arity_from_specs(TypeSpecs)}
+        end,
     {attribute,Aa,Kind,{NewSpecFun, TypeSpecs}}.
 
 find_arity_from_specs([Spec|_]) ->
diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl
index 1d35cc71a5..3c746a13d7 100644
--- a/lib/stdlib/test/erl_lint_SUITE.erl
+++ b/lib/stdlib/test/erl_lint_SUITE.erl
@@ -65,7 +65,7 @@
 	  too_many_arguments/1,
 	  basic_errors/1,bin_syntax_errors/1,
           predef/1,
-          maps/1,maps_type/1,otp_11851/1
+          maps/1,maps_type/1,otp_11851/1,otp_11879/1
         ]).
 
 % Default timetrap timeout (set in init_per_testcase).
@@ -94,7 +94,7 @@ all() ->
      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, otp_11851].
+     maps, maps_type, otp_11851, otp_11879].
 
 groups() -> 
     [{unused_vars_warn, [],
@@ -3849,6 +3849,29 @@ otp_11851(Config) when is_list(Config) ->
     [] = run(Config, Ts),
     ok.
 
+otp_11879(doc) ->
+    "OTP-11879: The -spec f/a :: (As) -> B; syntax removed, "
+    "and is_subtype/2 deprecated";
+otp_11879(_Config) ->
+    Fs = [{attribute,0,file,{"file.erl",0}},
+          {attribute,0,module,m},
+          {attribute,1,spec,
+           {{f,1},
+            [{type,2,'fun',[{type,3,product,[{var,4,'V1'},
+                                             {var,5,'V1'}]},
+                            {type,6,integer,[]}]}]}},
+          {attribute,20,callback,
+           {{cb,21},
+            [{type,22,'fun',[{type,23,product,[{var,24,'V1'},
+                                               {var,25,'V1'}]},
+                             {type,6,integer,[]}]}]}}],
+    {error,[{"file.erl",
+             [{1,erl_lint,{spec_fun_undefined,{f,1}}},
+              {2,erl_lint,spec_wrong_arity},
+              {22,erl_lint,callback_wrong_arity}]}],
+     []} = compile:forms(Fs, [return,report]),
+    ok.
+
 run(Config, Tests) ->
     F = fun({N,P,Ws,E}, BadL) ->
                 case catch run_test(Config, P, Ws) of
diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl
index 8cdd2ceca9..8a128b3815 100644
--- a/lib/stdlib/test/erl_pp_SUITE.erl
+++ b/lib/stdlib/test/erl_pp_SUITE.erl
@@ -876,6 +876,9 @@ type_examples() ->
      {ex30,<<"-type t99() ::"
        "{t2(),'\\'t::4'(),t5(),t6(),t7(),t8(),t10(),t14(),"
        "t15(),t20(),t21(), t22(),t25()}. ">>},
+     %% Writing constraints as is_subtype(V, T) is not supported since
+     %% Erlang/OTP 19.0, but as long as the parser recognizes the
+     %% is_subtype(V, T) syntax, we need a few examples of the syntax.
      {ex31,<<"-spec t1(FooBar :: t99()) -> t99();"
                           "(t2()) -> t2();"
                           "('\\'t::4'()) -> '\\'t::4'() when is_subtype('\\'t::4'(), t24);"
@@ -1000,18 +1003,10 @@ otp_8567(Config) when is_list(Config) ->
           "t() ->\n"
           "    3.\n"
           "\n"
-          "-spec(t1/1 :: (ot()) -> ot1()).\n"
-          "t1(A) ->\n"
-          "    A.\n"
-          "\n"
           "-spec(t2 (ot()) -> ot1()).\n"
           "t2(A) ->\n"
           "    A.\n"
           "\n"
-          "-spec(otp_8567:t3/1 :: (ot()) -> ot1()).\n"
-          "t3(A) ->\n"
-          "    A.\n"
-          "\n"
           "-spec(otp_8567:t4 (ot()) -> ot1()).\n"
           "t4(A) ->\n"
           "    A.\n">>,
diff --git a/system/doc/reference_manual/typespec.xml b/system/doc/reference_manual/typespec.xml
index 22627058c1..a238e3135a 100644
--- a/system/doc/reference_manual/typespec.xml
+++ b/system/doc/reference_manual/typespec.xml
@@ -495,7 +495,8 @@
     </p>
     <pre>  -spec id(X) -> X when X :: tuple().</pre>
     <p>
-      Currently, the <c>::</c> constraint (read as <c>is_subtype</c>) is
+      Currently, the <c>::</c> constraint
+      (read as &laquo;is a subtype of&raquo;) is
       the only guard constraint that can be used in the <c>'when'</c>
       part of a <c>'-spec'</c> attribute.
     </p>
@@ -529,16 +530,6 @@
     <pre>
   -spec foo({X, integer()}) -> X when X :: atom()
          ; ([Y]) -> Y when Y :: number().</pre>
-    <note>
-      <p>
-      For backwards compatibility the following form is also allowed:
-      </p>
-      <pre>  -spec id(X) -> X when is_subtype(X, tuple()).</pre>
-      <p>
-	but its use is discouraged. It will be removed in a future
-	Erlang/OTP release.
-      </p>
-    </note>
     <p>
       Some functions in Erlang are not meant to return; 
       either because they define servers or because they are used to