Merge branch 'sa/dialyzer-contract-variables' into maint

* sa/dialyzer-contract-variables:
  Correct handling of type names in contracts
  Don't rewrite unchanged PLT
  Fix crash related to contract checking

OTP-10083

7 files changed, 382 insertions, 22 deletions

diff --git a/lib/dialyzer/src/dialyzer_cl.erl b/lib/dialyzer/src/dialyzer_cl.erl
index 04a0db890f..6d3b1f0531 100644
--- a/lib/dialyzer/src/dialyzer_cl.erl
+++ b/lib/dialyzer/src/dialyzer_cl.erl
@@ -188,6 +188,7 @@ plt_common(#options{init_plts = [InitPlt]} = Opts, RemoveFiles, AddFiles) ->
     ok ->
       case Opts#options.output_plt of
 	none -> ok;
+	InitPlt -> ok;
 	OutPlt ->
 	  {ok, Binary} = file:read_file(InitPlt),
 	  ok = file:write_file(OutPlt, Binary)
diff --git a/lib/dialyzer/src/dialyzer_contracts.erl b/lib/dialyzer/src/dialyzer_contracts.erl
index 2b78b736ab..76f23d00b9 100644
--- a/lib/dialyzer/src/dialyzer_contracts.erl
+++ b/lib/dialyzer/src/dialyzer_contracts.erl
@@ -344,7 +344,7 @@ insert_constraints([{subtype, Type1, Type2}|Left], Dict) ->
     false ->
       %% A lot of things should change to add supertypes
       throw({error, io_lib:format("First argument of is_subtype constraint "
-				  "must be a type variable\n", [])})
+				  "must be a type variable: ~p\n", [Type1])})
   end;
 insert_constraints([], Dict) -> Dict.
 
@@ -385,9 +385,8 @@ contract_from_form([{type, _L1, bounded_fun,
 		   RecDict, FileLine, TypeAcc, FormAcc) ->
   TypeFun =
     fun(ExpTypes, AllRecords) ->
-	Constr1 = [constraint_from_form(C, RecDict, ExpTypes, AllRecords)
-                   || C <- Constr],
-	VarDict = insert_constraints(Constr1, dict:new()),
+	{Constr1, VarDict} =
+	  process_constraints(Constr, RecDict, ExpTypes, AllRecords),
 	Type = erl_types:t_from_form(Form, RecDict, VarDict),
 	NewType = erl_types:t_solve_remote(Type, ExpTypes, AllRecords),
 	{NewType, Constr1}
@@ -398,18 +397,66 @@ contract_from_form([{type, _L1, bounded_fun,
 contract_from_form([], _RecDict, _FileLine, TypeAcc, FormAcc) ->
   {lists:reverse(TypeAcc), lists:reverse(FormAcc)}.
 
-constraint_from_form({type, _, constraint, [{atom, _, is_subtype},
-					    [Type1, Type2]]}, RecDict,
-                     ExpTypes, AllRecords) ->
-  T1 = erl_types:t_from_form(Type1, RecDict),
-  T2 = erl_types:t_from_form(Type2, RecDict),
-  T3 = erl_types:t_solve_remote(T1, ExpTypes, AllRecords),
-  T4 = erl_types:t_solve_remote(T2, ExpTypes, AllRecords),
-  {subtype, T3, T4};
-constraint_from_form({type, _, constraint, [{atom,_,Name}, List]}, _RecDict,
-                     _ExpTypes, _AllRecords) ->
-  N = length(List),
-  throw({error, io_lib:format("Unsupported type guard ~w/~w\n", [Name, N])}).
+process_constraints(Constrs, RecDict, ExpTypes, AllRecords) ->
+  Init = initialize_constraints(Constrs, RecDict, ExpTypes, AllRecords),
+  constraints_fixpoint(Init, RecDict, ExpTypes, AllRecords).
+
+initialize_constraints(Constrs, RecDict, ExpTypes, AllRecords) ->
+  initialize_constraints(Constrs, RecDict, ExpTypes, AllRecords, []).
+
+initialize_constraints([], _RecDict, _ExpTypes, _AllRecords, Acc) ->
+  Acc;
+initialize_constraints([Constr|Rest], RecDict, ExpTypes, AllRecords, Acc) ->
+  case Constr of
+    {type, _, constraint, [{atom, _, is_subtype}, [Type1, Type2]]} ->
+      T1 = final_form(Type1, RecDict, ExpTypes, AllRecords, dict:new()),
+      Entry = {T1, Type2},
+      initialize_constraints(Rest, RecDict, ExpTypes, AllRecords, [Entry|Acc]);
+    {type, _, constraint, [{atom,_,Name}, List]} ->
+      N = length(List),
+      throw({error,
+	     io_lib:format("Unsupported type guard ~w/~w\n", [Name, N])})
+  end.
+
+constraints_fixpoint(Constrs, RecDict, ExpTypes, AllRecords) ->
+  VarDict =
+    constraints_to_dict(Constrs, RecDict, ExpTypes, AllRecords, dict:new()),
+  constraints_fixpoint(VarDict, Constrs, RecDict, ExpTypes, AllRecords).
+
+constraints_fixpoint(OldVarDict, Constrs, RecDict, ExpTypes, AllRecords) ->
+  NewVarDict =
+    constraints_to_dict(Constrs, RecDict, ExpTypes, AllRecords, OldVarDict),
+  case NewVarDict of
+    OldVarDict ->
+      DictFold =
+	fun(Key, Value, Acc) ->
+	    [{subtype, erl_types:t_var(Key), Value}|Acc]
+	end,
+      FinalConstrs = dict:fold(DictFold, [], NewVarDict),
+      {FinalConstrs, NewVarDict};
+    _Other ->
+      constraints_fixpoint(NewVarDict, Constrs, RecDict, ExpTypes, AllRecords)
+  end.
+
+-define(TYPE_LIMIT, 4).
+
+final_form(Form, RecDict, ExpTypes, AllRecords, VarDict) ->
+  T1 = erl_types:t_from_form(Form, RecDict, VarDict),
+  T2 = erl_types:t_solve_remote(T1, ExpTypes, AllRecords),
+  erl_types:t_limit(T2, ?TYPE_LIMIT).
+
+constraints_to_dict(Constrs, RecDict, ExpTypes, AllRecords, VarDict) ->
+  Subtypes =
+    constraints_to_subs(Constrs, RecDict, ExpTypes, AllRecords, VarDict, []),
+  insert_constraints(Subtypes, dict:new()).
+
+constraints_to_subs([], _RecDict, _ExpTypes, _AllRecords, _VarDict, Acc) ->
+  Acc;
+constraints_to_subs([C|Rest], RecDict, ExpTypes, AllRecords, VarDict, Acc) ->
+  {T1, Form2} = C,
+  T2 = final_form(Form2, RecDict, ExpTypes, AllRecords, VarDict),
+  NewAcc = [{subtype, T1, T2}|Acc],
+  constraints_to_subs(Rest, RecDict, ExpTypes, AllRecords, VarDict, NewAcc).
 
 %% Gets the most general domain of a list of domains of all
 %% the overloaded contracts
diff --git a/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes
new file mode 100644
index 0000000000..8dc0361b0d
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/contracts_with_subtypes
@@ -0,0 +1,31 @@
+
+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:108: The call contracts_with_subtypes:rec_arg({'a',{'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:110: The call contracts_with_subtypes:rec_arg({'a',{'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:111: The call contracts_with_subtypes:rec_arg({'b',{'a',{'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:142: The pattern 1 can never match the type binary() | string()
+contracts_with_subtypes.erl:145: The pattern 'alpha' can never match the type {'ok',X} | {'ok',X,binary() | string()}
+contracts_with_subtypes.erl:147: The pattern 42 can never match the type {'ok',_} | {'ok',_,binary() | string()}
+contracts_with_subtypes.erl:163: The pattern 'alpha' can never match the type {'ok',X}
+contracts_with_subtypes.erl:165: The pattern 42 can never match the type {'ok',X}
+contracts_with_subtypes.erl:183: The pattern 'alpha' can never match the type {'ok',X}
+contracts_with_subtypes.erl:185: The pattern 42 can never match the type {'ok',X}
+contracts_with_subtypes.erl:202: The pattern 1 can never match the type binary() | string()
+contracts_with_subtypes.erl:205: The pattern {'ok', _} can never match the type {'ok',X,binary() | string()}
+contracts_with_subtypes.erl:206: The pattern 'alpha' can never match the type {'ok',X,binary() | string()}
+contracts_with_subtypes.erl:207: The pattern {'ok', 42} can never match the type {'ok',X,binary() | string()}
+contracts_with_subtypes.erl:208: The pattern 42 can never match the type {'ok',X,binary() | string()}
+contracts_with_subtypes.erl:234: Function flat_ets_new_t/0 has no local return
+contracts_with_subtypes.erl:235: 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:23: Invalid type specification for function contracts_with_subtypes:extract2/0. The success typing is () -> 'something'
+contracts_with_subtypes.erl:261: Function factored_ets_new_t/0 has no local return
+contracts_with_subtypes.erl:262: 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: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: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())
diff --git a/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/a.erl b/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/a.erl
new file mode 100644
index 0000000000..7efe870b0d
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/a.erl
@@ -0,0 +1,9 @@
+-module(a).
+-export([g/1]).
+
+-export_type([a/0, t/0]).
+-type a() :: integer().
+-type t() :: a() | maybe_improper_list(t(), t()).
+
+-spec g(t()) -> t().
+g(X) -> X.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/b.erl b/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/b.erl
new file mode 100644
index 0000000000..b08bc5e66c
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/collapse_lists/b.erl
@@ -0,0 +1,5 @@
+-module(b).
+-export([f/1]).
+
+-spec f(a:t()) -> a:t().
+f(X) -> a:g(X).
diff --git a/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl
new file mode 100644
index 0000000000..d72138d509
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl
@@ -0,0 +1,267 @@
+-module(contracts_with_subtypes).
+
+-compile(export_all).
+
+%===============================================================================
+
+-spec extract() -> 'ok'.
+
+extract() ->
+   case dz_extract() of
+       {ok, Val} -> Val;
+       error -> exit(boom)
+   end.
+
+-spec dz_extract() -> RetValue when
+     FileList :: something,
+     RetValue :: {ok, FileList} | error.
+
+dz_extract() -> get(foo).
+
+%-------------------------------------------------------------------------------
+
+-spec extract2() -> 'ok'.
+
+extract2() ->
+   case dz_extract2() of
+       {ok, Val} -> Val;
+       error -> exit(boom)
+   end.
+
+-spec dz_extract2() -> RetValue when
+     RetValue :: {ok, FileList} | error,
+     FileList :: something.
+
+dz_extract2() -> get(foo).
+
+%===============================================================================
+
+-spec foo1(Arg1) -> Res when
+      Arg1 :: atom(),
+      Res  :: atom().
+
+foo1(X) -> X.
+
+-spec foo2(Arg1) -> Res when
+      Arg1 :: Arg2,
+      Arg2 :: atom(),
+      Res  :: atom().
+
+foo2(X) -> X.
+
+-spec foo3(Arg1) -> Res when
+      Arg2 :: atom(),
+      Arg1 :: Arg2,
+      Res  :: atom().
+
+foo3(X) -> X.
+
+-spec foo4(Type) -> Type when is_subtype(Type, atom()).
+
+foo4(X) -> X.
+
+-spec foo5(Type :: atom()) -> Type :: atom().
+
+foo5(X) -> X.
+
+-spec foo6(Type) -> Type when Type :: atom().
+
+foo6(X) -> X.
+
+-spec foo7(Type) -> Type.
+
+foo7(X) -> X.
+
+%-------------------------------------------------------------------------------
+
+bar(1) -> foo1(5);
+bar(2) -> foo2(5);
+bar(3) -> foo3(5);
+bar(4) -> foo4(5);
+bar(5) -> foo5(5);
+bar(6) -> foo6(5);
+bar(7) -> foo7(5).
+
+wrong_foo6() ->
+    b = foo6(a).
+
+%===============================================================================
+
+-spec rec_arg(Arg) -> ok when
+      Arg :: {a, A} | {b, B},
+      A   :: a | {b, B},
+      B   :: b | {a, A}.
+
+rec_arg(X) -> get(X).
+
+c(aa) -> rec_arg({a, a});
+c(bb) -> rec_arg({b, b});
+c(abb) -> rec_arg({a, {b, b}});
+c(baa) -> rec_arg({b, {a, a}});
+c(abaa) -> rec_arg({a, {b, {a, a}}});
+c(babb) -> rec_arg({b, {a, {b, b}}});
+c(ababb) -> rec_arg({a, {b, {a, {b, b}}}});
+c(babaa) -> rec_arg({b, {a, {b, {a, a}}}}).
+
+w(ab) -> rec_arg({a, b});
+w(ba) -> rec_arg({b, a});
+w(aba) -> rec_arg({a, {b, a}});
+w(bab) -> rec_arg({b, {a, b}});
+w(abab) -> rec_arg({a, {b, {a, b}}});
+w(baba) -> rec_arg({b, {a, {b, a}}});
+w(ababa) -> rec_arg({a, {b, {a, {b, a}}}});
+w(babab) -> rec_arg({b, {a, {b, {a, b}}}}).
+
+%===============================================================================
+
+-type dublo(X) :: {X, X}.
+
+-type weird(X,Y) :: {X, Y, X, X}.
+
+-spec forfun(dublo(Var)) -> ok when Var :: atom().
+
+forfun(_) -> ok.
+
+-spec forfun2(weird(Var, Var)) -> ok when Var :: atom().
+
+forfun2(_) -> ok.
+
+%===============================================================================
+
+-spec shallow(X) -> {ok, X} | {ok, X, file:filename()} | err1 | err2.
+
+shallow(X) -> get(X).
+
+st(X) when is_atom(X) ->
+    case shallow(X) of
+	err1 -> ok;
+	err2 -> ok;
+	{ok, X} -> ok;
+	{ok, X, Res} ->
+	    case Res of
+		1      -> bad;
+		_Other -> ok
+	    end;
+	alpha -> bad;
+	{ok, 42} -> bad;
+	42 -> bad
+    end.
+
+%-------------------------------------------------------------------------------
+
+-spec deep(X) -> Ret when
+      Ret :: {ok, X} | Err,
+      Err :: err1 | err2.
+
+deep(X) -> get(X).
+
+dt(X) when is_atom(X) ->
+    case deep(X) of
+	err1 -> ok;
+	err2 -> ok;
+	{ok, X} -> ok;
+	alpha -> bad;
+	{ok, 42} -> bad;
+	42 -> bad
+    end.
+
+%-------------------------------------------------------------------------------
+
+-type local_errors() :: err1 | err2.
+
+-spec deep2(X) -> Ret when
+      Ret :: {ok, X} | Err,
+      Err :: local_errors().
+
+deep2(X) -> get(X).
+
+dt2(X) when is_atom(X) ->
+    case deep2(X) of
+	err1 -> ok;
+	err2 -> ok;
+	{ok, X} -> ok;
+	alpha -> bad;
+	{ok, 42} -> bad;
+	42 -> bad
+    end.
+
+%-------------------------------------------------------------------------------
+
+-spec deep3(X) -> Ret when
+      Ret :: {ok, X, file:filename()} | Err,
+      Err :: local_errors().
+
+deep3(X) -> get(X).
+
+dt3(X) when is_atom(X) ->
+    case deep3(X) of
+	err1 -> ok;
+	err2 -> ok;
+	{ok, X, Res} ->
+	    case Res of
+		1      -> bad;
+		_Other -> ok
+	    end;
+	{ok, X} -> bad;
+	alpha -> bad;
+	{ok, 42} -> bad;
+	42 -> bad
+    end.
+
+%===============================================================================
+
+-spec flat_ets_new(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.
+
+flat_ets_new(Name, Options) ->
+    get({Name, Options}).
+
+flat_ets_new_t() ->
+    flat_ets_new(12,[]),
+    flat_ets_new({a,b},[]),
+    flat_ets_new(name,[foo]),
+    flat_ets_new(name,{bag}),
+    flat_ets_new(name,bag),
+    ok.
+
+-type access()     :: public | protected | private.
+-type type()       :: set | ordered_set | bag | duplicate_bag.
+
+-spec factored_ets_new(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().
+
+factored_ets_new(Name, Options) ->
+    get({Name, Options}).
+
+factored_ets_new_t() ->
+    factored_ets_new(12,[]),
+    factored_ets_new({a,b},[]),
+    factored_ets_new(name,[foo]),
+    factored_ets_new(name,{bag}),
+    factored_ets_new(name,bag),
+    ok.
diff --git a/lib/hipe/cerl/erl_types.erl b/lib/hipe/cerl/erl_types.erl
index ceec31742e..1789fc79fa 100644
--- a/lib/hipe/cerl/erl_types.erl
+++ b/lib/hipe/cerl/erl_types.erl
@@ -2555,8 +2555,8 @@ t_subst_dict(?list(Contents, Termination, Size), Dict) ->
 	?nil -> ?list(NewContents, ?nil, Size);
 	?any -> ?list(NewContents, ?any, Size);
 	Other ->
-	  ?list(NewContents, NewTermination, _) = t_cons(NewContents, Other),
-	  ?list(NewContents, NewTermination, Size)
+	  ?list(NewContents2, NewTermination, _) = t_cons(NewContents, Other),
+	  ?list(NewContents2, NewTermination, Size)
       end
   end;
 t_subst_dict(?function(Domain, Range), Dict) ->
@@ -2597,8 +2597,8 @@ t_subst_aux(?list(Contents, Termination, Size), VarMap) ->
 	?nil -> ?list(NewContents, ?nil, Size);
 	?any -> ?list(NewContents, ?any, Size);
 	Other ->
-	  ?list(NewContents, NewTermination, _) = t_cons(NewContents, Other),
-	  ?list(NewContents, NewTermination, Size)
+	  ?list(NewContents2, NewTermination, _) = t_cons(NewContents, Other),
+	  ?list(NewContents2, NewTermination, Size)
       end
   end;
 t_subst_aux(?function(Domain, Range), VarMap) ->
@@ -3186,8 +3186,8 @@ t_abstract_records(?list(Contents, Termination, Size), RecDict) ->
 	?nil -> ?list(NewContents, ?nil, Size);
 	?any -> ?list(NewContents, ?any, Size);
 	Other ->
-	  ?list(NewContents, NewTermination, _) = t_cons(NewContents, Other),
-	  ?list(NewContents, NewTermination, Size)
+	  ?list(NewContents2, NewTermination, _) = t_cons(NewContents, Other),
+	  ?list(NewContents2, NewTermination, Size)
       end
   end;
 t_abstract_records(?function(Domain, Range), RecDict) ->