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

4 files changed, 312 insertions, 0 deletions

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.