2 files changed, 78 insertions, 9 deletions

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
index d72138d509..d7dfd9752e 100644
--- a/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl
+++ b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl
@@ -103,15 +103,44 @@ 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(ab) -> rec_arg({a, b}); % breaks the contract
+w(ba) -> rec_arg({b, a}); % breaks the contract
+w(aba) -> rec_arg({a, {b, a}}); % no longer breaks the contract
+w(bab) -> rec_arg({b, {a, b}}); % breaks the contract
+w(abab) -> rec_arg({a, {b, {a, b}}}); % no longer breaks the contract
+w(baba) -> rec_arg({b, {a, {b, a}}}); % no longer breaks the contract
 w(ababa) -> rec_arg({a, {b, {a, {b, a}}}});
 w(babab) -> rec_arg({b, {a, {b, {a, b}}}}).
 
+%% For comparison: the same thing with types
+
+-type ab() :: {a, a()} | {b, b()}.
+-type a() :: a | {b, b()}.
+-type b() :: b | {a, a()}.
+
+-spec rec2(Arg) -> ok when
+      Arg :: ab().
+
+rec2(X) -> get(X).
+
+d(aa) -> rec2({a, a});
+d(bb) -> rec2({b, b});
+d(abb) -> rec2({a, {b, b}});
+d(baa) -> rec2({b, {a, a}});
+d(abaa) -> rec2({a, {b, {a, a}}});
+d(babb) -> rec2({b, {a, {b, b}}});
+d(ababb) -> rec2({a, {b, {a, {b, b}}}});
+d(babaa) -> rec2({b, {a, {b, {a, a}}}}).
+
+q(ab) -> rec2({a, b}); % breaks the contract
+q(ba) -> rec2({b, a}); % breaks the contract
+q(aba) -> rec2({a, {b, a}}); % breaks the contract
+q(bab) -> rec2({b, {a, b}}); % breaks the contract
+q(abab) -> rec2({a, {b, {a, b}}});
+q(baba) -> rec2({b, {a, {b, a}}});
+q(ababa) -> rec2({a, {b, {a, {b, a}}}});
+q(babab) -> rec2({b, {a, {b, {a, b}}}}).
+
 %===============================================================================
 
 -type dublo(X) :: {X, X}.
@@ -143,7 +172,7 @@ st(X) when is_atom(X) ->
 		_Other -> ok
 	    end;
 	alpha -> bad;
-	{ok, 42} -> bad;
+	{ok, 42} -> ok;
 	42 -> bad
     end.
 
@@ -161,7 +190,7 @@ dt(X) when is_atom(X) ->
 	err2 -> ok;
 	{ok, X} -> ok;
 	alpha -> bad;
-	{ok, 42} -> bad;
+	{ok, 42} -> ok;
 	42 -> bad
     end.
 
@@ -181,7 +210,7 @@ dt2(X) when is_atom(X) ->
 	err2 -> ok;
 	{ok, X} -> ok;
 	alpha -> bad;
-	{ok, 42} -> bad;
+	{ok, 42} -> ok;
 	42 -> bad
     end.
 
diff --git a/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes2.erl b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes2.erl
new file mode 100644
index 0000000000..d2f945b284
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes2.erl
@@ -0,0 +1,40 @@
+-module(contracts_with_subtypes2).
+
+-compile(export_all).
+
+-behaviour(supervisor).
+
+-spec t(Arg) -> ok when
+      Arg :: {a, A},
+      A :: {b, B},
+      B :: {c, C},
+      C :: {d, D},
+      D :: {e, E},
+      E :: {f, _}.
+
+t(X) ->
+    get(X).
+
+t() ->
+    t({a, {b, {c, {d, {e, {g, 3}}}}}}). % breaks the contract
+
+%% This one should possibly result in warnings about unused variables.
+-spec l() -> ok when
+      X :: Y,
+      Y :: X.
+
+l() ->
+    ok.
+
+%% This is the example from seq12547 (ticket OTP-11798).
+%% There used to be a warning.
+
+-spec init(term()) -> Result when
+      Result :: {ok, {{supervisor:strategy(),
+                       non_neg_integer(),
+                       pos_integer()},
+                      [supervisor:child_spec()]}}
+              | ignore.
+
+init(_) ->
+    foo:bar().