dialyzer: Fix a bug concerning parameterized opaque types

The example is provided by James Fish in
http://erlang.org/pipermail/erlang-questions/2014-December/082204.html.

Note that warnings with text such as "the _ variable breaks
opaqueness" are still possible.

2 files changed, 32 insertions, 0 deletions

diff --git a/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue.erl b/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue.erl
new file mode 100644
index 0000000000..0f76680464
--- /dev/null
+++ b/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue.erl
@@ -0,0 +1,17 @@
+-module(myqueue).
+
+-export([new/0, in/2]).
+
+-record(myqueue, {queue = queue:new() :: queue:queue({integer(), _})}).
+
+-opaque myqueue(Item) :: #myqueue{queue :: queue:queue({integer(), Item})}.
+
+-export_type([myqueue/1]).
+
+-spec new() -> myqueue(_).
+new() ->
+    #myqueue{queue=queue:new()}.
+
+-spec in(Item, myqueue(Item)) -> myqueue(Item).
+in(Item, #myqueue{queue=Q}) ->
+    #myqueue{queue=queue:in({1, Item}, Q)}.
diff --git a/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue_params.erl b/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue_params.erl
new file mode 100644
index 0000000000..8d766b7804
--- /dev/null
+++ b/lib/dialyzer/test/opaque_SUITE_data/src/para/myqueue_params.erl
@@ -0,0 +1,15 @@
+-module(myqueue_params).
+
+-export([new/0, in/2]).
+
+-record(myqueue_params, {myqueue = myqueue:new() :: myqueue:myqueue(integer())}).
+
+-type myqueue_params() :: #myqueue_params{myqueue ::
+                                          myqueue:myqueue(integer())}.
+-spec new() -> myqueue_params().
+new() ->
+    #myqueue_params{myqueue=myqueue:new()}.
+
+-spec in(integer(), myqueue_params()) -> myqueue_params().
+in(Item, #myqueue_params{myqueue=Q} = P) when is_integer(Item) ->
+    P#myqueue_params{myqueue=myqueue:in(Item, Q)}.