Test suites for Dialyzer

This is a transcription of most of the cvs.srv.it.uu.se:/hipe repository
dialyzer_tests into test suites that use the test server framework.

See README for information on how to use the included scripts for
modifications and updates.

When testing Dialyzer it's important that several OTP modules
are included in the plt. The suites takes care of that too.

59 files changed, 2833 insertions, 0 deletions

diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/dialyzer_options b/lib/dialyzer/test/opaque_tests_SUITE_data/dialyzer_options
new file mode 100644
index 0000000000..3ff26b87db
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/dialyzer_options
@@ -0,0 +1 @@
+{dialyzer_options, [{warnings, [no_unused, no_return]}]}.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/array b/lib/dialyzer/test/opaque_tests_SUITE_data/results/array
new file mode 100644
index 0000000000..b05d088a03
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/array
@@ -0,0 +1,3 @@
+
+array_use.erl:12: The type test is_tuple(array()) breaks the opaqueness of the term array()
+array_use.erl:9: The attempt to match a term of type array() against the pattern {'array', _, _, 'undefined', _} breaks the opaqueness of the term
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/crash b/lib/dialyzer/test/opaque_tests_SUITE_data/results/crash
new file mode 100644
index 0000000000..4cf4da687f
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/crash
@@ -0,0 +1,6 @@
+
+crash_1.erl:45: Record construction #targetlist{list::[]} violates the declared type for #targetlist{}
+crash_1.erl:48: The call crash_1:get_using_branch2(Branch::maybe_improper_list(),L::'undefined' | crash_1:target()) contains an opaque term as 2nd argument argument when terms of different types are expected in these positions
+crash_1.erl:50: The pattern <_Branch, []> can never match the type <maybe_improper_list(),'undefined' | crash_1:target()>
+crash_1.erl:52: The attempt to match a term of type crash_1:target() against the pattern [H = {'target', _, _} | _T] breaks the opaqueness of the term
+crash_1.erl:54: The attempt to match a term of type crash_1:target() against the pattern [{'target', _, _} | T] breaks the opaqueness of the term
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/dict b/lib/dialyzer/test/opaque_tests_SUITE_data/results/dict
new file mode 100644
index 0000000000..5c6bf6a927
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/dict
@@ -0,0 +1,15 @@
+
+dict_use.erl:41: The attempt to match a term of type dict() against the pattern 'gazonk' breaks the opaqueness of the term
+dict_use.erl:45: The attempt to match a term of type dict() against the pattern [] breaks the opaqueness of the term
+dict_use.erl:46: The attempt to match a term of type dict() against the pattern 42 breaks the opaqueness of the term
+dict_use.erl:51: The attempt to match a term of type dict() against the pattern [] breaks the opaqueness of the term
+dict_use.erl:52: The attempt to match a term of type dict() against the pattern 42 breaks the opaqueness of the term
+dict_use.erl:58: Attempt to test for equality between a term of type maybe_improper_list() and a term of opaque type dict()
+dict_use.erl:60: Attempt to test for inequality between a term of type atom() and a term of opaque type dict()
+dict_use.erl:64: Guard test length(D::dict()) breaks the opaqueness of its argument
+dict_use.erl:65: Guard test is_atom(D::dict()) breaks the opaqueness of its argument
+dict_use.erl:66: Guard test is_list(D::dict()) breaks the opaqueness of its argument
+dict_use.erl:70: The type test is_list(dict()) breaks the opaqueness of the term dict()
+dict_use.erl:73: The call dict:fetch('foo',[1 | 2 | 3,...]) does not have an opaque term of type dict() as 2nd argument
+dict_use.erl:76: The call dict:merge(Fun::any(),42,[1 | 2,...]) does not have opaque terms as 2nd and 3rd arguments
+dict_use.erl:79: The call dict:store(42,'elli',{'dict',0,16,16,8,80,48,{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},{{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]}}}) does not have an opaque term of type dict() as 3rd argument
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/ets b/lib/dialyzer/test/opaque_tests_SUITE_data/results/ets
new file mode 100644
index 0000000000..5498ba1538
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/ets
@@ -0,0 +1,3 @@
+
+ets_use.erl:12: Guard test is_integer(T::atom() | tid()) breaks the opaqueness of its argument
+ets_use.erl:7: Guard test is_integer(T::tid()) breaks the opaqueness of its argument
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/gb_sets b/lib/dialyzer/test/opaque_tests_SUITE_data/results/gb_sets
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/gb_sets
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/int b/lib/dialyzer/test/opaque_tests_SUITE_data/results/int
new file mode 100644
index 0000000000..3ee4def34b
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/int
@@ -0,0 +1,3 @@
+
+int_adt.erl:28: Invalid type specification for function int_adt:add_f/2. The success typing is (number(),float()) -> number()
+int_adt.erl:32: Invalid type specification for function int_adt:div_f/2. The success typing is (number(),number()) -> float()
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/mixed_opaque b/lib/dialyzer/test/opaque_tests_SUITE_data/results/mixed_opaque
new file mode 100644
index 0000000000..63623f752c
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/mixed_opaque
@@ -0,0 +1,2 @@
+
+mixed_opaque_use.erl:31: The call mixed_opaque_rec_adt:get_a(Q::mixed_opaque_queue_adt:my_queue()) contains an opaque term as 1st argument argument when an opaque term of type mixed_opaque_rec_adt:rec() is expected
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_digraph b/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_digraph
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_digraph
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_queue b/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_queue
new file mode 100644
index 0000000000..2860b91084
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/my_queue
@@ -0,0 +1,7 @@
+
+my_queue_use.erl:15: The call my_queue_adt:is_empty([]) does not have an opaque term of type my_queue_adt:my_queue() as 1st argument
+my_queue_use.erl:19: The call my_queue_adt:add(42,Q0::[]) does not have an opaque term of type my_queue_adt:my_queue() as 2nd argument
+my_queue_use.erl:24: The attempt to match a term of type my_queue_adt:my_queue() against the pattern [42 | Q2] breaks the opaqueness of the term
+my_queue_use.erl:30: Attempt to test for equality between a term of type [] and a term of opaque type my_queue_adt:my_queue()
+my_queue_use.erl:34: Cons will produce an improper list since its 2nd argument is my_queue_adt:my_queue()
+my_queue_use.erl:34: The call my_queue_adt:dequeue(nonempty_improper_list(42,my_queue_adt:my_queue())) does not have an opaque term of type my_queue_adt:my_queue() as 1st argument
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/opaque b/lib/dialyzer/test/opaque_tests_SUITE_data/results/opaque
new file mode 100644
index 0000000000..ca76f57b54
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/opaque
@@ -0,0 +1,2 @@
+
+opaque_bug4.erl:20: The attempt to match a term of type opaque_adt:abc() against the pattern 'a' breaks the opaqueness of the term
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/queue b/lib/dialyzer/test/opaque_tests_SUITE_data/results/queue
new file mode 100644
index 0000000000..fb44758e0b
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/queue
@@ -0,0 +1,11 @@
+
+queue_use.erl:18: The call queue:is_empty({[],[]}) does not have an opaque term of type queue() as 1st argument
+queue_use.erl:22: The call queue:in(42,Q0::{[],[]}) does not have an opaque term of type queue() as 2nd argument
+queue_use.erl:27: The attempt to match a term of type queue() against the pattern {"*", Q2} breaks the opaqueness of the term
+queue_use.erl:33: Attempt to test for equality between a term of type {[42,...],[]} and a term of opaque type queue()
+queue_use.erl:36: The attempt to match a term of type queue() against the pattern {F, _R} breaks the opaqueness of the term
+queue_use.erl:40: The call queue:out({[42,...],[]}) does not have an opaque term of type queue() as 1st argument
+queue_use.erl:51: The call queue_use:is_in_queue(E::42,DB::#db{p::[],q::queue()}) contains an opaque term as 2nd argument argument when terms of different types are expected in these positions
+queue_use.erl:56: The attempt to match a term of type #db{p::[],q::queue()} against the pattern {'db', _, {L1, L2}} breaks the opaqueness of queue()
+queue_use.erl:62: The call queue_use:tuple_queue({42,'gazonk'}) does not have a term of type {_,queue()} (with opaque subterms) as 1st argument
+queue_use.erl:65: The call queue:in(F::42,Q::'gazonk') does not have an opaque term of type queue() as 2nd argument
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/rec b/lib/dialyzer/test/opaque_tests_SUITE_data/results/rec
new file mode 100644
index 0000000000..7a3b97bc09
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/rec
@@ -0,0 +1,6 @@
+
+rec_use.erl:17: The attempt to match a term of type rec_adt:rec() against the pattern {'rec', _, 42} breaks the opaqueness of the term
+rec_use.erl:18: Guard test tuple_size(R::rec_adt:rec()) breaks the opaqueness of its argument
+rec_use.erl:23: The call rec_adt:get_a(R::tuple()) does not have an opaque term of type rec_adt:rec() as 1st argument
+rec_use.erl:27: Attempt to test for equality between a term of type {'rec','gazonk',42} and a term of opaque type rec_adt:rec()
+rec_use.erl:30: The call erlang:tuple_size(rec_adt:rec()) contains an opaque term as 1st argument argument when a structured term of type tuple() is expected
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/timer b/lib/dialyzer/test/opaque_tests_SUITE_data/results/timer
new file mode 100644
index 0000000000..e917b76b08
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/timer
@@ -0,0 +1,4 @@
+
+timer_use.erl:16: The pattern 'gazonk' can never match the type {'error',_} | {'ok',timer:tref()}
+timer_use.erl:17: The attempt to match a term of type {'ok',timer:tref()} against the pattern {'ok', 42} breaks the opaqueness of timer:tref()
+timer_use.erl:18: The attempt to match a term of type {'error',_} | {'ok',timer:tref()} against the pattern {Tag, 'gazonk'} breaks the opaqueness of timer:tref()
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/union b/lib/dialyzer/test/opaque_tests_SUITE_data/results/union
new file mode 100644
index 0000000000..98829b424a
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/union
@@ -0,0 +1,5 @@
+
+union_use.erl:12: The attempt to match a term of type union_adt:u() against the pattern 'aaa' breaks the opaqueness of the term
+union_use.erl:16: The type test is_tuple(union_adt:u()) breaks the opaqueness of the term union_adt:u()
+union_use.erl:7: Guard test is_atom(A::union_adt:u()) breaks the opaqueness of its argument
+union_use.erl:8: Guard test is_tuple(T::union_adt:u()) breaks the opaqueness of its argument
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/results/wings b/lib/dialyzer/test/opaque_tests_SUITE_data/results/wings
new file mode 100644
index 0000000000..67e8674b9c
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/results/wings
@@ -0,0 +1,11 @@
+
+wings_dissolve.erl:103: Guard test is_list(List::gb_set()) breaks the opaqueness of its argument
+wings_dissolve.erl:19: Guard test is_list(Faces::gb_set()) breaks the opaqueness of its argument
+wings_dissolve.erl:272: Guard test is_list(Faces::gb_set()) breaks the opaqueness of its argument
+wings_dissolve.erl:31: The call gb_sets:is_empty(Faces::[any(),...]) does not have an opaque term of type gb_set() as 1st argument
+wings_edge.erl:205: The pattern <Edge, 'hard', Htab> can never match the type <_,'soft',_>
+wings_edge_cmd.erl:30: The call gb_trees:size(P::gb_set()) contains an opaque term as 1st argument argument when an opaque term of type gb_tree() is expected
+wings_edge_cmd.erl:32: The pattern [_ | Parts] can never match the type []
+wings_edge_cmd.erl:32: The pattern [{_, P} | _] can never match the type []
+wings_io.erl:30: The attempt to match a term of type {'empty',queue()} against the pattern {'empty', {In, Out}} breaks the opaqueness of queue()
+wings_we.erl:155: The call wings_util:gb_trees_largest_key(Etab::gb_tree()) contains an opaque term as 1st argument argument when a structured term of type {_,{_,_,_,'nil' | {_,_,_,'nil' | {_,_,_,_}}}} is expected
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/array/array_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/array/array_use.erl
new file mode 100644
index 0000000000..1702dc8f03
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/array/array_use.erl
@@ -0,0 +1,15 @@
+-module(array_use).
+
+-export([ok1/0, wrong1/0, wrong2/0]).
+
+ok1() ->
+  array:set(17, gazonk, array:new()).
+
+wrong1() ->
+  {array, _, _, undefined, _} = array:new(42).
+
+wrong2() ->
+  case is_tuple(array:new(42)) of
+    true -> structure_is_exposed;
+    false -> cannot_possibly_be
+  end.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/crash/crash_1.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/crash/crash_1.erl
new file mode 100644
index 0000000000..eebeed15af
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/crash/crash_1.erl
@@ -0,0 +1,55 @@
+%%%-------------------------------------------------------------------
+%%% From : Fredrik Thulin <[email protected]>
+%%%
+%%% A module with an erroneous record field declaration which mixes up
+%%% structured and opaque terms and causes a crash in dialyzer.
+%%%
+%%% In addition, it revealed that the compiler produced extraneous
+%%% warnings about unused record definitions when in fact they are
+%%% needed for type declarations. This is now fixed.
+%%%-------------------------------------------------------------------
+-module(crash_1).
+
+-export([add/3, empty/0]).
+
+%%--------------------------------------------------------------------
+
+-record(sipurl,  {proto = "sip" :: string(), host :: string()}).
+-record(keylist, {list = [] :: [_]}).
+-type sip_headers() :: #keylist{}.
+-record(request, {uri :: #sipurl{}, header :: sip_headers()}).
+-type sip_request() :: #request{}.
+
+%%--------------------------------------------------------------------
+
+-record(target, {branch	:: string(), request :: sip_request()}).
+-opaque target() :: #target{}.
+
+-record(targetlist, {list :: target()}).  % XXX: THIS ONE SHOULD READ [target()]
+-opaque targetlist() :: #targetlist{}.
+
+%%====================================================================
+
+add(Branch, #request{} = Request, #targetlist{list = L} = TargetList) ->
+    case get_using_branch(Branch, TargetList) of
+	none ->
+	    NewTarget = #target{branch = Branch, request = Request},
+	    #targetlist{list = L ++ [NewTarget]};
+	#target{} ->
+	    TargetList
+    end.
+
+-spec empty() -> targetlist().
+
+empty() ->
+    #targetlist{list = []}.
+
+get_using_branch(Branch, #targetlist{list = L}) when is_list(Branch) ->
+    get_using_branch2(Branch, L).
+
+get_using_branch2(_Branch, []) ->
+    none;
+get_using_branch2(Branch, [#target{branch=Branch}=H | _T]) ->
+    H;
+get_using_branch2(Branch, [#target{} | T]) ->
+    get_using_branch2(Branch, T).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/dict/dict_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/dict/dict_use.erl
new file mode 100644
index 0000000000..2a632a910d
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/dict/dict_use.erl
@@ -0,0 +1,83 @@
+-module(dict_use).
+
+-export([ok1/0, ok2/0, ok3/0, ok4/0, ok5/0, ok6/0]).
+-export([middle/0]).
+-export([w1/0, w2/0, w3/0, w4/1, w5/0, w6/0, w7/0, w8/1, w9/0]).
+
+-define(DICT, dict).
+
+%%---------------------------------------------------------------------
+%% Cases that are OK
+%%---------------------------------------------------------------------
+
+ok1() ->
+  dict:new().
+
+ok2() ->
+  case dict:new() of X -> X end.
+
+ok3() ->
+  Dict1 = dict:new(),
+  Dict2 = dict:new(),
+  Dict1 =:= Dict2.
+
+ok4() ->
+  dict:fetch(foo, dict:new()).
+
+ok5() ->  % this is OK since some_mod:new/0 might be returning a dict()
+  dict:fetch(foo, some_mod:new()).
+
+ok6() ->
+  dict:store(42, elli, dict:new()).
+
+middle() ->
+  {w1(), w2()}.
+
+%%---------------------------------------------------------------------
+%% Cases that are problematic w.r.t. opaqueness of types
+%%---------------------------------------------------------------------
+
+w1() ->
+  gazonk = dict:new().
+
+w2() ->
+  case dict:new() of
+    [] -> nil;
+    42 -> weird
+  end.
+
+w3() ->
+  try dict:new() of
+    [] -> nil;
+    42 -> weird
+  catch
+    _:_ -> exception
+  end.
+
+w4(Dict) when is_list(Dict) ->
+  Dict =:= dict:new();
+w4(Dict) when is_atom(Dict) ->
+  Dict =/= dict:new().
+
+w5() ->
+  case dict:new() of
+    D when length(D) =/= 42 -> weird;
+    D when is_atom(D) -> weirder;
+    D when is_list(D) -> gazonk
+  end.
+
+w6() ->
+  is_list(dict:new()).
+
+w7() ->
+  dict:fetch(foo, [1,2,3]).
+
+w8(Fun) ->
+  dict:merge(Fun, 42, [1,2]).
+
+w9() ->
+  dict:store(42, elli,
+	     {dict,0,16,16,8,80,48,
+	           {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
+	           {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]}}}).
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/ets/ets_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/ets/ets_use.erl
new file mode 100644
index 0000000000..20be9803eb
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/ets/ets_use.erl
@@ -0,0 +1,17 @@
+-module(ets_use).
+-export([t1/0, t2/0]).
+
+t1() ->
+    case n() of
+	T when is_atom(T) -> atm;
+	T when is_integer(T) -> int
+    end.
+
+t2() ->
+    case n() of
+	T when is_integer(T) -> int;
+	T when is_atom(T) -> atm
+    end.
+
+n() -> ets:new(n, [named_table]).
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/gb_sets/gb_sets_rec.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/gb_sets/gb_sets_rec.erl
new file mode 100644
index 0000000000..008b0a486a
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/gb_sets/gb_sets_rec.erl
@@ -0,0 +1,23 @@
+%%---------------------------------------------------------------------
+%% This module does not test gb_sets. Instead it tests that we can
+%% create records whose fields are declared with an opaque type and
+%% retrieve these fields without problems. Unitialized record fields
+%% used to cause trouble for the analysis due to the implicit
+%% 'undefined' value that record fields contain. The problem was the
+%% strange interaction of ?opaque() and ?union() in the definition of
+%% erl_types:t_inf/3. This was fixed 18/1/2009.
+%% --------------------------------------------------------------------
+
+-module(gb_sets_rec).
+
+-export([new/0, get_g/1]).
+
+-record(rec, {g :: gb_set()}).
+
+-spec new() -> #rec{}.
+new() ->
+  #rec{g = gb_sets:empty()}.
+
+-spec get_g(#rec{}) -> gb_set().
+get_g(R) ->
+  R#rec.g.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/inf_loop1.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/inf_loop1.erl
new file mode 100644
index 0000000000..0dff16cf14
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/inf_loop1.erl
@@ -0,0 +1,172 @@
+%% -*- erlang-indent-level: 2 -*-
+%%----------------------------------------------------------------------------
+%% Non-sensical (i.e., stripped-down) program that sends the analysis
+%% into an infinite loop. The #we.es field was originally a gb_tree()
+%% but the programmer declared it as an array in order to change it to
+%% that data type instead. In the file, there are two calls to function
+%% gb_trees:get/2 which seem to be the ones responsible for sending the
+%% analysis into an infinite loop. Currently, these calls are marked and
+%% have been changed to gbee_trees:get/2 in order to be able to see that
+%% the analysis works if these two calls are taken out of the picture.
+%%----------------------------------------------------------------------------
+-module(inf_loop1).
+
+-export([command/1]).
+
+-record(we, {id,
+	     es = array:new() :: array(),
+	     vp,
+	     mirror = none}).
+-record(edge, {vs,ve,a = none,b = none,lf,rf,ltpr,ltsu,rtpr,rtsu}).
+
+command(St) ->
+  State = drag_mode(offset_region),
+  SetupSt = wings_sel_conv:more(St),
+  Tvs = wings_sel:fold(fun(Faces, #we{id = Id} = We, Acc) ->
+			   FaceRegions = wings_sel:face_regions(Faces, We),
+			   {AllVs0,VsData} =
+			     collect_offset_regions_data(FaceRegions, We, [], []),
+			   AllVs = ordsets:from_list(AllVs0),
+			   [{Id,{AllVs,offset_regions_fun(VsData, State)}}|Acc]
+                       end,
+                       [],
+                       SetupSt),
+    wings_drag:setup(Tvs, 42, [], St).
+
+drag_mode(Type) ->
+    {Mode,Norm} = wings_pref:get_value(Type, {average,loop}),
+    {Type,Mode,Norm}.
+
+collect_offset_regions_data([Faces|Regions], We, AllVs, VsData) ->
+  {FaceNormTab,OuterEdges,RegVs} =
+    some_fake_module:faces_data_0(Faces, We, [], [], []),
+  {LoopNorm,LoopVsData,LoopVs} =
+    offset_regions_loop_data(OuterEdges, Faces, We, FaceNormTab),
+  Vs = RegVs -- LoopVs,
+  RegVsData = vertex_normals(Vs, FaceNormTab, We, LoopVsData),
+  collect_offset_regions_data(Regions, We, RegVs ++ AllVs,
+			      [{LoopNorm,RegVsData}|VsData]);
+collect_offset_regions_data([], _, AllVs, VsData) ->
+  {AllVs,VsData}.
+
+offset_regions_loop_data(Edges, Faces, We, FNtab) ->
+  EdgeSet = gb_sets:from_list(Edges),
+  offset_loop_data_0(EdgeSet, Faces, We, FNtab, [], [], []).
+
+offset_loop_data_0(EdgeSet0, Faces, We, FNtab, LNorms, VData0, Vs0) ->
+  case gb_sets:is_empty(EdgeSet0) of
+    false ->
+      {Edge,EdgeSet1} = gb_sets:take_smallest(EdgeSet0),
+      {EdgeSet,VData,Links,LoopNorm,Vs} =
+	offset_loop_data_1(Edge, EdgeSet1, Faces, We, FNtab, VData0, Vs0),
+      offset_loop_data_0(EdgeSet, Faces, We, FNtab,
+			 [{Links,LoopNorm}|LNorms], VData, Vs);
+    true ->
+      AvgLoopNorm = average_loop_norm(LNorms),
+      {AvgLoopNorm,VData0,Vs0}
+  end.
+
+offset_loop_data_1(Edge, EdgeSet, _Faces,
+                   #we{es = Etab, vp = Vtab} = We, FNtab, VData, Vs) ->
+  #edge{vs = Va, ve = Vb, lf = Lf, ltsu = NextLeft} = gb_trees:get(Edge, Etab),
+  VposA = gb_trees:get(Va, Vtab),
+  VposB = gb_trees:get(Vb, Vtab),
+  VDir = e3d_vec:sub(VposB, VposA),
+  FNorm = wings_face:normal(Lf, We),
+  EdgeData = gb_trees:get(NextLeft, Etab),
+  offset_loop_data_2(NextLeft, EdgeData, Va, VposA, Lf, Edge, We, FNtab,
+		     EdgeSet, VDir, [], [FNorm], VData, [], Vs, 0).
+
+offset_loop_data_2(CurE, #edge{vs = Va, ve = Vb, lf = PrevFace,
+			       rtsu = NextEdge, ltsu = IfCurIsMember},
+                   Vb, VposB, PrevFace, LastE,
+                   #we{mirror = M} = We,
+                   FNtab, EdgeSet0, VDir, EDir0, VNorms0, VData0, VPs0, Vs0,
+                   Links) ->
+  Mirror = M == PrevFace,
+  offset_loop_is_member(Mirror, Vb, Va, VposB, CurE, IfCurIsMember, VNorms0,
+			NextEdge, EdgeSet0, VDir, EDir0, FNtab, PrevFace,
+			LastE, We, VData0, VPs0, Vs0, Links).
+
+offset_loop_is_member(Mirror, V1, V2, Vpos1, CurE, NextE, VNorms0, NEdge,
+                      EdgeSet0, VDir, EDir0, FNtab, PFace, LastE, We,
+                      VData0, VPs0, Vs0, Links) ->
+  #we{es = Etab, vp = Vtab} = We,
+  Vpos2 = gb_trees:get(V2, Vtab),
+  Dir = e3d_vec:sub(Vpos2, Vpos1),
+  NextVDir = e3d_vec:neg(Dir),
+  EdgeSet = gb_sets:delete(CurE, EdgeSet0),
+  EdgeData = gbee_trees:get(NextE, Etab), %% HERE
+  [FNorm|_] = VNorms0,
+  VData = offset_loop_data_3(Mirror, V1, Vpos1, VNorms0, NEdge, VDir,
+			     Dir, EDir0, FNtab, We, VData0),
+  VPs = [Vpos1|VPs0],
+  Vs = [V1|Vs0],
+  offset_loop_data_2(NextE, EdgeData, V2, Vpos2, PFace, LastE, We, FNtab,
+		     EdgeSet, NextVDir, [], [FNorm], VData, VPs, Vs, Links + 1).
+
+offset_loop_data_3(false, V, Vpos, VNorms0, NextEdge,
+                   VDir, Dir, EDir0, FNtab, We, VData0) ->
+  #we{es = Etab} = We,
+  VNorm = e3d_vec:norm(e3d_vec:add(VNorms0)),
+  NV = wings_vertex:other(V, gbee_trees:get(NextEdge, Etab)), %% HERE
+  ANorm = vertex_normal(NV, FNtab, We),
+  EDir = some_fake_module:average_edge_dir(VNorm, VDir, Dir, EDir0),
+  AvgDir = some_fake_module:evaluate_vdata(VDir, Dir, VNorm),
+  ScaledDir = some_fake_module:along_edge_scale_factor(VDir, Dir, EDir, ANorm),
+  [{V,{Vpos,AvgDir,EDir,ScaledDir}}|VData0].
+
+average_loop_norm([{_,LNorms}]) ->
+  e3d_vec:norm(LNorms);
+average_loop_norm([{LinksA,LNormA},{LinksB,LNormB}]) ->
+  case LinksA < LinksB of
+    true ->
+      e3d_vec:norm(e3d_vec:add(e3d_vec:neg(LNormA), LNormB));
+    false ->
+      e3d_vec:norm(e3d_vec:add(e3d_vec:neg(LNormB), LNormA))
+  end;
+average_loop_norm(LNorms) ->
+  LoopNorms = [Norm || {_,Norm} <- LNorms],
+  e3d_vec:norm(e3d_vec:neg(e3d_vec:add(LoopNorms))).
+
+vertex_normals([V|Vs], FaceNormTab, #we{vp = Vtab, mirror = M} = We, Acc) ->
+  FaceNorms =
+    wings_vertex:fold(fun(_, Face, _, A) when Face == M ->
+			  [e3d_vec:neg(wings_face:normal(M, We))|A];
+			 (_, Face, _, A) ->
+			  [gb_trees:get(Face, FaceNormTab)|A]
+		      end, [], V, We),
+  VNorm = e3d_vec:norm(e3d_vec:add(FaceNorms)),
+  Vpos = gb_trees:get(V, Vtab),
+  vertex_normals(Vs, FaceNormTab, We, [{V,{Vpos,VNorm}}|Acc]);
+vertex_normals([], _, _, Acc) ->
+  Acc.
+
+vertex_normal(V, FaceNormTab, #we{mirror = M} = We) ->
+  wings_vertex:fold(fun(_, Face, _, A) when Face == M ->
+			[e3d_vec:neg(wings_face:normal(Face, We))|A];
+		       (_, Face, _, A) ->
+			N = gb_trees:get(Face, FaceNormTab),
+			case e3d_vec:is_zero(N) of
+			  true -> A;
+			  false -> [N|A]
+			end
+		    end, [], V, We).
+
+offset_regions_fun(OffsetData, {_,Solution,_} = State) ->
+  fun(new_mode_data, {NewState,_}) ->
+      offset_regions_fun(OffsetData, NewState);
+     ([Dist,_,_,Bump|_], A) ->
+      lists:foldl(fun({LoopNormal,VsData}, VsAcc0) ->
+		      lists:foldl(fun({V,{Vpos0,VNorm}}, VsAcc) ->
+				      [{V,Vpos0}|VsAcc];
+				     ({V,{Vpos0,Dir,EDir,ScaledEDir}}, VsAcc) ->
+				      Vec = case Solution of
+					      average -> Dir;
+					      along_edges -> EDir;
+					      scaled -> ScaledEDir
+					    end,
+				      [{V,Vpos0}|VsAcc]
+				  end, VsAcc0, VsData)
+		  end, A, OffsetData)
+  end.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_adt.erl
new file mode 100644
index 0000000000..99f8cbdc4a
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_adt.erl
@@ -0,0 +1,33 @@
+%%----------------------------------------------------------------------------
+%% Module that tests consistency of spec declarations in the presence of
+%% opaque types.  Contains both valid and invalid contracts with opaque types.
+%%----------------------------------------------------------------------------
+
+-module(int_adt).
+
+-export([new_i/0, add_i/2, div_i/2, add_f/2, div_f/2]).
+
+-export_type([int/0]).
+
+-opaque int() :: integer().
+
+%% the user has declared the return to be an opaque type, but the success
+%% typing inference is too strong and finds a subtype as a return: this is OK
+-spec new_i() -> int().
+new_i() -> 42.
+
+%% the success typing is more general than the contract: this is OK
+-spec add_i(int(), int()) -> int().
+add_i(X, Y) -> X + Y.
+
+%% the success typing coincides with the contract: this is OK, of course
+-spec div_i(int(), int()) -> int().
+div_i(X, Y) -> X div Y.
+
+%% the success typing has an incompatible domain element: this is invalid
+-spec add_f(int(), int()) -> int().
+add_f(X, Y) when is_float(Y) -> X + trunc(Y).
+
+%% the success typing has an incompatible range: this is invalid
+-spec div_f(int(), int()) -> int().
+div_f(X, Y) -> X / Y.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_use.erl
new file mode 100644
index 0000000000..b4471e1cee
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/int/int_use.erl
@@ -0,0 +1,11 @@
+%%---------------------------------------------------------------------------
+%% Module that uses the opaque types of int_adt.
+%% TODO: Should be extended with invalid contracts.
+%%---------------------------------------------------------------------------
+-module(int_use).
+
+-export([test/0]).
+
+-spec test() -> int_adt:int().
+test() ->
+  int_adt:new_i().
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_queue_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_queue_adt.erl
new file mode 100644
index 0000000000..ac59f19cd3
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_queue_adt.erl
@@ -0,0 +1,26 @@
+%%---------------------------------------------------------------------------
+%% A clone of 'queue_adt' so as to test its combination with 'rec_adt'
+%%---------------------------------------------------------------------------
+-module(mixed_opaque_queue_adt).
+
+-export([new/0, add/2, dequeue/1, is_empty/1]).
+
+-opaque my_queue() :: list().
+
+-spec new() -> my_queue().
+new() ->
+    [].
+
+-spec add(term(), my_queue()) -> my_queue().
+add(E, Q) ->
+    Q ++ [E].
+
+-spec dequeue(my_queue()) -> {term(), my_queue()}.
+dequeue([H|T]) ->
+    {H, T}.
+
+-spec is_empty(my_queue()) -> boolean().
+is_empty([]) ->
+    true;
+is_empty([_|_]) ->
+    false.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_rec_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_rec_adt.erl
new file mode 100644
index 0000000000..61bae5110d
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_rec_adt.erl
@@ -0,0 +1,25 @@
+%%---------------------------------------------------------------------------
+%% A clone of 'rec_adt' so as to test its combination with 'queue_adt'
+%%---------------------------------------------------------------------------
+-module(mixed_opaque_rec_adt).
+
+-export([new/0, get_a/1, get_b/1, set_a/2, set_b/2]).
+
+-record(rec, {a :: atom(), b = 0 :: integer()}).
+
+-opaque rec() :: #rec{}.
+
+-spec new() -> rec().
+new() -> #rec{a = gazonk, b = 42}.
+
+-spec get_a(rec()) -> atom().
+get_a(#rec{a = A}) -> A.
+
+-spec get_b(rec()) -> integer().
+get_b(#rec{b = B}) -> B.
+
+-spec set_a(rec(), atom()) -> rec().
+set_a(R, A) -> R#rec{a = A}.
+
+-spec set_b(rec(), integer()) -> rec().
+set_b(R, B) -> R#rec{b = B}.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_use.erl
new file mode 100644
index 0000000000..e82dcd5f38
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/mixed_opaque/mixed_opaque_use.erl
@@ -0,0 +1,31 @@
+%%---------------------------------------------------------------------------
+%% Test that tries some combinations of using more than one opaque data type
+%% in the same function(s).
+%%----------------------------------------------------------------------------
+-module(mixed_opaque_use).
+
+-export([ok1/1, ok2/0, wrong1/0]).
+
+-define(REC, mixed_opaque_rec_adt).
+-define(QUEUE, mixed_opaque_queue_adt).
+
+%% Currently returning unions of opaque types is considered OK
+ok1(Type) ->
+    case Type of
+	queue -> ?QUEUE:new();
+	rec -> ?REC:new()
+    end.
+
+%% Constructing a queue of records is OK
+ok2() ->
+    Q0 = ?QUEUE:new(),
+    R0 = ?REC:new(),
+    Q1 = ?QUEUE:add(R0, Q0),
+    {R1,_Q2} = ?QUEUE:dequeue(Q1),
+    ?REC:get_a(R1).
+
+%% But of course calling a function expecting some opaque type
+%% with some other opaque typs is not OK
+wrong1() ->
+    Q = ?QUEUE:new(),
+    ?REC:get_a(Q).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_digraph/my_digraph_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_digraph/my_digraph_adt.erl
new file mode 100644
index 0000000000..20c72aa6eb
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_digraph/my_digraph_adt.erl
@@ -0,0 +1,51 @@
+-module(my_digraph_adt).
+
+-export([new/0, new/1]).
+
+-record(my_digraph, {vtab = notable,
+		     etab = notable,
+		     ntab = notable,
+		     cyclic = true   :: boolean()}).
+
+-opaque my_digraph() :: #my_digraph{}.
+
+-type d_protection() :: 'private' | 'protected'.
+-type d_cyclicity()  :: 'acyclic' | 'cyclic'.
+-type d_type()       :: d_cyclicity() | d_protection().
+
+-spec new() -> my_digraph().
+new() -> new([]).
+
+-spec new([atom()]) -> my_digraph().
+new(Type) ->
+    try check_type(Type, protected, []) of
+	{Access, Ts} ->
+	    V = ets:new(vertices, [set, Access]),
+	    E = ets:new(edges, [set, Access]),
+	    N = ets:new(neighbours, [bag, Access]),
+	    ets:insert(N, [{'$vid', 0}, {'$eid', 0}]),
+	    set_type(Ts, #my_digraph{vtab=V, etab=E, ntab=N})
+    catch
+	throw:Error -> throw(Error)
+    end.
+
+-spec check_type([atom()], d_protection(), [{'cyclic', boolean()}]) ->
+       	{d_protection(), [{'cyclic', boolean()}]}.
+
+check_type([acyclic|Ts], A, L) ->
+    check_type(Ts, A,[{cyclic,false} | L]);
+check_type([cyclic | Ts], A, L) ->
+    check_type(Ts, A, [{cyclic,true} | L]);
+check_type([protected | Ts], _, L) ->
+    check_type(Ts, protected, L);
+check_type([private | Ts], _, L) ->
+    check_type(Ts, private, L);
+check_type([T | _], _, _) -> 
+    throw({error, {unknown_type, T}});
+check_type([], A, L) -> {A, L}.
+
+-spec set_type([{'cyclic', boolean()}], my_digraph()) -> my_digraph().
+
+set_type([{cyclic,V} | Ks], G) ->
+    set_type(Ks, G#my_digraph{cyclic = V});
+set_type([], G) -> G.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_adt.erl
new file mode 100644
index 0000000000..52688062ce
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_adt.erl
@@ -0,0 +1,23 @@
+-module(my_queue_adt).
+
+-export([new/0, add/2, dequeue/1, is_empty/1]).
+
+-opaque my_queue() :: list().
+
+-spec new() -> my_queue().
+new() ->
+    [].
+
+-spec add(term(), my_queue()) -> my_queue().
+add(E, Q) ->
+    Q ++ [E].
+
+-spec dequeue(my_queue()) -> {term(), my_queue()}.
+dequeue([H|T]) ->
+    {H, T}.
+
+-spec is_empty(my_queue()) -> boolean().
+is_empty([]) ->
+    true;
+is_empty([_|_]) ->
+    false.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_use.erl
new file mode 100644
index 0000000000..98f9972c1e
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/my_queue/my_queue_use.erl
@@ -0,0 +1,35 @@
+-module(my_queue_use).
+
+-export([ok1/0, ok2/0, wrong1/0, wrong2/0, wrong3/0, wrong4/0, wrong5/0]).
+
+ok1() ->
+    my_queue_adt:is_empty(my_queue_adt:new()).
+
+ok2() ->
+    Q0 = my_queue_adt:new(),
+    Q1 = my_queue_adt:add(42, Q0),
+    {42, Q2} = my_queue_adt:dequeue(Q1),
+    my_queue_adt:is_empty(Q2).
+
+wrong1() ->
+    my_queue_adt:is_empty([]).
+
+wrong2() ->
+    Q0 = [],
+    my_queue_adt:add(42, Q0).
+
+wrong3() ->
+    Q0 = my_queue_adt:new(),
+    Q1 = my_queue_adt:add(42, Q0),
+    [42|Q2] = Q1,
+    Q2.
+
+wrong4() ->
+    Q0 = my_queue_adt:new(),
+    Q1 = my_queue_adt:add(42, Q0),
+    Q1 =:= [].
+
+wrong5() ->
+    Q0 = my_queue_adt:new(),
+    {42, Q2} = my_queue_adt:dequeue([42|Q0]),
+    Q2.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_adt.erl
new file mode 100644
index 0000000000..3456f0e9c6
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_adt.erl
@@ -0,0 +1,9 @@
+-module(opaque_adt).
+-export([atom_or_list/1]).
+
+-opaque abc() :: 'a' | 'b' | 'c'.
+
+atom_or_list(1) -> a;
+atom_or_list(2) -> b;
+atom_or_list(3) -> c;
+atom_or_list(N) -> lists:duplicate(N, a).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug1.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug1.erl
new file mode 100644
index 0000000000..ff0b1d05ab
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug1.erl
@@ -0,0 +1,17 @@
+%%---------------------------------------------------------------------
+%% A test for which the analysis went into an infinite loop due to
+%% specialization using structured type instead of the opaque one.
+%%---------------------------------------------------------------------
+
+-module(opaque_bug1).
+
+-export([test/1]).
+
+-record(c, {a::atom()}).
+
+-opaque erl_type() :: 'any' | #c{}.
+
+test(#c{a=foo} = T) -> local(T).
+
+local(#c{a=foo}) -> any.
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug2.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug2.erl
new file mode 100644
index 0000000000..f193a58f59
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug2.erl
@@ -0,0 +1,13 @@
+%%---------------------------------------------------------------------
+%% A test for which the analysis gave a bogus warning due to
+%% considering the function call name to be of opaque type...
+%%---------------------------------------------------------------------
+
+-module(opaque_bug2).
+
+-export([test/0]).
+
+-opaque o() :: 'map'.
+
+test() ->
+  lists:map(fun(X) -> X+1 end, [1,2]).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug3.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug3.erl
new file mode 100644
index 0000000000..71da82a1f6
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug3.erl
@@ -0,0 +1,19 @@
+%%---------------------------------------------------------------------
+%% A test for which the analysis gave wrong results because it did not
+%% handle the is_tuple/1 guard properly.
+%%---------------------------------------------------------------------
+
+-module(opaque_bug3).
+
+-export([test/1]).
+
+-record(c, {}).
+
+-opaque o() :: 'a' | #c{}.
+
+-spec test(o()) -> 42.
+
+test(#c{} = O) -> t(O).
+
+t(T) when is_tuple(T) -> 42;
+t(a) -> gazonk.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug4.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug4.erl
new file mode 100644
index 0000000000..a7ddc80fe8
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/opaque/opaque_bug4.erl
@@ -0,0 +1,21 @@
+%%---------------------------------------------------------------------
+%% A test for which the analysis gave wrong results due to erroneous
+%% specialization and incorrect handling of unions.
+%%---------------------------------------------------------------------
+
+-module(opaque_bug4).
+
+-export([ok/0, wrong/0]).
+
+%-spec ok() -> 'ok'.
+ok() ->
+   L = opaque_adt:atom_or_list(42),
+   foo(L).
+
+%-spec wrong() -> 'not_ok'.
+wrong() ->
+   A = opaque_adt:atom_or_list(1),
+   foo(A).
+
+foo(a) -> not_ok;
+foo([_|_]) -> ok.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/queue/queue_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/queue/queue_use.erl
new file mode 100644
index 0000000000..5682f2281e
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/queue/queue_use.erl
@@ -0,0 +1,66 @@
+-module(queue_use).
+
+-export([ok1/0, ok2/0]).
+-export([wrong1/0, wrong2/0, wrong3/0, wrong4/0, wrong5/0, wrong6/0, wrong7/0, wrong8/0]).
+
+ok1() ->
+    queue:is_empty(queue:new()).
+
+ok2() ->
+    Q0 = queue:new(),
+    Q1 = queue:in(42, Q0),
+    {{value, 42}, Q2} = queue:out(Q1),
+    queue:is_empty(Q2).
+
+%%--------------------------------------------------
+
+wrong1() ->
+    queue:is_empty({[],[]}).
+
+wrong2() ->
+    Q0 = {[],[]},
+    queue:in(42, Q0).
+
+wrong3() ->
+    Q0 = queue:new(),
+    Q1 = queue:in(42, Q0),
+    {[42],Q2} = Q1,
+    Q2.
+
+wrong4() ->
+    Q0 = queue:new(),
+    Q1 = queue:in(42, Q0),
+    Q1 =:= {[42],[]}.
+
+wrong5() ->
+    {F, _R} = queue:new(),
+    F.
+
+wrong6() ->
+    {{value, 42}, Q2} = queue:out({[42],[]}),
+    Q2.
+
+%%--------------------------------------------------
+
+-record(db, {p, q}).
+
+wrong7() ->
+    add_unique(42, #db{p = [], q = queue:new()}).
+
+add_unique(E, DB) ->
+    case is_in_queue(E, DB) of
+	true -> DB;
+	false -> DB#db{q = queue:in(E, DB#db.q)}
+    end.
+
+is_in_queue(P, #db{q = {L1,L2}}) ->
+    lists:member(P, L1) orelse lists:member(P, L2).
+
+%%--------------------------------------------------
+
+wrong8() ->
+    tuple_queue({42, gazonk}).
+
+tuple_queue({F, Q}) ->
+    queue:in(F, Q).
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_adt.erl
new file mode 100644
index 0000000000..f01cc5e519
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_adt.erl
@@ -0,0 +1,22 @@
+-module(rec_adt).
+
+-export([new/0, get_a/1, get_b/1, set_a/2, set_b/2]).
+
+-record(rec, {a :: atom(), b = 0 :: integer()}).
+
+-opaque rec() :: #rec{}.
+
+-spec new() -> rec().
+new() -> #rec{a = gazonk, b = 42}.
+
+-spec get_a(rec()) -> atom().
+get_a(#rec{a = A}) -> A.
+
+-spec get_b(rec()) -> integer().
+get_b(#rec{b = B}) -> B.
+
+-spec set_a(rec(), atom()) -> rec().
+set_a(R, A) -> R#rec{a = A}.
+
+-spec set_b(rec(), integer()) -> rec().
+set_b(R, B) -> R#rec{b = B}.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_use.erl
new file mode 100644
index 0000000000..358e9f918c
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/rec/rec_use.erl
@@ -0,0 +1,30 @@
+-module(rec_use).
+
+-export([ok1/0, ok2/0, wrong1/0, wrong2/0, wrong3/0, wrong4/0]).
+
+ok1() ->
+    rec_adt:set_a(rec_adt:new(), foo).
+
+ok2() ->
+    R1 = rec_adt:new(),
+    B1 = rec_adt:get_b(R1),
+    R2 = rec_adt:set_b(R1, 42),
+    B2 = rec_adt:get_b(R2),
+    B1 =:= B2.
+
+wrong1() ->
+    case rec_adt:new() of
+	{rec, _, 42} -> weird1;
+	R when tuple_size(R) =:= 3 -> weird2
+    end.
+
+wrong2() ->
+    R = list_to_tuple([rec, a, 42]),
+    rec_adt:get_a(R).
+
+wrong3() ->
+    R = rec_adt:new(),
+    R =:= {rec, gazonk, 42}.
+
+wrong4() ->
+    tuple_size(rec_adt:new()).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/timer/timer_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/timer/timer_use.erl
new file mode 100644
index 0000000000..9c8ea0af1c
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/timer/timer_use.erl
@@ -0,0 +1,20 @@
+%%---------------------------------------------------------------------------
+%% A test case with:
+%%   - a genuine matching error					-- 1st branch
+%%   - a violation of the opaqueness of timer:tref()		-- 2nd branch
+%%   - a subtle violation of the opaqueness of timer:tref()	-- 3rd branch
+%% The test is supposed to check that these cases are treated properly.
+%%---------------------------------------------------------------------------
+
+-module(timer_use).
+-export([wrong/0]).
+
+-spec wrong() -> error.
+
+wrong() ->
+  case timer:kill_after(42, self()) of
+    gazonk -> weird;
+    {ok, 42} -> weirder;
+    {Tag, gazonk} when Tag =/= error -> weirdest;
+    {error, _} -> error
+  end.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_adt.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_adt.erl
new file mode 100644
index 0000000000..5ca3202bba
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_adt.erl
@@ -0,0 +1,19 @@
+-module(union_adt).
+-export([new/1, new_a/1, new_rec/1]).
+
+-record(rec, {x = 42 :: integer()}).
+
+-opaque u() :: 'aaa' | 'bbb' | #rec{}.
+
+new(a) -> aaa;
+new(b) -> bbb;
+new(X) when is_integer(X) ->
+  #rec{x = X}.
+
+%% the following two functions (and their uses in union_use.erl) test
+%% that the return type is the opaque one and not just a subtype of it
+
+new_a(a) -> aaa.
+
+new_rec(X) when is_integer(X) ->
+  #rec{x = X}.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_use.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_use.erl
new file mode 100644
index 0000000000..6a103279cd
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/union/union_use.erl
@@ -0,0 +1,16 @@
+-module(union_use).
+
+-export([test/1, wrong_a/0, wrong_rec/0]).
+
+test(X) ->
+  case union_adt:new(X) of
+    A when is_atom(A)  -> atom;
+    T when is_tuple(T) -> tuple
+  end.
+
+wrong_a() ->
+  aaa = union_adt:new_a(a),
+  ok.
+
+wrong_rec() ->
+  is_tuple(union_adt:new_rec(42)).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings.hrl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings.hrl
new file mode 100644
index 0000000000..b9339a8eb1
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings.hrl
@@ -0,0 +1,205 @@
+%%
+%%  wings.hrl --
+%%
+%%     Global record definition and defines.
+%%
+%%  Copyright (c) 2001-2005 Bjorn Gustavsson
+%%
+%%  See the file "license.terms" for information on usage and redistribution
+%%  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+%%
+%%     $Id: wings.hrl,v 1.1 2009/01/25 18:55:33 kostis Exp $
+%%
+
+-include("wings_intl.hrl").
+
+-ifdef(NEED_ESDL).
+-include_lib("esdl/include/sdl.hrl").
+-include_lib("esdl/include/sdl_events.hrl").
+-include_lib("esdl/include/sdl_video.hrl").
+-include_lib("esdl/include/sdl_keyboard.hrl").
+-include_lib("esdl/include/sdl_mouse.hrl").
+-include_lib("esdl/src/sdl_util.hrl").
+-define(CTRL_BITS, ?KMOD_CTRL).
+-define(ALT_BITS, ?KMOD_ALT).
+-define(SHIFT_BITS, ?KMOD_SHIFT).
+-define(META_BITS, ?KMOD_META).
+-endif.
+
+-define(WINGS_VERSION, ?wings_version).
+
+-define(CHAR_HEIGHT, wings_text:height()).
+-define(CHAR_WIDTH, wings_text:width()).
+
+-define(LINE_HEIGHT, (?CHAR_HEIGHT+2)).
+-define(GROUND_GRID_SIZE, 1).
+-define(CAMERA_DIST, (8.0*?GROUND_GRID_SIZE)).
+-define(NORMAL_LINEWIDTH, 1.0).
+-define(DEGREE, 176).				%Degree character.
+
+-define(HIT_BUF_SIZE, (1024*1024)).
+
+-define(PANE_COLOR, {0.52,0.52,0.52}).
+-define(BEVEL_HIGHLIGHT, {0.9,0.9,0.9}).
+-define(BEVEL_LOWLIGHT, {0.3,0.3,0.3}).
+-define(BEVEL_HIGHLIGHT_MIX, 0.5).
+-define(BEVEL_LOWLIGHT_MIX, 0.5).
+
+-define(SLOW(Cmd), begin wings_io:hourglass(), Cmd end).
+-define(TC(Cmd), wings_util:tc(fun() -> Cmd end, ?MODULE, ?LINE)).
+
+-ifdef(DEBUG).
+-define(ASSERT(E), case E of
+		       true -> ok;
+		       _ ->
+			   erlang:error({assertion_failed,?MODULE,?LINE})
+		   end).
+-define(CHECK_ERROR(), wings_gl:check_error(?MODULE, ?LINE)).
+-else.
+-define(ASSERT(E),ok).
+-define(CHECK_ERROR(), ok).
+-endif.
+
+%% Display lists per object.
+%%  Important: Plain integers and integers in lists will be assumed to
+%%  be display lists. Arbitrary integers must be stored inside a tuple
+%%  or record to not be interpreted as a display list.
+-record(dlo,
+	{work=none,				%Workmode faces.
+	 smooth=none,				%Smooth-shaded faces.
+	 edges=none,				%Edges and wire-frame.
+	 vs=none,				%Unselected vertices.
+	 hard=none,				%Hard edges.
+	 sel=none,				%Selected items.
+	 orig_sel=none,				%Original selection.
+	 normals=none,				%Normals.
+	 pick=none,				%For picking.
+	 proxy_faces=none,			%Smooth proxy faces.
+	 proxy_edges=none,			%Smooth proxy edges.
+
+	 %% Miscellanous.
+	 hilite=none,				%Hilite display list.
+	 mirror=none,				%Virtual mirror data.
+	 ns=none,				%Normals/positions per face.
+
+	 %% Source for display lists.
+	 src_we=none,				%Source object.
+	 src_sel=none,				%Source selection.
+	 orig_mode=none,			%Original selection mode.
+	 split=none,				%Split data.
+	 drag=none,				%For dragging.
+	 transparent=false,			%Object includes transparancy.
+	 proxy_data=none,			%Data for smooth proxy.
+	 open=false,				%Open (has hole).
+
+	 %% List of display lists known to be needed only based
+	 %% on display modes, not whether the lists themselves exist.
+	 %% Example: [work,edges]
+	 needed=[]
+	}).
+
+%% Main state record containing all objects and other important state.
+-record(st,
+	{shapes,				%All visible shapes
+	 selmode,				%Selection mode:
+						% vertex, edge, face, body
+	 sh=false,				%Smart highlight active: true|false
+	 sel=[],				%Current sel: [{Id,GbSet}]
+	 ssels=[],				%Saved selections:
+	 					%  [{Name,Mode,GbSet}]
+	 temp_sel=none,			        %Selection only temporary?
+
+	 mat,					%Defined materials (GbTree).
+	 pal=[],                                %Palette
+	 file,					%Current filename.
+	 saved,					%True if model has been saved.
+	 onext,					%Next object id to use.
+	 bb=none,				%Saved bounding box.
+	 edge_loop=none,			%Previous edge loop.
+	 views={0,{}},				%{Current,TupleOfViews}
+	 pst=gb_trees:empty(),                  %Plugin State Info
+						%   gb_tree where key is plugin	module 
+
+	 %% Previous commands.
+	 repeatable,			        %Last repeatable command.
+	 ask_args,				%Ask arguments.
+	 drag_args,			        %Drag arguments for command.
+	 def,					%Default operations.
+
+	 %% Undo information.
+	 top,					%Top of stack.
+	 bottom,				%Bottom of stack.
+	 next_is_undo,				%State of undo/redo toggle.
+	 undone				        %States that were undone.
+	}).
+
+%% The Winged-Edge data structure.
+%% See http://www.cs.mtu.edu/~shene/COURSES/cs3621/NOTES/model/winged-e.html
+-record(we,
+	{id,					%Shape id.
+	 perm=0,				%Permissions:
+						% 0 - Everything allowed.
+						% 1 - Visible, can't select.
+						% [] or {Mode,GbSet} -
+						%  Invisible, can't select.
+						%  The GbSet contains the
+						%  object's selection.
+	 name,					%Name.
+	 es,					%gb_tree containing edges
+	 fs,					%gb_tree containing faces
+	 he,					%gb_sets containing hard edges
+	 vc,					%Connection info (=incident edge)
+						% for vertices.
+	 vp,					%Vertex positions.
+	 pst=gb_trees:empty(),                  %Plugin State Info, 
+						%   gb_tree where key is plugin module
+	 mat=default,				%Materials.
+	 next_id,				%Next free ID for vertices,
+						% edges, and faces.
+						% (Needed because we never re-use
+						%  IDs.)
+	 mode,					%'vertex'/'material'/'uv'
+	 mirror=none,				%Mirror: none|Face
+	 light=none,				%Light data: none|Light
+	 has_shape=true				%true|false
+	}).
+
+-define(IS_VISIBLE(Perm), (Perm =< 1)).
+-define(IS_NOT_VISIBLE(Perm), (Perm > 1)).
+-define(IS_SELECTABLE(Perm), (Perm == 0)).
+-define(IS_NOT_SELECTABLE(Perm), (Perm =/= 0)).
+
+-define(IS_LIGHT(We), ((We#we.light =/= none) and (not We#we.has_shape))).
+-define(IS_ANY_LIGHT(We), (We#we.light =/= none)).
+-define(HAS_SHAPE(We), (We#we.has_shape)).
+%-define(IS_LIGHT(We), (We#we.light =/= none)).
+%-define(IS_NOT_LIGHT(We), (We#we.light =:= none)).
+
+%% Edge in a winged-edge shape.
+-record(edge,
+	{vs,					%Start vertex for edge
+	 ve,					%End vertex for edge
+	 a=none,			        %Color or UV coordinate.
+	 b=none,			        %Color or UV coordinate.
+	 lf,					%Left face
+	 rf,					%Right face
+	 ltpr,					%Left traversal predecessor
+	 ltsu,					%Left traversal successor
+	 rtpr,					%Right traversal predecessor
+	 rtsu					%Right traversal successor
+	}).
+
+%% The current view/camera.
+-record(view,
+	{origin,
+	 distance,				% From origo.
+	 azimuth,
+	 elevation,
+	 pan_x,					%Panning in X direction.
+	 pan_y,					%Panning in Y direction.
+	 along_axis=none,			%Which axis viewed along.
+	 fov,					%Field of view.
+	 hither,				%Near clipping plane.
+	 yon					%Far clipping plane.
+	}).
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_dissolve.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_dissolve.erl
new file mode 100644
index 0000000000..d7af9bb1d3
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_dissolve.erl
@@ -0,0 +1,375 @@
+%%
+%%  wings_dissolve.erl --
+%%
+%%     This module implements dissolve of faces.
+%%
+
+-module(wings_dissolve).
+
+-export([faces/2, complement/2]).
+
+-include("wings.hrl").
+
+%% faces([Face], We) -> We'
+%%  Dissolve the given faces.
+faces([], We) -> We;
+faces(Faces, #we{fs=Ftab0}=We) ->
+    case gb_sets:is_empty(Faces) of
+	true -> We;
+	false when is_list(Faces) -> 
+	    Complement = ordsets:subtract(gb_trees:keys(Ftab0), 
+					  ordsets:from_list(Faces)),
+	    dissolve_1(Faces, Complement, We);
+	false ->
+	    Complement = ordsets:subtract(gb_trees:keys(Ftab0), 
+					  gb_sets:to_list(Faces)),
+	    dissolve_1(Faces, Complement, We)
+    end.
+
+faces([], _, We) -> We;
+faces(Faces,Complement,We) ->
+    case gb_sets:is_empty(Faces) of
+        true -> We;
+        false -> dissolve_1(Faces, Complement,We)
+    end.
+
+dissolve_1(Faces, Complement, We0) ->
+    We1 = optimistic_dissolve(Faces,Complement,We0#we{vc=undefined}),
+    NewFaces = wings_we:new_items_as_ordset(face, We0, We1),
+    We2 = wings_face:delete_bad_faces(NewFaces, We1),
+    We = wings_we:rebuild(We2),
+    case wings_we:is_consistent(We) of
+	true ->
+	    We;
+	false ->
+	    io:format("Dissolving would cause an inconsistent object structure.")
+    end.
+
+%% complement([Face], We) -> We'
+%%  Dissolve all faces BUT the given faces. Also invalidate the
+%%  mirror face if it existed and was dissolved.
+complement(Fs0, #we{fs=Ftab0}=We0) when is_list(Fs0) ->
+    Fs = ordsets:subtract(gb_trees:keys(Ftab0), ordsets:from_list(Fs0)),
+    case faces(Fs, Fs0, We0) of
+        #we{mirror=none}=We -> We;
+        #we{mirror=Face,fs=Ftab}=We ->
+            case gb_trees:is_defined(Face, Ftab) of
+                false -> We;
+                true -> We#we{mirror=none}
+            end
+    end;
+complement(Fs, We) -> complement(gb_sets:to_list(Fs), We).
+
+optimistic_dissolve(Faces0, Compl, We0) ->
+    %% Optimistically assume that we have a simple region without
+    %% any holes.
+    case outer_edge_loop(Faces0, We0) of
+	error ->
+	    %% Assumption was wrong. We need to partition the selection
+	    %% and dissolve each partition in turn.
+	    Parts = wings_sel:face_regions(Faces0, We0),
+	    complex_dissolve(Parts, We0);
+	[_|_]=Loop ->
+	    %% Assumption was correct.
+	    simple_dissolve(Faces0, Compl, Loop, We0)
+    end.
+
+%% simple_dissolve(Faces, Loop, We0) -> We
+%%  Dissolve a region of faces with no holes and no
+%%  repeated vertices in the outer edge loop.
+
+simple_dissolve(Faces0, Compl, Loop, We0) ->
+    Faces = to_gb_set(Faces0),
+    OldFace = gb_sets:smallest(Faces),
+    Mat = wings_facemat:face(OldFace, We0),
+    We1 = fix_materials(Faces, Compl, We0),
+    #we{es=Etab0,fs=Ftab0,he=Htab0} = We1,
+    {Ftab1,Etab1,Htab} = simple_del(Faces, Ftab0, Etab0, Htab0, We1),
+    {NewFace,We2} = wings_we:new_id(We1),
+    Ftab = gb_trees:insert(NewFace, hd(Loop), Ftab1),
+    Last = lists:last(Loop),
+    Etab = update_outer([Last|Loop], Loop, NewFace, Ftab, Etab1),
+    We = We2#we{es=Etab,fs=Ftab,he=Htab},
+    wings_facemat:assign(Mat, [NewFace], We).
+
+fix_materials(Del,Keep,We) ->
+    case gb_sets:size(Del) < length(Keep) of
+	true ->
+	    wings_facemat:delete_faces(Del,We);
+	false ->
+	    wings_facemat:keep_faces(Keep,We)
+    end.
+
+to_gb_set(List) when is_list(List) ->
+    gb_sets:from_list(List);
+to_gb_set(S) -> S.
+
+%% Delete faces and inner edges for a simple region.
+simple_del(Faces, Ftab0, Etab0, Htab0, We) ->
+    case {gb_trees:size(Ftab0),gb_sets:size(Faces)} of
+	{AllSz,FaceSz} when AllSz < 2*FaceSz ->
+	    %% At least half of the faces are selected.
+	    %% It is faster to find the edges for the
+	    %% unselected faces.
+	    UnselFaces = ordsets:subtract(gb_trees:keys(Ftab0),
+					  gb_sets:to_list(Faces)),
+
+	    UnselSet = sofs:from_external(UnselFaces, [face]),
+	    Ftab1 = sofs:from_external(gb_trees:to_list(Ftab0),
+				       [{face,edge}]),
+	    Ftab2 = sofs:restriction(Ftab1, UnselSet),
+	    Ftab = gb_trees:from_orddict(sofs:to_external(Ftab2)),
+
+	    Keep0 = wings_face:to_edges(UnselFaces, We),
+	    Keep = sofs:set(Keep0, [edge]),
+	    Etab1 = sofs:from_external(gb_trees:to_list(Etab0),
+				       [{edge,info}]),
+	    Etab2 = sofs:restriction(Etab1, Keep),
+	    Etab = gb_trees:from_orddict(sofs:to_external(Etab2)),
+	    
+	    Htab = simple_del_hard(Htab0, sofs:to_external(Keep), undefined),
+	    {Ftab,Etab,Htab};
+	{_,_} ->
+	    Ftab = lists:foldl(fun(Face, Ft) ->
+				       gb_trees:delete(Face, Ft)
+			       end, Ftab0, gb_sets:to_list(Faces)),
+	    Inner = wings_face:inner_edges(Faces, We),
+	    Etab = lists:foldl(fun(Edge, Et) ->
+				       gb_trees:delete(Edge, Et)
+			       end, Etab0, Inner),
+	    Htab = simple_del_hard(Htab0, undefined, Inner),
+	    {Ftab,Etab,Htab}
+    end.
+
+simple_del_hard(Htab, Keep, Remove) ->
+    case gb_sets:is_empty(Htab) of
+	true -> Htab;
+	false -> simple_del_hard_1(Htab, Keep, Remove)
+    end.
+
+simple_del_hard_1(Htab, Keep, undefined) ->
+    gb_sets:intersection(Htab, gb_sets:from_ordset(Keep));
+simple_del_hard_1(Htab, undefined, Remove) ->
+    gb_sets:difference(Htab, gb_sets:from_ordset(Remove)).
+
+%% complex([Partition], We0) -> We0
+%%  The general dissolve.
+
+complex_dissolve([Faces|T], We0) ->
+    Face = gb_sets:smallest(Faces),
+    Mat = wings_facemat:face(Face, We0),
+    We1 = wings_facemat:delete_faces(Faces, We0),
+    Parts = outer_edge_partition(Faces, We1),
+    We = do_dissolve(Faces, Parts, Mat, We0, We1),
+    complex_dissolve(T, We);
+complex_dissolve([], We) -> We.
+
+do_dissolve(Faces, Ess, Mat, WeOrig, We0) ->
+    We1 = do_dissolve_faces(Faces, We0),
+    Inner = wings_face:inner_edges(Faces, WeOrig),
+    We2 = delete_inner(Inner, We1),
+    #we{he=Htab0} = We = do_dissolve_1(Ess, Mat, We2),
+    Htab = gb_sets:difference(Htab0, gb_sets:from_list(Inner)),
+    We#we{he=Htab}.
+
+do_dissolve_1([EdgeList|Ess], Mat, #we{es=Etab0,fs=Ftab0}=We0) ->
+    {Face,We1} = wings_we:new_id(We0),
+    Ftab = gb_trees:insert(Face, hd(EdgeList), Ftab0),
+    Last = lists:last(EdgeList),
+    Etab = update_outer([Last|EdgeList], EdgeList, Face, Ftab, Etab0),
+    We2 = We1#we{es=Etab,fs=Ftab},
+    We = wings_facemat:assign(Mat, [Face], We2),
+    do_dissolve_1(Ess, Mat, We);
+do_dissolve_1([], _Mat, We) -> We.
+
+do_dissolve_faces(Faces, #we{fs=Ftab0}=We) ->
+    Ftab = lists:foldl(fun(Face, Ft) ->
+			       gb_trees:delete(Face, Ft)
+		       end, Ftab0, gb_sets:to_list(Faces)),
+    We#we{fs=Ftab}.
+
+delete_inner(Inner, #we{es=Etab0}=We) ->
+    Etab = lists:foldl(fun(Edge, Et) ->
+			       gb_trees:delete(Edge, Et)
+		       end, Etab0, Inner),
+    We#we{es=Etab}.
+
+update_outer([Pred|[Edge|Succ]=T], More, Face, Ftab, Etab0) ->
+    #edge{rf=Rf} = R0 = gb_trees:get(Edge, Etab0),
+    Rec = case gb_trees:is_defined(Rf, Ftab) of
+	      true ->
+		  ?ASSERT(false == gb_trees:is_defined(R0#edge.lf, Ftab)),
+		  LS = succ(Succ, More),
+		  R0#edge{lf=Face,ltpr=Pred,ltsu=LS};
+	      false ->
+		  ?ASSERT(true == gb_trees:is_defined(R0#edge.lf, Ftab)),
+		  RS = succ(Succ, More),
+		  R0#edge{rf=Face,rtpr=Pred,rtsu=RS}
+	  end,
+    Etab = gb_trees:update(Edge, Rec, Etab0),
+    update_outer(T, More, Face, Ftab, Etab);
+update_outer([_], _More, _Face, _Ftab, Etab) -> Etab.
+
+succ([Succ|_], _More) -> Succ;
+succ([], [Succ|_]) -> Succ.
+
+%% outer_edge_loop(FaceSet,WingedEdge) -> [Edge] | error.
+%%  Partition the outer edges of the FaceSet into a single closed loop.
+%%  Return 'error' if the faces in FaceSet does not form a
+%%  simple region without holes.
+%%
+%%  Equvivalent to
+%%      case outer_edge_partition(FaceSet,WingedEdge) of
+%%         [Loop] -> Loop;
+%%         [_|_] -> error
+%%      end.
+%%  but faster.
+
+outer_edge_loop(Faces, We) ->
+    case lists:sort(collect_outer_edges(Faces, We)) of
+	[] -> error;
+	[{Key,Val}|Es0] ->
+	    case any_duplicates(Es0, Key) of
+		false ->
+		    Es = gb_trees:from_orddict(Es0),
+		    N = gb_trees:size(Es),
+		    outer_edge_loop_1(Val, Es, Key, N, []);
+		true -> error
+	    end
+    end.
+
+outer_edge_loop_1({Edge,V}, _, V, 0, Acc) ->
+    %% This edge completes the loop, and we have used all possible edges.
+    [Edge|Acc];
+outer_edge_loop_1({_,V}, _, V, _N, _) ->
+    %% Loop is complete, but we haven't used all edges.
+    error;
+outer_edge_loop_1({_,_}, _, _, 0, _) ->
+    %% We have used all possible edges, but somehow the loop
+    %% is not complete. I can't see how this is possible.
+    erlang:error(internal_error);
+outer_edge_loop_1({Edge,Vb}, Es, EndV, N, Acc0) ->
+    Acc = [Edge|Acc0],
+    outer_edge_loop_1(gb_trees:get(Vb, Es), Es, EndV, N-1, Acc).
+
+any_duplicates([{V,_}|_], V) -> true;
+any_duplicates([_], _) -> false;
+any_duplicates([{V,_}|Es], _) -> any_duplicates(Es, V).
+
+%% outer_edge_partition(FaceSet, WingedEdge) -> [[Edge]].
+%%  Partition the outer edges of the FaceSet. Each partion
+%%  of edges form a closed loop with no repeated vertices.
+%%    Outer edges are edges that have one face in FaceSet
+%%  and one outside.
+%%    It is assumed that FaceSet consists of one region returned by
+%%  wings_sel:face_regions/2.
+
+outer_edge_partition(Faces, We) ->
+    F0 = collect_outer_edges(Faces, We),
+    F = gb_trees:from_orddict(wings_util:rel2fam(F0)),
+    partition_edges(F, []).
+
+collect_outer_edges(Faces, We) when is_list(Faces) ->
+    collect_outer_edges_1(Faces, gb_sets:from_list(Faces), We);
+collect_outer_edges(Faces, We) ->
+    collect_outer_edges_1(gb_sets:to_list(Faces), Faces, We).
+
+collect_outer_edges_1(Fs0, Faces0, #we{fs=Ftab}=We) ->
+    case {gb_trees:size(Ftab),gb_sets:size(Faces0)} of
+	{AllSz,FaceSz} when AllSz < 2*FaceSz ->
+	    Fs = ordsets:subtract(gb_trees:keys(Ftab), Fs0),
+	    Faces = gb_sets:from_ordset(Fs),
+	    Coll = collect_outer_edges_a(Faces),
+	    wings_face:fold_faces(Coll, [], Fs, We);
+	{_,_} ->
+	    Coll = collect_outer_edges_b(Faces0),
+	    wings_face:fold_faces(Coll, [], Fs0, We)
+    end.
+
+collect_outer_edges_a(Faces) ->
+    fun(Face, _, Edge, #edge{ve=V,vs=OtherV,lf=Face,rf=Other}, Acc) ->
+	    case gb_sets:is_member(Other, Faces) of
+		false -> [{V,{Edge,OtherV}}|Acc];
+		true -> Acc
+	    end;
+       (Face, _, Edge, #edge{ve=OtherV,vs=V,rf=Face,lf=Other}, Acc) ->
+	    case gb_sets:is_member(Other, Faces) of
+		false -> [{V,{Edge,OtherV}}|Acc];
+		true -> Acc
+	    end
+    end.
+
+collect_outer_edges_b(Faces) ->
+    fun(Face, _, Edge, #edge{vs=V,ve=OtherV,lf=Face,rf=Other}, Acc) ->
+	    case gb_sets:is_member(Other, Faces) of
+		false -> [{V,{Edge,OtherV}}|Acc];
+		true -> Acc
+	    end;
+       (Face, _, Edge, #edge{vs=OtherV,ve=V,rf=Face,lf=Other}, Acc) ->
+	    case gb_sets:is_member(Other, Faces) of
+		false -> [{V,{Edge,OtherV}}|Acc];
+		true -> Acc
+	    end
+    end.
+
+partition_edges(Es0, Acc) ->
+    case gb_trees:is_empty(Es0) of
+	true -> Acc;
+	false ->
+ 	    {Key,Val,Es1} = gb_trees:take_smallest(Es0),
+	    {Cycle,Es} = part_collect_cycle(Key, Val, Es1, []),
+	    partition_edges(Es, [Cycle|Acc])
+    end.
+
+%% part_collect_cycle(Vertex, VertexInfo, EdgeInfo, Acc0) ->
+%%    none | {[Edge],EdgeInfo}
+%%  Collect the cycle starting with Vertex.
+%%
+%%  Note: This function can only return 'none' when called
+%%  recursively.
+
+part_collect_cycle(_, repeated, _, _) ->
+    %% Repeated vertex - we are not allowed to go this way.
+    %% Can only happen if we were called recursively because
+    %% a fork was encountered.
+    none;
+part_collect_cycle(_Va, [{Edge,Vb}], Es0, Acc0) ->
+    %% Basic case. Only one way to go.
+    Acc = [Edge|Acc0],
+    case gb_trees:lookup(Vb, Es0) of
+	none ->
+	    {Acc,Es0};
+	{value,Val} ->
+	    Es = gb_trees:delete(Vb, Es0),
+	    part_collect_cycle(Vb, Val, Es, Acc)
+    end;
+part_collect_cycle(Va, [Val|More], Es0, []) ->
+    %% No cycle started yet and we have multiple choice of
+    %% edges out from this vertex. It doesn't matter which
+    %% edge we follow, so we'll follow the first one.
+    {Cycle,Es} = part_collect_cycle(Va, [Val], Es0, []),
+    {Cycle,gb_trees:insert(Va, More, Es)};
+part_collect_cycle(Va, Edges, Es0, Acc) ->
+    %% We have a partially collected cycle and we have a
+    %% fork (multiple choice of edges). Here we must choose
+    %% an edge that closes the cycle without passing Va
+    %% again (because repeated vertices are not allowed).
+    Es = gb_trees:insert(Va, repeated, Es0),
+    part_fork(Va, Edges, Es, Acc, []).
+    
+part_fork(Va, [Val|More], Es0, Acc, Tried) ->
+    %% Try to complete the cycle by following this edge.
+    case part_collect_cycle(Va, [Val], Es0, Acc) of
+	none ->
+	    %% Failure - try the next edge.
+	    part_fork(Va, More, Es0, Acc, [Val|Tried]);
+	{Cycle,Es} ->
+	    %% Found a cycle. Update the vertex information
+	    %% with all edges remaining.
+	    {Cycle,gb_trees:update(Va, lists:reverse(Tried, More), Es)}
+    end;
+part_fork(_, [], _, _, _) ->
+    %% None of edges were possible. Can only happen if this function
+    %% was called recursively (i.e. if we hit another fork while
+    %% processing a fork).
+    none.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge.erl
new file mode 100644
index 0000000000..3483acb711
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge.erl
@@ -0,0 +1,243 @@
+%%
+%%  wings_edge.erl --
+%%
+%%     This module contains most edge command and edge utility functions.
+%%
+%%  Copyright (c) 2001-2008 Bjorn Gustavsson.
+%%
+%%  See the file "license.terms" for information on usage and redistribution
+%%  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+%%
+%%     $Id: wings_edge.erl,v 1.1 2009/01/25 18:55:33 kostis Exp $
+%%
+
+-module(wings_edge).
+
+-export([dissolve_edges/2]).
+
+-include("wings.hrl").
+
+%%%
+%%% Dissolve.
+%%%
+
+dissolve_edges(Edges0, We0) when is_list(Edges0) ->
+    #we{es=Etab} = We1 = lists:foldl(fun internal_dissolve_edge/2, We0, Edges0),
+    case [E || E <- Edges0, gb_trees:is_defined(E, Etab)] of
+	Edges0 ->
+	    %% No edge was deleted in the last pass. We are done.
+	    We = wings_we:rebuild(We0#we{vc=undefined}),
+	    wings_we:validate_mirror(We);
+	Edges ->
+	    dissolve_edges(Edges, We1)
+    end;
+dissolve_edges(Edges, We) ->
+    dissolve_edges(gb_sets:to_list(Edges), We).
+
+internal_dissolve_edge(Edge, #we{es=Etab}=We0) ->
+    case gb_trees:lookup(Edge, Etab) of
+	none -> We0;
+	{value,#edge{ltpr=Same,ltsu=Same,rtpr=Same,rtsu=Same}} ->
+	    Empty = gb_trees:empty(),
+	    We0#we{vc=Empty,vp=Empty,es=Empty,fs=Empty,he=gb_sets:empty()};
+	{value,#edge{rtpr=Back,ltsu=Back}=Rec} ->
+	    merge_edges(backward, Edge, Rec, We0);
+	{value,#edge{rtsu=Forward,ltpr=Forward}=Rec} ->
+	    merge_edges(forward, Edge, Rec, We0);
+	{value,Rec} ->
+	    try dissolve_edge_1(Edge, Rec, We0) of
+		We -> We
+	    catch
+		throw:hole -> We0
+	    end
+    end.
+
+%% dissolve_edge_1(Edge, EdgeRecord, We) -> We
+%%  Remove an edge and a face. If one of the faces is degenerated
+%%  (only consists of two edges), remove that one. Otherwise, it
+%%  doesn't matter which face we remove.
+dissolve_edge_1(Edge, #edge{lf=Remove,rf=Keep,ltpr=Same,ltsu=Same}=Rec, We) ->
+    dissolve_edge_2(Edge, Remove, Keep, Rec, We);
+dissolve_edge_1(Edge, #edge{lf=Keep,rf=Remove}=Rec, We) ->
+    dissolve_edge_2(Edge, Remove, Keep, Rec, We).
+
+dissolve_edge_2(Edge, FaceRemove, FaceKeep,
+		#edge{ltpr=LP,ltsu=LS,rtpr=RP,rtsu=RS},
+		#we{fs=Ftab0,es=Etab0,he=Htab0}=We0) ->
+    %% First change face for all edges surrounding the face we will remove.
+    Etab1 = wings_face:fold(
+	      fun (_, E, _, IntEtab) when E =:= Edge -> IntEtab;
+		  (_, E, R, IntEtab) ->
+		      case R of
+			  #edge{lf=FaceRemove,rf=FaceKeep} ->
+			      throw(hole);
+			  #edge{rf=FaceRemove,lf=FaceKeep} ->
+			      throw(hole);
+			  #edge{lf=FaceRemove} ->
+			      gb_trees:update(E, R#edge{lf=FaceKeep}, IntEtab);
+			  #edge{rf=FaceRemove} ->
+			      gb_trees:update(E, R#edge{rf=FaceKeep}, IntEtab)
+		      end
+	      end, Etab0, FaceRemove, We0),
+
+    %% Patch all predecessors and successor of the edge we will remove.
+    Etab2 = patch_edge(LP, RS, Edge, Etab1),
+    Etab3 = patch_edge(LS, RP, Edge, Etab2),
+    Etab4 = patch_edge(RP, LS, Edge, Etab3),
+    Etab5 = patch_edge(RS, LP, Edge, Etab4),
+
+    %% Remove the edge.
+    Etab = gb_trees:delete(Edge, Etab5),
+    Htab = hardness(Edge, soft, Htab0),
+
+    %% Remove the face. Patch the face entry for the remaining face.
+    Ftab1 = gb_trees:delete(FaceRemove, Ftab0),
+    We1 = wings_facemat:delete_face(FaceRemove, We0),
+    Ftab = gb_trees:update(FaceKeep, LP, Ftab1),
+
+    %% Return result.
+    We = We1#we{es=Etab,fs=Ftab,vc=undefined,he=Htab},
+    AnEdge = gb_trees:get(FaceKeep, Ftab),
+    case gb_trees:get(AnEdge, Etab) of
+	#edge{lf=FaceKeep,ltpr=Same,ltsu=Same} ->
+	    internal_dissolve_edge(AnEdge, We);
+	#edge{rf=FaceKeep,rtpr=Same,rtsu=Same} ->
+	    internal_dissolve_edge(AnEdge, We);
+	_Other ->
+	    case wings_we:is_face_consistent(FaceKeep, We) of
+		true ->
+		    We;
+		false ->
+		    io:format("Dissolving would cause a badly formed face.")
+	    end
+    end.
+
+%%
+%% We like winged edges, but not winged vertices (a vertex with
+%% only two edges connected to it). We will remove the winged vertex
+%% by joining the two edges connected to it.
+%%
+
+merge_edges(Dir, Edge, Rec, #we{es=Etab}=We) ->
+    {Va,Vb,_,_,_,_,To,To} = half_edge(Dir, Rec),
+    case gb_trees:get(To, Etab) of
+	#edge{vs=Va,ve=Vb} ->
+	    del_2edge_face(Dir, Edge, Rec, To, We);
+	#edge{vs=Vb,ve=Va} ->
+	    del_2edge_face(Dir, Edge, Rec, To, We);
+	_Other ->
+	    merge_1(Dir, Edge, Rec, To, We)
+    end.
+
+merge_1(Dir, Edge, Rec, To, #we{es=Etab0,fs=Ftab0,he=Htab0}=We) ->
+    OtherDir = reverse_dir(Dir),
+    {Vkeep,Vdelete,Lf,Rf,A,B,L,R} = half_edge(OtherDir, Rec),
+    Etab1 = patch_edge(L, To, Edge, Etab0),
+    Etab2 = patch_edge(R, To, Edge, Etab1),
+    Etab3 = patch_half_edge(To, Vkeep, Lf, A, L, Rf, B, R, Vdelete, Etab2),
+    Htab = hardness(Edge, soft, Htab0),
+    Etab = gb_trees:delete(Edge, Etab3),
+    #edge{lf=Lf,rf=Rf} = Rec,
+    Ftab1 = update_face(Lf, To, Edge, Ftab0),
+    Ftab = update_face(Rf, To, Edge, Ftab1),
+    merge_2(To, We#we{es=Etab,fs=Ftab,he=Htab,vc=undefined}).
+
+merge_2(Edge, #we{es=Etab}=We) ->
+    %% If the merged edge is part of a two-edge face, we must
+    %% remove that edge too.
+    case gb_trees:get(Edge, Etab) of
+	#edge{ltpr=Same,ltsu=Same} ->
+	    internal_dissolve_edge(Edge, We);
+	#edge{rtpr=Same,rtsu=Same} ->
+	    internal_dissolve_edge(Edge, We);
+	_Other -> We
+    end.
+
+update_face(Face, Edge, OldEdge, Ftab) ->
+    case gb_trees:get(Face, Ftab) of
+	OldEdge -> gb_trees:update(Face, Edge, Ftab);
+	_Other -> Ftab
+    end.
+
+del_2edge_face(Dir, EdgeA, RecA, EdgeB,
+	       #we{es=Etab0,fs=Ftab0,he=Htab0}=We) ->
+    {_,_,Lf,Rf,_,_,_,_} = half_edge(reverse_dir(Dir), RecA),
+    RecB = gb_trees:get(EdgeB, Etab0),
+    Del = gb_sets:from_list([EdgeA,EdgeB]),
+    EdgeANear = stabile_neighbor(RecA, Del),
+    EdgeBNear = stabile_neighbor(RecB, Del),
+    Etab1 = patch_edge(EdgeANear, EdgeBNear, EdgeA, Etab0),
+    Etab2 = patch_edge(EdgeBNear, EdgeANear, EdgeB, Etab1),
+    Etab3 = gb_trees:delete(EdgeA, Etab2),
+    Etab = gb_trees:delete(EdgeB, Etab3),
+
+    %% Patch hardness table.
+    Htab1 = hardness(EdgeA, soft, Htab0),
+    Htab = hardness(EdgeB, soft, Htab1),
+
+    %% Patch the face table.
+    #edge{lf=Klf,rf=Krf} = gb_trees:get(EdgeANear, Etab),
+    KeepFaces = ordsets:from_list([Klf,Krf]),
+    EdgeAFaces = ordsets:from_list([Lf,Rf]),
+    [DelFace] = ordsets:subtract(EdgeAFaces, KeepFaces),
+    Ftab1 = gb_trees:delete(DelFace, Ftab0),
+    [KeepFace] = ordsets:intersection(KeepFaces, EdgeAFaces),
+    Ftab2 = update_face(KeepFace, EdgeANear, EdgeA, Ftab1),
+    Ftab = update_face(KeepFace, EdgeBNear, EdgeB, Ftab2),
+
+    %% Return result.
+    We#we{vc=undefined,es=Etab,fs=Ftab,he=Htab}.
+
+stabile_neighbor(#edge{ltpr=Ea,ltsu=Eb,rtpr=Ec,rtsu=Ed}, Del) ->
+    [Edge] = lists:foldl(fun(E, A) ->
+				 case gb_sets:is_member(E, Del) of
+				     true -> A;
+				     false -> [E|A]
+			   end
+			 end, [], [Ea,Eb,Ec,Ed]),
+    Edge.
+
+%%%
+%%% Setting hard/soft edges.
+%%%
+
+hardness(Edge, soft, Htab) -> gb_sets:delete_any(Edge, Htab);
+hardness(Edge, hard, Htab) -> gb_sets:add(Edge, Htab).
+
+%%%
+%%% Utilities.
+%%%
+
+reverse_dir(forward) -> backward;
+reverse_dir(backward) -> forward.
+
+half_edge(backward, #edge{vs=Va,ve=Vb,lf=Lf,rf=Rf,a=A,b=B,ltsu=L,rtpr=R}) ->
+    {Va,Vb,Lf,Rf,A,B,L,R};
+half_edge(forward, #edge{ve=Va,vs=Vb,lf=Lf,rf=Rf,a=A,b=B,ltpr=L,rtsu=R}) ->
+    {Va,Vb,Lf,Rf,A,B,L,R}.
+
+patch_half_edge(Edge, V, FaceA, A, Ea, FaceB, B, Eb, OrigV, Etab) ->
+    New = case gb_trees:get(Edge, Etab) of
+	      #edge{vs=OrigV,lf=FaceA,rf=FaceB}=Rec ->
+		  Rec#edge{a=A,vs=V,ltsu=Ea,rtpr=Eb};
+	      #edge{vs=OrigV,lf=FaceB,rf=FaceA}=Rec ->
+		  Rec#edge{a=B,vs=V,ltsu=Eb,rtpr=Ea};
+	      #edge{ve=OrigV,lf=FaceA,rf=FaceB}=Rec ->
+		  Rec#edge{b=B,ve=V,ltpr=Ea,rtsu=Eb};
+	      #edge{ve=OrigV,lf=FaceB,rf=FaceA}=Rec ->
+		  Rec#edge{b=A,ve=V,ltpr=Eb,rtsu=Ea}
+	  end,
+    gb_trees:update(Edge, New, Etab).
+
+patch_edge(Edge, ToEdge, OrigEdge, Etab) ->
+    New = case gb_trees:get(Edge, Etab) of
+	      #edge{ltsu=OrigEdge}=R ->
+		  R#edge{ltsu=ToEdge};
+	      #edge{ltpr=OrigEdge}=R ->
+		  R#edge{ltpr=ToEdge};
+	      #edge{rtsu=OrigEdge}=R ->
+		  R#edge{rtsu=ToEdge};
+	      #edge{rtpr=OrigEdge}=R ->
+		  R#edge{rtpr=ToEdge}
+	  end,
+    gb_trees:update(Edge, New, Etab).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge_cmd.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge_cmd.erl
new file mode 100644
index 0000000000..e478ec245b
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_edge_cmd.erl
@@ -0,0 +1,91 @@
+%%
+%%  wings_edge.erl --
+%%
+%%     This module contains most edge command and edge utility functions.
+%%
+
+-module(wings_edge_cmd).
+
+-export([loop_cut/1]).
+
+-include("wings.hrl").
+
+%%%
+%%% The Loop Cut command.
+%%%
+
+loop_cut(St0) ->
+    {Sel,St} = wings_sel:fold(fun loop_cut/3, {[],St0}, St0),
+    wings_sel:set(body, Sel, St).
+
+loop_cut(Edges, #we{name=Name,id=Id,fs=Ftab}=We0, {Sel,St0}) ->
+    AdjFaces = wings_face:from_edges(Edges, We0),
+    case loop_cut_partition(AdjFaces, Edges, We0, []) of
+	[_] ->
+	    io:format("Edge loop doesn't divide ~p into two parts.", [Name]);
+	Parts0 ->
+	    %% We arbitrarily decide that the largest part of the object
+	    %% will be left unselected and will keep the name of the object.
+
+	    Parts1 = [{gb_trees:size(P),P} || P <- Parts0],
+	    Parts2 = lists:reverse(lists:sort(Parts1)),
+	    [_|Parts] = [gb_sets:to_list(P) || {_,P} <- Parts2],
+
+	    %% Also, this first part will also contain any sub-object
+	    %% that was not reachable from any of the edges. Therefore,
+	    %% we calculate the first part as the complement of the union
+	    %% of all other parts.
+
+	    FirstComplement = ordsets:union(Parts),
+	    First = ordsets:subtract(gb_trees:keys(Ftab), FirstComplement),
+
+	    We = wings_dissolve:complement(First, We0),
+	    Shs = St0#st.shapes,
+	    St = St0#st{shapes=gb_trees:update(Id, We, Shs)},
+	    loop_cut_make_copies(Parts, We0, Sel, St)
+    end.
+
+loop_cut_make_copies([P|Parts], We0, Sel0, #st{onext=Id}=St0) ->
+    Sel = [{Id,gb_sets:singleton(0)}|Sel0],
+    We = wings_dissolve:complement(P, We0),
+    St = wings_shape:insert(We, cut, St0),
+    loop_cut_make_copies(Parts, We0, Sel, St);
+loop_cut_make_copies([], _, Sel, St) -> {Sel,St}.
+
+loop_cut_partition(Faces0, Edges, We, Acc) ->
+    case gb_sets:is_empty(Faces0) of
+	true -> Acc;
+	false ->
+	    {AFace,Faces1} = gb_sets:take_smallest(Faces0),
+	    Reachable = collect_faces(AFace, Edges, We),
+	    Faces = gb_sets:difference(Faces1, Reachable),
+	    loop_cut_partition(Faces, Edges, We, [Reachable|Acc])
+    end.
+
+collect_faces(Face, Edges, We) ->
+    collect_faces(gb_sets:singleton(Face), We, Edges, gb_sets:empty()).
+
+collect_faces(Work0, We, Edges, Acc0) ->
+    case gb_sets:is_empty(Work0) of
+	true -> Acc0;
+	false ->
+	    {Face,Work1} = gb_sets:take_smallest(Work0),
+	    Acc = gb_sets:insert(Face, Acc0),
+	    Work = collect_maybe_add(Work1, Face, Edges, We, Acc),
+	    collect_faces(Work, We, Edges, Acc)
+    end.
+
+collect_maybe_add(Work, Face, Edges, We, Res) ->
+    wings_face:fold(
+      fun(_, Edge, Rec, A) ->
+	      case gb_sets:is_member(Edge, Edges) of
+		  true -> A;
+		  false ->
+		      Of = wings_face:other(Face, Rec),
+		      case gb_sets:is_member(Of, Res) of
+			  true -> A;
+			  false -> gb_sets:add(Of, A)
+		      end
+	      end
+      end, Work, Face, We).
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_face.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_face.erl
new file mode 100644
index 0000000000..487c05aa58
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_face.erl
@@ -0,0 +1,127 @@
+%%
+%%  wings_face.erl --
+%%
+%%     This module contains help routines for faces, such as fold functions
+%%     face iterators.
+%%
+
+-module(wings_face).
+
+-export([delete_bad_faces/2, fold/4, fold_faces/4, from_edges/2,
+	 inner_edges/2, to_edges/2, other/2]).
+
+-include("wings.hrl").
+
+from_edges(Es, #we{es=Etab}) when is_list(Es) ->
+    from_edges_1(Es, Etab, []);
+from_edges(Es, We) ->
+    from_edges(gb_sets:to_list(Es), We).
+
+from_edges_1([E|Es], Etab, Acc) ->
+    #edge{lf=Lf,rf=Rf} = gb_trees:get(E, Etab),
+    from_edges_1(Es, Etab, [Lf,Rf|Acc]);
+from_edges_1([], _, Acc) -> gb_sets:from_list(Acc).
+
+%% other(Face, EdgeRecord) -> OtherFace
+%%  Pick up the "other face" from an edge record.
+other(Face, #edge{lf=Face,rf=Other}) -> Other;
+other(Face, #edge{rf=Face,lf=Other}) -> Other.
+
+%% to_edges(Faces, We) -> [Edge]
+%%  Convert a set or list of faces to a list of edges.
+to_edges(Fs, We) ->
+    ordsets:from_list(to_edges_raw(Fs, We)).
+
+%% inner_edges(Faces, We) -> [Edge]
+%%  Given a set of faces, return all inner edges.
+inner_edges(Faces, We) ->
+    S = to_edges_raw(Faces, We),
+    inner_edges_1(lists:sort(S), []).
+
+inner_edges_1([E,E|T], In) ->
+    inner_edges_1(T, [E|In]);
+inner_edges_1([_|T], In) ->
+    inner_edges_1(T, In);
+inner_edges_1([], In) -> lists:reverse(In).
+
+%% Fold over all edges surrounding a face.
+
+fold(F, Acc, Face, #we{es=Etab,fs=Ftab}) ->
+    Edge = gb_trees:get(Face, Ftab),
+    fold(Edge, Etab, F, Acc, Face, Edge, not_done).
+
+fold(LastEdge, _, _, Acc, _, LastEdge, done) -> Acc;
+fold(Edge, Etab, F, Acc0, Face, LastEdge, _) ->
+    case gb_trees:get(Edge, Etab) of
+	#edge{ve=V,lf=Face,ltsu=NextEdge}=E ->
+	    Acc = F(V, Edge, E, Acc0),
+	    fold(NextEdge, Etab, F, Acc, Face, LastEdge, done);
+	#edge{vs=V,rf=Face,rtsu=NextEdge}=E ->
+	    Acc = F(V, Edge, E, Acc0),
+	    fold(NextEdge, Etab, F, Acc, Face, LastEdge, done)
+    end.
+
+%% Fold over a set of faces.
+
+fold_faces(F, Acc0, [Face|Faces], #we{es=Etab,fs=Ftab}=We) ->
+    Edge = gb_trees:get(Face, Ftab),
+    Acc = fold_faces_1(Edge, Etab, F, Acc0, Face, Edge, not_done),
+    fold_faces(F, Acc, Faces, We);
+fold_faces(_F, Acc, [], _We) -> Acc;
+fold_faces(F, Acc, Faces, We) ->
+    fold_faces(F, Acc, gb_sets:to_list(Faces), We).
+
+fold_faces_1(LastEdge, _, _, Acc, _, LastEdge, done) -> Acc;
+fold_faces_1(Edge, Etab, F, Acc0, Face, LastEdge, _) ->
+    case gb_trees:get(Edge, Etab) of
+	#edge{ve=V,lf=Face,ltsu=NextEdge}=E ->
+	    Acc = F(Face, V, Edge, E, Acc0),
+	    fold_faces_1(NextEdge, Etab, F, Acc, Face, LastEdge, done);
+	#edge{vs=V,rf=Face,rtsu=NextEdge}=E ->
+	    Acc = F(Face, V, Edge, E, Acc0),
+	    fold_faces_1(NextEdge, Etab, F, Acc, Face, LastEdge, done)
+    end.
+
+%% Return an unsorted list of edges for the faces (with duplicates).
+
+to_edges_raw(Faces, #we{es=Etab,fs=Ftab}) when is_list(Faces) ->
+    to_edges_raw(Faces, Ftab, Etab, []);
+to_edges_raw(Faces, We) ->
+    to_edges_raw(gb_sets:to_list(Faces), We).
+
+to_edges_raw([Face|Faces], Ftab, Etab, Acc0) ->
+    Edge = gb_trees:get(Face, Ftab),
+    Acc = to_edges_raw_1(Edge, Etab, Acc0, Face, Edge, not_done),
+    to_edges_raw(Faces, Ftab, Etab, Acc);
+to_edges_raw([], _, _, Acc) -> Acc.
+
+to_edges_raw_1(LastEdge, _, Acc, _, LastEdge, done) -> Acc;
+to_edges_raw_1(Edge, Etab, Acc, Face, LastEdge, _) ->
+    case gb_trees:get(Edge, Etab) of
+	#edge{lf=Face,ltsu=NextEdge} ->
+	    to_edges_raw_1(NextEdge, Etab, [Edge|Acc], Face, LastEdge, done);
+	#edge{rf=Face,rtsu=NextEdge} ->
+	    to_edges_raw_1(NextEdge, Etab, [Edge|Acc], Face, LastEdge, done)
+    end.
+
+delete_bad_faces(Fs, #we{fs=Ftab,es=Etab}=We) when is_list(Fs) ->
+    Es = bad_edges(Fs, Ftab, Etab, []),
+    wings_edge:dissolve_edges(Es, We);
+delete_bad_faces(Fs, We) ->
+    delete_bad_faces(gb_sets:to_list(Fs), We).
+
+bad_edges([F|Fs], Ftab, Etab, Acc) ->
+    case gb_trees:lookup(F, Ftab) of
+	{value,Edge} ->
+	    case gb_trees:get(Edge, Etab) of
+		#edge{ltpr=Same,ltsu=Same,rtpr=Same,rtsu=Same} ->
+		    erlang:error({internal_error,one_edged_face,F});
+		#edge{ltpr=Same,ltsu=Same} ->
+		    bad_edges(Fs, Ftab, Etab, [Edge|Acc]);
+		#edge{rtpr=Same,rtsu=Same} ->
+		    bad_edges(Fs, Ftab, Etab, [Edge|Acc]);
+		_ -> bad_edges(Fs, Ftab, Etab, Acc)
+	    end;
+	none -> bad_edges(Fs, Ftab, Etab, Acc)
+    end;
+bad_edges([], _, _, Acc) -> Acc.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_facemat.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_facemat.erl
new file mode 100644
index 0000000000..6e018e49b5
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_facemat.erl
@@ -0,0 +1,299 @@
+%%
+%%  wings_facemat.erl --
+%%
+%%     This module keeps tracks of the mapping from a face number
+%%     to its material name.
+%%
+%%  Copyright (c) 2001-2005 Bjorn Gustavsson
+%%
+%%  See the file "license.terms" for information on usage and redistribution
+%%  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+%%
+%%     $Id: wings_facemat.erl,v 1.1 2009/01/25 18:55:33 kostis Exp $
+%%
+%%
+%%
+
+-module(wings_facemat).
+-export([all/1,face/2,used_materials/1,mat_faces/2,
+	 assign/2,assign/3,
+	 delete_face/2,delete_faces/2,keep_faces/2,
+	 hide_faces/1,show_faces/1,
+	 renumber/2,gc/1,merge/1]).
+
+-include("wings.hrl").
+-import(lists, [keysearch/3,reverse/1,reverse/2,sort/1]).
+
+%%%
+%%% API functions for retrieving information.
+%%%
+
+%% all(We) -> [{Face,MaterialName}]
+%%  Return materials for all faces as an ordered list.
+all(#we{mat=M}=We) when is_atom(M) ->
+    Vis = visible_faces(We),
+    make_tab(Vis, M);
+all(#we{mat=L}) when is_list(L) ->
+    remove_invisible(L).
+
+%% face(Face, We) -> MaterialName
+%%  Return the material for the face Face.
+face(_, #we{mat=M}) when is_atom(M) -> M;
+face(Face, #we{mat=Tab}) ->
+    {value,{_,Mat}} = keysearch(Face, 1, Tab),
+    Mat.
+
+%% used_materials(We) -> [MaterialName]
+%%  Return an ordered list of all materials used in the We.
+used_materials(#we{mat=M}) when is_atom(M) -> [M];
+used_materials(#we{mat=L}) when is_list(L) ->
+    used_materials_1(L, []).
+
+%% mat_faces([{Face,Info}], We) -> [{Mat,[{Face,Info}]}]
+%%  Group face tab into groups based on material.
+%%  Used for displaying objects.
+mat_faces(Ftab, #we{mat=AtomMat}) when is_atom(AtomMat) ->
+    [{AtomMat,Ftab}];
+mat_faces(Ftab, #we{mat=MatTab}) ->
+    mat_faces_1(Ftab, remove_invisible(MatTab), []).
+
+%%%
+%%% API functions for updating material name mapping.
+%%%
+
+%% assign([{Face,MaterialName}], We) -> We'
+%%  Assign materials.
+assign([], We)  -> We;
+assign([{F,M}|_]=FaceMs, We) when is_atom(M), is_integer(F) ->
+    Tab = ordsets:from_list(FaceMs),
+    assign_face_ms(Tab, We).
+
+%% assign(MaterialName, Faces, We) -> We'
+%%  Assign MaterialName to all faces Faces.
+assign(Mat, _, #we{mat=Mat}=We) when is_atom(Mat) -> We;
+assign(Mat, Fs, We) when is_atom(Mat), is_list(Fs) ->
+    assign_1(Mat, Fs, We);
+assign(Mat, Fs, We) when is_atom(Mat) ->
+    assign_1(Mat, gb_sets:to_list(Fs), We).
+
+%% delete_face(Face, We) -> We'
+%%  Delete the material name mapping for the face Face.
+delete_face(_, #we{mat=AtomMat}=We) when is_atom(AtomMat) -> We;
+delete_face(Face, #we{mat=MatTab0}=We) ->
+    MatTab = orddict:erase(Face, MatTab0),
+    We#we{mat=MatTab}.
+
+%% delete_face(Faces, We) -> We'
+%%  Delete the material name mapping for all faces Faces.
+delete_faces(_, #we{mat=AtomMat}=We) when is_atom(AtomMat) -> We;
+delete_faces(Faces0, #we{mat=MatTab0}=We) when is_list(Faces0) ->
+    Faces = sofs:from_external(Faces0, [face]),
+    MatTab1 = sofs:from_external(MatTab0, [{face,mat}]),
+    MatTab2 = sofs:drestriction(MatTab1, Faces),
+    MatTab = sofs:to_external(MatTab2),
+    We#we{mat=MatTab};
+delete_faces(Faces, We) ->
+    delete_faces(gb_sets:to_list(Faces), We).
+
+%% keep_faces(Faces, We) -> We'
+%%  Delete all the other material names mapping for all faces other Faces.
+keep_faces(_, #we{mat=AtomMat}=We) when is_atom(AtomMat) -> We;
+keep_faces([Face], We) ->
+    Mat = face(Face,We),
+    We#we{mat=[{Face,Mat}]};
+keep_faces(Faces0, #we{mat=MatTab0}=We) when is_list(Faces0) ->
+    Faces = sofs:from_external(Faces0, [face]),
+    MatTab1 = sofs:from_external(MatTab0, [{face,mat}]),
+    MatTab2 = sofs:restriction(MatTab1, Faces),
+    MatTab = sofs:to_external(MatTab2),
+    We#we{mat=MatTab};
+keep_faces(Faces, We) ->
+    keep_faces(gb_sets:to_list(Faces), We).
+
+%% hide_faces(We) -> We'
+%%  Update the material name mapping in the We to reflect
+%%  the newly hidden faces in the face tab.
+hide_faces(#we{mat=M}=We) when is_atom(M) -> We;
+hide_faces(#we{mat=L0,fs=Ftab}=We) ->
+    L = hide_faces_1(L0, Ftab, []),
+    We#we{mat=L}.
+
+%% show_faces(We) -> We'
+%%  Update the material name mapping in the We to reflect
+%%  that all faces are again visible.
+show_faces(#we{mat=M}=We) when is_atom(M) -> We;
+show_faces(#we{mat=L0}=We) ->
+    L = show_faces_1(L0, []),
+    We#we{mat=L}.
+
+%% renumber(MaterialMapping, FaceOldToNew) -> MaterialMapping.
+%%  Renumber face number in material name mapping.
+renumber(Mat, _) when is_atom(Mat) -> Mat;
+renumber(L, Fmap) when is_list(L) -> renumber_1(L, Fmap, []).
+
+%% gc(We) -> We'
+%%  Garbage collect the material mapping information, removing
+%%  the mapping for any face no longer present in the face table.
+gc(#we{mat=Mat}=We) when is_atom(Mat) -> We;
+gc(#we{mat=Tab0,fs=Ftab}=We) ->
+    Fs = sofs:from_external(gb_trees:keys(Ftab), [face]),
+    Tab1 = sofs:from_external(Tab0, [{face,material}]),
+    Tab2 = sofs:restriction(Tab1, Fs),
+    Tab = sofs:to_external(Tab2),
+    We#we{mat=compress(Tab)}.
+
+%% merge([We]) -> [{Face,MaterialName}] | MaterialName.
+%%  Merge materials for several objects.
+merge([#we{mat=M}|Wes]=L) when is_atom(M) ->
+    case merge_all_same(Wes, M) of
+	true -> M;
+	false -> merge_1(L, [])
+    end;
+merge(L) -> merge_1(L, []).
+
+merge_1([#we{mat=M,es=Etab}|T], Acc) when is_atom(M) ->
+    FsM = merge_2(gb_trees:values(Etab), M, []),
+    merge_1(T, [FsM|Acc]);
+merge_1([#we{mat=FsMs}|T], Acc) ->
+    merge_1(T, [FsMs|Acc]);
+merge_1([], Acc) -> lists:merge(Acc).
+
+merge_2([#edge{lf=Lf,rf=Rf}|T], M, Acc) ->
+    merge_2(T, M, [{Lf,M},{Rf,M}|Acc]);
+merge_2([], _, Acc) -> ordsets:from_list(Acc).
+
+merge_all_same([#we{mat=M}|Wes], M) -> merge_all_same(Wes, M);
+merge_all_same([_|_], _) -> false;
+merge_all_same([], _) -> true.
+
+%%%
+%%% Local functions.
+%%%
+
+assign_1(Mat, Fs, #we{fs=Ftab}=We) ->
+    case length(Fs) =:= gb_trees:size(Ftab) of
+	true -> We#we{mat=Mat};
+	false -> assign_2(Mat, Fs, We)
+    end.
+
+assign_2(Mat, Fs0, #we{fs=Ftab,mat=Mat0}=We) when is_atom(Mat0) ->
+    Fs = ordsets:from_list(Fs0),
+    OtherFaces = ordsets:subtract(gb_trees:keys(Ftab), Fs),
+    Tab0 = make_tab(OtherFaces, Mat0),
+    Tab1 = make_tab(Fs, Mat),
+    Tab = lists:merge(Tab0, Tab1),
+    We#we{mat=Tab};
+assign_2(Mat, Fs0, #we{mat=Tab0}=We) when is_list(Tab0) ->
+    Fs = ordsets:from_list(Fs0),
+    Tab1 = make_tab(Fs, Mat),
+    Tab = mat_merge(Tab1, Tab0, []),
+    We#we{mat=Tab}.
+
+assign_face_ms(Tab, #we{fs=Ftab}=We) ->
+    case length(Tab) =:= gb_trees:size(Ftab) of
+	true -> We#we{mat=compress(Tab)};
+	false -> assign_face_ms_1(Tab, We)
+    end.
+
+assign_face_ms_1(Tab1, #we{fs=Ftab,mat=Mat0}=We) when is_atom(Mat0) ->
+    Tab0 = make_tab(gb_trees:keys(Ftab), Mat0),
+    Tab = mat_merge(Tab1, Tab0, []),
+    We#we{mat=Tab};
+assign_face_ms_1(Tab1, #we{mat=Tab0}=We) when is_list(Tab0) ->
+    Tab = mat_merge(Tab1, Tab0, []),
+    We#we{mat=Tab}.
+
+mat_merge([{Fn,_}|_]=Fns, [{Fo,_}=Fold|Fos], Acc) when Fo < Fn ->
+    mat_merge(Fns, Fos, [Fold|Acc]);
+mat_merge([{Fn,_}=Fnew|Fns], [{Fo,_}|_]=Fos, Acc) when Fo > Fn ->
+    mat_merge(Fns, Fos, [Fnew|Acc]);
+mat_merge([Fnew|Fns], [_|Fos], Acc) -> % Equality
+    mat_merge(Fns, Fos, [Fnew|Acc]);
+mat_merge([], Fos, Acc) ->
+    rev_compress(Acc, Fos);
+mat_merge(Fns, [], Acc) ->
+    rev_compress(Acc, Fns).
+    
+make_tab(Fs, M) ->
+    make_tab_1(Fs, M, []).
+
+make_tab_1([F|Fs], M, Acc) ->
+    make_tab_1(Fs, M, [{F,M}|Acc]);
+make_tab_1([], _, Acc) -> reverse(Acc).
+
+
+visible_faces(#we{fs=Ftab}) ->
+    visible_faces_1(gb_trees:keys(Ftab)).
+
+visible_faces_1([F|Fs]) when F < 0 ->
+    visible_faces_1(Fs);
+visible_faces_1(Fs) -> Fs.
+    
+remove_invisible([{F,_}|Fs]) when F < 0 ->
+    remove_invisible(Fs);
+remove_invisible(Fs) -> Fs.
+
+hide_faces_1([{F,_}=P|Fms], Ftab, Acc) when F < 0 ->
+    hide_faces_1(Fms, Ftab, [P|Acc]);
+hide_faces_1([{F,M}=P|Fms], Ftab, Acc) ->
+    case gb_trees:is_defined(F, Ftab) of
+	false -> hide_faces_1(Fms, Ftab, [{-F-1,M}|Acc]);
+	true -> hide_faces_1(Fms, Ftab, [P|Acc])
+    end;
+hide_faces_1([], _, Acc) -> sort(Acc).
+
+show_faces_1([{F,M}|Fms], Acc) when F < 0 ->
+    show_faces_1(Fms, [{-F-1,M}|Acc]);
+show_faces_1(Fs, Acc) -> sort(Acc++Fs).
+
+renumber_1([{F,M}|T], Fmap, Acc) ->
+    renumber_1(T, Fmap, [{gb_trees:get(F, Fmap),M}|Acc]);
+renumber_1([], _, Acc) -> sort(Acc).
+
+%% rev_compress([{Face,Mat}], [{Face,Mat}]) -> [{Face,Mat}] | Mat.
+%%  Reverse just like lists:reverse/2, but if all materials
+%%  turns out to be just the same, return that material.
+rev_compress(L, Acc) ->
+    case same_mat(Acc) of
+	[] -> reverse(L, Acc);
+	M -> rev_compress_1(L, M, Acc)
+    end.
+
+rev_compress_1([{_,M}=E|T], M, Acc) ->
+    %% Same material.
+    rev_compress_1(T, M, [E|Acc]);
+rev_compress_1([_|_]=L, _, Acc) ->
+    %% Another material. Finish by using reverse/2.
+    reverse(L, Acc);
+rev_compress_1([], M, _) ->
+    %% All materials turned out to be the same.
+    M.
+
+%% compress(MaterialTab) -> [{Face,Mat}] | Mat.
+%%  Compress a face mapping if possible.
+compress(M) when is_atom(M) -> M;
+compress(L) when is_list(L) ->
+    case same_mat(L) of
+	[] -> L;
+	M -> M
+    end.
+    
+same_mat([]) -> [];
+same_mat([{_,M}|T]) -> same_mat_1(T, M).
+
+same_mat_1([{_,M}|T], M) -> same_mat_1(T, M);
+same_mat_1([], M) -> M;
+same_mat_1(_, _) -> [].
+
+used_materials_1([{_,M}|T], [M|_]=Acc) ->
+    used_materials_1(T, Acc);
+used_materials_1([{_,M}|T], Acc) ->
+    used_materials_1(T, [M|Acc]);
+used_materials_1([], Acc) ->
+    ordsets:from_list(Acc).
+
+mat_faces_1([{F1,_}|_]=Fs, [{F2,_}|Ms], Acc) when F2 < F1 ->
+    mat_faces_1(Fs, Ms, Acc);
+mat_faces_1([{F,Info}|Fs], [{F,Mat}|Ms], Acc) ->
+    mat_faces_1(Fs, Ms, [{Mat,{F,Info}}|Acc]);
+mat_faces_1([], _, Acc) -> wings_util:rel2fam(Acc).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_intl.hrl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_intl.hrl
new file mode 100644
index 0000000000..ebcb560f27
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_intl.hrl
@@ -0,0 +1,15 @@
+%%
+%%  wings_intl.hrl --
+%%
+%%     Defines for translations
+%%
+%%  Copyright (c) 2001-2005 Bjorn Gustavsson
+%%
+%%  See the file "license.terms" for information on usage and redistribution
+%%  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+%%
+%%     $Id: wings_intl.hrl,v 1.1 2009/01/25 18:55:33 kostis Exp $
+%%
+
+-define(STR(A,B,Str), wings_lang:str({?MODULE,A,B},Str)).
+-define(__(Key,Str), wings_lang:str({?MODULE,Key},Str)).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_io.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_io.erl
new file mode 100644
index 0000000000..39002c675d
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_io.erl
@@ -0,0 +1,37 @@
+%%
+%%  wings_io.erl --
+%%
+%%     This module contains most of the low-level GUI for Wings.
+%%
+
+-module(wings_io).
+
+-export([get_matching_events/1]).
+
+-define(EVENT_QUEUE, wings_io_event_queue).
+
+%%%
+%%% Input.
+%%%
+
+get_matching_events(Filter) ->
+    Eq = get(?EVENT_QUEUE),
+    get_matching_events_1(Filter, Eq, [], []).
+
+get_matching_events_1(Filter, Eq0, Match, NoMatch) ->
+    case queue:out(Eq0) of
+	{{value,Ev},Eq} ->
+	    case Filter(Ev) of
+		false ->
+		    get_matching_events_1(Filter, Eq, Match, [Ev|NoMatch]);
+		true ->
+		    get_matching_events_1(Filter, Eq, [Ev|Match], NoMatch)
+	    end;
+	{empty,{In,Out}} ->
+	    case Match of
+		[] -> [];
+		_ ->
+		    put(?EVENT_QUEUE, {In, lists:reverse(NoMatch, Out)}),
+		    Match
+	    end
+    end.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_sel.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_sel.erl
new file mode 100644
index 0000000000..eef797027e
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_sel.erl
@@ -0,0 +1,68 @@
+%%
+%%  wings_sel.erl --
+%%
+%%     This module implements selection utilities.
+%%
+
+-module(wings_sel).
+
+-export([face_regions/2, fold/3, set/3]).
+
+-include("wings.hrl").
+
+set(Mode, Sel, St) ->
+    St#st{selmode=Mode, sel=lists:sort(Sel), sh=false}.
+
+%%%
+%%% Fold over the selection.
+%%%
+
+fold(F, Acc, #st{sel=Sel,shapes=Shapes}) ->
+    fold_1(F, Acc, Shapes, Sel).
+
+fold_1(F, Acc0, Shapes, [{Id,Items}|T]) ->
+    We = gb_trees:get(Id, Shapes),
+    ?ASSERT(We#we.id =:= Id),
+    fold_1(F, F(Items, We, Acc0), Shapes, T);
+fold_1(_F, Acc, _Shapes, []) -> Acc.
+
+%%%
+%%% Divide the face selection into regions where each face shares at least
+%%% one edge with another face in the same region. Two faces can share a
+%%% vertex without necessarily being in the same region.
+%%%
+
+face_regions(Faces, We) when is_list(Faces) ->
+    face_regions_1(gb_sets:from_list(Faces), We);
+face_regions(Faces, We) ->
+    face_regions_1(Faces, We).
+
+face_regions_1(Faces, We) ->
+    find_face_regions(Faces, We, fun collect_face_fun/5, []).
+
+find_face_regions(Faces0, We, Coll, Acc) ->
+    case gb_sets:is_empty(Faces0) of
+	true -> Acc;
+	false ->
+	    {Face,Faces1} = gb_sets:take_smallest(Faces0),
+	    Ws = [Face],
+	    {Reg,Faces} = collect_face_region(Ws, We, Coll, [], Faces1),
+	    find_face_regions(Faces, We, Coll, [Reg|Acc])
+    end.
+
+collect_face_region([_|_]=Ws0, We, Coll, Reg0, Faces0) ->
+    Reg = Ws0++Reg0,
+    {Ws,Faces} = wings_face:fold_faces(Coll, {[],Faces0}, Ws0, We),
+    collect_face_region(Ws, We, Coll, Reg, Faces);
+collect_face_region([], _, _, Reg, Faces) ->
+    {gb_sets:from_list(Reg),Faces}.
+
+collect_face_fun(Face, _, _, Rec, {Ws,Faces}=A) ->
+    Of = case Rec of
+	     #edge{lf=Face,rf=Of0} -> Of0;
+	     #edge{rf=Face,lf=Of0} -> Of0
+	 end,
+    case gb_sets:is_member(Of, Faces) of
+	true -> {[Of|Ws],gb_sets:delete(Of, Faces)};
+	false -> A
+    end.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_shape.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_shape.erl
new file mode 100644
index 0000000000..0df8ca68eb
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_shape.erl
@@ -0,0 +1,69 @@
+%%
+%%  wings_shape.erl --
+%%
+%%     Utilities for shape records.
+%%
+
+-module(wings_shape).
+
+-export([insert/3]).
+
+-include("wings.hrl").
+
+%%%
+%%% Exported functions.
+%%%
+
+%% new(We, Suffix, St0) -> St.
+%%  Suffix = cut | clone | copy | extract | sep
+%%
+%%  Create a new object based on an old object. The name
+%%  will be created from the old name (with digits and known
+%%  suffixes stripped) with the given Suffix and a number
+%%  appended.
+insert(#we{name=OldName}=We0, Suffix, #st{shapes=Shapes0,onext=Oid}=St) ->
+    Name = new_name(OldName, Suffix, Oid),
+    We = We0#we{id=Oid,name=Name},
+    Shapes = gb_trees:insert(Oid, We, Shapes0),
+    St#st{shapes=Shapes,onext=Oid+1}.
+
+%%%
+%%% Local functions follow.
+%%%
+
+new_name(OldName, Suffix0, Id) ->
+    Suffix = suffix(Suffix0),
+    Base = base(lists:reverse(OldName)),
+    lists:reverse(Base, "_" ++ Suffix ++ integer_to_list(Id)).
+
+%% Note: Filename suffixes are intentionally not translated.
+%% If we are to translate them in the future, base/1 below
+%% must be updated to strip suffixes (both for the current language
+%% and for English).
+
+suffix(cut) -> "cut";
+suffix(clone) -> "clone";
+suffix(copy) -> "copy";
+suffix(extract) -> "extract";
+suffix(mirror) -> "mirror";
+suffix(sep) -> "sep".
+
+%% base_1(ReversedName) -> ReversedBaseName
+%%  Given an object name, strip digits and known suffixes to
+%%  create a base name. Returns the unchanged name if
+%%  no known suffix could be stripped.
+
+base(OldName) ->
+    case base_1(OldName) of
+	error -> OldName;
+	Base -> Base
+    end.
+
+base_1([H|T]) when $0 =< H, H =< $9 -> base_1(T);
+base_1("tuc_"++Base) -> Base;			%"_cut"
+base_1("enolc_"++Base) -> Base;			%"_clone"
+base_1("ypoc_"++Base) -> Base;			%"_copy"
+base_1("tcartxe_"++Base) -> Base;		%"_extract"
+base_1("rorrim_"++Base) -> Base;		%"_mirror"
+base_1("pes_"++Base) -> Base;			%"_sep"
+base_1(_Base) -> error.
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_util.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_util.erl
new file mode 100644
index 0000000000..9572e19955
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_util.erl
@@ -0,0 +1,39 @@
+%%
+%%  wings_util.erl --
+%%
+%%     Various utility functions that not obviously fit somewhere else.
+%%
+
+-module(wings_util).
+
+-export([gb_trees_smallest_key/1, gb_trees_largest_key/1,
+	 gb_trees_map/2, rel2fam/1]).
+
+-include("wings.hrl").
+
+rel2fam(Rel) ->
+    sofs:to_external(sofs:relation_to_family(sofs:relation(Rel))).
+
+%% a definition that does not violate the opaqueness of gb_tree()
+gb_trees_smallest_key(Tree) ->
+    {Key, _V} = gb_trees:smallest(Tree),
+    Key.
+
+%% a definition that violates the opaqueness of gb_tree()
+gb_trees_largest_key({_, Tree}) ->
+    largest_key1(Tree).
+
+largest_key1({Key, _Value, _Smaller, nil}) ->
+    Key;
+largest_key1({_Key, _Value, _Smaller, Larger}) ->
+    largest_key1(Larger).
+
+gb_trees_map(F, {Size,Tree}) ->
+    {Size,gb_trees_map_1(F, Tree)}.
+
+gb_trees_map_1(_, nil) -> nil;
+gb_trees_map_1(F, {K,V,Smaller,Larger}) ->
+    {K,F(K, V),
+     gb_trees_map_1(F, Smaller),
+     gb_trees_map_1(F, Larger)}.
+
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_we.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_we.erl
new file mode 100644
index 0000000000..d782144def
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/wings/wings_we.erl
@@ -0,0 +1,250 @@
+%%
+%%  wings_we.erl --
+%%
+%%     This module contains functions to build and manipulate
+%%     we records (winged-edged records, the central data structure
+%%     in Wings 3D).
+
+-module(wings_we).
+
+-export([rebuild/1, is_consistent/1, is_face_consistent/2, new_id/1,
+	 new_items_as_ordset/3, validate_mirror/1, visible/1, visible_edges/1]).
+ 
+-include("wings.hrl").
+
+%%%
+%%% API.
+%%%
+
+validate_mirror(#we{mirror=none}=We) -> We;
+validate_mirror(#we{fs=Ftab,mirror=Face}=We) ->
+    case gb_trees:is_defined(Face, Ftab) of
+        false -> We#we{mirror=none};
+        true -> We
+    end.
+
+%% rebuild(We) -> We'
+%%  Rebuild any missing 'vc' and 'fs' tables. If there are
+%%  fewer elements in the 'vc' table than in the 'vp' table,
+%%  remove redundant entries in the 'vp' table. Updated id
+%%  bounds.
+rebuild(#we{vc=undefined,fs=undefined,es=Etab0}=We0) ->
+    Etab = gb_trees:to_list(Etab0),
+    Ftab = rebuild_ftab(Etab),
+    VctList = rebuild_vct(Etab),
+    We = We0#we{vc=gb_trees:from_orddict(VctList),fs=Ftab},
+    rebuild_1(VctList, We);
+rebuild(#we{vc=undefined,es=Etab}=We) ->
+    VctList = rebuild_vct(gb_trees:to_list(Etab), []),
+    rebuild_1(VctList, We#we{vc=gb_trees:from_orddict(VctList)});
+rebuild(#we{fs=undefined,es=Etab}=We) ->
+    Ftab = rebuild_ftab(gb_trees:to_list(Etab)),
+    rebuild(We#we{fs=Ftab});
+rebuild(We) -> update_id_bounds(We).
+
+%%% Utilities for allocating IDs.
+
+new_id(#we{next_id=Id}=We) ->
+    {Id,We#we{next_id=Id+1}}.
+
+%%% Returns sets of newly created items.
+
+new_items_as_ordset(vertex, #we{next_id=Wid}, #we{next_id=NewWid,vp=Tab}) ->
+    new_items_as_ordset_1(Tab, Wid, NewWid);
+new_items_as_ordset(edge, #we{next_id=Wid}, #we{next_id=NewWid,es=Tab}) ->
+    new_items_as_ordset_1(Tab, Wid, NewWid);
+new_items_as_ordset(face, #we{next_id=Wid}, #we{next_id=NewWid,fs=Tab}) ->
+    new_items_as_ordset_1(Tab, Wid, NewWid).
+
+any_hidden(#we{fs=Ftab}) ->
+    not gb_trees:is_empty(Ftab) andalso
+	wings_util:gb_trees_smallest_key(Ftab) < 0.
+
+%%%
+%%% Local functions.
+%%%
+
+rebuild_1(VctList, #we{vc=Vct,vp=Vtab0}=We) ->
+    case {gb_trees:size(Vct),gb_trees:size(Vtab0)} of
+	{Same,Same} -> rebuild(We);
+	{Sz1,Sz2} when Sz1 < Sz2 ->
+	    Vtab = vertex_gc_1(VctList, gb_trees:to_list(Vtab0), []),
+	    rebuild(We#we{vp=Vtab})
+    end.
+
+rebuild_vct(Es) ->
+    rebuild_vct(Es, []).
+
+rebuild_vct([{Edge,#edge{vs=Va,ve=Vb}}|Es], Acc0) ->
+    Acc = rebuild_maybe_add(Va, Vb, Edge, Acc0),
+    rebuild_vct(Es, Acc);
+rebuild_vct([], VtoE) ->
+    build_incident_tab(VtoE).
+
+rebuild_ftab(Es) ->
+    rebuild_ftab_1(Es, []).
+
+rebuild_ftab_1([{Edge,#edge{lf=Lf,rf=Rf}}|Es], Acc0) ->
+    Acc = rebuild_maybe_add(Lf, Rf, Edge, Acc0),
+    rebuild_ftab_1(Es, Acc);
+rebuild_ftab_1([], FtoE) ->
+    gb_trees:from_orddict(build_incident_tab(FtoE)).
+
+rebuild_maybe_add(Ka, Kb, E, [_,{Ka,_}|_]=Acc) ->
+    [{Kb,E}|Acc];
+rebuild_maybe_add(Ka, Kb, E, [_,{Kb,_}|_]=Acc) ->
+    [{Ka,E}|Acc];
+rebuild_maybe_add(Ka, Kb, E, [{Ka,_}|_]=Acc) ->
+    [{Kb,E}|Acc];
+rebuild_maybe_add(Ka, Kb, E, [{Kb,_}|_]=Acc) ->
+    [{Ka,E}|Acc];
+rebuild_maybe_add(Ka, Kb, E, Acc) ->
+    [{Ka,E},{Kb,E}|Acc].
+
+vertex_gc_1([{V,_}|Vct], [{V,_}=Vtx|Vpos], Acc) ->
+    vertex_gc_1(Vct, Vpos, [Vtx|Acc]);
+vertex_gc_1([_|_]=Vct, [_|Vpos], Acc) ->
+    vertex_gc_1(Vct, Vpos, Acc);
+vertex_gc_1([], _, Acc) ->
+    gb_trees:from_orddict(lists:reverse(Acc)).
+
+%%%
+%%% Handling of hidden faces.
+%%%
+
+visible(#we{mirror=none,fs=Ftab}) ->
+    visible_2(gb_trees:keys(Ftab));
+visible(#we{mirror=Face,fs=Ftab}) ->
+    visible_2(gb_trees:keys(gb_trees:delete(Face, Ftab))).
+
+visible_2([F|Fs]) when F < 0 -> visible_2(Fs);
+visible_2(Fs) -> Fs.
+
+visible_edges(#we{es=Etab,mirror=Face}=We) ->
+    case any_hidden(We) of
+	false -> gb_trees:keys(Etab);
+	true -> visible_es_1(gb_trees:to_list(Etab), Face, [])
+    end.
+
+visible_es_1([{E,#edge{lf=Lf,rf=Rf}}|Es], Face, Acc) ->
+    if
+	Lf < 0 ->
+	    %% Left face hidden.
+	    if
+		Rf < 0; Rf =:= Face ->
+		    %% Both faces invisible (in some way).
+		    visible_es_1(Es, Face, Acc);
+		true ->
+		    %% Right face is visible.
+		    visible_es_1(Es, Face, [E|Acc])
+	    end;
+	Lf =:= Face, Rf < 0 ->
+	    %% Left face mirror, right face hidden.
+	    visible_es_1(Es, Face, Acc);
+	true ->
+	    %% At least one face visible.
+	    visible_es_1(Es, Face, [E|Acc])
+    end;
+visible_es_1([], _, Acc) -> ordsets:from_list(Acc).
+
+update_id_bounds(#we{vp=Vtab,es=Etab,fs=Ftab}=We) ->
+    case gb_trees:is_empty(Etab) of
+	true -> We#we{next_id=0};
+	false ->
+	    LastId = lists:max([wings_util:gb_trees_largest_key(Vtab),
+				wings_util:gb_trees_largest_key(Etab),
+				wings_util:gb_trees_largest_key(Ftab)]),
+	    We#we{next_id=LastId+1}
+    end.
+
+%% build_incident_tab([{Elem,Edge}]) -> [{Elem,Edge}]
+%%      Elem = Face or Vertex
+%%  Build the table of incident edges for either faces or vertices.
+%%  Returns an ordered list where each Elem is unique.
+
+build_incident_tab(ElemToEdgeRel) ->
+    T = ets:new(?MODULE, [ordered_set]),
+    ets:insert(T, ElemToEdgeRel),
+    R = ets:tab2list(T),
+    ets:delete(T),
+    R.
+
+%%%
+%%% Calculate normals.
+%%%
+
+new_items_as_ordset_1(Tab, Wid, NewWid) when NewWid-Wid < 32 ->
+    new_items_as_ordset_2(Wid, NewWid, Tab, []);
+new_items_as_ordset_1(Tab, Wid, _NewWid) ->
+    [Item || Item <- gb_trees:keys(Tab), Item >= Wid].
+
+new_items_as_ordset_2(Wid, NewWid, Tab, Acc) when Wid < NewWid ->
+    case gb_trees:is_defined(Wid, Tab) of
+	true -> new_items_as_ordset_2(Wid+1, NewWid, Tab, [Wid|Acc]);
+	false -> new_items_as_ordset_2(Wid+1, NewWid, Tab, Acc)
+    end;
+new_items_as_ordset_2(_Wid, _NewWid, _Tab, Acc) -> lists:reverse(Acc).
+
+%%%
+%%% Test the consistency of a #we{}.
+%%%
+
+is_consistent(#we{}=We) ->
+    try
+	validate_vertex_tab(We),
+	validate_faces(We)
+    catch error:_ -> false
+    end.
+
+is_face_consistent(Face, #we{fs=Ftab,es=Etab}) ->
+    Edge = gb_trees:get(Face, Ftab),
+    try validate_face(Face, Edge, Etab)
+    catch error:_ -> false
+    end.
+
+validate_faces(#we{fs=Ftab,es=Etab}) ->
+    validate_faces_1(gb_trees:to_list(Ftab), Etab).
+
+validate_faces_1([{Face,Edge}|Fs], Etab) ->
+    validate_face(Face, Edge, Etab),
+    validate_faces_1(Fs, Etab);
+validate_faces_1([], _) -> true.
+
+validate_face(Face, Edge, Etab) ->
+    Ccw = walk_face_ccw(Edge, Etab, Face, Edge, []),
+    Edge = walk_face_cw(Edge, Etab, Face, Ccw),
+    [V|Vs] = lists:sort(Ccw),
+    validate_face_vertices(Vs, V).
+
+validate_face_vertices([V|_], V) ->
+    erlang:error(repeated_vertex);
+validate_face_vertices([_], _) ->
+    true;
+validate_face_vertices([V|Vs], _) ->
+    validate_face_vertices(Vs, V).
+
+walk_face_ccw(LastEdge, _, _, LastEdge, [_|_]=Acc) -> Acc;
+walk_face_ccw(Edge, Etab, Face, LastEdge, Acc) ->
+    case gb_trees:get(Edge, Etab) of
+	#edge{ve=V,lf=Face,ltpr=Next} ->
+	    walk_face_ccw(Next, Etab, Face, LastEdge, [V|Acc]);
+	#edge{vs=V,rf=Face,rtpr=Next} ->
+	    walk_face_ccw(Next, Etab, Face, LastEdge, [V|Acc])
+    end.
+
+walk_face_cw(Edge, _, _, []) -> Edge;
+walk_face_cw(Edge, Etab, Face, [V|Vs]) ->
+    case gb_trees:get(Edge, Etab) of
+	#edge{vs=V,lf=Face,ltsu=Next} ->
+	    walk_face_cw(Next, Etab, Face, Vs);
+	#edge{ve=V,rf=Face,rtsu=Next} ->
+	    walk_face_cw(Next, Etab, Face, Vs)
+    end.
+
+validate_vertex_tab(#we{es=Etab,vc=Vct}) ->
+    lists:foreach(fun({V,Edge}) ->
+			  case gb_trees:get(Edge, Etab) of
+			      #edge{vs=V} -> ok;
+			      #edge{ve=V} -> ok
+			  end
+		  end, gb_trees:to_list(Vct)).
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis1.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis1.erl
new file mode 100644
index 0000000000..82bcf2edcf
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis1.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis1).
+
+-export([f/0, gen/0]).
+
+-opaque id() :: string().
+
+-spec f() -> integer().
+
+%BIF and Unification(t_unify) issue
+f() -> erlang:length(gen()).
+
+-spec gen() -> id().
+
+gen() -> "Dummy".
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis2.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis2.erl
new file mode 100644
index 0000000000..3a269622fd
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis2.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis2).
+
+-export([get/2]).
+
+-opaque data() :: gb_tree().
+
+-spec get(term(), data()) -> term().
+
+get(Key, Data) ->
+  %%Should unopaque data for remote calls
+  case gb_trees:lookup(Key, Data) of
+    'none' -> 'undefined';
+    {'value', Val} -> Val
+  end. 
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis3.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis3.erl
new file mode 100644
index 0000000000..d92c6766ff
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis3.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis3).
+
+-export([f/0, gen/0]).
+
+-opaque id() :: string().
+
+-spec f() -> char().
+
+%%List pattern matching issue  
+f() -> [H|_T] = gen(), H.
+
+-spec gen() -> id().
+
+gen() -> "Dummy".
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis4.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis4.erl
new file mode 100644
index 0000000000..aa1a4abcb7
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis4.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis4).
+
+-export([f/0, gen/0]).
+
+-opaque id() :: string().
+
+-spec f() -> boolean().
+
+%%Equality test issue  
+f() -> "Dummy" == gen().
+
+-spec gen() -> id().
+
+gen() -> "Dummy".
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis5.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis5.erl
new file mode 100644
index 0000000000..30cebf806a
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis5.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis5).
+
+-export([f/0, gen/0]).
+
+-opaque id() :: string().
+
+-spec f() -> boolean().
+
+%% Equality test issue  
+f() -> "Dummy" == gen().
+
+-spec gen() -> id().
+
+gen() -> "Dummy".
diff --git a/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis6.erl b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis6.erl
new file mode 100644
index 0000000000..6f0779d7d1
--- /dev/null
+++ b/lib/dialyzer/test/opaque_tests_SUITE_data/src/zoltan_kis6.erl
@@ -0,0 +1,14 @@
+-module(zoltan_kis6).
+
+-export([f/0, gen/0]).
+
+-opaque id() :: {integer(),atom()}.
+
+%%-spec f() -> id().
+
+%% Tuple Unification (t_unify) issue
+f() -> {X,Y} = gen().
+
+-spec gen() -> id().
+
+gen() -> {34, leprecon}.