From 6e422d499fe079b87cfa226491b11016f36b9a31 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Tue, 19 Aug 2014 16:16:08 +0200
Subject: dialyzer: fix a -Wunderspecs bug

Sometimes bogus warnings were generated for parametrized types.

Thanks to Krzesimir Sarnecki for pointing the bug out.

Also corrected warnings where the structure of opaque types were
exposed (thanks to Kostis for pointing the bug out).
---
 lib/dialyzer/src/dialyzer_contracts.erl            |  7 ++--
 .../test/underspecs_SUITE_data/results/arr         |  4 +++
 .../test/underspecs_SUITE_data/src/arr.erl         | 41 ++++++++++++++++++++++
 3 files changed, 48 insertions(+), 4 deletions(-)
 create mode 100644 lib/dialyzer/test/underspecs_SUITE_data/results/arr
 create mode 100644 lib/dialyzer/test/underspecs_SUITE_data/src/arr.erl

diff --git a/lib/dialyzer/src/dialyzer_contracts.erl b/lib/dialyzer/src/dialyzer_contracts.erl
index 1d2dfc7b2d..f27fc1a842 100644
--- a/lib/dialyzer/src/dialyzer_contracts.erl
+++ b/lib/dialyzer/src/dialyzer_contracts.erl
@@ -20,8 +20,6 @@
 
 -module(dialyzer_contracts).
 
--compile(export_all).
-
 -export([check_contract/2,
 	 check_contracts/4,
 	 contracts_without_fun/3,
@@ -686,7 +684,7 @@ picky_contract_check(CSig0, Sig0, MFA, FileLine, Contract, RecDict, Acc) ->
 	true -> Acc;
 	false ->
 	  case extra_contract_warning(MFA, FileLine, Contract,
-				      CSig, Sig, RecDict) of
+				      CSig0, Sig0, RecDict) of
 	    no_warning -> Acc;
 	    {warning, Warning} -> [Warning|Acc]
 	  end
@@ -752,7 +750,8 @@ is_remote_types_related(Contract, CSig, Sig, RecDict) ->
 
 t_from_forms_without_remote([{FType, []}], RecDict) ->
   Type0 = erl_types:t_from_form(FType, RecDict),
-  {ok, erl_types:subst_all_remote(Type0, erl_types:t_none())};
+  Type1 = erl_types:subst_all_remote(Type0, erl_types:t_none()),
+  {ok, erl_types:subst_all_vars_to_any(Type1)};
 t_from_forms_without_remote([{_FType, _Constrs}], _RecDict) ->
   %% 'When' constraints
   unsupported;
diff --git a/lib/dialyzer/test/underspecs_SUITE_data/results/arr b/lib/dialyzer/test/underspecs_SUITE_data/results/arr
new file mode 100644
index 0000000000..9497d12eec
--- /dev/null
+++ b/lib/dialyzer/test/underspecs_SUITE_data/results/arr
@@ -0,0 +1,4 @@
+
+arr.erl:14: Type specification arr:test2(array:array(T),non_neg_integer(),T) -> array:array(T) is a supertype of the success typing: arr:test2(array:array(_),pos_integer(),_) -> array:array(_)
+arr.erl:24: Type specification arr:test4(array:array(T),non_neg_integer(),_) -> array:array(T) is a supertype of the success typing: arr:test4(array:array(_),pos_integer(),_) -> array:array(_)
+arr.erl:29: Type specification arr:test5(array:array(T),non_neg_integer(),T) -> array:array(T) is a supertype of the success typing: arr:test5(array:array(_),non_neg_integer(),integer()) -> array:array(_)
diff --git a/lib/dialyzer/test/underspecs_SUITE_data/src/arr.erl b/lib/dialyzer/test/underspecs_SUITE_data/src/arr.erl
new file mode 100644
index 0000000000..3b265ccec2
--- /dev/null
+++ b/lib/dialyzer/test/underspecs_SUITE_data/src/arr.erl
@@ -0,0 +1,41 @@
+-module(arr).
+
+%% http://erlang.org/pipermail/erlang-questions/2014-August/080445.html
+
+-define(A, array).
+
+-export([test/3, test2/3, test3/3, test4/3, test5/3, test6/3]).
+
+-spec test(?A:array(T), non_neg_integer(), T) -> ?A:array(T).
+
+test(Array, N, Value) ->
+    ?A:set(N, Value, Array).
+
+-spec test2(?A:array(T), non_neg_integer(), T) -> ?A:array(T).
+
+test2(Array, N, Value) when N > 0 ->
+    ?A:set(N, Value, Array).
+
+-spec test3(?A:array(T), non_neg_integer(), _) -> ?A:array(T).
+
+test3(Array, N, Value) ->
+    ?A:set(N, Value, Array).
+
+-spec test4(?A:array(T), non_neg_integer(), _) -> ?A:array(T).
+
+test4(Array, N, Value) when N > 0 ->
+    ?A:set(N, Value, Array).
+
+-spec test5(?A:array(T), non_neg_integer(), T) -> ?A:array(T).
+
+test5(Array, N, Value) when is_integer(Value) ->
+    ?A:set(N, Value, Array).
+
+%% One would ideally want a warning also for test6(), but the current
+%% analysis of parametrized opaque types is not strong enough to
+%% discover this.
+-spec test6(?A:array(integer()), non_neg_integer(), integer()) ->
+                   ?A:array(any()).
+
+test6(Array, N, Value) ->
+     ?A:set(N, Value, Array).
-- 
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