dialyzer: Improve check of unknown types

The implementation of OTP-14218 (commit 6d3b38a) has a weakness: only
a very limited part of the type form is checked. This is now fixed:
types not used by specs are checked equally well as types used by
specs.

The new function erl_types:t_from_form_check_remote() checks usage of
remote types. It does not expand used local types, and has (almost) no
limits on depth and size.

1 files changed, 31 insertions, 1 deletions

diff --git a/lib/dialyzer/test/options2_SUITE_data/src/unused_unknown_type.erl b/lib/dialyzer/test/options2_SUITE_data/src/unused_unknown_type.erl
index 90df7d528a..e6f9d2392c 100644
--- a/lib/dialyzer/test/options2_SUITE_data/src/unused_unknown_type.erl
+++ b/lib/dialyzer/test/options2_SUITE_data/src/unused_unknown_type.erl
@@ -1,10 +1,40 @@
 -module(unused_unknown_type).
 
+-export([t/0]).
+
 -export_type([unused/0]).
 
+-export_type([wide/0, deep/0]).
+-export_type([owide/0, odeep/0]).
+-export_type([arg/0, rargs1/0, rargs2/0]).
+
 -type unused() :: unknown:type1().
 
--record(unused_rec, {a :: unknown:type2()}).
+-record(unused_rec,
+        {a :: unknown:type2(),
+         b :: {{{{{{{{{{{{{{{{{{{{rfoo:rbar()}}}}}}}}}}}}}}}}}}}}}).
 
 -record(rec, {a}).
 -type unused_rec() :: #rec{a :: unknown:type3()}.
+
+-type wide() :: {a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,xxx:y()}.
+-type owide() :: {a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,owww:y()}.
+
+%% Deeper than the hardcoded limit in erl_types.erl of 16.
+-type deep() :: {{{{{{{{{{{{{{{{{{{{foo:bar()}}}}}}}}}}}}}}}}}}}}.
+-type odeep() :: {{{{{{{{{{{{{{{{{{{{ofoo:obar()}}}}}}}}}}}}}}}}}}}}.
+
+-type arg1(A) :: [A].
+-type arg() :: arg1({a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,yyy:x()}).
+
+%% No warning about www:x/0 because parameters are currently not
+%% handled if the parameterized type cannot be found.
+-type rargs1() :: zzz:arg({a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,www:x()}).
+
+-type rargs2() :: dict:dict({a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,zzz:x()},
+                            any()).
+
+%% No warning. The check is commented out as it takes too long.
+-spec t() -> 'a' | {{{{{{{{{{{{{{{{{{{{sfoo:sbar()}}}}}}}}}}}}}}}}}}}}.
+t() ->
+    a.