erl_types: Fix crash merging maps with opaque keys

Opaque keys in maps broke an assumption in
erl_types:mapmerge_otherv/3 (that the infinimum of a singleton type and
some other type would either be none() or that same singleton type),
causing a case_clause crash.

4 files changed, 189 insertions, 2 deletions

diff --git a/lib/dialyzer/test/map_SUITE_data/results/opaque_key b/lib/dialyzer/test/map_SUITE_data/results/opaque_key
new file mode 100644
index 0000000000..df8c825b18
--- /dev/null
+++ b/lib/dialyzer/test/map_SUITE_data/results/opaque_key
@@ -0,0 +1,21 @@
+
+opaque_key_adt.erl:32: Invalid type specification for function opaque_key_adt:s1/0. The success typing is () -> #{3:='a'}
+opaque_key_adt.erl:35: Invalid type specification for function opaque_key_adt:s2/0. The success typing is () -> #{3:='a'}
+opaque_key_adt.erl:41: Invalid type specification for function opaque_key_adt:s4/0. The success typing is () -> #{1:='a'}
+opaque_key_adt.erl:53: Invalid type specification for function opaque_key_adt:sm1/0. The success typing is () -> #{1:=2, 3:='a'}
+opaque_key_adt.erl:56: Invalid type specification for function opaque_key_adt:smt1/0. The success typing is () -> #{3:='a'}
+opaque_key_adt.erl:59: Invalid type specification for function opaque_key_adt:smt2/0. The success typing is () -> #{1:='a'}
+opaque_key_use.erl:13: The test opaque_key_use:t() =:= opaque_key_use:t(integer()) can never evaluate to 'true'
+opaque_key_use.erl:24: Attempt to test for equality between a term of type opaque_key_adt:t(integer()) and a term of opaque type opaque_key_adt:t()
+opaque_key_use.erl:26: Function adt_tt2/0 has no local return
+opaque_key_use.erl:37: Function adt_mm1/0 has no local return
+opaque_key_use.erl:40: The attempt to match a term of type opaque_key_adt:m() against the pattern #{A:=R} breaks the opaqueness of the term
+opaque_key_use.erl:48: Function adt_mu1/0 has no local return
+opaque_key_use.erl:51: Guard test is_map(M::opaque_key_adt:m()) breaks the opaqueness of its argument
+opaque_key_use.erl:53: Function adt_mu2/0 has no local return
+opaque_key_use.erl:56: Guard test is_map(M::opaque_key_adt:m()) breaks the opaqueness of its argument
+opaque_key_use.erl:58: Function adt_mu3/0 has no local return
+opaque_key_use.erl:60: Guard test is_map(M::opaque_key_adt:m()) breaks the opaqueness of its argument
+opaque_key_use.erl:62: Function adt_mtm1/0 has no local return
+opaque_key_use.erl:73: Function adt_mtu1/0 has no local return
+opaque_key_use.erl:78: Function adt_mtu2/0 has no local return
diff --git a/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_adt.erl b/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_adt.erl
new file mode 100644
index 0000000000..53ec09b062
--- /dev/null
+++ b/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_adt.erl
@@ -0,0 +1,69 @@
+-module(opaque_key_adt).
+
+-compile(export_all).
+
+-export_type([t/0, t/1, m/0, s/1, sm/1]).
+
+-opaque t()    :: #{atom() => integer()}.
+-opaque t(A)   :: #{A => integer()}.
+
+-opaque m()    :: #{t() => integer()}.
+-type   mt()   :: #{t() => integer()}.
+
+-opaque s(K)   :: #{K => integer(), integer() => atom()}.
+-opaque sm(K)  :: #{K := integer(), integer() := atom()}.
+-type   smt(K) :: #{K := integer(), integer() := atom()}.
+
+-spec t0() -> t().
+t0() -> #{}.
+
+-spec t1() -> t(integer()).
+t1() -> #{3 => 1}.
+
+-spec m0() -> m().
+m0() -> #{#{} => 3}.
+
+-spec mt0() -> mt().
+mt0() -> #{#{} => 3}.
+
+-spec s0() -> s(atom()).
+s0() -> #{}.
+
+-spec s1() -> s(atom()). %% No contract breakage (bad warning)
+s1() -> #{3 => a}.
+
+-spec s2() -> s(atom() | 3).
+s2() -> #{3 => a}. %% Contract breakage
+
+-spec s3() -> s(atom() | 3).
+s3() -> #{3 => 5, a => 6, 7 => 8}.
+
+-spec s4() -> s(integer()).
+s4() -> #{1 => a}. %% Actual contract breakage (good warning)
+
+-spec s5() -> s(1).
+s5() -> #{2 => 3}. %% Contract breakage (not found)
+
+-spec s6() -> s(1).
+s6() -> #{1 => 3}.
+
+-spec s7() -> s(integer()).
+s7() -> #{1 => 3}.
+
+-spec sm1() -> sm(1). %% No contract breakage (bad warning)
+sm1() -> #{1 => 2, 3 => a}.
+
+-spec smt1() -> smt(1).
+smt1() -> #{3 => a}. %% Contract breakage
+
+-spec smt2() -> smt(1).
+smt2() -> #{1 => a}.  %% Contract breakage
+
+-spec smt3() -> smt(q).
+smt3() -> #{q => 1}. %% Slight contract breakage (probably requires better map type)
+
+-spec smt4() -> smt(q).
+smt4() -> #{q => 2, 3 => a}.
+
+-spec smt5() -> smt(1).
+smt5() -> #{1 => 2, 3 => a}.
diff --git a/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_use.erl b/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_use.erl
new file mode 100644
index 0000000000..917413fdd2
--- /dev/null
+++ b/lib/dialyzer/test/map_SUITE_data/src/opaque_key/opaque_key_use.erl
@@ -0,0 +1,97 @@
+-module(opaque_key_use).
+
+-compile(export_all).
+
+-export_type([t/0, t/1]).
+
+-opaque t()  :: #{atom() => integer()}.
+-opaque t(A) :: #{A => integer()}.
+
+tt1() ->
+    A = t0(),
+    B = t1(),
+    A =:= B. % never 'true'
+
+-spec t0() -> t().
+t0() -> #{a => 1}.
+
+-spec t1() -> t(integer()).
+t1() -> #{3 => 1}.
+
+adt_tt1() ->
+    A = adt_t0(),
+    B = adt_t1(),
+    A =:= B. % opaque attempt
+
+adt_tt2() ->
+    A = adt_t0(),
+    B = adt_t1(),
+    #{A => 1 % opaque key
+     ,B => 2 % opaque key
+     }.
+
+adt_tt3() ->
+    A = map_adt:t0(),
+    #{A => 1}. % opaque key
+
+adt_mm1() ->
+    A = adt_t0(),
+    M = adt_m0(),
+    #{A := R} = M, % opaque attempt
+    R.
+
+%% adt_ms1() ->
+%%     A = adt_t0(),
+%%     M = adt_m0(),
+%%     M#{A}. % opaque arg
+
+adt_mu1() ->
+    A = adt_t0(),
+    M = adt_m0(),
+    M#{A := 4}. % opaque arg
+
+adt_mu2() ->
+    A = adt_t0(),
+    M = adt_m0(),
+    M#{A => 4}. % opaque arg
+
+adt_mu3() ->
+    M = adt_m0(),
+    M#{}. % opaque arg
+
+adt_mtm1() ->
+    A = adt_t0(),
+    M = adt_mt0(),
+    #{A := R} = M, % opaque key
+    R.
+
+%% adt_mts1() ->
+%%     A = adt_t0(),
+%%     M = adt_mt0(),
+%%     M#{A}. % opaque key
+
+adt_mtu1() ->
+    A = adt_t0(),
+    M = adt_mt0(),
+    M#{A := 4}. % opaque key
+
+adt_mtu2() ->
+    A = adt_t0(),
+    M = adt_mt0(),
+    M#{A => 4}. % opaque key
+
+adt_mtu3() ->
+    M = adt_mt0(),
+    M#{}. % Ok to not warn
+
+adt_t0() ->
+    opaque_key_adt:t0().
+
+adt_t1() ->
+    opaque_key_adt:t1().
+
+adt_m0() ->
+    opaque_key_adt:m0().
+
+adt_mt0() ->
+    opaque_key_adt:mt0().
diff --git a/lib/hipe/cerl/erl_types.erl b/lib/hipe/cerl/erl_types.erl
index ea69e54c83..8057e37d0c 100644
--- a/lib/hipe/cerl/erl_types.erl
+++ b/lib/hipe/cerl/erl_types.erl
@@ -1821,8 +1821,8 @@ map_pairwise_merge_foldr(F, AccIn, As0, ADefK, ADefV, Bs0, BDefK, BDefV) ->
 %% cases, at the cost of the creation of more tuples:
 mapmerge_otherv(K, ODefK, ODefV) ->
   case t_inf(K, ODefK) of
-    ?none -> ?none;
-    K     -> ODefV
+    ?none      -> ?none;
+    _KOrOpaque -> ODefV
   end.
 
 -spec t_map_put({erl_type(), erl_type()}, erl_type()) -> erl_type().