Merge branch 'hasse/dialyzer/maps_remove/OTP-16055/ERL-1002'

* hasse/dialyzer/maps_remove/OTP-16055/ERL-1002:
  dialyzer: Handle maps:remove/2 better

Author: uabboli

lib/dialyzer/test/map_SUITE_data/results/maps_remove

@@ -0,0 +1,4 @@
+
+maps_remove.erl:22: Function get/2 has no local return
+maps_remove.erl:23: The call maps:get(K::'a',M::#{}) will never return since the success typing arguments are (any(),map())
+maps_remove.erl:7: Function t1/0 has no local return

lib/dialyzer/test/map_SUITE_data/src/maps_remove.erl

@@ -0,0 +1,23 @@
+%% ERL-1002, maps:remove
+
+-module(maps_remove).
+
+-export([t1/0]).
+
+t1() ->
+    A = new(),
+    B = put(a, 1, A),
+    C = remove(a, B),
+    get(a, C).
+
+new() ->
+    maps:new().
+
+put(K, V, M) ->
+    maps:put(K, V, M).
+
+remove(K, M) ->
+    maps:remove(K, M).
+
+get(K, M) ->
+    maps:get(K, M).

lib/hipe/cerl/erl_bif_types.erl

@@ -115,6 +115,7 @@
 		    t_map_is_key/3,
 		    t_map_entries/2,
 		    t_map_put/3,
+		    t_map_remove/3,
 		    t_map_update/3,
 		    t_map_pairwise_merge/4
 		   ]).
@@ -1700,6 +1701,11 @@ type(maps, put, 3, Xs, Opaques) ->
 	 fun ([Key, Value, Map]) ->
 	     t_map_put({Key, Value}, Map, Opaques)
 	 end, Opaques);
+type(maps, remove, 2, Xs, Opaques) ->
+  strict(maps, remove, 2, Xs,
+         fun ([Key, Map]) ->
+             t_map_remove(Key, Map, Opaques)
+         end, Opaques);
 type(maps, size, 1, Xs, Opaques) ->
   strict(maps, size, 1, Xs,
 	 fun ([Map]) ->
@@ -2648,6 +2654,8 @@ arg_types(maps, merge, 2) ->
   [t_map(), t_map()];
 arg_types(maps, put, 3) ->
   [t_any(), t_any(), t_map()];
+arg_types(maps, remove, 2) ->
+  [t_any(), t_map()];
 arg_types(maps, size, 1) ->
   [t_map()];
 arg_types(maps, update, 3) ->

lib/hipe/cerl/erl_types.erl

@@ -154,6 +154,7 @@
 	 t_map_update/2, t_map_update/3,
 	 t_map_pairwise_merge/4,
 	 t_map_put/2, t_map_put/3,
+         t_map_remove/3,
 	 t_matchstate/0,
 	 t_matchstate/2,
 	 t_matchstate_present/1,
@@ -1925,6 +1926,27 @@ map_put({Key, Value}, ?map(Pairs,DefK,DefV), Opaques) ->
       end
   end.
 
+-spec t_map_remove(erl_type(), erl_type(), opaques()) -> erl_type().
+
+t_map_remove(Key, Map, Opaques) ->
+  do_opaque(Map, Opaques, fun(UM) -> map_remove(Key, UM) end).
+
+map_remove(_, ?none) -> ?none;
+map_remove(_, ?unit) -> ?none;
+map_remove(Key, Map) ->
+  %% ?map(lists:keydelete(Key, 1, Pairs), DefK, DefV).
+  case is_singleton_type(Key) of
+    false -> Map;
+    true ->
+      ?map(Pairs,DefK,DefV) = Map,
+      case lists:keyfind(Key, 1, Pairs) of
+        false -> Map;
+        {Key, _, _} ->
+          Pairs1 = lists:keydelete(Key, 1, Pairs),
+          t_map(Pairs1, DefK, DefV)
+      end
+  end.
+
 -spec t_map_update({erl_type(), erl_type()}, erl_type()) -> erl_type().
 
 t_map_update(KV, Map) ->

lib/stdlib/src/maps.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2013-2018. All Rights Reserved.
+%% Copyright Ericsson AB 2013-2019. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -100,6 +100,7 @@ merge(_,_) -> erlang:nif_error(undef).
 put(_,_,_) -> erlang:nif_error(undef).
 
 
+%% Shadowed by erl_bif_types: maps:remove/2
 -spec remove(Key,Map1) -> Map2 when
     Key :: term(),
     Map1 :: map(),