Fix evaluation of map updates in the debugger and erl_eval

Reported-by: José Valim

5 files changed, 18 insertions, 7 deletions

diff --git a/lib/debugger/src/dbg_ieval.erl b/lib/debugger/src/dbg_ieval.erl
index 0653ce4c00..77297de0f3 100644
--- a/lib/debugger/src/dbg_ieval.erl
+++ b/lib/debugger/src/dbg_ieval.erl
@@ -665,11 +665,11 @@ expr({map,Line,E0,Fs0}, Bs0, Ieval0) ->
     {value,E,Bs1} = expr(E0, Bs0, Ieval),
     case E of
         #{} ->
-            {Fs,Bs2} = eval_map_fields(Fs0, Bs1, Ieval),
+            {Fs,Bs2} = eval_map_fields(Fs0, Bs0, Ieval),
             Value = lists:foldl(fun ({map_assoc,K,V}, Mi) -> maps:put(K,V,Mi);
                                     ({map_exact,K,V}, Mi) -> maps:update(K,V,Mi)
                                 end, E, Fs),
-            {value,Value,Bs2};
+            {value,Value,merge_bindings(Bs2, Bs1, Ieval)};
         _ ->
             exception(error, {badarg,E}, Bs1, Ieval)
     end;
diff --git a/lib/debugger/test/int_eval_SUITE.erl b/lib/debugger/test/int_eval_SUITE.erl
index ecbd68ab40..9d7ef238e3 100644
--- a/lib/debugger/test/int_eval_SUITE.erl
+++ b/lib/debugger/test/int_eval_SUITE.erl
@@ -294,6 +294,7 @@ stacktrace(Config) when is_list(Config) ->
 maps(Config) when is_list(Config) ->
     Fun = fun () -> ?IM:empty_map_update([camembert]) end,
     {'EXIT',{{badarg,[camembert]},_}} = spawn_eval(Fun),
+    [#{hello := 0, price := 0}] = spawn_eval(fun () -> ?IM:update_in_fun() end),
     ok.
 
 
diff --git a/lib/debugger/test/int_eval_SUITE_data/my_int_eval_module.erl b/lib/debugger/test/int_eval_SUITE_data/my_int_eval_module.erl
index e047a33d8c..7f55360f48 100644
--- a/lib/debugger/test/int_eval_SUITE_data/my_int_eval_module.erl
+++ b/lib/debugger/test/int_eval_SUITE_data/my_int_eval_module.erl
@@ -29,7 +29,7 @@
 -export([more_catch/1,more_nocatch/1,exit_me/0]).
 -export([f/1, f_try/1, f_catch/1]).
 -export([otp_5837/1, otp_8310/0]).
--export([empty_map_update/1]).
+-export([empty_map_update/1, update_in_fun/0]).
 
 %% Internal exports.
 -export([echo/2,my_subtract/2,catch_a_ball/0,throw_a_ball/0]).
@@ -244,3 +244,6 @@ otp_8310() ->
     ok.
 
 empty_map_update(Map) -> Map#{}.
+
+update_in_fun() ->
+    lists:map(fun (X) -> X#{price := 0} end, [#{hello => 0, price => nil}]).
diff --git a/lib/stdlib/src/erl_eval.erl b/lib/stdlib/src/erl_eval.erl
index acde3ad5d6..3cfedfee97 100644
--- a/lib/stdlib/src/erl_eval.erl
+++ b/lib/stdlib/src/erl_eval.erl
@@ -244,17 +244,17 @@ expr({record,_,_,Name,_}, _Bs, _Lf, _Ef, _RBs) ->
     erlang:raise(error, {undef_record,Name}, stacktrace());
 
 %% map
-expr({map,_, Binding,Es}, Bs0, Lf, Ef, RBs) ->
-    {value, Map0, Bs1} = expr(Binding, Bs0, Lf, Ef, RBs),
+expr({map,_,Binding,Es}, Bs0, Lf, Ef, RBs) ->
+    {value, Map0, Bs1} = expr(Binding, Bs0, Lf, Ef, none),
     case Map0 of
         #{} ->
-            {Vs,Bs} = eval_map_fields(Es, Bs1, Lf, Ef),
+            {Vs,Bs2} = eval_map_fields(Es, Bs0, Lf, Ef),
             Map1 = lists:foldl(fun ({map_assoc,K,V}, Mi) ->
                                        maps:put(K, V, Mi);
                                    ({map_exact,K,V}, Mi) ->
                                        maps:update(K, V, Mi)
                                end, Map0, Vs),
-            ret_expr(Map1, Bs, RBs);
+            ret_expr(Map1, merge_bindings(Bs2, Bs1), RBs);
         _ ->
             erlang:raise(error, {badarg,Map0}, stacktrace())
     end;
diff --git a/lib/stdlib/test/erl_eval_SUITE.erl b/lib/stdlib/test/erl_eval_SUITE.erl
index b91d14b5b8..b55324161b 100644
--- a/lib/stdlib/test/erl_eval_SUITE.erl
+++ b/lib/stdlib/test/erl_eval_SUITE.erl
@@ -1451,6 +1451,13 @@ eep43(Config) when is_list(Config) ->
           "    {Map#{a := B},Map#{a => c},Map#{d => e}} "
           "end.",
           {#{a => b},#{a => c},#{a => b,d => e}}),
+    check(fun () ->
+                  lists:map(fun (X) -> X#{price := 0} end,
+                            [#{hello => 0, price => nil}])
+          end,
+          "lists:map(fun (X) -> X#{price := 0} end,
+                     [#{hello => 0, price => nil}]).",
+          [#{hello => 0, price => 0}]),
     error_check("[camembert]#{}.", {badarg,[camembert]}),
     error_check("#{} = 1.", {badmatch,1}),
     ok.