1 files changed, 42 insertions, 2 deletions
diff --git a/lib/compiler/test/map_SUITE.erl b/lib/compiler/test/map_SUITE.erl
index 14d175b92c..36e82c1459 100644
--- a/lib/compiler/test/map_SUITE.erl
+++ b/lib/compiler/test/map_SUITE.erl
@@ -66,7 +66,9 @@
         t_export/1,
 
 	%% errors in 18
-        t_register_corruption/1
+        t_register_corruption/1,
+	t_bad_update/1
+
     ]).
 
 suite() -> [].
@@ -117,7 +119,8 @@ all() ->
         t_export,
 
 	%% errors in 18
-        t_register_corruption
+        t_register_corruption,
+        t_bad_update
     ].
 
 groups() -> [].
@@ -1284,6 +1287,7 @@ t_guard_update(Config) when is_list(Config) ->
     first  = map_guard_update(#{}, #{x=>first}),
     second = map_guard_update(#{y=>old}, #{x=>second,y=>old}),
     third  = map_guard_update(#{x=>old,y=>old}, #{x=>third,y=>old}),
+    bad_map_guard_update(),
     ok.
 
 t_guard_update_large(Config) when is_list(Config) ->
@@ -1350,6 +1354,29 @@ map_guard_update(M1, M2) when M1#{x=>second} =:= M2 -> second;
 map_guard_update(M1, M2) when M1#{x:=third}  =:= M2 -> third;
 map_guard_update(_, _) -> error.
 
+bad_map_guard_update() ->
+    do_bad_map_guard_update(fun burns/1),
+    do_bad_map_guard_update(fun turns/1),
+    ok.
+
+do_bad_map_guard_update(Fun) ->
+    do_bad_map_guard_update_1(Fun, #{}),
+    do_bad_map_guard_update_1(Fun, #{true=>1}),
+    ok.
+
+do_bad_map_guard_update_1(Fun, Value) ->
+    %% Note: The business with the seemingly redundant fun
+    %% disables inlining, which would otherwise change the
+    %% EXIT reason.
+    {'EXIT',{function_clause,_}} = (catch Fun(Value)),
+    ok.
+
+burns(Richmond) when not (Richmond#{true := 0}); [Richmond] ->
+    specification.
+
+turns(Richmond) when not (Richmond#{true => 0}); [Richmond] ->
+    specification.
+
 t_guard_receive(Config) when is_list(Config) ->
     M0  = #{ id => 0 },
     Pid = spawn_link(fun() -> guard_receive_loop() end),
@@ -1922,6 +1949,19 @@ validate_frequency([{T,C}|Fs],Tf) ->
 validate_frequency([], _) -> ok.
 
 
+t_bad_update(_Config) ->
+    {#{0.0:=Id},#{}} = properly(#{}),
+    42 = Id(42),
+    {'EXIT',{{badmap,_},_}} = (catch increase(0)),
+    ok.
+
+properly(Item) ->
+    {Item#{0.0 => fun id/1},Item}.
+
+increase(Allows) ->
+    catch fun() -> Allows end#{[] => +Allows, "warranty" => fun id/1}.
+
+
 %% aux
 
 rand_terms(0) -> [];