core_lib: Handle patterns in map values

core_lib:is_var_used/2 would not consider a variable used in the
value of a map pattern such as:

  case Map of
    #{key := <<42:N>>} -> ok
  end

Here the variable 'N' would not be considered used.

It was assumed that there was no need to check map patterns at
all, since maps currently don't support variables in keys.

1 files changed, 22 insertions, 2 deletions

diff --git a/lib/compiler/test/bs_match_SUITE.erl b/lib/compiler/test/bs_match_SUITE.erl
index 149b9bbb8f..10e3451e8f 100644
--- a/lib/compiler/test/bs_match_SUITE.erl
+++ b/lib/compiler/test/bs_match_SUITE.erl
@@ -34,7 +34,7 @@
 	 otp_7188/1,otp_7233/1,otp_7240/1,otp_7498/1,
 	 match_string/1,zero_width/1,bad_size/1,haystack/1,
 	 cover_beam_bool/1,matched_out_size/1,follow_fail_branch/1,
-	 no_partition/1,calling_a_binary/1]).
+	 no_partition/1,calling_a_binary/1,binary_in_map/1]).
 
 -export([coverage_id/1,coverage_external_ignore/2]).
 
@@ -59,7 +59,7 @@ groups() ->
        matching_and_andalso,otp_7188,otp_7233,otp_7240,
        otp_7498,match_string,zero_width,bad_size,haystack,
        cover_beam_bool,matched_out_size,follow_fail_branch,
-       no_partition,calling_a_binary]}].
+       no_partition,calling_a_binary,binary_in_map]}].
 
 
 init_per_suite(Config) ->
@@ -1189,6 +1189,26 @@ call_binary(<<>>, Acc) ->
 call_binary(<<H,T/bits>>, Acc) ->
     T(<<Acc/binary,H>>).
 
+binary_in_map(Config) when is_list(Config) ->
+    ok = match_binary_in_map(#{key => <<42:8>>}),
+    {'EXIT',{{badmatch,#{key := 1}},_}} =
+	(catch match_binary_in_map(#{key => 1})),
+    {'EXIT',{{badmatch,#{key := <<1023:16>>}},_}} =
+	(catch match_binary_in_map(#{key => <<1023:16>>})),
+    {'EXIT',{{badmatch,#{key := <<1:8>>}},_}} =
+	(catch match_binary_in_map(#{key => <<1:8>>})),
+    {'EXIT',{{badmatch,not_a_map},_}} =
+	(catch match_binary_in_map(not_a_map)),
+    ok.
+
+match_binary_in_map(Map) ->
+    case 8 of
+	N ->
+	    #{key := <<42:N>>} = Map,
+	    ok
+    end.
+
+
 check(F, R) ->
     R = F().