From bb561b0dd58a89489acb93bdf7b5386e7f306835 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 19 Jan 2015 15:10:34 +0100
Subject: 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.
---
 lib/compiler/src/core_lib.erl        |  9 +++++++++
 lib/compiler/test/bs_match_SUITE.erl | 24 ++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

(limited to 'lib')

diff --git a/lib/compiler/src/core_lib.erl b/lib/compiler/src/core_lib.erl
index 2792fd8fa5..0d95971f91 100644
--- a/lib/compiler/src/core_lib.erl
+++ b/lib/compiler/src/core_lib.erl
@@ -212,6 +212,8 @@ vu_pattern(V, #c_tuple{es=Es}, St) ->
     vu_pattern_list(V, Es, St);
 vu_pattern(V, #c_binary{segments=Ss}, St) ->
     vu_pat_seg_list(V, Ss, St);
+vu_pattern(V, #c_map{es=Es}, St) ->
+    vu_map_pairs(V, Es, St);
 vu_pattern(V, #c_alias{var=Var,pat=P}, St0) ->
     case vu_pattern(V, Var, St0) of
 	{true,_}=St1 -> St1;
@@ -234,6 +236,13 @@ vu_pat_seg_list(V, Ss, St) ->
 			end
 		end, St, Ss).
 
+vu_map_pairs(V, [#c_map_pair{val=Pat}|T], St0) ->
+    case vu_pattern(V, Pat, St0) of
+	{true,_}=St -> St;
+	St -> vu_map_pairs(V, T, St)
+    end;
+vu_map_pairs(_, [], St) -> St.
+
 -spec vu_var_list(cerl:var_name(), [cerl:c_var()]) -> boolean().
 
 vu_var_list(V, Vs) ->
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().
 
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