From 7db359b7a1d9b33b25750b29c92c6074ab415c45 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Mon, 10 Sep 2018 12:20:57 +0200
Subject: syntax_tools: Correct unfolding of the stacktrace variable

The bug was introduced in 9ab233.

See also https://bugs.erlang.org/browse/ERL-719.
---
 lib/syntax_tools/src/erl_syntax.erl  |  2 +-
 lib/syntax_tools/test/merl_SUITE.erl | 14 ++++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/syntax_tools/src/erl_syntax.erl b/lib/syntax_tools/src/erl_syntax.erl
index 758aff32fd..331081a07e 100644
--- a/lib/syntax_tools/src/erl_syntax.erl
+++ b/lib/syntax_tools/src/erl_syntax.erl
@@ -3897,7 +3897,7 @@ unfold_try_clauses(Cs) ->
 
 unfold_try_clause({clause, Pos, [{tuple, _, [{atom, _, throw},
                                              V,
-                                             [{var, _, '_'}]]}],
+                                             {var, _, '_'}]}],
 		   Guard, Body}) ->
     {clause, Pos, [V], Guard, Body};
 unfold_try_clause({clause, Pos, [{tuple, _, [C, V, Stacktrace]}],
diff --git a/lib/syntax_tools/test/merl_SUITE.erl b/lib/syntax_tools/test/merl_SUITE.erl
index 52bbd9b3b8..6389ad7738 100644
--- a/lib/syntax_tools/test/merl_SUITE.erl
+++ b/lib/syntax_tools/test/merl_SUITE.erl
@@ -30,13 +30,14 @@
 
 %% Test cases
 -export([merl_smoke_test/1,
-         transform_parse_error_test/1]).
+         transform_parse_error_test/1, otp_15291/1]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() ->
     [merl_smoke_test,
-     transform_parse_error_test].
+     transform_parse_error_test,
+     otp_15291].
 
 groups() -> 
     [].
@@ -101,6 +102,15 @@ transform_parse_error_test(_Config) ->
                      [?Q("merl:qquote(2, \"{\", [{var, V}])")], []))),
     ok.
 
+otp_15291(_Config) ->
+    C0 = merl:quote("() -> ok"),
+    {clause,1,[],[],[{atom,1,ok}]} = C0,
+    C2 = merl:quote("(_,_) -> ok"),
+    {clause,1,[{var,1,'_'},{var,1,'_'}],[],[{atom,1,ok}]} = C2,
+    C1 = merl:quote("(_) -> ok"),
+    {clause,1,[{var,1,'_'}],[],[{atom,1,ok}]} = C1,
+    ok.
+
 %% utilities
 
 f(Ts) when is_list(Ts) ->
-- 
cgit v1.2.3