From 9dce8fe582cecb586375dafff4b84c11a1b3ac7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 21 Nov 2017 14:39:58 +0100
Subject: Update syntax_tools to support the stacktrace variable

---
 lib/syntax_tools/src/erl_prettypr.erl | 14 ++++++++---
 lib/syntax_tools/src/erl_syntax.erl   | 44 +++++++++++++++++++++++++++++++----
 2 files changed, 50 insertions(+), 8 deletions(-)

(limited to 'lib/syntax_tools')

diff --git a/lib/syntax_tools/src/erl_prettypr.erl b/lib/syntax_tools/src/erl_prettypr.erl
index 40ddd2b22a..f03f326278 100644
--- a/lib/syntax_tools/src/erl_prettypr.erl
+++ b/lib/syntax_tools/src/erl_prettypr.erl
@@ -774,9 +774,17 @@ lay_2(Node, Ctxt) ->
 	class_qualifier ->
 	    Ctxt1 = set_prec(Ctxt, max_prec()),
 	    D1 = lay(erl_syntax:class_qualifier_argument(Node), Ctxt1),
-	    D2 = lay(erl_syntax:class_qualifier_body(Node), Ctxt1),
-	    beside(D1, beside(text(":"), D2));
-
+            D2 = lay(erl_syntax:class_qualifier_body(Node), Ctxt1),
+            Stacktrace = erl_syntax:class_qualifier_stacktrace(Node),
+            case erl_syntax:variable_name(Stacktrace) of
+                '_' ->
+                    beside(D1, beside(text(":"), D2));
+                _ ->
+                    D3 = lay(erl_syntax:class_qualifier_stacktrace(Node),
+                             Ctxt1),
+                    beside(D1, beside(beside(text(":"), D2),
+                                      beside(text(":"), D3)))
+            end;
 	comment ->
 	    D = stack_comment_lines(
 		  erl_syntax:comment_text(Node)),
diff --git a/lib/syntax_tools/src/erl_syntax.erl b/lib/syntax_tools/src/erl_syntax.erl
index 9b2b503762..ed552b73df 100644
--- a/lib/syntax_tools/src/erl_syntax.erl
+++ b/lib/syntax_tools/src/erl_syntax.erl
@@ -342,8 +342,10 @@
 	 typed_record_field_body/1,
          typed_record_field_type/1,
 	 class_qualifier/2,
+	 class_qualifier/3,
 	 class_qualifier_argument/1,
 	 class_qualifier_body/1,
+	 class_qualifier_stacktrace/1,
 	 tuple/1,
 	 tuple_elements/1,
 	 tuple_size/1,
@@ -3884,7 +3886,7 @@ fold_try_clause({clause, Pos, [P], Guard, Body}) ->
 	     class_qualifier ->
 		 {tuple, Pos, [class_qualifier_argument(P),
 			       class_qualifier_body(P),
-			       {var, Pos, '_'}]};
+			       class_qualifier_stacktrace(P)]};
 	     _ ->
 		 {tuple, Pos, [{atom, Pos, throw}, P, {var, Pos, '_'}]}
 	 end,
@@ -3896,9 +3898,9 @@ unfold_try_clauses(Cs) ->
 unfold_try_clause({clause, Pos, [{tuple, _, [{atom, _, throw}, V, _]}],
 		   Guard, Body}) ->
     {clause, Pos, [V], Guard, Body};
-unfold_try_clause({clause, Pos, [{tuple, _, [C, V, _]}],
+unfold_try_clause({clause, Pos, [{tuple, _, [C, V, Stacktrace]}],
 		   Guard, Body}) ->
-    {clause, Pos, [class_qualifier(C, V)], Guard, Body}.
+    {clause, Pos, [class_qualifier(C, V, Stacktrace)], Guard, Body}.
 
 
 %% =====================================================================
@@ -6725,9 +6727,12 @@ try_expr_after(Node) ->
 %%
 %% @see class_qualifier_argument/1
 %% @see class_qualifier_body/1
+%% @see class_qualifier_stacktrace/1
 %% @see try_expr/4
 
--record(class_qualifier, {class :: syntaxTree(), body :: syntaxTree()}).
+-record(class_qualifier, {class :: syntaxTree(),
+                          body :: syntaxTree(),
+                          stacktrace :: syntaxTree()}).
 
 %% type(Node) = class_qualifier
 %% data(Node) = #class_qualifier{class :: Class, body :: Body}
@@ -6737,8 +6742,27 @@ try_expr_after(Node) ->
 -spec class_qualifier(syntaxTree(), syntaxTree()) -> syntaxTree().
 
 class_qualifier(Class, Body) ->
+    Underscore = {var, get_pos(Body), '_'},
     tree(class_qualifier,
-	 #class_qualifier{class = Class, body = Body}).
+	 #class_qualifier{class = Class, body = Body,
+                          stacktrace = Underscore}).
+
+%% =====================================================================
+%% @doc Creates an abstract class qualifier. The result represents
+%% "<code><em>Class</em>:<em>Body</em>:<em>Stacktrace</em></code>".
+%%
+%% @see class_qualifier_argument/1
+%% @see class_qualifier_body/1
+%% @see try_expr/4
+
+-spec class_qualifier(syntaxTree(), syntaxTree(), syntaxTree()) ->
+                             syntaxTree().
+
+class_qualifier(Class, Body, Stacktrace) ->
+    tree(class_qualifier,
+	 #class_qualifier{class = Class,
+                          body = Body,
+                          stacktrace = Stacktrace}).
 
 
 %% =====================================================================
@@ -6763,6 +6787,16 @@ class_qualifier_argument(Node) ->
 class_qualifier_body(Node) ->
     (data(Node))#class_qualifier.body.
 
+%% =====================================================================
+%% @doc Returns the stacktrace subtree of a `class_qualifier' node.
+%%
+%% @see class_qualifier/2
+
+-spec class_qualifier_stacktrace(syntaxTree()) -> syntaxTree().
+
+class_qualifier_stacktrace(Node) ->
+    (data(Node))#class_qualifier.stacktrace.
+
 
 %% =====================================================================
 %% @doc Creates an abstract "implicit fun" expression. If
-- 
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