File 1173-syntax_tools-Improve-reverting-lists.patch of Package erlang
From b4bc274accd4e8a24d32509e7b596e44b82d3024 Mon Sep 17 00:00:00 2001
From: Richard Carlsson <carlsson.richard@gmail.com>
Date: Wed, 1 Jan 2025 16:44:22 +0100
Subject: [PATCH 3/4] syntax_tools: Improve reverting lists.
Avoids copying other annotations than location onto the cons nodes.
Propagates correct end information to the nil node if available, and
if not, avoids setting a wrong location for the nil.
---
lib/syntax_tools/src/erl_syntax.erl | 43 ++++++++++++++++++++---------
1 file changed, 30 insertions(+), 13 deletions(-)
diff --git a/lib/syntax_tools/src/erl_syntax.erl b/lib/syntax_tools/src/erl_syntax.erl
index 930e1c6307..bf1acc81d4 100644
--- a/lib/syntax_tools/src/erl_syntax.erl
+++ b/lib/syntax_tools/src/erl_syntax.erl
@@ -2455,22 +2455,39 @@ list(Elements, Tail) when Elements =/= [] ->
revert_list(Node) ->
Pos = get_pos(Node),
Prefix = list_prefix(Node),
- Suffix = case list_suffix(Node) of
+ Suffix =
+ case list_suffix(Node) of
none ->
- LastPos = get_pos(lists:last(Prefix)),
- LastLocation = case erl_anno:end_location(LastPos) of
- undefined -> erl_anno:location(LastPos);
- Location -> Location
- end,
- revert_nil(set_pos(nil(), erl_anno:set_location(LastLocation, Pos)));
+ %% there is no explicit `| Tail]` part, just a plain list
+ %% `[X1,...XN]`, so we must invent a nil node
+ case erl_anno:end_location(Pos) of
+ undefined ->
+ LastPos = get_pos(lists:last(Prefix)),
+ case erl_anno:end_location(LastPos) of
+ undefined ->
+ %% use a zero location rather than a wrong one
+ {nil, erl_anno:new(0)};
+ EndLoc ->
+ %% if the last element has an end location,
+ %% we take that as both start and end
+ {nil, erl_anno:set_end_location(EndLoc, erl_anno:new(EndLoc))}
+ end;
+ EndLoc ->
+ %% if the whole list node has an end location, we
+ %% take that as both start and end of the nil
+ {nil, erl_anno:set_end_location(EndLoc, erl_anno:new(EndLoc))}
+ end;
Suffix1 ->
- Suffix1
+ Suffix1
end,
- lists:foldr(fun (Head, Tail) ->
- HeadPos = get_pos(Head),
- HeadLocation = erl_anno:location(HeadPos),
- {cons, erl_anno:set_location(HeadLocation, Pos), Head, Tail}
- end, Suffix, Prefix).
+ F = fun (Head, Tail) ->
+ %% the nested conses get the location from the list
+ %% elements, but other annotations must not be copied
+ HeadLoc = erl_anno:location(get_pos(Head)),
+ {cons, erl_anno:new(HeadLoc), Head, Tail}
+ end,
+ %% the outermost cons gets the full annotations of the list
+ setelement(2, lists:foldr(F, Suffix, Prefix), Pos).
%% =====================================================================
%% @doc Creates an abstract empty list. The result represents
--
2.43.0
