Crash when using sigils in ignored expressions

[eproxus]

When using sigils in ignored expressions, erlfmt crashes. The following module:

-module(sigil).
-export([f/0]).
% erlfmt:ignore
f() -> ~"foo".

will crash with the following error:

$ rebar3 fmt
rebar3 fmt Internal Error
exit:{badarg,[{erlang,'++',
                      [undefined,"}.\n"],
                      [{error_info,#{module => erl_erts_errors}}]},
              {lists,flatmap_1,2,[{file,"lists.erl"},{line,2116}]},
              {lists,flatmap_1,2,[{file,"lists.erl"},{line,2116}]},
              {erlfmt_scan,last_node_string_trimmed,1,
                           [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt_scan.erl"},
                            {line,200}]},
              {erlfmt,node_string,1,
                      [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt.erl"},
                       {line,597}]},
              {erlfmt,parse_node,6,
                      [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt.erl"},
                       {line,525}]},
              {erlfmt,read_nodes_loop,5,
                      [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt.erl"},
                       {line,499}]},
              {erlfmt,read_file,2,
                      [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt.erl"},
                       {line,408}]}]}
[{erlfmt_cli,parallel_loop,5,
             [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt_cli.erl"},
              {line,509}]},
 {erlfmt_cli,unprotected_with_config,2,
             [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt_cli.erl"},
              {line,148}]},
 {erlfmt_cli,with_parsed,2,
             [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/erlfmt_cli.erl"},
              {line,103}]},
 {rebar3_fmt_prv,do,1,
                 [{file,"/Users/user/Developer/Code/build/default/plugins/erlfmt/src/rebar3_fmt_prv.erl"},
                  {line,43}]},
 {rebar_core,do,2,
             [{file,"/private/var/folders/lg/pnq7gqs91d7fh08tyb2jlwth0000gn/T/rebar3-3.24.0/apps/rebar/src/rebar_core.erl"},
              {line,155}]},
 {rebar3,run_aux,2,
         [{file,"/private/var/folders/lg/pnq7gqs91d7fh08tyb2jlwth0000gn/T/rebar3-3.24.0/apps/rebar/src/rebar3.erl"},
          {line,205}]},
 {rebar3,main,1,
         [{file,"/private/var/folders/lg/pnq7gqs91d7fh08tyb2jlwth0000gn/T/rebar3-3.24.0/apps/rebar/src/rebar3.erl"},
          {line,66}]},
 {escript,run,2,[{file,"escript.erl"},{line,904}]}]

Without the ignore, the formatting works fine.

[michalmuskala]

Thank you, I'll take a look, though this might be only next week