diff --git a/crates/elp/src/bin/lint_cli.rs b/crates/elp/src/bin/lint_cli.rs
index acc903517b..8f2ef1093c 100644
--- a/crates/elp/src/bin/lint_cli.rs
+++ b/crates/elp/src/bin/lint_cli.rs
@@ -172,7 +172,7 @@ pub fn do_codemod(cli: &mut dyn Cli, loaded: &mut LoadResult, args: &Lint) -> Re
             ..
         } => {
             let cfg_from_file = if *read_config {
-                config_file(project)
+                config_file(project)?
             } else {
                 LintConfig::default()
             };
@@ -352,7 +352,7 @@ pub fn do_codemod(cli: &mut dyn Cli, loaded: &mut LoadResult, args: &Lint) -> Re
 
 const LINT_CONFIG_FILE: &str = ".elp_lint.toml";
 
-fn config_file(project: &PathBuf) -> LintConfig {
+fn config_file(project: &PathBuf) -> Result<LintConfig> {
     let mut potential_path = Some(project.as_path());
     while let Some(path) = potential_path {
         let file_path = path.join(LINT_CONFIG_FILE);
@@ -361,15 +361,16 @@ fn config_file(project: &PathBuf) -> LintConfig {
             potential_path = path.parent();
             continue;
         } else {
-            if let Ok(content) = fs::read_to_string(file_path) {
-                if let Ok(config) = toml::from_str::<LintConfig>(&content) {
-                    return config;
+            if let Ok(content) = fs::read_to_string(file_path.clone()) {
+                match toml::from_str::<LintConfig>(&content) {
+                    Ok(config) => return Ok(config),
+                    Err(err) => bail!("failed to read {:?}:{err}", file_path),
                 }
             }
         }
         break;
     }
-    LintConfig::default()
+    Ok(LintConfig::default())
 }
 
 fn print_diagnostic(
diff --git a/crates/elp/src/bin/main.rs b/crates/elp/src/bin/main.rs
index 47a4afec31..109dcc6b9f 100644
--- a/crates/elp/src/bin/main.rs
+++ b/crates/elp/src/bin/main.rs
@@ -140,7 +140,9 @@ mod tests {
 
     use bpaf::Args;
     use elp::cli::Fake;
+    use expect_test::expect;
     use expect_test::expect_file;
+    use expect_test::Expect;
     use expect_test::ExpectFile;
     use tempfile::Builder;
     use tempfile::TempDir;
@@ -582,6 +584,30 @@ mod tests {
         .expect("bad test");
     }
 
+    #[test_case(false ; "rebar")]
+    #[test_case(true  ; "buck")]
+    fn lint_config_file_parse_error(buck: bool) {
+        let tmp_dir = TempDir::new().expect("Could not create temporary directory");
+        let tmp_path = tmp_dir.path();
+        fs::create_dir_all(tmp_path).expect("Could not create temporary directory path");
+        check_lint_fix_stderr(
+            args_vec!["lint", "--experimental", "--read-config"],
+            "linter_bad_config",
+            expect_file!("../resources/test/linter/parse_elp_lint_bad_config_output.stdout"),
+            101,
+            buck,
+            None,
+            &tmp_path,
+            Path::new("../resources/test/lint/lint_recursive"),
+            &[],
+            false,
+            Some(expect![[r#"
+                failed to read "../../test_projects/linter_bad_config/.elp_lint.toml":expected a right bracket, found an identifier at line 6 column 4
+            "#]]),
+        )
+        .expect("bad test");
+    }
+
     #[test_case(false ; "rebar")]
     #[test_case(true  ; "buck")]
     fn lint_no_diagnostics_enabled(buck: bool) {
@@ -857,6 +883,34 @@ mod tests {
         expected_dir: &Path,
         files: &[(&str, &str)],
         backup_files: bool,
+    ) -> Result<()> {
+        check_lint_fix_stderr(
+            args,
+            project,
+            expected,
+            expected_code,
+            buck,
+            file,
+            actual_dir,
+            expected_dir,
+            files,
+            backup_files,
+            None,
+        )
+    }
+
+    fn check_lint_fix_stderr(
+        args: Vec<OsString>,
+        project: &str,
+        expected: ExpectFile,
+        expected_code: i32,
+        buck: bool,
+        file: Option<&str>,
+        actual_dir: &Path,
+        expected_dir: &Path,
+        files: &[(&str, &str)],
+        backup_files: bool,
+        expected_stderr: Option<Expect>,
     ) -> Result<()> {
         if !buck || cfg!(feature = "buck") {
             let (mut args, path) = add_project(args, project, file);
@@ -876,6 +930,9 @@ mod tests {
                 "Expected exit code {expected_code}, got: {}\nstdout:\n{}\nstderr:\n{}",
                 code, stdout, stderr
             );
+            if let Some(expected_stderr) = expected_stderr {
+                expected_stderr.assert_eq(&stderr);
+            }
             assert_normalised_file(expected, &stdout, path);
             for (expected_file, file) in files {
                 let expected = expect_file!(expected_dir.join(expected_file));
diff --git a/test_projects/linter_bad_config/.elp.toml b/test_projects/linter_bad_config/.elp.toml
new file mode 100644
index 0000000000..a887ab835c
--- /dev/null
+++ b/test_projects/linter_bad_config/.elp.toml
@@ -0,0 +1,5 @@
+[buck]
+enabled = true
+build_deps = false
+included_targets = [ "fbcode//whatsapp/elp/test_projects/linter/..." ]
+source_root = "whatsapp/elp/test_projects/linter"
diff --git a/test_projects/linter_bad_config/.elp_lint.toml b/test_projects/linter_bad_config/.elp_lint.toml
new file mode 100644
index 0000000000..77311d91ed
--- /dev/null
+++ b/test_projects/linter_bad_config/.elp_lint.toml
@@ -0,0 +1,8 @@
+# @lint-ignore-every TOMLSYNTAX
+enabled_lints =[
+   'L1268',
+   'W0011',
+   'P1700'
+   syntax error
+   ]
+disabled_lints = ['W0010']
diff --git a/test_projects/linter_bad_config/.gitignore b/test_projects/linter_bad_config/.gitignore
new file mode 100644
index 0000000000..d811070a54
--- /dev/null
+++ b/test_projects/linter_bad_config/.gitignore
@@ -0,0 +1,4 @@
+.idea
+build_info.etf
+/_build/
+rebar.lock
diff --git a/test_projects/linter_bad_config/app_a/include/app_a.hrl b/test_projects/linter_bad_config/app_a/include/app_a.hrl
new file mode 100644
index 0000000000..f4378955c0
--- /dev/null
+++ b/test_projects/linter_bad_config/app_a/include/app_a.hrl
@@ -0,0 +1 @@
+-typing([eqwalizer]).
diff --git a/test_projects/linter_bad_config/app_a/src/app_a.app.src b/test_projects/linter_bad_config/app_a/src/app_a.app.src
new file mode 100644
index 0000000000..1381435a46
--- /dev/null
+++ b/test_projects/linter_bad_config/app_a/src/app_a.app.src
@@ -0,0 +1,3 @@
+{application, app_a,
+  [{description, "example app A"}, {vsn, "inplace"}, {applications, [kernel, stdlib]}]
+}.
diff --git a/test_projects/linter_bad_config/app_a/src/app_a.erl b/test_projects/linter_bad_config/app_a/src/app_a.erl
new file mode 100644
index 0000000000..9c00f2dd95
--- /dev/null
+++ b/test_projects/linter_bad_config/app_a/src/app_a.erl
@@ -0,0 +1 @@
+-module(app_a).
diff --git a/test_projects/linter_bad_config/linter/.elp.toml b/test_projects/linter_bad_config/linter/.elp.toml
new file mode 100644
index 0000000000..a887ab835c
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/.elp.toml
@@ -0,0 +1,5 @@
+[buck]
+enabled = true
+build_deps = false
+included_targets = [ "fbcode//whatsapp/elp/test_projects/linter/..." ]
+source_root = "whatsapp/elp/test_projects/linter"
diff --git a/test_projects/linter_bad_config/linter/.elp_lint.toml b/test_projects/linter_bad_config/linter/.elp_lint.toml
new file mode 100644
index 0000000000..0379322d88
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/.elp_lint.toml
@@ -0,0 +1,2 @@
+enabled_lints =['L1268', 'W0011', 'P1700']
+disabled_lints = ['W0010']
diff --git a/test_projects/linter_bad_config/linter/.gitignore b/test_projects/linter_bad_config/linter/.gitignore
new file mode 100644
index 0000000000..d811070a54
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/.gitignore
@@ -0,0 +1,4 @@
+.idea
+build_info.etf
+/_build/
+rebar.lock
diff --git a/test_projects/linter_bad_config/linter/app_a/include/app_a.hrl b/test_projects/linter_bad_config/linter/app_a/include/app_a.hrl
new file mode 100644
index 0000000000..f4378955c0
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/include/app_a.hrl
@@ -0,0 +1 @@
+-typing([eqwalizer]).
diff --git a/test_projects/linter_bad_config/linter/app_a/src/app_a.app.src b/test_projects/linter_bad_config/linter/app_a/src/app_a.app.src
new file mode 100644
index 0000000000..1381435a46
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/src/app_a.app.src
@@ -0,0 +1,3 @@
+{application, app_a,
+  [{description, "example app A"}, {vsn, "inplace"}, {applications, [kernel, stdlib]}]
+}.
diff --git a/test_projects/linter_bad_config/linter/app_a/src/app_a.erl b/test_projects/linter_bad_config/linter/app_a/src/app_a.erl
new file mode 100644
index 0000000000..c47f70751a
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/src/app_a.erl
@@ -0,0 +1,10 @@
+-module(app_a).
+-export([application_env_error_app_a/0]).
+
+application_env_error_app_a() ->
+    application:get_env(misc, key).
+
+food(0) ->
+    ok;
+fooX(X) ->
+    no.
diff --git a/test_projects/linter_bad_config/linter/app_a/src/app_a_unused_param.erl b/test_projects/linter_bad_config/linter/app_a/src/app_a_unused_param.erl
new file mode 100644
index 0000000000..5b9fb07d27
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/src/app_a_unused_param.erl
@@ -0,0 +1,6 @@
+-module(app_a_unused_param).
+
+-export([foo/1]).
+
+foo(X) ->
+    ok.
diff --git a/test_projects/linter_bad_config/linter/app_a/test/app_a_SUITE.erl b/test_projects/linter_bad_config/linter/app_a/test/app_a_SUITE.erl
new file mode 100644
index 0000000000..ff17886c13
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/test/app_a_SUITE.erl
@@ -0,0 +1,19 @@
+-module(app_a_SUITE).
+-compile([export_all, nowarn_export_all]).
+-typing([eqwalizer]).
+
+-include_lib("stdlib/include/assert.hrl").
+-include("app_a.hrl").
+
+-spec ok() -> ok.
+ok() ->
+    ?assert(true),
+    case rand:uniform(1) of
+        1 -> app_a_test_helpers:ok();
+        _ -> app_a_test_helpers_not_opted_in:ok()
+    end.
+
+-spec fail() -> ok.
+fail() ->
+    app_a_test_helpers:fail().
+
diff --git a/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers.erl b/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers.erl
new file mode 100644
index 0000000000..52077306c7
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers.erl
@@ -0,0 +1,10 @@
+-module(app_a_test_helpers).
+-typing([eqwalizer]).
+-compile([export_all, nowarn_export_all]).
+
+-spec fail() -> error.
+fail() -> wrong_ret.
+
+-spec ok() -> ok.
+ok() -> ok.
+
diff --git a/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers_not_opted_in.erl b/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers_not_opted_in.erl
new file mode 100644
index 0000000000..dc280d10bb
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/test/app_a_test_helpers_not_opted_in.erl
@@ -0,0 +1,9 @@
+-module(app_a_test_helpers_not_opted_in).
+-compile([export_all, nowarn_export_all]).
+
+-spec fail() -> ok.
+fail() -> error.
+
+-spec ok() -> ok.
+ok() -> ok.
+
diff --git a/test_projects/linter_bad_config/linter/app_a/test/app_test_helpers_no_errors.erl b/test_projects/linter_bad_config/linter/app_a/test/app_test_helpers_no_errors.erl
new file mode 100644
index 0000000000..35af9911ed
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_a/test/app_test_helpers_no_errors.erl
@@ -0,0 +1,6 @@
+-module(app_a_test_helpers_no_errors).
+-compile([export_all, nowarn_export_all]).
+
+-spec ok() -> ok.
+ok() -> ok.
+
diff --git a/test_projects/linter_bad_config/linter/app_b/src/app_b.app.src b/test_projects/linter_bad_config/linter/app_b/src/app_b.app.src
new file mode 100644
index 0000000000..4112b4129f
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_b/src/app_b.app.src
@@ -0,0 +1,3 @@
+{application, app_b,
+  [{description, "example app B"}, {vsn, "inplace"}, {applications, [kernel, stdlib]}]
+}.
diff --git a/test_projects/linter_bad_config/linter/app_b/src/app_b.erl b/test_projects/linter_bad_config/linter/app_b/src/app_b.erl
new file mode 100644
index 0000000000..a71ef9123f
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_b/src/app_b.erl
@@ -0,0 +1,5 @@
+-module(app_b).
+-export([application_env_error/0]).
+
+application_env_error() ->
+    application:get_env(misc, key).
diff --git a/test_projects/linter_bad_config/linter/app_b/src/app_b_unused_param.erl b/test_projects/linter_bad_config/linter/app_b/src/app_b_unused_param.erl
new file mode 100644
index 0000000000..81f3f876aa
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/app_b/src/app_b_unused_param.erl
@@ -0,0 +1,6 @@
+-module(app_b_unused_param).
+
+-export([foo/1]).
+
+foo(X) ->
+    ok.
diff --git a/test_projects/linter_bad_config/linter/rebar.config b/test_projects/linter_bad_config/linter/rebar.config
new file mode 100644
index 0000000000..344eb71dd8
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/rebar.config
@@ -0,0 +1,9 @@
+{checkouts_dir, ["."]}.
+{plugins, [wa_utils]}.
+{project_app_dirs, [
+    "app_a",
+    "app_b"
+]}.
+
+{erl_opts, [debug_info]}.
+{deps, []}.
diff --git a/test_projects/linter_bad_config/linter/wa_utils/src/wa_build_info_prv.erl b/test_projects/linter_bad_config/linter/wa_utils/src/wa_build_info_prv.erl
new file mode 100644
index 0000000000..a085e0b548
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/wa_utils/src/wa_build_info_prv.erl
@@ -0,0 +1,384 @@
+%% % @format
+-module(wa_build_info_prv).
+-oncall("whatsapp_elp").
+
+-export([init/1, do/1]).
+
+-define(NUM_RETRIES_FETCH_DEPS, 5).
+
+-type app_build_opts() :: #{
+    name := binary(),
+    dir := binary(),
+    ebin := binary(),
+    src_dirs := [binary()],
+    extra_src_dirs := [binary()],
+    include_dirs := [binary()],
+    macros := [atom() | {atom(), any()}],
+    parse_transforms := [any()]
+}.
+
+init(State) ->
+    State1 = rebar_state:add_provider(
+        State,
+        providers:create([
+            {name, build_info},
+            {module, wa_build_info_prv},
+            {bare, true},
+            {deps, [app_discovery]},
+            {example, "rebar3 build_info"},
+            {short_desc, "Get build_info"},
+            {desc, "Get build_info"},
+            {opts, [
+                {to, $t, "to", {string, undefined},
+                    "file to write buid_info in file (ETF for LAP, or erlang_ls.config format)"},
+                {mode, $m, "mode", {string, "etf"},
+                    "build info format, can be etf (generic build info for ELP and Eqwalizer), els (Erlang LS), rl (Readme lint), wm (wiki_moduledocs lint)"},
+                {els_config, $e, "els-config", {string, undefined}, "existing erlang_ls.config"}
+            ]}
+        ])
+    ),
+    {ok, State1}.
+
+do(State0) ->
+    {RawOpts, _} = rebar_state:command_parsed_args(State0),
+    Mode = proplists:get_value(mode, RawOpts),
+    State1 = maybe_get_deps(State0, Mode),
+    case Mode of
+        "etf" -> etf_build_info(State1, RawOpts);
+        "els" -> els_build_info(State1, RawOpts);
+        "rl" -> rl_build_info(State1, RawOpts);
+        "wm" -> wm_build_info(State1, RawOpts)
+    end,
+    {ok, State1}.
+
+maybe_get_deps(State0, Mode) ->
+    %% fetching dependencies in CI may require multiple attemps due to
+    %% some unreliable source constrol infra
+    case Mode of
+        %% Dependencies not needed for "rl" or "wm" modes
+        Mode when Mode == "rl"; Mode == "wm" ->
+            State0;
+        _ ->
+            State1 = safe_get_install_deps(State0, ?NUM_RETRIES_FETCH_DEPS),
+            {ok, State2} = rebar_prv_lock:do(State1),
+            State2
+    end.
+
+safe_get_install_deps(_State, 0) ->
+    rebar_log:log(error, "Unable to fetch dependencies after ~b tries, aborting", [
+        ?NUM_RETRIES_FETCH_DEPS
+    ]),
+    throw(rebar_abort);
+safe_get_install_deps(State, N) ->
+    try rebar_prv_install_deps:do(State) of
+        {ok, NewState} -> NewState
+    catch
+        E:R:ST ->
+            rebar_log:log(warn, "error fetching deps: {~p, ~p}~n~p", [E, R, ST]),
+            safe_get_install_deps(State, N - 1)
+    end.
+
+get_data(State) ->
+    ProjectApps = rebar_state:project_apps(State),
+    DepApps = rebar_state:all_deps(State),
+    #{
+        apps => [app_build_opts(App) || App <- ProjectApps],
+        deps => [app_build_opts(App) || App <- DepApps],
+        otp_lib_dir => list_to_binary(code:lib_dir()),
+        source_root => list_to_binary(rebar_state:dir(State))
+    }.
+
+etf_build_info(State, RawOpts) ->
+    Data = get_data(State),
+
+    To = proplists:get_value(to, RawOpts),
+    case To of
+        undefined ->
+            rebar_log:log(info, "Build info:~n", []),
+            io:fwrite("~p.~n", [Data]);
+        File ->
+            ok = file:write_file(File, term_to_binary(Data)),
+            rebar_log:log(info, "Build info written to: ~ts", [File])
+    end.
+
+write_output(Encoded, RawOpts, Name) ->
+    To = proplists:get_value(to, RawOpts),
+    case To of
+        undefined ->
+            rebar_log:log(info, "~s:", [Name]),
+            io:fwrite("~s~n", [Encoded]);
+        File ->
+            ok = file:write_file(File, [Encoded, "\n"]),
+            rebar_log:log(info, "~s written to: ~ts", [Name, File])
+    end.
+
+all_include_dirs(Apps, Deps) ->
+    lists:concat(
+        [
+            [filename:join(Dir, SrcDir) || SrcDir <- SrcDirs] ++ IncludeDirs
+         || #{include_dirs := IncludeDirs, src_dirs := SrcDirs, dir := Dir} <- Apps
+        ] ++
+            [
+                IncludeDirs
+             || #{include_dirs := IncludeDirs} <- Deps
+            ]
+    ).
+
+els_build_info(State, RawOpts) ->
+    #{deps := Deps, apps := Apps} = get_data(State),
+
+    %% prepare data
+    BaseDir = rebar_state:dir(State),
+    IncludeDirs = [
+        Dir
+     || IncludeDir <- all_include_dirs(Apps, Deps),
+        Dir <- [make_relative(BaseDir, IncludeDir), make_relative(BaseDir, enclosing_app_folder(IncludeDir))],
+        filelib:is_dir(Dir)
+    ],
+    AppsDirs = [make_relative(BaseDir, AppDir) || #{dir := AppDir} <- Apps],
+
+    %% extract feature config from exsiting config file
+    Erlang_LS_Config = proplists:get_value(els_config, RawOpts),
+    Config = maybe_get_existing_config(Erlang_LS_Config),
+
+    %% prepare JSON term
+    JSONData = [
+        {<<"include_dirs">>, lists:usort(IncludeDirs)},
+        {<<"apps_dirs">>, lists:usort(AppsDirs)}
+        | Config
+    ],
+    Encoded = jsone:encode(JSONData, [{indent, 2}, native_forward_slash]),
+    write_output(Encoded, RawOpts, <<"erlang_ls.config">>).
+
+rl_build_info(State, RawOpts) ->
+    Data = get_data(State),
+
+    %% prepare data
+    #{apps := Apps} = Data,
+    BaseDir = rebar_state:dir(State),
+    AppsDirs = [
+        make_relative(BaseDir, AppDir)
+     || #{
+            dir := AppDir
+        } <- Apps
+    ],
+
+    %% output
+    Encoded = string:join(lists:map(fun binary_to_list/1, AppsDirs), "\n"),
+    write_output(Encoded, RawOpts, <<"erlang_rl.config">>).
+
+%% report a guess as to what files would be created by running `wiki_moduledocs extract'
+%% in the DOCS file format used by fbsphinx.
+%%
+%% the result should be an over-estimate; not every module/app will necessarily be
+%% successfully processed (and some will be generated/private); fbsphinx will leniently
+%% ignore any missing files.  if TODO(T96305665) is ever implemented, this and the
+%% associated linter should be removed.
+%%
+%% this is meant to be used with and support a single use case: updating the
+%% `erl/docs/DOCS' file as part of an `arc lint'.  it assumes presence of specific
+%% template vars in that file.  it assumes the presence of `erl/docs/DOCS.src' as a
+%% template file.
+wm_build_info(State, RawOpts) ->
+    #{apps := Apps} = get_data(State),
+    BaseDir = rebar_state:dir(State),
+
+    %% find the source modules of each app:
+    AppSources = wm_app_sources(BaseDir, Apps),
+
+    %% convert each source path to its corresponding DOCS path, and check each appdir for
+    %% presence of an existing readme to determine the final output readme name seen by
+    %% fbsphinx:
+    DocsPaths = wm_output_pathnames(AppSources),
+
+    %% substitute the docs/readmes content for the relevant template variables:
+    FinalContent = wm_populate_template(BaseDir, DocsPaths),
+
+    write_output(FinalContent, RawOpts, <<"wiki_moduledocs DOCS">>).
+
+%% given the build options for an app, return its name, its directory, and a list of its
+%% source pathnames. each such source file has a corresponding entry in erl/docs/DOCS as
+%% "erlang/AppName/modname.rst". each app has a README.md or README.rst in the same
+%% location (if it had any modules).
+-spec wm_app_sources(binary(), [app_build_opts()]) -> [{binary(), binary(), [binary()]}].
+wm_app_sources(BaseDir, Apps) ->
+    lists:foldl(
+        fun(#{name := AppName, dir := AppDir, src_dirs := SrcDirs}, Acc) ->
+            RelativeAppDir = make_relative(BaseDir, AppDir),
+            %% currently, wiki_moduledocs ignores most/all non-toplevel apps; this ignores
+            %% app paths containing more than a single "/":
+            ShouldIgnore =
+                case filename:split(RelativeAppDir) of
+                    [<<".">>, _] ->
+                        false;
+                    [_] ->
+                        false;
+                    _ ->
+                        rebar_log:log(debug, "ignoring appdir ~s", [RelativeAppDir]),
+                        true
+                end,
+            case ShouldIgnore of
+                true ->
+                    Acc;
+                false ->
+                    [
+                        {AppName, RelativeAppDir,
+                            lists:append([
+                                lists_to_binaries(
+                                    filelib:wildcard(
+                                        unicode:characters_to_list(
+                                            filename:join([RelativeAppDir, SrcDir, "*.erl"])
+                                        )
+                                    )
+                                )
+                             || SrcDir <- SrcDirs
+                            ])}
+                        | Acc
+                    ]
+            end
+        end,
+        [],
+        Apps
+    ).
+
+%% given the output of `wm_app_sources', produce a list of relative pathnames to be
+%% handled by fbsphinx corresponding to module docs and app readmes.
+-spec wm_output_pathnames([{AppName :: binary(), AppDir :: binary(), Sources :: [binary()]}]) ->
+    {Docs :: [binary()], Readmes :: [binary()]}.
+wm_output_pathnames(AppSources) ->
+    {A, B} =
+        lists:foldl(
+            fun({AppName, AppDir, Sources}, {DocsAcc, ReadmesAcc}) ->
+                DocsAcc1 = [
+                    [
+                        filename:join([
+                            "erlang",
+                            AppName,
+                            [filename:basename(Source, ".erl"), ".rst"]
+                        ])
+                     || Source <- Sources
+                    ]
+                    | DocsAcc
+                ],
+
+                %% readmes are handled in their own section to work around an fbsphinx
+                %% bug (parent paths must be created before same-named children):
+                ReadmeExt =
+                    case filelib:is_regular(filename:join(AppDir, "README.md")) of
+                        true ->
+                            ".md";
+                        false ->
+                            ".rst"
+                    end,
+                ReadmesAcc1 = [[filename:join(["erlang", AppName, "README"]), ReadmeExt] | ReadmesAcc],
+                {DocsAcc1, ReadmesAcc1}
+            end,
+            {[], []},
+            AppSources
+        ),
+    {lists:append(A), B}.
+
+%% given the output of `wm_output_pathnames', produce the final corresponding DOCS content
+%% by substituting into the static source template file.
+-spec wm_populate_template(binary(), {[binary()], [binary()]}) -> binary().
+wm_populate_template(BaseDir, {Docs, Readmes}) ->
+    DocsSrc = filename:join([BaseDir, "docs", "DOCS.src"]),
+    {ok, DocsSrcContent} = file:read_file(DocsSrc),
+
+    %% items should be sorted, but readmes should occur before deeper children in order to
+    %% work around an fbsphinx bug:
+    Items = lists:sort(["erlang/README.rst" | Readmes]) ++ lists:sort(Docs),
+    Srcs = ["[", lists:join(",\n          ", Items), "]"],
+
+    %% substitute template variables for actual content. note: `re:split' with a fold is
+    %% ~6x faster than using `re:replace'.
+    Substitutions = #{<<"%%SRCS%%">> => Srcs},
+    SplitPattern = ["(", lists:join("|", maps:keys(Substitutions)), ")"],
+    SplitContent = re:split(DocsSrcContent, SplitPattern, [{return, binary}, unicode]),
+    lists:foldl(
+        fun(Part, Acc) ->
+            case Substitutions of
+                #{Part := Replacement} ->
+                    [Acc, Replacement];
+                _ ->
+                    [Acc, Part]
+            end
+        end,
+        [],
+        SplitContent
+    ).
+
+make_relative(Base, Full) ->
+    case string:split(Full, Base) of
+        [Prefix, Relative] ->
+            case string:is_empty(Prefix) of
+                true ->
+                    unicode:characters_to_binary([".", Relative]);
+                _ ->
+                    make_relative_error(Full, Base)
+            end;
+        _ ->
+            make_relative_error(Full, Base)
+    end.
+
+enclosing_app_folder(Dir) ->
+    filename:dirname(filename:dirname(Dir)).
+
+make_relative_error(Full, Base) ->
+    rebar_log:log(error, "the path ~s is not an extension of the base path ~s", [Full, Base]),
+    throw(rebar_abort).
+
+maybe_get_existing_config(undefined) ->
+    [];
+maybe_get_existing_config(File) ->
+    case file:read_file(File) of
+        {ok, Json} ->
+            try
+                Data = jsone:decode(Json),
+                maps:to_list(Data)
+            catch
+                E:R ->
+                    rebar_log:log(error, "error parsing erlang_ls config at ~s (~p)", [File, {E, R}]),
+                    throw(rebar_abort)
+            end;
+        {error, _} = Error ->
+            rebar_log:log(error, "could not open erlang_ls config at ~s (~p)", [File, Error]),
+            throw(rebar_abort)
+    end.
+
+%% From rebar_compiler:context/1
+
+-spec app_build_opts(rebar_app_info:t()) -> app_build_opts().
+app_build_opts(AppInfo) ->
+    Name = rebar_app_info:name(AppInfo),
+    AppDir = rebar_app_info:dir(AppInfo),
+    EbinDir = rebar_app_info:ebin_dir(AppInfo),
+    RebarOpts = rebar_app_info:opts(AppInfo),
+    SrcDirs = rebar_dir:src_dirs(RebarOpts, ["src"]),
+    ExistingSrcDirs = [Dir || Dir <- SrcDirs, ec_file:is_dir(filename:join(AppDir, Dir))],
+    ExtraSrcDirs = rebar_dir:extra_src_dirs(RebarOpts),
+    ErlOpts = rebar_opts:erl_opts(RebarOpts),
+    ErlOptIncludes = proplists:get_all_values(i, ErlOpts),
+    InclDirs =
+        [filename:join(AppDir, "include")] ++ [filename:absname(Dir) || Dir <- ErlOptIncludes],
+    PTrans = proplists:get_all_values(parse_transform, ErlOpts),
+    Macros = macros(ErlOpts),
+
+    #{
+        name => Name,
+        dir => list_to_binary(AppDir),
+        ebin => list_to_binary(EbinDir),
+        src_dirs => lists_to_binaries(ExistingSrcDirs),
+        extra_src_dirs => lists_to_binaries(ExtraSrcDirs),
+        include_dirs => lists_to_binaries(InclDirs),
+        macros => Macros,
+        parse_transforms => PTrans
+    }.
+
+macros([{d, Name} | Rest]) -> [Name | macros(Rest)];
+macros([{d, Name, Value} | Rest]) -> [{Name, Value} | macros(Rest)];
+macros([_ | Rest]) -> macros(Rest);
+macros([]) -> [].
+
+lists_to_binaries(Strings) ->
+    [list_to_binary(String) || String <- Strings].
diff --git a/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.app.src b/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.app.src
new file mode 100644
index 0000000000..731eb1325d
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.app.src
@@ -0,0 +1,3 @@
+{application, wa_utils,
+  [{description, "wa_utils"}, {vsn, "inplace"}, {applications, [kernel, stdlib]}]
+}.
diff --git a/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.erl b/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.erl
new file mode 100644
index 0000000000..9974dc25d8
--- /dev/null
+++ b/test_projects/linter_bad_config/linter/wa_utils/src/wa_utils.erl
@@ -0,0 +1,15 @@
+-module(wa_utils).
+
+-export([init/1]).
+
+init(State0) ->
+    Providers = [wa_build_info_prv],
+    State1 = lists:foldl(
+        fun(Provider, State) ->
+            {ok, NewState} = Provider:init(State),
+            NewState
+        end,
+        State0,
+        Providers
+    ),
+    {ok, State1}.
diff --git a/test_projects/linter_bad_config/rebar.config b/test_projects/linter_bad_config/rebar.config
new file mode 100644
index 0000000000..4dd09dc463
--- /dev/null
+++ b/test_projects/linter_bad_config/rebar.config
@@ -0,0 +1,8 @@
+{checkouts_dir, ["."]}.
+{plugins, [wa_utils]}.
+{project_app_dirs, [
+    "app_a"
+]}.
+
+{erl_opts, [debug_info]}.
+{deps, []}.
diff --git a/test_projects/linter_bad_config/wa_utils/src/wa_build_info_prv.erl b/test_projects/linter_bad_config/wa_utils/src/wa_build_info_prv.erl
new file mode 100644
index 0000000000..a085e0b548
--- /dev/null
+++ b/test_projects/linter_bad_config/wa_utils/src/wa_build_info_prv.erl
@@ -0,0 +1,384 @@
+%% % @format
+-module(wa_build_info_prv).
+-oncall("whatsapp_elp").
+
+-export([init/1, do/1]).
+
+-define(NUM_RETRIES_FETCH_DEPS, 5).
+
+-type app_build_opts() :: #{
+    name := binary(),
+    dir := binary(),
+    ebin := binary(),
+    src_dirs := [binary()],
+    extra_src_dirs := [binary()],
+    include_dirs := [binary()],
+    macros := [atom() | {atom(), any()}],
+    parse_transforms := [any()]
+}.
+
+init(State) ->
+    State1 = rebar_state:add_provider(
+        State,
+        providers:create([
+            {name, build_info},
+            {module, wa_build_info_prv},
+            {bare, true},
+            {deps, [app_discovery]},
+            {example, "rebar3 build_info"},
+            {short_desc, "Get build_info"},
+            {desc, "Get build_info"},
+            {opts, [
+                {to, $t, "to", {string, undefined},
+                    "file to write buid_info in file (ETF for LAP, or erlang_ls.config format)"},
+                {mode, $m, "mode", {string, "etf"},
+                    "build info format, can be etf (generic build info for ELP and Eqwalizer), els (Erlang LS), rl (Readme lint), wm (wiki_moduledocs lint)"},
+                {els_config, $e, "els-config", {string, undefined}, "existing erlang_ls.config"}
+            ]}
+        ])
+    ),
+    {ok, State1}.
+
+do(State0) ->
+    {RawOpts, _} = rebar_state:command_parsed_args(State0),
+    Mode = proplists:get_value(mode, RawOpts),
+    State1 = maybe_get_deps(State0, Mode),
+    case Mode of
+        "etf" -> etf_build_info(State1, RawOpts);
+        "els" -> els_build_info(State1, RawOpts);
+        "rl" -> rl_build_info(State1, RawOpts);
+        "wm" -> wm_build_info(State1, RawOpts)
+    end,
+    {ok, State1}.
+
+maybe_get_deps(State0, Mode) ->
+    %% fetching dependencies in CI may require multiple attemps due to
+    %% some unreliable source constrol infra
+    case Mode of
+        %% Dependencies not needed for "rl" or "wm" modes
+        Mode when Mode == "rl"; Mode == "wm" ->
+            State0;
+        _ ->
+            State1 = safe_get_install_deps(State0, ?NUM_RETRIES_FETCH_DEPS),
+            {ok, State2} = rebar_prv_lock:do(State1),
+            State2
+    end.
+
+safe_get_install_deps(_State, 0) ->
+    rebar_log:log(error, "Unable to fetch dependencies after ~b tries, aborting", [
+        ?NUM_RETRIES_FETCH_DEPS
+    ]),
+    throw(rebar_abort);
+safe_get_install_deps(State, N) ->
+    try rebar_prv_install_deps:do(State) of
+        {ok, NewState} -> NewState
+    catch
+        E:R:ST ->
+            rebar_log:log(warn, "error fetching deps: {~p, ~p}~n~p", [E, R, ST]),
+            safe_get_install_deps(State, N - 1)
+    end.
+
+get_data(State) ->
+    ProjectApps = rebar_state:project_apps(State),
+    DepApps = rebar_state:all_deps(State),
+    #{
+        apps => [app_build_opts(App) || App <- ProjectApps],
+        deps => [app_build_opts(App) || App <- DepApps],
+        otp_lib_dir => list_to_binary(code:lib_dir()),
+        source_root => list_to_binary(rebar_state:dir(State))
+    }.
+
+etf_build_info(State, RawOpts) ->
+    Data = get_data(State),
+
+    To = proplists:get_value(to, RawOpts),
+    case To of
+        undefined ->
+            rebar_log:log(info, "Build info:~n", []),
+            io:fwrite("~p.~n", [Data]);
+        File ->
+            ok = file:write_file(File, term_to_binary(Data)),
+            rebar_log:log(info, "Build info written to: ~ts", [File])
+    end.
+
+write_output(Encoded, RawOpts, Name) ->
+    To = proplists:get_value(to, RawOpts),
+    case To of
+        undefined ->
+            rebar_log:log(info, "~s:", [Name]),
+            io:fwrite("~s~n", [Encoded]);
+        File ->
+            ok = file:write_file(File, [Encoded, "\n"]),
+            rebar_log:log(info, "~s written to: ~ts", [Name, File])
+    end.
+
+all_include_dirs(Apps, Deps) ->
+    lists:concat(
+        [
+            [filename:join(Dir, SrcDir) || SrcDir <- SrcDirs] ++ IncludeDirs
+         || #{include_dirs := IncludeDirs, src_dirs := SrcDirs, dir := Dir} <- Apps
+        ] ++
+            [
+                IncludeDirs
+             || #{include_dirs := IncludeDirs} <- Deps
+            ]
+    ).
+
+els_build_info(State, RawOpts) ->
+    #{deps := Deps, apps := Apps} = get_data(State),
+
+    %% prepare data
+    BaseDir = rebar_state:dir(State),
+    IncludeDirs = [
+        Dir
+     || IncludeDir <- all_include_dirs(Apps, Deps),
+        Dir <- [make_relative(BaseDir, IncludeDir), make_relative(BaseDir, enclosing_app_folder(IncludeDir))],
+        filelib:is_dir(Dir)
+    ],
+    AppsDirs = [make_relative(BaseDir, AppDir) || #{dir := AppDir} <- Apps],
+
+    %% extract feature config from exsiting config file
+    Erlang_LS_Config = proplists:get_value(els_config, RawOpts),
+    Config = maybe_get_existing_config(Erlang_LS_Config),
+
+    %% prepare JSON term
+    JSONData = [
+        {<<"include_dirs">>, lists:usort(IncludeDirs)},
+        {<<"apps_dirs">>, lists:usort(AppsDirs)}
+        | Config
+    ],
+    Encoded = jsone:encode(JSONData, [{indent, 2}, native_forward_slash]),
+    write_output(Encoded, RawOpts, <<"erlang_ls.config">>).
+
+rl_build_info(State, RawOpts) ->
+    Data = get_data(State),
+
+    %% prepare data
+    #{apps := Apps} = Data,
+    BaseDir = rebar_state:dir(State),
+    AppsDirs = [
+        make_relative(BaseDir, AppDir)
+     || #{
+            dir := AppDir
+        } <- Apps
+    ],
+
+    %% output
+    Encoded = string:join(lists:map(fun binary_to_list/1, AppsDirs), "\n"),
+    write_output(Encoded, RawOpts, <<"erlang_rl.config">>).
+
+%% report a guess as to what files would be created by running `wiki_moduledocs extract'
+%% in the DOCS file format used by fbsphinx.
+%%
+%% the result should be an over-estimate; not every module/app will necessarily be
+%% successfully processed (and some will be generated/private); fbsphinx will leniently
+%% ignore any missing files.  if TODO(T96305665) is ever implemented, this and the
+%% associated linter should be removed.
+%%
+%% this is meant to be used with and support a single use case: updating the
+%% `erl/docs/DOCS' file as part of an `arc lint'.  it assumes presence of specific
+%% template vars in that file.  it assumes the presence of `erl/docs/DOCS.src' as a
+%% template file.
+wm_build_info(State, RawOpts) ->
+    #{apps := Apps} = get_data(State),
+    BaseDir = rebar_state:dir(State),
+
+    %% find the source modules of each app:
+    AppSources = wm_app_sources(BaseDir, Apps),
+
+    %% convert each source path to its corresponding DOCS path, and check each appdir for
+    %% presence of an existing readme to determine the final output readme name seen by
+    %% fbsphinx:
+    DocsPaths = wm_output_pathnames(AppSources),
+
+    %% substitute the docs/readmes content for the relevant template variables:
+    FinalContent = wm_populate_template(BaseDir, DocsPaths),
+
+    write_output(FinalContent, RawOpts, <<"wiki_moduledocs DOCS">>).
+
+%% given the build options for an app, return its name, its directory, and a list of its
+%% source pathnames. each such source file has a corresponding entry in erl/docs/DOCS as
+%% "erlang/AppName/modname.rst". each app has a README.md or README.rst in the same
+%% location (if it had any modules).
+-spec wm_app_sources(binary(), [app_build_opts()]) -> [{binary(), binary(), [binary()]}].
+wm_app_sources(BaseDir, Apps) ->
+    lists:foldl(
+        fun(#{name := AppName, dir := AppDir, src_dirs := SrcDirs}, Acc) ->
+            RelativeAppDir = make_relative(BaseDir, AppDir),
+            %% currently, wiki_moduledocs ignores most/all non-toplevel apps; this ignores
+            %% app paths containing more than a single "/":
+            ShouldIgnore =
+                case filename:split(RelativeAppDir) of
+                    [<<".">>, _] ->
+                        false;
+                    [_] ->
+                        false;
+                    _ ->
+                        rebar_log:log(debug, "ignoring appdir ~s", [RelativeAppDir]),
+                        true
+                end,
+            case ShouldIgnore of
+                true ->
+                    Acc;
+                false ->
+                    [
+                        {AppName, RelativeAppDir,
+                            lists:append([
+                                lists_to_binaries(
+                                    filelib:wildcard(
+                                        unicode:characters_to_list(
+                                            filename:join([RelativeAppDir, SrcDir, "*.erl"])
+                                        )
+                                    )
+                                )
+                             || SrcDir <- SrcDirs
+                            ])}
+                        | Acc
+                    ]
+            end
+        end,
+        [],
+        Apps
+    ).
+
+%% given the output of `wm_app_sources', produce a list of relative pathnames to be
+%% handled by fbsphinx corresponding to module docs and app readmes.
+-spec wm_output_pathnames([{AppName :: binary(), AppDir :: binary(), Sources :: [binary()]}]) ->
+    {Docs :: [binary()], Readmes :: [binary()]}.
+wm_output_pathnames(AppSources) ->
+    {A, B} =
+        lists:foldl(
+            fun({AppName, AppDir, Sources}, {DocsAcc, ReadmesAcc}) ->
+                DocsAcc1 = [
+                    [
+                        filename:join([
+                            "erlang",
+                            AppName,
+                            [filename:basename(Source, ".erl"), ".rst"]
+                        ])
+                     || Source <- Sources
+                    ]
+                    | DocsAcc
+                ],
+
+                %% readmes are handled in their own section to work around an fbsphinx
+                %% bug (parent paths must be created before same-named children):
+                ReadmeExt =
+                    case filelib:is_regular(filename:join(AppDir, "README.md")) of
+                        true ->
+                            ".md";
+                        false ->
+                            ".rst"
+                    end,
+                ReadmesAcc1 = [[filename:join(["erlang", AppName, "README"]), ReadmeExt] | ReadmesAcc],
+                {DocsAcc1, ReadmesAcc1}
+            end,
+            {[], []},
+            AppSources
+        ),
+    {lists:append(A), B}.
+
+%% given the output of `wm_output_pathnames', produce the final corresponding DOCS content
+%% by substituting into the static source template file.
+-spec wm_populate_template(binary(), {[binary()], [binary()]}) -> binary().
+wm_populate_template(BaseDir, {Docs, Readmes}) ->
+    DocsSrc = filename:join([BaseDir, "docs", "DOCS.src"]),
+    {ok, DocsSrcContent} = file:read_file(DocsSrc),
+
+    %% items should be sorted, but readmes should occur before deeper children in order to
+    %% work around an fbsphinx bug:
+    Items = lists:sort(["erlang/README.rst" | Readmes]) ++ lists:sort(Docs),
+    Srcs = ["[", lists:join(",\n          ", Items), "]"],
+
+    %% substitute template variables for actual content. note: `re:split' with a fold is
+    %% ~6x faster than using `re:replace'.
+    Substitutions = #{<<"%%SRCS%%">> => Srcs},
+    SplitPattern = ["(", lists:join("|", maps:keys(Substitutions)), ")"],
+    SplitContent = re:split(DocsSrcContent, SplitPattern, [{return, binary}, unicode]),
+    lists:foldl(
+        fun(Part, Acc) ->
+            case Substitutions of
+                #{Part := Replacement} ->
+                    [Acc, Replacement];
+                _ ->
+                    [Acc, Part]
+            end
+        end,
+        [],
+        SplitContent
+    ).
+
+make_relative(Base, Full) ->
+    case string:split(Full, Base) of
+        [Prefix, Relative] ->
+            case string:is_empty(Prefix) of
+                true ->
+                    unicode:characters_to_binary([".", Relative]);
+                _ ->
+                    make_relative_error(Full, Base)
+            end;
+        _ ->
+            make_relative_error(Full, Base)
+    end.
+
+enclosing_app_folder(Dir) ->
+    filename:dirname(filename:dirname(Dir)).
+
+make_relative_error(Full, Base) ->
+    rebar_log:log(error, "the path ~s is not an extension of the base path ~s", [Full, Base]),
+    throw(rebar_abort).
+
+maybe_get_existing_config(undefined) ->
+    [];
+maybe_get_existing_config(File) ->
+    case file:read_file(File) of
+        {ok, Json} ->
+            try
+                Data = jsone:decode(Json),
+                maps:to_list(Data)
+            catch
+                E:R ->
+                    rebar_log:log(error, "error parsing erlang_ls config at ~s (~p)", [File, {E, R}]),
+                    throw(rebar_abort)
+            end;
+        {error, _} = Error ->
+            rebar_log:log(error, "could not open erlang_ls config at ~s (~p)", [File, Error]),
+            throw(rebar_abort)
+    end.
+
+%% From rebar_compiler:context/1
+
+-spec app_build_opts(rebar_app_info:t()) -> app_build_opts().
+app_build_opts(AppInfo) ->
+    Name = rebar_app_info:name(AppInfo),
+    AppDir = rebar_app_info:dir(AppInfo),
+    EbinDir = rebar_app_info:ebin_dir(AppInfo),
+    RebarOpts = rebar_app_info:opts(AppInfo),
+    SrcDirs = rebar_dir:src_dirs(RebarOpts, ["src"]),
+    ExistingSrcDirs = [Dir || Dir <- SrcDirs, ec_file:is_dir(filename:join(AppDir, Dir))],
+    ExtraSrcDirs = rebar_dir:extra_src_dirs(RebarOpts),
+    ErlOpts = rebar_opts:erl_opts(RebarOpts),
+    ErlOptIncludes = proplists:get_all_values(i, ErlOpts),
+    InclDirs =
+        [filename:join(AppDir, "include")] ++ [filename:absname(Dir) || Dir <- ErlOptIncludes],
+    PTrans = proplists:get_all_values(parse_transform, ErlOpts),
+    Macros = macros(ErlOpts),
+
+    #{
+        name => Name,
+        dir => list_to_binary(AppDir),
+        ebin => list_to_binary(EbinDir),
+        src_dirs => lists_to_binaries(ExistingSrcDirs),
+        extra_src_dirs => lists_to_binaries(ExtraSrcDirs),
+        include_dirs => lists_to_binaries(InclDirs),
+        macros => Macros,
+        parse_transforms => PTrans
+    }.
+
+macros([{d, Name} | Rest]) -> [Name | macros(Rest)];
+macros([{d, Name, Value} | Rest]) -> [{Name, Value} | macros(Rest)];
+macros([_ | Rest]) -> macros(Rest);
+macros([]) -> [].
+
+lists_to_binaries(Strings) ->
+    [list_to_binary(String) || String <- Strings].
diff --git a/test_projects/linter_bad_config/wa_utils/src/wa_utils.app.src b/test_projects/linter_bad_config/wa_utils/src/wa_utils.app.src
new file mode 100644
index 0000000000..731eb1325d
--- /dev/null
+++ b/test_projects/linter_bad_config/wa_utils/src/wa_utils.app.src
@@ -0,0 +1,3 @@
+{application, wa_utils,
+  [{description, "wa_utils"}, {vsn, "inplace"}, {applications, [kernel, stdlib]}]
+}.
diff --git a/test_projects/linter_bad_config/wa_utils/src/wa_utils.erl b/test_projects/linter_bad_config/wa_utils/src/wa_utils.erl
new file mode 100644
index 0000000000..9974dc25d8
--- /dev/null
+++ b/test_projects/linter_bad_config/wa_utils/src/wa_utils.erl
@@ -0,0 +1,15 @@
+-module(wa_utils).
+
+-export([init/1]).
+
+init(State0) ->
+    Providers = [wa_build_info_prv],
+    State1 = lists:foldl(
+        fun(Provider, State) ->
+            {ok, NewState} = Provider:init(State),
+            NewState
+        end,
+        State0,
+        Providers
+    ),
+    {ok, State1}.