Use info from -spec for inlay hints if available.

apps/els_lsp/priv/code_navigation/src/inlay_hint.erl

@@ -8,19 +8,34 @@ test() ->
     b(1, 2),
     c(1),
     d(1, 2),
+    e(1, 2),
+    f(1, 2),
+    g(1, 2),
     lists:append([], []).
 
-a(Hej, Hoj) ->
-    Hej + Hoj.
+a(A1, A2) ->
+    A1 + A2.
 
 b(x, y) ->
     0;
-b(A, _B) ->
-    A.
+b(B1, _B2) ->
+    B1.
 
 c(#foo{}) ->
     ok.
 
-d([1,2,3] = Foo,
-  Bar = #{hej := 123}) ->
+d([1,2,3] = D1,
+  D2 = #{hej := 123}) ->
+    ok.
+
+-spec e(E1 :: any(), E2 :: any()) -> ok.
+e(_, _) ->
+    ok.
+
+-spec f(F1, F2) -> ok when F1 :: any(), F2 :: any().
+f(_, _) ->
+    ok.
+
+-spec g(G1, any()) -> ok when G1 :: any().
+g(_, G2) ->
     ok.

apps/els_lsp/src/els_arg.erl

@@ -1,25 +1,54 @@
 -module(els_arg).
+-export([new/2]).
 -export([name/1]).
 -export([name/2]).
 -export([index/1]).
+-export([merge_args/2]).
+
 -export_type([arg/0]).
+-export_type([args/0]).
 
+-type args() :: [arg()].
 -type arg() :: #{
     index := pos_integer(),
-    name := string() | undefined,
+    name := string() | undefined | {type, string()},
     range => els_poi:poi_range()
 }.
 
+-spec new(pos_integer(), string()) -> arg().
+new(Index, Name) ->
+    #{index => Index, name => Name}.
+
 -spec name(arg()) -> string().
 name(Arg) ->
     name("Arg", Arg).
 
 -spec name(string(), arg()) -> string().
 name(Prefix, #{index := N, name := undefined}) ->
     Prefix ++ integer_to_list(N);
+name(_Prefix, #{name := {type, Name}}) ->
+    Name;
 name(_Prefix, #{name := Name}) ->
     Name.
 
 -spec index(arg()) -> string().
 index(#{index := Index}) ->
     integer_to_list(Index).
+
+-spec merge_args(args(), args()) -> args().
+merge_args([], []) ->
+    [];
+merge_args([#{name := undefined} | T1], [Arg | T2]) ->
+    [Arg | merge_args(T1, T2)];
+merge_args(
+    [#{name := {type, Name}} = Arg | T1],
+    [#{name := undefined} | T2]
+) ->
+    [Arg#{name := Name} | merge_args(T1, T2)];
+merge_args(
+    [#{name := {type, _}} | T1],
+    [Arg | T2]
+) ->
+    [Arg | merge_args(T1, T2)];
+merge_args([Arg | T1], [_ | T2]) ->
+    [Arg | merge_args(T1, T2)].

apps/els_lsp/src/els_completion_provider.erl

@@ -1039,10 +1039,10 @@ bif_pois(define) ->
      || {Id, Args} <- Macros
     ].
 
--spec generate_arguments(string(), integer()) -> els_parser:args().
+-spec generate_arguments(string(), integer()) -> els_arg:args().
 generate_arguments(Prefix, Arity) ->
     [
-        #{index => N, name => Prefix ++ integer_to_list(N)}
+        els_arg:new(N, Prefix ++ integer_to_list(N))
      || N <- lists:seq(1, Arity)
     ].
 
@@ -1134,7 +1134,7 @@ completion_item(#{kind := Kind = define, id := Name, data := Info}, Data, _, _Ur
         data => Data
     }.
 
--spec args(els_poi:poi(), uri()) -> els_parser:args().
+-spec args(els_poi:poi(), uri()) -> els_arg:args().
 args(#{kind := type_definition, data := POIData}, _Uri) ->
     maps:get(args, POIData);
 args(#{kind := _Kind, data := POIData}, _Uri = undefined) ->
@@ -1145,19 +1145,11 @@ args(#{kind := function, data := POIData, id := Id}, Uri) ->
     POIs = els_dt_document:pois(Document, [spec]),
     case [P || #{id := SpecId} = P <- POIs, SpecId == Id] of
         [#{data := #{args := SpecArgs}} | _] when SpecArgs /= [] ->
-            merge_args(SpecArgs, maps:get(args, POIData));
+            els_arg:merge_args(SpecArgs, maps:get(args, POIData));
         _ ->
             maps:get(args, POIData)
     end.
 
--spec merge_args(els_parser:args(), els_parser:args()) -> els_parser:args().
-merge_args([], []) ->
-    [];
-merge_args([#{name := undefined} | T1], [Arg | T2]) ->
-    [Arg | merge_args(T1, T2)];
-merge_args([Arg | T1], [_ | T2]) ->
-    [Arg | merge_args(T1, T2)].
-
 -spec features() -> items().
 features() ->
     %% Hardcoded for now. Could use erl_features:all() in the future.
@@ -1179,13 +1171,13 @@ macro_label({Name, Arity}) ->
 macro_label(Name) ->
     atom_to_binary(Name, utf8).
 
--spec format_function(atom(), els_parser:args(), boolean(), els_poi:poi_kind()) -> binary().
+-spec format_function(atom(), els_arg:args(), boolean(), els_poi:poi_kind()) -> binary().
 format_function(Name, Args, SnippetSupport, Kind) ->
     format_args(atom_to_label(Name), Args, SnippetSupport, Kind).
 
 -spec format_macro(
     atom() | {atom(), non_neg_integer()},
-    els_parser:args(),
+    els_arg:args(),
     boolean()
 ) -> binary().
 format_macro({Name0, _Arity}, Args, SnippetSupport) ->
@@ -1196,7 +1188,7 @@ format_macro(Name, none, _SnippetSupport) ->
 
 -spec format_args(
     binary(),
-    els_parser:args(),
+    els_arg:args(),
     boolean(),
     els_poi:poi_kind()
 ) -> binary().

apps/els_lsp/src/els_docs.erl

@@ -541,7 +541,7 @@ format_edoc(Desc) when is_map(Desc) ->
     FormattedDoc = els_utils:to_list(docsh_edoc:format_edoc(Doc, #{})),
     [{text, FormattedDoc}].
 
--spec macro_signature(els_poi:poi_id(), els_parser:args()) -> unicode:charlist().
+-spec macro_signature(els_poi:poi_id(), els_arg:args()) -> unicode:charlist().
 macro_signature({Name, _Arity}, Args) ->
     [atom_to_list(Name), "(", lists:join(", ", [els_arg:name(A) || A <- Args]), ")"];
 macro_signature(Name, none) ->

apps/els_lsp/src/els_inlay_hint_provider.erl

@@ -48,23 +48,33 @@ run_inlay_hints_job(Uri, Range) ->
     },
     els_background_job:new(Config).
 
+%% Dialyzer doesn't like this for some reason:
+%% {DefUri, DefPOI} <- [definition(Uri, POI)]
+-dialyzer({nowarn_function, get_inlay_hints/2}).
+
 -spec get_inlay_hints({uri(), els_poi:poi_range()}, any()) ->
     [inlay_hint()].
 get_inlay_hints({Uri, Range}, _) ->
     %% Wait for indexing job to finish, so that we have the updated document
     wait_for_indexing_job(Uri),
     %% Read the document to get the latest version
+    TS = erlang:timestamp(),
     {ok, [Document]} = els_dt_document:lookup(Uri),
     %% Fetch all application POIs that are in the given range
     AppPOIs = els_dt_document:pois_in_range(Document, [application], Range),
-    [
-        arg_hint(ArgRange, ArgName)
+    Res = [
+        arg_hint(ArgRange, DefArgName)
      || #{data := #{args := CallArgs}} = POI <- AppPOIs,
-        #{index := N, name := Name, range := ArgRange} <- CallArgs,
-        #{data := #{args := DefArgs}} <- [definition(Uri, POI)],
-        ArgName <- [arg_name(N, DefArgs)],
-        should_show_arg_hint(Name, ArgName)
-    ].
+        #{index := N, range := ArgRange} = Arg <- CallArgs,
+        {DefUri, DefPOI} <- [definition(Uri, POI)],
+        DefArgName <- [arg_name(N, get_args(DefUri, DefPOI))],
+        should_show_arg_hint(els_arg:name(Arg), DefArgName)
+    ],
+    ?LOG_DEBUG(
+        "Inlay hints took ~p ms",
+        [timer:now_diff(erlang:timestamp(), TS) div 1000]
+    ),
+    Res.
 
 -spec arg_hint(els_poi:poi_range(), string()) -> inlay_hint().
 arg_hint(#{from := {FromL, FromC}}, ArgName) ->
@@ -81,12 +91,18 @@ should_show_arg_hint(Name, Name) ->
     false;
 should_show_arg_hint(_Name, undefined) ->
     false;
-should_show_arg_hint(_Name, _DefArgName) ->
-    true.
+should_show_arg_hint(undefined, _Name) ->
+    true;
+should_show_arg_hint(Name, DefArgName) ->
+    strip_trailing_digits(Name) /= strip_trailing_digits(DefArgName).
+
+-spec strip_trailing_digits(string()) -> string().
+strip_trailing_digits(String) ->
+    string:trim(String, trailing, "0123456789").
 
 -spec wait_for_indexing_job(uri()) -> ok.
 wait_for_indexing_job(Uri) ->
-    %% Add delay to allowing indexing job to finish
+    %% Add delay to allowing indexing job to start
     timer:sleep(10),
     JobTitles = els_background_job:list_titles(),
     case lists:member(<<"Indexing ", Uri/binary>>, JobTitles) of
@@ -98,10 +114,12 @@ wait_for_indexing_job(Uri) ->
             wait_for_indexing_job(Uri)
     end.
 
--spec arg_name(non_neg_integer(), els_parser:args()) -> string() | undefined.
+-spec arg_name(non_neg_integer(), els_arg:args()) -> string() | undefined.
+arg_name(_N, []) ->
+    undefined;
 arg_name(N, Args) ->
-    #{name := Name0} = lists:nth(N, Args),
-    case Name0 of
+    Arg = lists:nth(N, Args),
+    case els_arg:name(Arg) of
         "_" ++ Name ->
             Name;
         Name ->
@@ -111,9 +129,29 @@ arg_name(N, Args) ->
 -spec definition(uri(), els_poi:poi()) -> els_poi:poi() | error.
 definition(Uri, POI) ->
     case els_code_navigation:goto_definition(Uri, POI) of
-        {ok, [{_Uri, DefPOI} | _]} ->
-            DefPOI;
+        {ok, [Match | _]} ->
+            Match;
         Err ->
             ?LOG_INFO("Error: ~p ~p", [Err, POI]),
             error
     end.
+
+-spec get_args(uri(), els_poi:poi()) -> els_arg:args().
+get_args(Uri, #{
+    id := {F, A},
+    data := #{args := Args}
+}) ->
+    {ok, Document} = els_utils:lookup_document(Uri),
+    SpecPOIs = els_dt_document:pois(Document, [spec]),
+    SpecMatches = [
+        SpecArgs
+     || #{id := Id, data := #{args := SpecArgs}} <- SpecPOIs,
+        Id == {F, A},
+        SpecArgs /= []
+    ],
+    case SpecMatches of
+        [] ->
+            Args;
+        [SpecArgs | _] ->
+            els_arg:merge_args(SpecArgs, Args)
+    end.