complete with parens if there are remote calls (#916)

* complete with parens if there are remote calls

* move to context and using Code.Fragment.cursor_context/1

Author: Milo Lee

apps/language_server/lib/language_server/providers/completion.ex

@@ -138,6 +138,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
       text_before_cursor: text_before_cursor,
       text_after_cursor: text_after_cursor,
       prefix: prefix,
+      remote_calls?: match?({:dot, _, _}, Code.Fragment.cursor_context(prefix)),
       def_before: def_before,
       pipe_before?: Regex.match?(Regex.recompile!(~r/\|>\s*#{prefix}$/), text_before_cursor),
       capture_before?: Regex.match?(Regex.recompile!(~r/&#{prefix}$/), text_before_cursor),
@@ -1030,6 +1031,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
     } = info
 
     %{
+      remote_calls?: remote_calls?,
       pipe_before?: pipe_before?,
       capture_before?: capture_before?,
       text_after_cursor: text_after_cursor
@@ -1038,7 +1040,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
     locals_without_parens = Keyword.get(options, :locals_without_parens)
     signature_help_supported? = Keyword.get(options, :signature_help_supported, false)
     signature_after_complete? = Keyword.get(options, :signature_after_complete, true)
-    with_parens? = function_name_with_parens?(name, arity, locals_without_parens)
+    with_parens? = remote_calls? || function_name_with_parens?(name, arity, locals_without_parens)
 
     trigger_signature? = signature_help_supported? && ((arity == 1 && !pipe_before?) || arity > 1)
 

apps/language_server/test/providers/completion_test.exs

@@ -829,6 +829,25 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
       assert item["command"] == @signature_command
     end
 
+    test "complete with parens if there are remote calls" do
+      text = """
+      defmodule MyModule do
+        def dummy_function() do
+          Map.drop
+          #       ^
+        end
+      end
+      """
+
+      {line, char} = {2, 12}
+      TestUtils.assert_has_cursor_char(text, line, char)
+
+      opts = Keyword.merge(@supports, locals_without_parens: MapSet.new(drop: 2))
+      {:ok, %{"items" => [item]}} = Completion.completion(text, line, char, opts)
+
+      assert item["insertText"] == "drop($1)$0"
+    end
+
     test "function with arity 0 does not triggers signature" do
       text = """
       defmodule MyModule do