Autocompletion: more specific CompletionItemKind (#419)

* Autocompletion: more specific CompletionItemKind

Instead of returning module for all types of modules, return "interface"
for behaviours and protocols, and "struct" for structs.

Also add the subtype to the label

* fix server test

* Treat exceptions as structs

* Fix formatting

Author: axelson

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

@@ -246,9 +246,25 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
         "module"
       end
 
+    kind =
+      case subtype do
+        :behaviour -> :interface
+        :protocol -> :interface
+        :exception -> :struct
+        :struct -> :struct
+        _ -> :module
+      end
+
+    label =
+      if subtype do
+        "#{name} (#{subtype})"
+      else
+        name
+      end
+
     %__MODULE__{
-      label: name,
-      kind: :module,
+      label: label,
+      kind: kind,
       detail: detail,
       documentation: summary,
       insert_text: name,
@@ -582,8 +598,9 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
     text != ""
   end
 
-  defp completion_kind(type) do
-    case type do
+  # LSP CompletionItemKind enumeration
+  defp completion_kind(kind) do
+    case kind do
       :text -> 1
       :method -> 2
       :function -> 3

apps/language_server/test/providers/completion_test.exs

@@ -110,6 +110,26 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
     assert length(items) == 0
   end
 
+  test "completions of protocols are rendered as an interface" do
+    text = """
+    defmodule MyModule do
+      def dummy_function() do
+        ElixirLS.LanguageServer.Fixtures.ExampleP
+        #                                        ^
+      end
+    end
+    """
+
+    {line, char} = {2, 45}
+    TestUtils.assert_has_cursor_char(text, line, char)
+
+    {:ok, %{"items" => [item]}} = Completion.completion(text, line, char, @supports)
+
+    # 8 is interface
+    assert item["kind"] == 8
+    assert item["label"] == "ExampleProtocol (protocol)"
+  end
+
   test "provides completions for protocol functions" do
     text = """
     defimpl ElixirLS.LanguageServer.Fixtures.ExampleProtocol, for: MyModule do
@@ -132,6 +152,50 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
            ]
   end
 
+  test "completions of behaviours are rendered as an interface" do
+    text = """
+    defmodule MyModule do
+      def dummy_function() do
+        ElixirLS.LanguageServer.Fixtures.ExampleB
+        #                                        ^
+      end
+    end
+    """
+
+    {line, char} = {2, 45}
+    TestUtils.assert_has_cursor_char(text, line, char)
+
+    {:ok, %{"items" => items}} = Completion.completion(text, line, char, @supports)
+
+    assert [item, _] = items
+
+    # 8 is interface
+    assert item["kind"] == 8
+    assert item["label"] == "ExampleBehaviour (behaviour)"
+  end
+
+  test "completions of exceptions are rendered as a struct" do
+    text = """
+    defmodule MyModule do
+      def dummy_function() do
+        ElixirLS.LanguageServer.Fixtures.ExampleE
+        #                                        ^
+      end
+    end
+    """
+
+    {line, char} = {2, 45}
+    TestUtils.assert_has_cursor_char(text, line, char)
+
+    {:ok, %{"items" => items}} = Completion.completion(text, line, char, @supports)
+
+    assert [item] = items
+
+    # 22 is struct
+    assert item["kind"] == 22
+    assert item["label"] == "ExampleException (exception)"
+  end
+
   test "provides completions for callbacks without `def` before" do
     text = """
     defmodule MyModule do
@@ -199,7 +263,7 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
       |> Enum.filter(&(&1["detail"] =~ "struct"))
       |> Enum.map(& &1["label"])
 
-    assert "NaiveDateTime" in completions
+    assert "NaiveDateTime (struct)" in completions
 
     {line, char} = {4, 17}
     TestUtils.assert_has_cursor_char(text, line, char)
@@ -221,7 +285,7 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
       |> Enum.filter(&(&1["detail"] =~ "struct"))
       |> Enum.map(& &1["label"])
 
-    assert "NaiveDateTime" in completions
+    assert "NaiveDateTime (struct)" in completions
   end
 
   describe "deprecated" do
@@ -257,6 +321,28 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
   end
 
   describe "structs and maps" do
+    test "completions of structs are rendered as a struct" do
+      text = """
+      defmodule MyModule do
+        def dummy_function() do
+          ElixirLS.LanguageServer.Fixtures.ExampleS
+          #                                        ^
+        end
+      end
+      """
+
+      {line, char} = {2, 45}
+      TestUtils.assert_has_cursor_char(text, line, char)
+
+      {:ok, %{"items" => items}} = Completion.completion(text, line, char, @supports)
+
+      assert [item] = items
+
+      # 22 is struct
+      assert item["kind"] == 22
+      assert item["label"] == "ExampleStruct (struct)"
+    end
+
     test "returns struct fields in call syntax" do
       text = """
       defmodule MyModule do

apps/language_server/test/server_test.exs

@@ -675,8 +675,8 @@ defmodule ElixirLS.LanguageServer.ServerTest do
                %{
                  "detail" => "behaviour",
                  "documentation" => _,
-                 "kind" => 9,
-                 "label" => "GenServer"
+                 "kind" => 8,
+                 "label" => "GenServer (behaviour)"
                }
                | _
              ]

apps/language_server/test/support/fixtures/example_exception.ex

@@ -0,0 +1,3 @@
+defmodule ElixirLS.LanguageServer.Fixtures.ExampleException do
+  defexception [:message]
+end

apps/language_server/test/support/fixtures/example_struct.ex

@@ -0,0 +1,3 @@
+defmodule ElixirLS.LanguageServer.Fixtures.ExampleStruct do
+  defstruct [:name]
+end