Do not extract comments without a newline

Author: josevalim

lib/elixir/lib/code/formatter.ex

@@ -1873,19 +1873,25 @@ defmodule Code.Formatter do
   end
 
   defp each_quoted_to_algebra_with_comments([arg | args], acc, max_line, state, comments?, fun) do
-    {doc_start, doc_end} = traverse_line(arg, {@max_line, @min_line})
+    case traverse_line(arg, {@max_line, @min_line}) do
+      {@max_line, @min_line} ->
+        {doc_triplet, state} = fun.(arg, args, state)
+        acc = [doc_triplet | acc]
+        each_quoted_to_algebra_with_comments(args, acc, max_line, state, comments?, fun)
 
-    {acc, comments, comments?} =
-      extract_comments_before(doc_start, acc, state.comments, comments?)
+      {doc_start, doc_end} ->
+        {acc, comments, comments?} =
+          extract_comments_before(doc_start, acc, state.comments, comments?)
 
-    {doc_triplet, state} = fun.(arg, args, %{state | comments: comments})
+        {doc_triplet, state} = fun.(arg, args, %{state | comments: comments})
 
-    {acc, comments, comments?} =
-      extract_comments_trailing(doc_start, doc_end, acc, state.comments, comments?)
+        {acc, comments, comments?} =
+          extract_comments_trailing(doc_start, doc_end, acc, state.comments, comments?)
 
-    acc = [adjust_trailing_newlines(doc_triplet, doc_end, comments) | acc]
-    state = %{state | comments: comments}
-    each_quoted_to_algebra_with_comments(args, acc, max_line, state, comments?, fun)
+        acc = [adjust_trailing_newlines(doc_triplet, doc_end, comments) | acc]
+        state = %{state | comments: comments}
+        each_quoted_to_algebra_with_comments(args, acc, max_line, state, comments?, fun)
+    end
   end
 
   defp extract_comments_before(max, acc, [%{line: line} = comment | rest], _) when line < max do

lib/elixir/test/elixir/code_normalizer/formatted_ast_test.exs

@@ -15,11 +15,14 @@ defmodule Code.Normalizer.FormatterASTTest do
     good = String.trim(good)
 
     to_quoted_opts =
-      [
-        literal_encoder: &{:ok, {:__block__, &2, [&1]}},
-        token_metadata: true,
-        unescape: false
-      ] ++ opts
+      Keyword.merge(
+        [
+          literal_encoder: &{:ok, {:__block__, &2, [&1]}},
+          token_metadata: true,
+          unescape: false
+        ],
+        opts
+      )
 
     {quoted, comments} = Code.string_to_quoted_with_comments!(good, to_quoted_opts)
 
@@ -464,6 +467,29 @@ defmodule Code.Normalizer.FormatterASTTest do
       """
     end
 
+    test "handles comments with unescaped literal" do
+      assert_same """
+                  # before
+                  Mix.install([:foo])
+                  # after
+                  """,
+                  literal_encoder: fn literal, _ -> {:ok, literal} end
+
+      assert_same """
+                  # before
+                  Mix.install([1 + 2, :foo])
+                  # after
+                  """,
+                  literal_encoder: fn literal, _ -> {:ok, literal} end
+
+      assert_same """
+                  # before
+                  Mix.install([:foo, 1 + 2])
+                  # after
+                  """,
+                  literal_encoder: fn literal, _ -> {:ok, literal} end
+    end
+
     test "before and after expressions with newlines" do
       assert_same """
       # before comment