diff --git a/lib/parser/source/range.rb b/lib/parser/source/range.rb
index 9463651b5..1850ae527 100644
--- a/lib/parser/source/range.rb
+++ b/lib/parser/source/range.rb
@@ -13,7 +13,7 @@ module Source
     #        ^^
     #
     # @!attribute [r] source_buffer
-    #  @return [Parser::Diagnostic::Engine]
+    #  @return [Parser::Source::Buffer]
     #
     # @!attribute [r] begin_pos
     #  @return [Integer] index of the first character in the range
diff --git a/lib/parser/source/tree_rewriter.rb b/lib/parser/source/tree_rewriter.rb
index 180d246c6..c60f98822 100644
--- a/lib/parser/source/tree_rewriter.rb
+++ b/lib/parser/source/tree_rewriter.rb
@@ -129,6 +129,8 @@ def empty?
       ##
       # Merges the updates of argument with the receiver.
       # Policies of the receiver are used.
+      # This action is atomic in that it won't change the receiver
+      # unless it succeeds.
       #
       # @param [Rewriter] with
       # @return [Rewriter] self