DEV: Handle comments between list elements.

src/ast/printer/mod.rs

@@ -86,10 +86,8 @@ where
     fn print_comment_group(&mut self, line: usize) -> std::io::Result<()> {
         if let Some(ref map) = self.comment_map {
             let empty: Vec<Token> = Vec::new();
-            //eprintln!("comment line candidate: {}", line);
             let cg = map.get(&line).unwrap_or(&empty);
             let indent = self.make_indent();
-            //eprintln!("comment_group: {:?}", cg);
             for c in cg.iter() {
                 write!(self.w, "{}// {}\n", indent, c.fragment.trim())?;
             }
@@ -134,6 +132,7 @@ where
             write!(self.w, "\n")?;
         }
         for e in def.elems.iter() {
+            self.render_comment_if_needed(e.pos().line)?;
             write!(self.w, "{}", indent)?;
             self.render_expr(e)?;
             write!(self.w, ",\n")?;
@@ -434,9 +433,6 @@ where
             self.render_stmt(v)?;
         }
         if let Some(last_comment_line) = self.comment_group_lines.first() {
-            //eprintln!("last_comment_line is: {}", last_comment_line);
-            //eprintln!("comment_map is: {:?}", self.comment_map);
-            //eprintln!("coment_group_lines is: {:?}", self.comment_group_lines);
             self.render_missed_comments(*last_comment_line + 1)?;
         }
         Ok(())

src/ast/printer/test.rs

@@ -450,3 +450,17 @@ fn test_tuple_expression_with_embedded_comment_and_mid_field_expr() {
         )
     );
 }
+
+#[test]
+fn test_list_expression_with_embedded_comment() {
+    let mut comment_map = BTreeMap::new();
+    let input = "[\n  bar,\n  // a comment\n  foo,\n];";
+    let stmts = assert_parse(input, Some(&mut comment_map));
+    let mut buffer: Vec<u8> = Vec::new();
+    let mut printer = AstPrinter::new(2, &mut buffer).with_comment_map(&comment_map);
+    assert!(printer.render(&stmts).is_ok());
+    assert_eq!(
+        String::from_utf8(buffer).unwrap(),
+        format!("{}\n", input.trim())
+    );
+}