Fix for issue #4546 - proper indent multiline post-comment in a list

Author: davidBar-On

src/formatting/lists.rs

@@ -461,6 +461,13 @@ where
 
             let mut formatted_comment = rewrite_post_comment(&mut item_max_width)?;
 
+            // Mmultiline comments are not included in a previous "indentation group".
+            // Each multiline comment is a considered as a separage group.
+            if formatted_comment.contains('\n') {
+                item_max_width = None;
+                formatted_comment = rewrite_post_comment(&mut item_max_width)?;
+            }
+
             if !starts_with_newline(comment) {
                 if formatting.align_comments {
                     let mut comment_alignment = post_comment_alignment(
@@ -537,10 +544,21 @@ where
     for item in items.clone().into_iter().skip(i) {
         let item = item.as_ref();
         let inner_item_width = UnicodeSegmentation::graphemes(item.inner_as_ref(), true).count();
+        let post_comment_is_multiline = item
+            .post_comment
+            .as_ref()
+            .map_or(false, |s| s.trim().contains('\n'));
+
+        // Each multiline comment is an "indentation group" on its own
+        if first && post_comment_is_multiline {
+            return inner_item_width;
+        }
+
         if !first
             && (item.is_different_group()
                 || item.post_comment.is_none()
-                || inner_item_width + overhead > max_budget)
+                || inner_item_width + overhead > max_budget
+                || post_comment_is_multiline)
         {
             return max_width;
         }

tests/source/issue-4546.rs

@@ -0,0 +1,29 @@
+fn main() {
+    let v = [
+        "A",            /* item A comment */
+		"BBB",    /* item B comment */
+        "CCCCCC",      /* item C comment line 1
+                   * item C comment line 2 */
+        "D",  /* item D comment line 1
+                   * item D comment line 2 */
+        "EEEEE",                /* item E comment */
+		"FFF", /* item F comment */
+        "GG",            /* item G comment line 1
+                * item G comment line 2 */
+    ];
+}
+
+fn main() {
+    let v = [
+        "GG",            /* item G comment line 1
+                * item G comment line 2 */
+        "AAAAA",            /* item A comment */
+		"BBB",    /* item B comment */
+        "CCCCCC",      /* item C comment line 1
+                   * item C comment line 2 */
+        "D",  /* item D comment line 1
+                   * item D comment line 2 */
+        "E",                /* item E comment */
+		"FFF", /* item F comment */
+    ];
+}

tests/target/issue-4546.rs

@@ -0,0 +1,29 @@
+fn main() {
+    let v = [
+        "A",   /* item A comment */
+        "BBB", /* item B comment */
+        "CCCCCC", /* item C comment line 1
+                   * item C comment line 2 */
+        "D", /* item D comment line 1
+              * item D comment line 2 */
+        "EEEEE", /* item E comment */
+        "FFF",   /* item F comment */
+        "GG", /* item G comment line 1
+               * item G comment line 2 */
+    ];
+}
+
+fn main() {
+    let v = [
+        "GG", /* item G comment line 1
+               * item G comment line 2 */
+        "AAAAA", /* item A comment */
+        "BBB",   /* item B comment */
+        "CCCCCC", /* item C comment line 1
+                   * item C comment line 2 */
+        "D", /* item D comment line 1
+              * item D comment line 2 */
+        "E",   /* item E comment */
+        "FFF", /* item F comment */
+    ];
+}