lists: Detect block comment by starting from the end.

src/lists.rs

@@ -566,14 +566,9 @@ where
 
 pub fn extract_pre_comment(pre_snippet: &str) -> (Option<String>, ListItemCommentStyle) {
     let trimmed_pre_snippet = pre_snippet.trim();
+    let has_block_comment = trimmed_pre_snippet.ends_with("*/");
     let has_single_line_comment = trimmed_pre_snippet.starts_with("//");
-    let has_block_comment = trimmed_pre_snippet.starts_with("/*");
-    if has_single_line_comment {
-        (
-            Some(trimmed_pre_snippet.to_owned()),
-            ListItemCommentStyle::DifferentLine,
-        )
-    } else if has_block_comment {
+    if has_block_comment {
         let comment_end = pre_snippet.chars().rev().position(|c| c == '/').unwrap();
         if pre_snippet
             .chars()
@@ -591,6 +586,11 @@ pub fn extract_pre_comment(pre_snippet: &str) -> (Option<String>, ListItemCommen
                 ListItemCommentStyle::SameLine,
             )
         }
+    } else if has_single_line_comment {
+        (
+            Some(trimmed_pre_snippet.to_owned()),
+            ListItemCommentStyle::DifferentLine,
+        )
     } else {
         (None, ListItemCommentStyle::None)
     }

tests/source/expr-block.rs

@@ -280,6 +280,21 @@ fn issue_1862() {
     )
 }
 
+fn issue_3025() {
+    foo(
+        // This describes the argument below.
+        /* bar = */ None ,
+        // This describes the argument below.
+        something_something,
+        // This describes the argument below. */
+        None ,
+        // This describes the argument below.
+        /* This comment waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaay too long to be kept on the same line */ None ,
+        // This describes the argument below.
+        /* com */ this_last_arg_is_tooooooooooooooooooooooooooooooooo_long_to_be_kept_with_the_pre_comment ,
+    )
+}
+
 fn issue_1878() {
     let channel: &str = seq.next_element()?.ok_or_else(|| de::Error::invalid_length(2, &self))?;
 }

tests/target/expr-block.rs

@@ -281,6 +281,23 @@ fn issue_1862() {
     )
 }
 
+fn issue_3025() {
+    foo(
+        // This describes the argument below.
+        /* bar = */ None,
+        // This describes the argument below.
+        something_something,
+        // This describes the argument below. */
+        None,
+        // This describes the argument below.
+        /* This comment waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaay too long to be kept on the same line */
+        None,
+        // This describes the argument below.
+        /* com */
+        this_last_arg_is_tooooooooooooooooooooooooooooooooo_long_to_be_kept_with_the_pre_comment,
+    )
+}
+
 fn issue_1878() {
     let channel: &str = seq
         .next_element()?