Code change:
} fn unindent_fragments(docs: &mut Vec<DocFragment>) { <del> for fragment in docs { fragment.doc = unindent(&fragment.doc); } } fn unindent(s: &str) -> String { let lines = s.lines().collect::<Vec<&str>>(); let mut saw_first_line = false; let mut saw_second_line = false; let min_indent = lines.iter().fold(usize::MAX, |min_indent, line| { // After we see the first non-whitespace line, look at // the line we have. If it is not whitespace, and therefore // part of the first paragraph, then ignore the indentation // level of the first line let ignore_previous_indents = saw_first_line && !saw_second_line && !line.chars().all(|c| c.is_whitespace()); </del> <ins> // `add` is used in case the most common sugared doc syntax is used ("/// "). The other // fragments kind's lines are never starting with a whitespace unless they are using some // markdown formatting requiring it. Therefore, if the doc block have a mix between the two, // we need to take into account the fact that the minimum indent minus one (to take this // whitespace into account). // // For example: // // /// hello! // #[doc = "another"] // // In this case, you want "hello! another" and not "hello!  another". let add = if docs.windows(2).any(|arr| arr[0].kind != arr[1].kind) && docs.iter().any(|d| d.kind == DocFragmentKind::SugaredDoc) { // In case we have a mix of sugared doc comments and "raw" ones, we want the sugared one to // "decide" how much the minimum indent will be. 1 } else { 0 }; </ins> <del> let min_indent = if ignore_previous_indents { usize::MAX } else { min_indent }; </del> <ins> // `min_indent` is used to know how much whitespaces from the start of each lines must be // removed. Example: // // ///     hello! // #[doc = "another"] // // In here, the `min_indent` is 1 (because non-sugared fragment are always counted with minimum // 1 whitespace), meaning that "hello!" will be considered a codeblock because it starts with 4 // (5 - 1) whitespaces. let min_indent = match docs .iter() .map(|fragment| { fragment.doc.lines().fold(usize::MAX, |min_indent, line| { if line.chars().all(|c| c.is_whitespace()) { min_indent } else { // Compare against either space or tab, ignoring whether they are // mixed or not. let whitespace = line.chars().take_while(|c| *c == ' ' || *c == 't').count(); cmp::min(min_indent, whitespace) + if fragment.kind == DocFragmentKind::SugaredDoc { 0 } else { add } } }) }) .min() { Some(x) => x, None => return, }; </ins> <del> if saw_first_line { saw_second_line = true; </del> <ins> for fragment in docs { if fragment.doc.lines().count() == 0 { continue; </ins> } <del> if line.chars().all(|c| c.is_whitespace()) { min_indent </del> <ins> let min_indent = if fragment.kind != DocFragmentKind::SugaredDoc && min_indent > 0 { min_indent - add </ins> } else { <del> saw_first_line = true; let mut whitespace = 0; line.chars().all(|char| { // Compare against either space or tab, ignoring whether they // are mixed or not if char == ' ' || char == 't' { whitespace += 1; true </del> <ins> min_indent }; fragment.doc = fragment .doc .lines() .map(|line| { if line.chars().all(|c| c.is_whitespace()) { line.to_string() </ins> } else { <del> false </del> <ins> assert!(line.len() >= min_indent); line[min_indent..].to_string() </ins> } <del> }); cmp::min(min_indent, whitespace) } }); if !lines.is_empty() { let mut unindented = vec![lines[0].trim_start().to_string()]; unindented.extend_from_slice( &lines[1..] .iter() .map(|&line| { if line.chars().all(|c| c.is_whitespace()) { line.to_string() } else { assert!(line.len() >= min_indent); line[min_indent..].to_string() } }) .collect::<Vec<_>>(), ); unindented.join("n") } else { s.to_string() </del> <ins> }) .collect::<Vec<_>>() .join("n"); </ins> } }

Related discussion:
text: (x, "n bar();n"); //!
They are not supposed to be applied to a doc comment I do not think that. Your example would make sense for which I also consider to be wrong, but I am talking about which should insert the attribute conditionally but that is not the point. It might help to illustrate my thought process; We have some kind of documented item: rust /// let example = Example::new() /// .first() /// .build(); /// and each of those is turned into a doc attribute rust"] #[doc = "let example = Example::new()"] #[doc = " .first()"] #[doc = " .build();"] #[doc = " In a later step those attributes would then be concatenated and parsed as markdown or whatever. I want to use this behavior to document items conditionally, depending on which features the crate user has enabled. One way to do this would be to do rust let example = Example::new() .first() .build(); rust let example = Example::new() .first() .second() .build(); but that would blow up the source code with many duplicate lines, where only some minor things were changed. So I thought that it might make more sense to conditionally include a doc comment like this: rust /// let example = Example::new() /// .first() #[cfgattr(feature = "one", doc = " .second()")] /// .build(); /// which would turn into rust"] #[doc = "let example = Example::new()"] #[doc = " .first()"] #[doc = " .second()"] #[doc = " .build();"] #[doc = " or rust"] #[doc = "let example = Example::new()"] #[doc = " .first()"] #[doc = " .build();"] #[doc = " depending on whether the feature is enabled. So the attribute should not be inserted and not applied to the following doc comment. The weird thing is that the manually expanded version is working as expected. rust"] #[doc = "let example = Example::new()"] #[doc = " .first()"] #[cfg_attr(feature = "one", doc = " .second()")] #[doc = " .build();"] #[doc = " but this is very unhandy to work with :/
I was randomly looking at passes for another reason and noticed what is likely the source of this issue.