Newlines in deprecation warning are handled strangely - double newlines are stripped completely

[orlp]

Code

pub struct A;

impl A {
    #[deprecated(note =
"Foo some.
Bar sentence.")]
    /// Function 1.
    pub fn func1() {}

    #[deprecated(note =
"Foo some.

Bar sentence.")]
    /// Function 2.
    pub fn func2() {}
}

Reproduction Steps

cargo doc

Expected Outcome

I would expect single newlines to get replaced with a space, and double newlines to start a new paragraph, like in the rest of the documentation.

Actual Output

Single newlines are kept verbatim, double newlines are stripped entirely. Note the lack of a space between sentences in func2:

Version

rustdoc 1.93.0-nightly (25d319a 2025-11-11)

[lolbinarycat]

rust/src/librustdoc/html/markdown.rs

Line 1463 in 1d6c526

pub(crate) fn write_into(self, mut f: impl fmt::Write) -> fmt::Result {

It seems like we're doing some kinda odd stuff, only partially interpreting these strings as markdown (for example, they're styled with white-space: pre-wrap.

[lolbinarycat]

Yeah, strangely, this seems to be intentional behavior, we are explicitly removing the Tag::Paragraph events, but that seems very ill advised. I believe this is actually working around a quirk in write_html_fmt where it adds \n between <p> elements, but there are better ways of doing that.