Param attributes stripped when functions have certain length

[bbqsrc]

Create a file with this input:

fn a1(#[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] a: u8) {}
fn b1(#[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] bb: u8) {}
fn a2(#[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] a: u8) {}
fn b2(#[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] bb: u8) {}

Run cargo fmt. a1 and b1 will have their attributes stripped. Remove one letter from the line and it will not be stripped as seen in a2 and b2.

fn a1(a: u8) {}
fn b1(bb: u8) {}
fn a2(
    #[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] a: u8,
) {
}
fn b2(
    #[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] bb: u8,
) {
}

[calebcartwright]

Confirmed bug that's still reproducible on master/v2.0.0-rc.1-nightly.

I believe this could be fixed by updating the Spanned impl for Param

Changing:

rustfmt/rustfmt-core/rustfmt-lib/src/spanned.rs

Lines 112 to 120 in facba6a

	impl Spanned for ast::Param {
	fn span(&self) -> Span {
	if crate::items::is_named_param(self) {
	mk_sp(self.pat.span.lo(), self.ty.span.hi())
	} else {
	self.ty.span
	}
	}
	}

to something like:

impl Spanned for ast::Param {
    fn span(&self) -> Span {
        if crate::items::is_named_param(self) {
            mk_sp(crate::items::span_lo_for_param(self), self.ty.span.hi())
        } else {
            self.ty.span
        }
    }
}