Const expressions break formatting

[DianaNites]

stable

rustc --version: rustc 1.59.0 (9d1b2106e 2022-02-23)
rustfmt --version: rustfmt 1.4.38-stable (9d1b210 2022-02-23)

nightly

rustc --version: rustc 1.61.0-nightly (8d60bf427 2022-03-19)
rustfmt --version: rustfmt 1.4.38-nightly (8d60bf4 2022-03-19)

Current stable and nightly rustfmts format the following code incorrectly

struct Example<const N: usize = { 1048576 }> {
    //
}

to

struct Example<const N: usize = { 1048576 }> {
    1048576 }> {
//
}

Or, with normalize_comments = true set

struct Example<const N: usize = { 1048576 }> {
    // 1048576 }> {
}

In this case there is a new // 1048576 }> { prepended on every format operation

[ytmimi]

Thanks for the report!

looks like the Span we're using is off. A similar issue was seen with #5011, so I imagine the fix should be similar to that.