Enum inside enum - assertion failed: !self.in_variant

[dtolnay]

$ rustc --version
rustc 1.17.0-nightly (b1e31766d 2017-03-03)

enum E {
    A = {
        enum F { B }
        0
    }
}

thread 'rustc' panicked at 'assertion failed: !self.in_variant', /checkout/src/librustc_lint/builtin.rs:472

rust/src/librustc_lint/builtin.rs

Line 472 in b04ebef

assert!(!self.in_variant);

[TimNN]

Taking a quick look at the source, the fix here is probably to turn MissingDoc::in_variant into a depth counter and increment / decrement instead of setting to true / false.