rustfmt complains about the type_ascribe macro asking for the builtin to be replaced with the `... : ...` syntax: ``` Error: Diff in /checkout/library/core/src/macros/mod.rs at line 1712: reason = "placeholder syntax for type ascription" )] pub macro type_ascribe($expr:expr, $ty:ty) { - builtin # type_ascribe($expr, $ty) + $expr: $ty } ``` I've worked around this with `#[rustfmt::skip]` on the macro which seems to work, but filing an issue since it seems like somewhat odd behavior as well.