error: expected type, found `<[_]>::into_vec(box [0, 1])`
  --> $DIR/issue-47666.rs:3:25
   |
LL |     let _ = Option:Some(vec![0, 1]);
   |                   -     ^^^^^^^^^^
   |                   |     |
   |                   |     expected type
   |                   |     in this macro invocation
   |                   |     this macro call doesn't expand to a type
   |                   help: maybe write a path separator here: `::`
   |
   = note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `<expr>: <type>`
   = note: this error originates in the macro `$crate::__rust_force_expr` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error

