error: arbitrary expressions aren't allowed in patterns
  --> $DIR/vec-macro-in-pattern.rs:7:14
   |
LL |         Some(vec![43]) => {}
   |              ^^^^^^^^
   |
   = note: the `expr` fragment specifier forces the metavariable's content to be an expression
   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error