trait X {
    type Y<'a>;
}

const _: () = {
  fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
      //~^ ERROR: expected one of `>`, a const expression, lifetime, or type, found `:`
};

const _: () = {
  fn f1<'a>(arg : Box<dyn X< = 32 >>) {}
      //~^ ERROR: expected one of `>`, a const expression, lifetime, or type, found `=`
};

fn main() {}