error[E0214]: parenthesized parameters may only be used with a trait
  --> $DIR/unboxed-closure-sugar-used-on-struct-3.rs:24:16
   |
LL |     let b = Bar::(isize, usize)::new(); // OK too (for the parser)
   |                ^^^^^^^^^^^^^^^^ only traits may use parentheses

error: aborting due to previous error

For more information about this error, try `rustc --explain E0214`.