1error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
2  --> $DIR/unboxed-closure-sugar-used-on-struct.rs:7:15
3   |
4LL | fn foo(b: Box<Bar()>) {
5   |               ^^^^^ only `Fn` traits may use parentheses
6
7error[E0107]: this struct takes 1 generic argument but 0 generic arguments were supplied
8  --> $DIR/unboxed-closure-sugar-used-on-struct.rs:7:15
9   |
10LL | fn foo(b: Box<Bar()>) {
11   |               ^^^ expected 1 generic argument
12   |
13note: struct defined here, with 1 generic parameter: `A`
14  --> $DIR/unboxed-closure-sugar-used-on-struct.rs:3:8
15   |
16LL | struct Bar<A> {
17   |        ^^^ -
18help: add missing generic argument
19   |
20LL | fn foo(b: Box<Bar(A)>) {
21   |                   +
22
23error: aborting due to 2 previous errors
24
25Some errors have detailed explanations: E0107, E0214.
26For more information about an error, try `rustc --explain E0107`.
27