error: lifetime in trait object type must be followed by `+`
  --> $DIR/gat-trait-path-parenthesised-args.rs:7:29
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
   |                             ^^

error: parenthesized generic arguments cannot be used in associated type constraints
  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
   |                           ^^^^^

warning: trait objects without an explicit `dyn` are deprecated
  --> $DIR/gat-trait-path-parenthesised-args.rs:7:29
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
   |                             ^^ help: use `dyn`: `dyn 'a`
   |
   = note: `#[warn(bare_trait_objects)]` on by default
   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>

error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
   |                           ^ expected 1 lifetime argument
   |
note: associated type defined here, with 1 lifetime parameter: `'a`
  --> $DIR/gat-trait-path-parenthesised-args.rs:4:8
   |
LL |   type Y<'a>;
   |        ^ --
help: add missing lifetime argument
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a, 'a) = &'a ()>>) {}
   |                             +++

error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
   |
LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
   |                           ^---- help: remove these generics
   |                           |
   |                           expected 0 generic arguments
   |
note: associated type defined here, with 0 generic parameters
  --> $DIR/gat-trait-path-parenthesised-args.rs:4:8
   |
LL |   type Y<'a>;
   |        ^

error: aborting due to 4 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0107`.