error: ambiguous `+` in a type
  --> $DIR/impl-fn-parsing-ambiguities.rs:4:27
   |
LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
   |                           ^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + '_)`

error: ambiguous `+` in a type
  --> $DIR/impl-fn-parsing-ambiguities.rs:10:24
   |
LL | fn b() -> impl Fn() -> impl Debug + Send {
   |                        ^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + Send)`

error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
  --> $DIR/impl-fn-parsing-ambiguities.rs:4:40
   |
LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
   |                                        ^^
   |
note: lifetime declared here
  --> $DIR/impl-fn-parsing-ambiguities.rs:4:19
   |
LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
   |                   ^

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0657`.