error[E0107]: missing generics for struct `Vec`
  --> $DIR/issue-92305.rs:5:45
   |
LL | fn f<T>(data: &[T]) -> impl Iterator<Item = Vec> {
   |                                             ^^^ expected at least 1 generic argument
   |
note: struct defined here, with at least 1 generic parameter: `T`
  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
   |
LL | pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
   |            ^^^ -
help: add missing generic argument
   |
LL | fn f<T>(data: &[T]) -> impl Iterator<Item = Vec<T>> {
   |                                             ~~~~~~

error: aborting due to previous error

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