1 error[E0635]: unknown feature `tuple_trait`
2 --> $DIR/lang-item-missing-generator.rs:2:51
4 LL | #![feature(no_core, lang_items, unboxed_closures, tuple_trait)]
7 error: requires `generator` lang_item
8 --> $DIR/lang-item-missing-generator.rs:17:17
10 LL | pub fn abc() -> impl FnOnce(f32) {
13 error: aborting due to 2 previous errors
15 For more information about this error, try `rustc --explain E0635`.