error: usage of `Iterator::fold` on a type that implements `Try`
  --> $DIR/manual_try_fold.rs:59:10
   |
LL |         .fold(Some(0i32), |sum, i| sum?.checked_add(*i))
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `try_fold` instead: `try_fold(0i32, |sum, i| ...)`
   |
   = note: `-D clippy::manual-try-fold` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::manual_try_fold)]`

error: usage of `Iterator::fold` on a type that implements `Try`
  --> $DIR/manual_try_fold.rs:63:10
   |
LL |         .fold(NotOption(0i32, 0i32), |sum, i| NotOption(0i32, 0i32));
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `try_fold` instead: `try_fold(..., |sum, i| ...)`

error: usage of `Iterator::fold` on a type that implements `Try`
  --> $DIR/manual_try_fold.rs:66:10
   |
LL |         .fold(NotOptionButWorse(0i32), |sum, i| NotOptionButWorse(0i32));
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `try_fold` instead: `try_fold(0i32, |sum, i| ...)`

error: usage of `Iterator::fold` on a type that implements `Try`
  --> $DIR/manual_try_fold.rs:96:10
   |
LL |         .fold(Some(0i32), |sum, i| sum?.checked_add(*i))
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `try_fold` instead: `try_fold(0i32, |sum, i| ...)`

error: aborting due to 4 previous errors