error[E0277]: a value of type `Vec` cannot be built from an iterator over elements of type `&X` --> $DIR/invalid-iterator-chain.rs:6:7 | LL | i.collect() | ^^^^^^^ value of type `Vec` cannot be built from `std::iter::Iterator` | = help: the trait `FromIterator<&X>` is not implemented for `Vec` = help: the trait `FromIterator` is implemented for `Vec` note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:4:26 | LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec { | ^^^^^^^^^^^ `Iterator::Item` is `&X` here LL | let i = i.map(|x| x.clone()); | ------------------ `Iterator::Item` remains `&X` here note: required by a bound in `collect` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:15:33 | LL | println!("{}", scores.sum::()); | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator` | | | required by a bound introduced by this call | = help: the trait `Sum<()>` is not implemented for `i32` = help: the following other types implement trait `Sum`: > note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:12:10 | LL | let scores = vec![(0, 0)] | ------------ this expression has type `Vec<({integer}, {integer})>` LL | .iter() | ------ `Iterator::Item` is `&({integer}, {integer})` here LL | .map(|(a, b)| { | __________^ LL | | a + b; LL | | }); | |__________^ `Iterator::Item` changed to `()` here note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:26:20 | LL | .sum::(), | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator` | | | required by a bound introduced by this call | = help: the trait `Sum<()>` is not implemented for `i32` = help: the following other types implement trait `Sum`: > note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:25:14 | LL | vec![0, 1] | ---------- this expression has type `Vec<{integer}>` LL | .iter() | ------ `Iterator::Item` is `&{integer}` here LL | .map(|x| x * 2) | -------------- `Iterator::Item` changed to `{integer}` here LL | .map(|x| x as f64) | ----------------- `Iterator::Item` changed to `f64` here LL | .map(|x| x as i64) | ----------------- `Iterator::Item` changed to `i64` here LL | .filter(|x| *x > 0) | ------------------ `Iterator::Item` remains `i64` here LL | .map(|x| { x + 1 }) | ------------------ `Iterator::Item` remains `i64` here LL | .map(|x| { x; }) | ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `f64` --> $DIR/invalid-iterator-chain.rs:36:20 | LL | .sum::(), | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator` | | | required by a bound introduced by this call | = help: the trait `Sum` is not implemented for `i32` = help: the following other types implement trait `Sum`: > note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:33:14 | LL | vec![0, 1] | ---------- this expression has type `Vec<{integer}>` LL | .iter() | ------ `Iterator::Item` is `&{integer}` here LL | .map(|x| x * 2) | -------------- `Iterator::Item` changed to `{integer}` here LL | .map(|x| x as f64) | ^^^^^^^^^^^^^^^^^ `Iterator::Item` changed to `f64` here LL | .filter(|x| *x > 0.0) | -------------------- `Iterator::Item` remains `f64` here LL | .map(|x| { x + 1.0 }) | -------------------- `Iterator::Item` remains `f64` here note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:38:60 | LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::()); | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator` | | | required by a bound introduced by this call | = help: the trait `Sum<()>` is not implemented for `i32` = help: the following other types implement trait `Sum`: > note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:38:38 | LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::()); | ---------- ------ ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here | | | | | `Iterator::Item` is `&{integer}` here | this expression has type `Vec<{integer}>` note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `&()` --> $DIR/invalid-iterator-chain.rs:39:46 | LL | println!("{}", vec![(), ()].iter().sum::()); | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator` | | | required by a bound introduced by this call | = help: the trait `Sum<&()>` is not implemented for `i32` = help: the following other types implement trait `Sum`: > note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:39:33 | LL | println!("{}", vec![(), ()].iter().sum::()); | ------------ ^^^^^^ `Iterator::Item` is `&()` here | | | this expression has type `Vec<()>` note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error[E0277]: a value of type `Vec` cannot be built from an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:48:25 | LL | let g: Vec = f.collect(); | ^^^^^^^ value of type `Vec` cannot be built from `std::iter::Iterator` | = help: the trait `FromIterator<()>` is not implemented for `Vec` = help: the trait `FromIterator` is implemented for `Vec` note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:44:15 | LL | let a = vec![0]; | ------- this expression has type `Vec<{integer}>` LL | let b = a.into_iter(); | ----------- `Iterator::Item` is `{integer}` here LL | let c = b.map(|x| x + 1); | -------------- `Iterator::Item` remains `{integer}` here LL | let d = c.filter(|x| *x > 10 ); | -------------------- `Iterator::Item` remains `{integer}` here LL | let e = d.map(|x| { | _______________^ LL | | x + 1; LL | | }); | |______^ `Iterator::Item` changed to `()` here LL | let f = e.filter(|_| false); | ----------------- `Iterator::Item` remains `()` here note: required by a bound in `collect` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL error: aborting due to 7 previous errors For more information about this error, try `rustc --explain E0277`.