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6d23ee8430
When encountering method call chains of `Iterator`, check for trailing `;` in the body of closures passed into `Iterator::map`, as well as calls to `<T as Clone>::clone` when `T` is a type param and `T: !Clone`. Fix #9082.
158 lines
7.1 KiB
Plaintext
158 lines
7.1 KiB
Plaintext
error[E0277]: a value of type `Vec<X>` cannot be built from an iterator over elements of type `&X`
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--> $DIR/invalid-iterator-chain-fixable.rs:7:7
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LL | let i = i.map(|x| x.clone());
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| ------- this method call is cloning the reference `&X`, not `X` which doesn't implement `Clone`
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LL | i.collect()
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| ^^^^^^^ value of type `Vec<X>` cannot be built from `std::iter::Iterator<Item=&X>`
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= help: the trait `FromIterator<&X>` is not implemented for `Vec<X>`
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= help: the trait `FromIterator<X>` is implemented for `Vec<X>`
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= help: for that trait implementation, expected `X`, found `&X`
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note: the method call chain might not have had the expected associated types
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--> $DIR/invalid-iterator-chain-fixable.rs:5:26
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LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> {
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| ^^^^^^^^^^^ `Iterator::Item` is `&X` here
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LL | let i = i.map(|x| x.clone());
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| ------------------ `Iterator::Item` remains `&X` here
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note: required by a bound in `collect`
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--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
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help: consider further restricting type parameter `X`
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LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> where X: Clone {
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| ++++++++++++++
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error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
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--> $DIR/invalid-iterator-chain-fixable.rs:17:33
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LL | println!("{}", scores.sum::<i32>());
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| --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
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| |
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| required by a bound introduced by this call
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= help: the trait `Sum<()>` is not implemented for `i32`
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= help: the following other types implement trait `Sum<A>`:
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<i32 as Sum>
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<i32 as Sum<&'a i32>>
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note: the method call chain might not have had the expected associated types
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--> $DIR/invalid-iterator-chain-fixable.rs:14:10
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LL | let v = vec![(0, 0)];
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| ------------ this expression has type `Vec<({integer}, {integer})>`
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LL | let scores = v
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LL | .iter()
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| ------ `Iterator::Item` is `&({integer}, {integer})` here
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LL | .map(|(a, b)| {
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| __________^
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LL | | a + b;
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LL | | });
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| |__________^ `Iterator::Item` changed to `()` here
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note: required by a bound in `std::iter::Iterator::sum`
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--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
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help: consider removing this semicolon
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LL - a + b;
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LL + a + b
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error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
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--> $DIR/invalid-iterator-chain-fixable.rs:25:20
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LL | .sum::<i32>(),
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| --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
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| |
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| required by a bound introduced by this call
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= help: the trait `Sum<()>` is not implemented for `i32`
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= help: the following other types implement trait `Sum<A>`:
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<i32 as Sum>
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<i32 as Sum<&'a i32>>
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note: the method call chain might not have had the expected associated types
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--> $DIR/invalid-iterator-chain-fixable.rs:23:14
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LL | vec![0, 1]
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| ---------- this expression has type `Vec<{integer}>`
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LL | .iter()
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| ------ `Iterator::Item` is `&{integer}` here
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LL | .map(|x| x * 2)
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| -------------- `Iterator::Item` changed to `{integer}` here
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LL | .map(|x| { x; })
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| ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here
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LL | .map(|x| { x })
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| -------------- `Iterator::Item` remains `()` here
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note: required by a bound in `std::iter::Iterator::sum`
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--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
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help: consider removing this semicolon
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LL - .map(|x| { x; })
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LL + .map(|x| { x })
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error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
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--> $DIR/invalid-iterator-chain-fixable.rs:27:60
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LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
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| --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
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| |
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| required by a bound introduced by this call
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= help: the trait `Sum<()>` is not implemented for `i32`
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= help: the following other types implement trait `Sum<A>`:
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<i32 as Sum>
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<i32 as Sum<&'a i32>>
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note: the method call chain might not have had the expected associated types
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--> $DIR/invalid-iterator-chain-fixable.rs:27:38
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LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
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| ---------- ------ ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here
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| | |
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| | `Iterator::Item` is `&{integer}` here
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| this expression has type `Vec<{integer}>`
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note: required by a bound in `std::iter::Iterator::sum`
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--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
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help: consider removing this semicolon
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LL - println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
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LL + println!("{}", vec![0, 1].iter().map(|x| { x }).sum::<i32>());
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error[E0277]: a value of type `Vec<i32>` cannot be built from an iterator over elements of type `()`
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--> $DIR/invalid-iterator-chain-fixable.rs:36:25
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LL | let g: Vec<i32> = f.collect();
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| ^^^^^^^ value of type `Vec<i32>` cannot be built from `std::iter::Iterator<Item=()>`
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= help: the trait `FromIterator<()>` is not implemented for `Vec<i32>`
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= help: the trait `FromIterator<i32>` is implemented for `Vec<i32>`
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= help: for that trait implementation, expected `i32`, found `()`
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note: the method call chain might not have had the expected associated types
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--> $DIR/invalid-iterator-chain-fixable.rs:32:15
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LL | let a = vec![0];
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| ------- this expression has type `Vec<{integer}>`
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LL | let b = a.into_iter();
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| ----------- `Iterator::Item` is `{integer}` here
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LL | let c = b.map(|x| x + 1);
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| -------------- `Iterator::Item` remains `{integer}` here
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LL | let d = c.filter(|x| *x > 10 );
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| -------------------- `Iterator::Item` remains `{integer}` here
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LL | let e = d.map(|x| {
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| _______________^
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LL | | x + 1;
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LL | | });
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| |______^ `Iterator::Item` changed to `()` here
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LL | let f = e.filter(|_| false);
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| ----------------- `Iterator::Item` remains `()` here
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note: required by a bound in `collect`
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--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
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help: consider removing this semicolon
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LL - x + 1;
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LL + x + 1
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error: aborting due to 5 previous errors
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For more information about this error, try `rustc --explain E0277`.
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