Error with impl Iterator

Hello! I'm trying to create a function that takes an array of vectors and returns an iterator of pairs of that vectors. But I'm keep getting an error when I try to do it with impl Iterator.

This code produces an error:
```
// nalgebra = "0.18.0"
use nalgebra;

type Vec2 = nalgebra::Vector2;
fn foo(data: &Vec) -> impl Iterator {
data.iter().zip(data.iter().skip(1))
}
```

```
error[E0271]: type mismatch resolving `>>, std::iter::Skip>>>> as std::iter::Iterator>::Item == (&nalgebra::base::matrix::Matrix>::Buffer>, &nalgebra::base::matrix::Matrix>::Buffer>)`
--> src/main.rs:4:29
|
4 | fn foo(data: &Vec) -> impl Iterator {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `nalgebra::base::array_storage::ArrayStorage`, found associated type
|
= note: expected type `(&nalgebra::base::matrix::Matrix>, &nalgebra::base::matrix::Matrix>)`
found type `(&nalgebra::base::matrix::Matrix>::Buffer>, &nalgebra::base::matrix::Matrix>::Buffer>)`
= note: the return type of a function must have a statically known size
```

Turns out even the simplest code produces a similar error:
```
use nalgebra;

type Vec2 = nalgebra::Vector2;
fn foo(data: &Vec) -> impl Iterator {
data.iter()
}
```

```
error[E0271]: type mismatch resolving `>> as std::iter::Iterator>::Item == &nalgebra::base::matrix::Matrix>::Buffer>`
--> src/main.rs:4:29
|
4 | fn foo(data: &Vec) -> impl Iterator {
| ^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `nalgebra::base::array_storage::ArrayStorage`, found associated type
|
= note: expected type `&nalgebra::base::matrix::Matrix>`
found type `&nalgebra::base::matrix::Matrix>::Buffer>`
= note: the return type of a function must have a statically known size
```

Should it be possible to create an iterator of vectors from Vec?