An example from IRC just now:
https://play.rust-lang.org/?gist=ad253f7f1b851935890346136fe47912&version=stable&mode=debug&edition=2015
#[derive(Debug)]
struct Point
{
x: i32,
y: i32
}
impl Point
{
fn add(a: &Point, b: &Point) -> Point
{
Point {x: a.x + b.x, y: a.y + b.y}
}
}
trait Eq
{
fn equals<T>(a: &T, b: &T) -> bool;
}
impl Eq for Point
{
fn equals<Point>(a: &Point, b: &Point) -> bool
{
a.x == b.x && a.y == b.y
}
}
fn main()
{
let p1 = Point {x: 0, y: 10};
let p2 = Point {x: 20, y: 42};
println!("{:?}", Point::add(&p1, &p2));
println!("p1: {:?}, p2: {:?}", p1, p2);
println!("p1 == p2: {:?}", Eq::equals(&p1, &p2));
} Compiling playground v0.0.1 (file:///playground)
error[E0609]: no field `x` on type `&Point`
--> src/main.rs:25:11
|
25 | a.x == b.x && a.y == b.y
| ^
error[E0609]: no field `x` on type `&Point`
--> src/main.rs:25:18
|
25 | a.x == b.x && a.y == b.y
| ^
error[E0609]: no field `y` on type `&Point`
--> src/main.rs:25:25
|
25 | a.x == b.x && a.y == b.y
| ^
error[E0609]: no field `y` on type `&Point`
--> src/main.rs:25:32
|
25 | a.x == b.x && a.y == b.y
| ^
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0609`.
error: Could not compile `playground`.
To learn more, run the command again with --verbose.
The mistake here is that Point is also used as a shadowing type parameter inside the Function.
Maybe have a warn lint that tries to detect cases like this? (With a type parameter that also exist as a concrete type in the surrounding scope)
This issue has been assigned to @Baranowski via this comment.
An example from IRC just now:
https://play.rust-lang.org/?gist=ad253f7f1b851935890346136fe47912&version=stable&mode=debug&edition=2015
The mistake here is that
Pointis also used as a shadowing type parameter inside the Function.Maybe have a warn lint that tries to detect cases like this? (With a type parameter that also exist as a concrete type in the surrounding scope)
This issue has been assigned to @Baranowski via this comment.