1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
mod mul1 {
pub trait Mul {}
}
mod mul2 {
pub trait Mul {}
}
mod mul3 {
enum Mul {
Yes,
No
}
}
mod mul4 {
type Mul = String;
}
mod mul5 {
struct Mul{
left_term: u32,
right_term: u32
}
}
#[derive(Debug)]
struct Foo;
// When we comment the next line:
//use mul1::Mul;
// BEFORE, we got the following error for the `impl` below:
// error: use of undeclared trait name `Mul` [E0405]
// AFTER, we get this message:
// error: trait `Mul` is not in scope.
// help: ...
// help: you can import several candidates into scope (`use ...;`):
// help: `mul1::Mul`
// help: `mul2::Mul`
// help: `std::ops::Mul`
impl Mul for Foo {
//~^ ERROR cannot find trait `Mul`
}
// BEFORE, we got:
// error: use of undeclared type name `Mul` [E0412]
// AFTER, we get:
// error: type name `Mul` is not in scope. Maybe you meant:
// help: ...
// help: you can import several candidates into scope (`use ...;`):
// help: `mul1::Mul`
// help: `mul2::Mul`
// help: `mul3::Mul`
// help: `mul4::Mul`
// help: and 2 other candidates
fn getMul() -> Mul {
//~^ ERROR cannot find type `Mul`
}
// Let's also test what happens if the trait doesn't exist:
impl ThisTraitReallyDoesntExistInAnyModuleReally for Foo {
//~^ ERROR cannot find trait `ThisTraitReallyDoesntExistInAnyModuleReally`
}
// Let's also test what happens if there's just one alternative:
impl Div for Foo {
//~^ ERROR cannot find trait `Div`
}
fn main() {
let foo = Foo();
println!("Hello, {:?}!", foo);
}
|
