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Add long diagnostics for E0046 and E0054 #25190

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Merged
merged 2 commits into from
May 8, 2015
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Add long diagnostics for E0046 and E0054 #25190

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11cb5e5
Add long diagnostic for E0046
May 7, 2015
11a7bad
Add long diagnostic for E0054
May 7, 2015
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24 changes: 22 additions & 2 deletions src/librustc_typeck/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,28 @@

register_long_diagnostics! {

E0046: r##"
When trying to make some type implement a trait `Foo`, you must, at minimum,
provide implementations for all of `Foo`'s required methods (meaning the
methods that do not have default implementations), as well as any required
trait items like associated types or constants.
"##,

E0054: r##"
It is not allowed to cast to a bool. If you are trying to cast a numeric type
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Perhaps this could clarify "It is not allowed to cast a numeric type to a bool"?

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From my (admittedly shallow) reading of the code in librustc_typeck/check/cast.rs, it seemed like any casting to bool is disallowed. For example, you can try to cast a bare function to a bool and get E0054.

fn main() {
    fn foo() -> u8 { 5 }
    let x = foo as bool; // error: cannot cast as `bool`, compare with zero instead [E0054]
}

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Aha! Never mind then!

to a bool, you can compare it with zero instead:

```
let x = 5;

// Ok
let x_is_nonzero = x != 0;

// Not allowed, won't compile
let x_is_nonzero = x as bool;
```
"##,

E0081: r##"
Enum discriminants are used to differentiate enum variants stored in memory.
This error indicates that the same value was used for two or more variants,
Expand Down Expand Up @@ -106,11 +128,9 @@ register_diagnostics! {
E0040, // explicit use of destructor method
E0044,
E0045,
E0046,
E0049,
E0050,
E0053,
E0054,
E0055,
E0057,
E0059,
Expand Down