mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-22 23:04:33 +00:00
6b24fdf811
```
error: unconstrained generic constant
--> $DIR/const-argument-if-length.rs:18:10
|
LL | pad: [u8; is_zst::<T>()],
| ^^^^^^^^^^^^^^^^^^^
|
help: try adding a `where` bound
|
LL | pub struct AtLeastByte<T: ?Sized> where [(); is_zst::<T>()]: {
| ++++++++++++++++++++++++++
```
Detect when the constant expression isn't `usize` and suggest casting:
```
error: unconstrained generic constant
--> f300.rs:6:10
|
6 | bb::<{!N}>();
| ^^^^
-Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs:3539:36
|
help: try adding a `where` bound
|
5 | fn b<const N: bool>() where [(); {!N} as usize]: {
| ++++++++++++++++++++++++++
```
Fix #122395.
26 lines
598 B
Rust
26 lines
598 B
Rust
// This is a regression test for issue #104400.
|
|
|
|
//@ run-rustfix
|
|
|
|
// Test that we can constrain generic const items that appear inside associated consts by
|
|
// adding a (makeshift) "evaluatable"-bound to the item, after applying the suggestion.
|
|
|
|
#![feature(generic_const_items, generic_const_exprs)]
|
|
#![allow(incomplete_features)]
|
|
|
|
trait Trait {
|
|
const LEN: usize;
|
|
|
|
const ARRAY: [i32; Self::LEN]; //~ ERROR unconstrained generic constant
|
|
|
|
}
|
|
|
|
impl Trait for () {
|
|
const LEN: usize = 2;
|
|
const ARRAY: [i32; Self::LEN] = [360, 720];
|
|
}
|
|
|
|
fn main() {
|
|
let [_, _] = <() as Trait>::ARRAY;
|
|
}
|