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.
22 lines
637 B
Rust
22 lines
637 B
Rust
//@ run-rustfix
|
|
#![feature(generic_const_exprs)]
|
|
#![allow(incomplete_features, dead_code)]
|
|
|
|
struct Evaluatable<const N: u128> {}
|
|
|
|
struct Foo<const N: u8>([u8; N as usize])
|
|
//~^ ERROR unconstrained generic constant
|
|
where
|
|
Evaluatable<{N as u128}>:;
|
|
//~^ HELP try adding a `where` bound
|
|
|
|
struct Foo2<const N: u8>(Evaluatable::<{N as u128}>) where Evaluatable<{N as usize as u128 }>:;
|
|
//~^ ERROR unconstrained generic constant
|
|
//~| HELP try adding a `where` bound
|
|
|
|
struct Bar<const N: u8>([u8; (N + 2) as usize]) where [(); (N + 1) as usize]:;
|
|
//~^ ERROR unconstrained generic constant
|
|
//~| HELP try adding a `where` bound
|
|
|
|
fn main() {}
|