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Implement custom diagnostic for ConstParamTy

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This commit is contained in:
Michael Goulet 2023-05-17 04:05:46 +00:00
parent a9fcb524ff
commit 847d50453c
51 changed files with 455 additions and 152 deletions
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12
compiler/rustc_error_codes/src/error_codes/E0741.md
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@ -10,15 +10,19 @@ struct A;
struct B<const X: A>; // error!
```
Only structural-match types (that is, types that derive `PartialEq` and `Eq`)
may be used as the types of const generic parameters.
Only structural-match types, which are types that derive `PartialEq` and `Eq`
and implement `ConstParamTy`, may be used as the types of const generic
parameters.
To fix the previous code example, we derive `PartialEq` and `Eq`:
To fix the previous code example, we derive `PartialEq`, `Eq`, and
`ConstParamTy`:
```
#![feature(adt_const_params)]
#[derive(PartialEq, Eq)] // We derive both traits here.
use std::marker::ConstParamTy;
#[derive(PartialEq, Eq, ConstParamTy)] // We derive both traits here.
struct A;
struct B<const X: A>; // ok!