Make the structural_match error diagnostic for const generics clearer
#70845
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Ping from triage: @estebank could you review this? |
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| error[E0741]: `T` must be annotated with `#[derive(PartialEq, Eq)]` to be used as the type of a const parameter | ||
| --> $DIR/const-param-type-depends-on-type-param-ungated.rs:3:22 | ||
| | | ||
| LL | struct B<T, const N: T>(PhantomData<[T; N]>); |
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It'd be nice if we could detect that T is a type param and instead of suggesting the annotation we suggested binding it with PartialEq + Eq.
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Ah, actually we ought to emit a specific error for this case: we don't currently accept using generic parameters as the types of const generics yet.
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@estebank: I've added a specific message for the case you highlighted. |
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@bors r+ rollup |
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…gnostic, r=estebank Make the `structural_match` error diagnostic for const generics clearer The previous diagnostic caused confusion (rust-lang#70790), so this changes the message to be closer to the message for using non-`structural_match` constants in patterns, explicitly mentioning `#[derive(PartialEq, Eq)]`. Fixes rust-lang#70790. r? @estebank
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Rollup of 6 pull requests Successful merges: - rust-lang#70845 (Make the `structural_match` error diagnostic for const generics clearer) - rust-lang#71063 (Document unsafety in core::{option, hash}) - rust-lang#71068 (Stabilize UNICODE_VERSION (feature unicode_version)) - rust-lang#71426 (fix error code in E0751.md) - rust-lang#71459 (Add leading 0x to offset in Debug fmt of Pointer) - rust-lang#71492 (Document unsafety in core::{panicking, alloc::layout, hint, iter::adapters::zip}) Failed merges: r? @ghost
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The previous diagnostic caused confusion (#70790), so this changes the message to be closer to the message for using non-
structural_matchconstants in patterns, explicitly mentioning#[derive(PartialEq, Eq)].Fixes #70790.
r? @estebank