rust/compiler/rustc_const_eval/src/errors.rs

use rustc_macros::SessionDiagnostic;
use rustc_span::Span;

#[derive(SessionDiagnostic)]
#[error(const_eval::unstable_in_stable)]
pub(crate) struct UnstableInStable {
    pub gate: String,
    #[primary_span]
    pub span: Span,
    #[suggestion(
        const_eval::unstable_sugg,
        code = "#[rustc_const_unstable(feature = \"...\", issue = \"...\")]\n",
        applicability = "has-placeholders"
    )]
    #[suggestion(
        const_eval::bypass_sugg,
        code = "#[rustc_allow_const_fn_unstable({gate})]\n",
        applicability = "has-placeholders"
    )]
    pub attr_span: Span,
}