Allow restricted trait impls in macros with min_specialization

Implementing traits marked with `#[rustc_specialization_trait]` normally
requires (min-)specialization to be enabled for the enclosing crate.

With this change, that permission can also be granted by an
`allow_internal_unstable` attribute on the macro that generates the impl.
This commit is contained in:
Zalathar 2024-02-10 13:54:28 +11:00
parent b5c46dc542
commit 7b73e4fd44
2 changed files with 14 additions and 3 deletions

View file

@ -10,7 +10,7 @@ use rustc_errors::{codes::*, struct_span_code_err};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
use rustc_span::ErrorGuaranteed;
use rustc_span::{sym, ErrorGuaranteed};
use rustc_trait_selection::traits;
mod builtin;
@ -70,7 +70,11 @@ fn enforce_trait_manually_implementable(
if let ty::trait_def::TraitSpecializationKind::AlwaysApplicable =
tcx.trait_def(trait_def_id).specialization_kind
{
if !tcx.features().specialization && !tcx.features().min_specialization {
if !tcx.features().specialization
&& !tcx.features().min_specialization
&& !impl_header_span.allows_unstable(sym::specialization)
&& !impl_header_span.allows_unstable(sym::min_specialization)
{
return Err(tcx.dcx().emit_err(errors::SpecializationTrait { span: impl_header_span }));
}
}