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Split out async_fn_in_trait into a separate feature

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PR #101224 added support for async fn in trait desuraging behind the
return_position_impl_trait_in_trait feature.

Split this out so that it's behind its own feature gate, since async fn
in trait doesn't need to follow the same stabilization schedule.
This commit is contained in:
Dan Johnson
2022-08-18 16:27:16 -07:00
parent 9062b780b3
commit d0a07495be
13 changed files with 133 additions and 19 deletions
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23
compiler/rustc_ast_lowering/src/lib.rs
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@@ -332,6 +332,15 @@ impl FnDeclKind {
_ => false,
}
}
fn async_fn_allowed(&self, tcx: TyCtxt<'_>) -> bool {
match self {
FnDeclKind::Fn | FnDeclKind::Inherent => true,
FnDeclKind::Impl if tcx.features().async_fn_in_trait => true,
FnDeclKind::Trait if tcx.features().async_fn_in_trait => true,
_ => false,
}
}
}
#[derive(Copy, Clone)]
@@ -1692,14 +1701,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}));
let output = if let Some((ret_id, span)) = make_ret_async {
if !kind.impl_trait_allowed(self.tcx) {
if !kind.async_fn_allowed(self.tcx) {
match kind {
FnDeclKind::Trait | FnDeclKind::Impl => {
self.tcx
.sess
.create_feature_err(
TraitFnAsync { fn_span, span },
sym::return_position_impl_trait_in_trait,
sym::async_fn_in_trait,
)
.emit();
}
@@ -1917,9 +1926,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let future_bound = this.lower_async_fn_output_type_to_future_bound(
output,
span,
ImplTraitContext::ReturnPositionOpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
in_trait,
if in_trait && !this.tcx.features().return_position_impl_trait_in_trait {
ImplTraitContext::Disallowed(ImplTraitPosition::TraitReturn)
} else {
ImplTraitContext::ReturnPositionOpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
in_trait,
}
},
);