Add help for #![feature(impl_trait_in_fn_trait_return)]
This adds a new variant `ImplTraitContext::FeatureGated`, so we can generalize the help for `return_position_impl_trait_in_trait` to also work for `impl_trait_in_fn_trait_return`.
This commit is contained in:
Josh Stone
parent
b28d30e1e3
commit
e9dd59131b
@ -259,6 +259,8 @@ enum ImplTraitContext {
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},
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/// Impl trait in type aliases.
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TypeAliasesOpaqueTy,
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/// `impl Trait` is unstably accepted in this position.
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FeatureGated(ImplTraitPosition, Symbol),
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/// `impl Trait` is not accepted in this position.
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Disallowed(ImplTraitPosition),
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}
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@ -1372,17 +1374,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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}
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path
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}
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ImplTraitContext::Disallowed(
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position @ (ImplTraitPosition::TraitReturn | ImplTraitPosition::ImplReturn),
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) => {
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ImplTraitContext::FeatureGated(position, feature) => {
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self.tcx
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.sess
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.create_feature_err(
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MisplacedImplTrait {
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span: t.span,
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position: DiagnosticArgFromDisplay(&position),
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position: DiagnosticArgFromDisplay(position),
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},
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sym::return_position_impl_trait_in_trait,
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*feature,
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)
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.emit();
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hir::TyKind::Err
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@ -1390,7 +1390,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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ImplTraitContext::Disallowed(position) => {
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self.tcx.sess.emit_err(MisplacedImplTrait {
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span: t.span,
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position: DiagnosticArgFromDisplay(&position),
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position: DiagnosticArgFromDisplay(position),
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});
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hir::TyKind::Err
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}
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@ -1739,14 +1739,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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} else {
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match &decl.output {
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FnRetTy::Ty(ty) => {
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let mut context = if kind.return_impl_trait_allowed(self.tcx) {
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let context = if kind.return_impl_trait_allowed(self.tcx) {
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let fn_def_id = self.local_def_id(fn_node_id);
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ImplTraitContext::ReturnPositionOpaqueTy {
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origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
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in_trait: matches!(kind, FnDeclKind::Trait),
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}
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} else {
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ImplTraitContext::Disallowed(match kind {
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let position = match kind {
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FnDeclKind::Fn | FnDeclKind::Inherent => {
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unreachable!("fn should allow in-band lifetimes")
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}
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@ -1755,9 +1755,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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FnDeclKind::Pointer => ImplTraitPosition::PointerReturn,
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FnDeclKind::Trait => ImplTraitPosition::TraitReturn,
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FnDeclKind::Impl => ImplTraitPosition::ImplReturn,
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})
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};
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match kind {
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FnDeclKind::Trait | FnDeclKind::Impl => ImplTraitContext::FeatureGated(
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position,
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sym::return_position_impl_trait_in_trait,
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),
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_ => ImplTraitContext::Disallowed(position),
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}
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};
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hir::FnRetTy::Return(self.lower_ty(ty, &mut context))
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hir::FnRetTy::Return(self.lower_ty(ty, &context))
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}
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FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(self.lower_span(*span)),
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}
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@ -1938,7 +1945,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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output,
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span,
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if in_trait && !this.tcx.features().return_position_impl_trait_in_trait {
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ImplTraitContext::Disallowed(ImplTraitPosition::TraitReturn)
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ImplTraitContext::FeatureGated(
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ImplTraitPosition::TraitReturn,
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sym::return_position_impl_trait_in_trait,
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)
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} else {
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ImplTraitContext::ReturnPositionOpaqueTy {
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origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
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@ -9,7 +9,7 @@ use rustc_ast::{self as ast, *};
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, PartialRes, Res};
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use rustc_hir::GenericArg;
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use rustc_span::symbol::{kw, Ident};
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use rustc_span::symbol::{kw, sym, Ident};
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use rustc_span::{BytePos, Span, DUMMY_SP};
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use smallvec::{smallvec, SmallVec};
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@ -352,11 +352,18 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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// fn f(_: impl Fn() -> impl Debug) -> impl Fn() -> impl Debug
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// // disallowed --^^^^^^^^^^ allowed --^^^^^^^^^^
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// ```
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FnRetTy::Ty(ty)
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if matches!(itctx, ImplTraitContext::ReturnPositionOpaqueTy { .. })
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&& self.tcx.features().impl_trait_in_fn_trait_return =>
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{
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self.lower_ty(&ty, itctx)
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FnRetTy::Ty(ty) if matches!(itctx, ImplTraitContext::ReturnPositionOpaqueTy { .. }) => {
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if self.tcx.features().impl_trait_in_fn_trait_return {
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self.lower_ty(&ty, itctx)
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} else {
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self.lower_ty(
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&ty,
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&ImplTraitContext::FeatureGated(
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ImplTraitPosition::FnTraitReturn,
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sym::impl_trait_in_fn_trait_return,
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),
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)
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}
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}
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FnRetTy::Ty(ty) => {
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self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitReturn))
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@ -3,12 +3,18 @@ error[E0562]: `impl Trait` only allowed in function and inherent method return t
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LL | fn f() -> impl Fn() -> impl Sized { || () }
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| ^^^^^^^^^^
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= note: see issue #99697 <https://github.com/rust-lang/rust/issues/99697> for more information
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= help: add `#![feature(impl_trait_in_fn_trait_return)]` to the crate attributes to enable
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error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait return
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--> $DIR/feature-gate-impl_trait_in_fn_trait_return.rs:3:32
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LL | fn g() -> &'static dyn Fn() -> impl Sized { &|| () }
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| ^^^^^^^^^^
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= note: see issue #99697 <https://github.com/rust-lang/rust/issues/99697> for more information
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= help: add `#![feature(impl_trait_in_fn_trait_return)]` to the crate attributes to enable
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error: aborting due to 2 previous errors
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