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RPITITs capture all their lifetimes

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This commit is contained in:
Michael Goulet 2023-08-04 23:54:14 +00:00
parent 8550f15e14
commit 13d3e57237
4 changed files with 60 additions and 92 deletions
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53
compiler/rustc_ast_lowering/src/lib.rs
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@ -236,7 +236,7 @@ enum ImplTraitContext {
ReturnPositionOpaqueTy {
/// Origin: Either OpaqueTyOrigin::FnReturn or OpaqueTyOrigin::AsyncFn,
origin: hir::OpaqueTyOrigin,
in_trait: bool,
fn_kind: FnDeclKind,
},
/// Impl trait in type aliases.
TypeAliasesOpaqueTy { in_assoc_ty: bool },
@ -312,7 +312,7 @@ impl std::fmt::Display for ImplTraitPosition {
}
}
#[derive(Debug, PartialEq, Eq)]
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum FnDeclKind {
Fn,
Inherent,
@ -1401,13 +1401,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
TyKind::ImplTrait(def_node_id, bounds) => {
let span = t.span;
match itctx {
ImplTraitContext::ReturnPositionOpaqueTy { origin, in_trait } => self
ImplTraitContext::ReturnPositionOpaqueTy { origin, fn_kind } => self
.lower_opaque_impl_trait(
span,
*origin,
*def_node_id,
bounds,
*in_trait,
Some(*fn_kind),
itctx,
),
&ImplTraitContext::TypeAliasesOpaqueTy { in_assoc_ty } => self
@ -1416,7 +1416,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
hir::OpaqueTyOrigin::TyAlias { in_assoc_ty },
*def_node_id,
bounds,
false,
None,
itctx,
),
ImplTraitContext::Universal => {
@ -1523,7 +1523,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
origin: hir::OpaqueTyOrigin,
opaque_ty_node_id: NodeId,
bounds: &GenericBounds,
in_trait: bool,
fn_kind: Option<FnDeclKind>,
itctx: &ImplTraitContext,
) -> hir::TyKind<'hir> {
// Make sure we know that some funky desugaring has been going on here.
@ -1540,10 +1540,22 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
Vec::new()
}
hir::OpaqueTyOrigin::FnReturn(..) => {
// in fn return position, like the `fn test<'a>() -> impl Debug + 'a`
// example, we only need to duplicate lifetimes that appear in the
// bounds, since those are the only ones that are captured by the opaque.
lifetime_collector::lifetimes_in_bounds(&self.resolver, bounds)
if let FnDeclKind::Impl | FnDeclKind::Trait =
fn_kind.expect("expected RPITs to be lowered with a FnKind")
{
// return-position impl trait in trait was decided to capture all
// in-scope lifetimes, which we collect for all opaques during resolution.
self.resolver
.take_extra_lifetime_params(opaque_ty_node_id)
.into_iter()
.map(|(ident, id, _)| Lifetime { id, ident })
.collect()
} else {
// in fn return position, like the `fn test<'a>() -> impl Debug + 'a`
// example, we only need to duplicate lifetimes that appear in the
// bounds, since those are the only ones that are captured by the opaque.
lifetime_collector::lifetimes_in_bounds(&self.resolver, bounds)
}
}
hir::OpaqueTyOrigin::AsyncFn(..) => {
unreachable!("should be using `lower_async_fn_ret_ty`")
@ -1554,7 +1566,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
self.lower_opaque_inner(
opaque_ty_node_id,
origin,
in_trait,
matches!(fn_kind, Some(FnDeclKind::Trait)),
captured_lifetimes_to_duplicate,
span,
opaque_ty_span,
@ -1802,12 +1814,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
let fn_def_id = self.local_def_id(fn_node_id);
self.lower_async_fn_ret_ty(
&decl.output,
fn_def_id,
ret_id,
matches!(kind, FnDeclKind::Trait),
)
self.lower_async_fn_ret_ty(&decl.output, fn_def_id, ret_id, kind)
} else {
match &decl.output {
FnRetTy::Ty(ty) => {
@ -1815,7 +1822,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let fn_def_id = self.local_def_id(fn_node_id);
ImplTraitContext::ReturnPositionOpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
in_trait: matches!(kind, FnDeclKind::Trait),
fn_kind: kind,
}
} else {
let position = match kind {
@ -1883,7 +1890,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
output: &FnRetTy,
fn_def_id: LocalDefId,
opaque_ty_node_id: NodeId,
in_trait: bool,
fn_kind: FnDeclKind,
) -> hir::FnRetTy<'hir> {
let span = self.lower_span(output.span());
let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, span, None);
@ -1898,7 +1905,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let opaque_ty_ref = self.lower_opaque_inner(
opaque_ty_node_id,
hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
in_trait,
matches!(fn_kind, FnDeclKind::Trait),
captured_lifetimes,
span,
opaque_ty_span,
@ -1906,7 +1913,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let future_bound = this.lower_async_fn_output_type_to_future_bound(
output,
span,
if in_trait && !this.tcx.features().return_position_impl_trait_in_trait {
if let FnDeclKind::Trait = fn_kind
&& !this.tcx.features().return_position_impl_trait_in_trait
{
ImplTraitContext::FeatureGated(
ImplTraitPosition::TraitReturn,
sym::return_position_impl_trait_in_trait,
@ -1914,7 +1923,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
} else {
ImplTraitContext::ReturnPositionOpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
in_trait,
fn_kind,
}
},
);