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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
View File

@ -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,
}
},
);

21
compiler/rustc_resolve/src/late.rs
View File

@ -772,9 +772,10 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
self.r.record_partial_res(ty.id, PartialRes::new(res));
visit::walk_ty(self, ty)
}
TyKind::ImplTrait(..) => {
TyKind::ImplTrait(node_id, _) => {
let candidates = self.lifetime_elision_candidates.take();
visit::walk_ty(self, ty);
self.record_lifetime_params_for_impl_trait(*node_id);
self.lifetime_elision_candidates = candidates;
}
TyKind::TraitObject(bounds, ..) => {
@ -909,8 +910,8 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
&sig.decl.output,
);
if let Some((async_node_id, span)) = sig.header.asyncness.opt_return_id() {
this.record_lifetime_params_for_impl_trait(async_node_id, span);
if let Some((async_node_id, _)) = sig.header.asyncness.opt_return_id() {
this.record_lifetime_params_for_impl_trait(async_node_id);
}
},
);
@ -951,8 +952,8 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
&declaration.output,
);
if let Some((async_node_id, span)) = async_node_id {
this.record_lifetime_params_for_impl_trait(async_node_id, span);
if let Some((async_node_id, _)) = async_node_id {
this.record_lifetime_params_for_impl_trait(async_node_id);
}
},
);
@ -4367,7 +4368,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
/// We include all lifetime parameters, either named or "Fresh".
/// The order of those parameters does not matter, as long as it is
/// deterministic.
fn record_lifetime_params_for_impl_trait(&mut self, impl_trait_node_id: NodeId, span: Span) {
fn record_lifetime_params_for_impl_trait(&mut self, impl_trait_node_id: NodeId) {
let mut extra_lifetime_params = vec![];
for rib in self.lifetime_ribs.iter().rev() {
@ -4380,14 +4381,10 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
extra_lifetime_params.extend(earlier_fresh);
}
}
LifetimeRibKind::Generics { .. } => {}
_ => {
// We are in a function definition. We should only find `Generics`
// and `AnonymousCreateParameter` inside the innermost `Item`.
span_bug!(span, "unexpected rib kind: {:?}", rib.kind)
}
_ => {}
}
}
self.r.extra_lifetime_params_map.insert(impl_trait_node_id, extra_lifetime_params);
}

13
tests/ui/impl-trait/in-trait/object-safety.stderr
View File

@ -13,6 +13,14 @@ LL | fn baz(&self) -> impl Debug;
| ^^^^^^^^^^ ...because method `baz` references an `impl Trait` type in its return type
= help: consider moving `baz` to another trait
error[E0277]: the trait bound `dyn Foo: Foo` is not satisfied
--> $DIR/object-safety.rs:20:15
|
LL | let s = i.baz();
| ^^^ the trait `Foo` is not implemented for `dyn Foo`
|
= help: the trait `Foo` is implemented for `u32`
error[E0038]: the trait `Foo` cannot be made into an object
--> $DIR/object-safety.rs:20:13
|
@ -44,6 +52,7 @@ LL | fn baz(&self) -> impl Debug;
= help: consider moving `baz` to another trait
= note: required for the cast from `Box<u32>` to `Box<dyn Foo>`
error: aborting due to 3 previous errors
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0038`.
Some errors have detailed explanations: E0038, E0277.
For more information about an error, try `rustc --explain E0038`.

65
tests/ui/impl-trait/in-trait/signature-mismatch.stderr
View File

@ -1,61 +1,14 @@
error: return type captures more lifetimes than trait definition
--> $DIR/signature-mismatch.rs:34:47
|
LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
| -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: hidden type must only reference lifetimes captured by this impl trait
--> $DIR/signature-mismatch.rs:15:40
|
LL | fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a`
error: return type captures more lifetimes than trait definition
--> $DIR/signature-mismatch.rs:39:57
|
LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
| -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: hidden type must only reference lifetimes captured by this impl trait
--> $DIR/signature-mismatch.rs:16:57
|
LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a`
error: return type captures more lifetimes than trait definition
--> $DIR/signature-mismatch.rs:47:10
|
LL | fn async_fn_multiple<'a, 'b>(
| -- this lifetime was captured
...
LL | ) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: hidden type must only reference lifetimes captured by this impl trait
--> $DIR/signature-mismatch.rs:18:12
|
LL | -> impl Future<Output = Vec<u8>> + Captures<'a>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: hidden type inferred to be `impl Future<Output = Vec<u8>> + Captures2<'a, 'b>`
error[E0309]: the parameter type `T` may not live long enough
error[E0623]: lifetime mismatch
--> $DIR/signature-mismatch.rs:56:10
|
LL | &'a self,
| -------- this parameter and the return type are declared with different lifetimes...
...
LL | ) -> impl Future<Output = Vec<u8>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `impl Future<Output = Vec<u8>>` will meet its required lifetime bounds...
|
note: ...that is required by this bound
--> $DIR/signature-mismatch.rs:23:42
|
LL | ) -> impl Future<Output = Vec<u8>> + 'a;
| ^^
help: consider adding an explicit lifetime bound...
|
LL | fn async_fn_reduce_outlive<'a, 'b, T: 'a>(
| ++++
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| ...but data from `buff` is returned here
error: aborting due to 4 previous errors
error: aborting due to previous error
For more information about this error, try `rustc --explain E0309`.
For more information about this error, try `rustc --explain E0623`.