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Rollup merge of #91640 - cjgillot:in-band-collect, r=oli-obk

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Simplify collection of in-band lifetimes

Split from https://github.com/rust-lang/rust/pull/91403

r? ````@oli-obk````
This commit is contained in:
Matthias Krüger 2021-12-11 16:02:46 +01:00 • committed by GitHub
commit 7083f8edfd
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GPG key ID: 4AEE18F83AFDEB23
14 changed files with 212 additions and 200 deletions
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9
compiler/rustc_ast_lowering/src/item.rs
View file

@ -247,12 +247,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
AnonymousLifetimeMode::PassThrough,
|this, idty| {
let ret_id = asyncness.opt_return_id();
this.lower_fn_decl(
&decl,
Some((fn_def_id.to_def_id(), idty)),
true,
ret_id,
)
this.lower_fn_decl(&decl, Some((fn_def_id, idty)), true, ret_id)
},
);
let sig = hir::FnSig {
@ -1264,7 +1259,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
|this, idty| {
this.lower_fn_decl(
&sig.decl,
Some((fn_def_id.to_def_id(), idty)),
Some((fn_def_id, idty)),
impl_trait_return_allow,
is_async,
)

192
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -228,7 +228,7 @@ enum ImplTraitContext<'b, 'a> {
ReturnPositionOpaqueTy {
/// `DefId` for the parent function, used to look up necessary
/// information later.
fn_def_id: DefId,
fn_def_id: LocalDefId,
/// Origin: Either OpaqueTyOrigin::FnReturn or OpaqueTyOrigin::AsyncFn,
origin: hir::OpaqueTyOrigin,
},
@ -646,31 +646,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
/// parameter while `f` is running (and restored afterwards).
fn collect_in_band_defs<T>(
&mut self,
parent_def_id: LocalDefId,
anonymous_lifetime_mode: AnonymousLifetimeMode,
f: impl FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T),
) -> (Vec<hir::GenericParam<'hir>>, T) {
assert!(!self.is_collecting_in_band_lifetimes);
assert!(self.lifetimes_to_define.is_empty());
let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode;
f: impl FnOnce(&mut Self) -> T,
) -> (Vec<(Span, ParamName)>, T) {
let was_collecting = std::mem::replace(&mut self.is_collecting_in_band_lifetimes, true);
let len = self.lifetimes_to_define.len();
self.anonymous_lifetime_mode = anonymous_lifetime_mode;
self.is_collecting_in_band_lifetimes = true;
let res = f(self);
let (in_band_ty_params, res) = f(self);
self.is_collecting_in_band_lifetimes = false;
self.anonymous_lifetime_mode = old_anonymous_lifetime_mode;
let lifetimes_to_define = self.lifetimes_to_define.split_off(0);
let params = lifetimes_to_define
.into_iter()
.map(|(span, hir_name)| self.lifetime_to_generic_param(span, hir_name, parent_def_id))
.chain(in_band_ty_params.into_iter())
.collect();
(params, res)
let lifetimes_to_define = self.lifetimes_to_define.split_off(len);
self.is_collecting_in_band_lifetimes = was_collecting;
(lifetimes_to_define, res)
}
/// Converts a lifetime into a new generic parameter.
@ -785,27 +770,39 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
anonymous_lifetime_mode: AnonymousLifetimeMode,
f: impl FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T,
) -> (hir::Generics<'hir>, T) {
let (in_band_defs, (mut lowered_generics, res)) =
self.with_in_scope_lifetime_defs(&generics.params, |this| {
this.collect_in_band_defs(parent_def_id, anonymous_lifetime_mode, |this| {
let mut params = Vec::new();
// Note: it is necessary to lower generics *before* calling `f`.
// When lowering `async fn`, there's a final step when lowering
// the return type that assumes that all in-scope lifetimes have
// already been added to either `in_scope_lifetimes` or
// `lifetimes_to_define`. If we swapped the order of these two,
// in-band-lifetimes introduced by generics or where-clauses
// wouldn't have been added yet.
let generics = this.lower_generics_mut(
generics,
ImplTraitContext::Universal(&mut params, this.current_hir_id_owner),
);
let res = f(this, &mut params);
(params, (generics, res))
let (lifetimes_to_define, (mut lowered_generics, impl_trait_defs, res)) = self
.collect_in_band_defs(|this| {
this.with_anonymous_lifetime_mode(anonymous_lifetime_mode, |this| {
this.with_in_scope_lifetime_defs(&generics.params, |this| {
let mut impl_trait_defs = Vec::new();
// Note: it is necessary to lower generics *before* calling `f`.
// When lowering `async fn`, there's a final step when lowering
// the return type that assumes that all in-scope lifetimes have
// already been added to either `in_scope_lifetimes` or
// `lifetimes_to_define`. If we swapped the order of these two,
// in-band-lifetimes introduced by generics or where-clauses
// wouldn't have been added yet.
let generics = this.lower_generics_mut(
generics,
ImplTraitContext::Universal(
&mut impl_trait_defs,
this.current_hir_id_owner,
),
);
let res = f(this, &mut impl_trait_defs);
(generics, impl_trait_defs, res)
})
})
});
lowered_generics.params.extend(in_band_defs);
lowered_generics.params.extend(
lifetimes_to_define
.into_iter()
.map(|(span, hir_name)| {
self.lifetime_to_generic_param(span, hir_name, parent_def_id)
})
.chain(impl_trait_defs),
);
let lowered_generics = lowered_generics.into_generics(self.arena);
(lowered_generics, res)
@ -1380,7 +1377,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn lower_opaque_impl_trait(
&mut self,
span: Span,
fn_def_id: Option<DefId>,
fn_def_id: Option<LocalDefId>,
origin: hir::OpaqueTyOrigin,
opaque_ty_node_id: NodeId,
capturable_lifetimes: Option<&FxHashSet<hir::LifetimeName>>,
@ -1452,7 +1449,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
span: lctx.lower_span(span),
},
bounds: hir_bounds,
impl_trait_fn: fn_def_id,
origin,
};
@ -1522,7 +1518,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn lower_fn_decl(
&mut self,
decl: &FnDecl,
mut in_band_ty_params: Option<(DefId, &mut Vec<hir::GenericParam<'hir>>)>,
mut in_band_ty_params: Option<(LocalDefId, &mut Vec<hir::GenericParam<'hir>>)>,
impl_trait_return_allow: bool,
make_ret_async: Option<NodeId>,
) -> &'hir hir::FnDecl<'hir> {
@ -1580,7 +1576,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
Some((def_id, _)) if impl_trait_return_allow => {
ImplTraitContext::ReturnPositionOpaqueTy {
fn_def_id: def_id,
origin: hir::OpaqueTyOrigin::FnReturn,
origin: hir::OpaqueTyOrigin::FnReturn(def_id),
}
}
_ => ImplTraitContext::disallowed(),
@ -1635,7 +1631,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn lower_async_fn_ret_ty(
&mut self,
output: &FnRetTy,
fn_def_id: DefId,
fn_def_id: LocalDefId,
opaque_ty_node_id: NodeId,
) -> hir::FnRetTy<'hir> {
debug!(
@ -1689,18 +1685,29 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// this is because the elided lifetimes from the return type
// should be figured out using the ordinary elision rules, and
// this desugaring achieves that.
//
// The variable `input_lifetimes_count` tracks the number of
// lifetime parameters to the opaque type *not counting* those
// lifetimes elided in the return type. This includes those
// that are explicitly declared (`in_scope_lifetimes`) and
// those elided lifetimes we found in the arguments (current
// content of `lifetimes_to_define`). Next, we will process
// the return type, which will cause `lifetimes_to_define` to
// grow.
let input_lifetimes_count = self.in_scope_lifetimes.len() + self.lifetimes_to_define.len();
let mut lifetime_params = Vec::new();
debug!("lower_async_fn_ret_ty: in_scope_lifetimes={:#?}", self.in_scope_lifetimes);
debug!("lower_async_fn_ret_ty: lifetimes_to_define={:#?}", self.lifetimes_to_define);
// Calculate all the lifetimes that should be captured
// by the opaque type. This should include all in-scope
// lifetime parameters, including those defined in-band.
//
// `lifetime_params` is a vector of tuple (span, parameter name, lifetime name).
// Input lifetime like `'a` or `'1`:
let mut lifetime_params: Vec<_> = self
.in_scope_lifetimes
.iter()
.cloned()
.map(|name| (name.ident().span, name, hir::LifetimeName::Param(name)))
.chain(
self.lifetimes_to_define
.iter()
.map(|&(span, name)| (span, name, hir::LifetimeName::Param(name))),
)
.collect();
self.with_hir_id_owner(opaque_ty_node_id, |this| {
// We have to be careful to get elision right here. The
// idea is that we create a lifetime parameter for each
@ -1710,34 +1717,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
//
// Then, we will create `fn foo(..) -> Foo<'_, '_>`, and
// hence the elision takes place at the fn site.
let future_bound = this
.with_anonymous_lifetime_mode(AnonymousLifetimeMode::CreateParameter, |this| {
this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span)
let (lifetimes_to_define, future_bound) =
this.with_anonymous_lifetime_mode(AnonymousLifetimeMode::CreateParameter, |this| {
this.collect_in_band_defs(|this| {
this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span)
})
});
debug!("lower_async_fn_ret_ty: future_bound={:#?}", future_bound);
debug!("lower_async_fn_ret_ty: lifetimes_to_define={:#?}", lifetimes_to_define);
// Calculate all the lifetimes that should be captured
// by the opaque type. This should include all in-scope
// lifetime parameters, including those defined in-band.
//
// Note: this must be done after lowering the output type,
// as the output type may introduce new in-band lifetimes.
lifetime_params = this
.in_scope_lifetimes
.iter()
.cloned()
.map(|name| (name.ident().span, name))
.chain(this.lifetimes_to_define.iter().cloned())
.collect();
debug!("lower_async_fn_ret_ty: in_scope_lifetimes={:#?}", this.in_scope_lifetimes);
debug!("lower_async_fn_ret_ty: lifetimes_to_define={:#?}", this.lifetimes_to_define);
lifetime_params.extend(
// Output lifetime like `'_`:
lifetimes_to_define
.into_iter()
.map(|(span, name)| (span, name, hir::LifetimeName::Implicit(false))),
);
debug!("lower_async_fn_ret_ty: lifetime_params={:#?}", lifetime_params);
let generic_params =
this.arena.alloc_from_iter(lifetime_params.iter().map(|(span, hir_name)| {
this.lifetime_to_generic_param(*span, *hir_name, opaque_ty_def_id)
this.arena.alloc_from_iter(lifetime_params.iter().map(|&(span, hir_name, _)| {
this.lifetime_to_generic_param(span, hir_name, opaque_ty_def_id)
}));
let opaque_ty_item = hir::OpaqueTy {
@ -1747,8 +1746,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
span: this.lower_span(span),
},
bounds: arena_vec![this; future_bound],
impl_trait_fn: Some(fn_def_id),
origin: hir::OpaqueTyOrigin::AsyncFn,
origin: hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
};
trace!("exist ty from async fn def id: {:#?}", opaque_ty_def_id);
@ -1771,25 +1769,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
//
// For the "output" lifetime parameters, we just want to
// generate `'_`.
let mut generic_args = Vec::with_capacity(lifetime_params.len());
generic_args.extend(lifetime_params[..input_lifetimes_count].iter().map(
|&(span, hir_name)| {
// Input lifetime like `'a` or `'1`:
let generic_args =
self.arena.alloc_from_iter(lifetime_params.into_iter().map(|(span, _, name)| {
GenericArg::Lifetime(hir::Lifetime {
hir_id: self.next_id(),
span: self.lower_span(span),
name: hir::LifetimeName::Param(hir_name),
name,
})
},
));
generic_args.extend(lifetime_params[input_lifetimes_count..].iter().map(|&(span, _)|
// Output lifetime like `'_`.
GenericArg::Lifetime(hir::Lifetime {
hir_id: self.next_id(),
span: self.lower_span(span),
name: hir::LifetimeName::Implicit(false),
})));
let generic_args = self.arena.alloc_from_iter(generic_args);
}));
// Create the `Foo<...>` reference itself. Note that the `type
// Foo = impl Trait` is, internally, created as a child of the
@ -1805,7 +1792,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn lower_async_fn_output_type_to_future_bound(
&mut self,
output: &FnRetTy,
fn_def_id: DefId,
fn_def_id: LocalDefId,
span: Span,
) -> hir::GenericBound<'hir> {
// Compute the `T` in `Future<Output = T>` from the return type.
@ -1816,7 +1803,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// generates.
let context = ImplTraitContext::ReturnPositionOpaqueTy {
fn_def_id,
origin: hir::OpaqueTyOrigin::FnReturn,
origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
};
self.lower_ty(ty, context)
}
@ -2453,17 +2440,12 @@ impl<'hir> GenericArgsCtor<'hir> {
}
}
#[tracing::instrument(level = "debug")]
fn lifetimes_from_impl_trait_bounds(
opaque_ty_id: NodeId,
bounds: hir::GenericBounds<'_>,
lifetimes_to_include: Option<&FxHashSet<hir::LifetimeName>>,
) -> Vec<(hir::LifetimeName, Span)> {
debug!(
"lifetimes_from_impl_trait_bounds(opaque_ty_id={:?}, \
bounds={:#?})",
opaque_ty_id, bounds,
);
// This visitor walks over `impl Trait` bounds and creates defs for all lifetimes that
// appear in the bounds, excluding lifetimes that are created within the bounds.
// E.g., `'a`, `'b`, but not `'c` in `impl for<'c> SomeTrait<'a, 'b, 'c>`.

2
compiler/rustc_borrowck/src/region_infer/opaque_types.rs
View file

@ -173,7 +173,7 @@ fn check_opaque_type_parameter_valid(
// fn foo<l0..'ln>() -> foo::<'static..'static>::Foo<'l0..'lm>.
//
// which would error here on all of the `'static` args.
OpaqueTyOrigin::FnReturn | OpaqueTyOrigin::AsyncFn => return true,
OpaqueTyOrigin::FnReturn(..) | OpaqueTyOrigin::AsyncFn(..) => return true,
// Check these
OpaqueTyOrigin::TyAlias => {}
}

9
compiler/rustc_hir/src/hir.rs
View file

@ -2248,7 +2248,6 @@ pub struct BareFnTy<'hir> {
pub struct OpaqueTy<'hir> {
pub generics: Generics<'hir>,
pub bounds: GenericBounds<'hir>,
pub impl_trait_fn: Option<DefId>,
pub origin: OpaqueTyOrigin,
}
@ -2256,9 +2255,9 @@ pub struct OpaqueTy<'hir> {
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum OpaqueTyOrigin {
/// `-> impl Trait`
FnReturn,
FnReturn(LocalDefId),
/// `async fn`
AsyncFn,
AsyncFn(LocalDefId),
/// type aliases: `type Foo = impl Trait;`
TyAlias,
}
@ -2809,7 +2808,9 @@ impl ItemKind<'_> {
Some(match *self {
ItemKind::Fn(_, ref generics, _)
| ItemKind::TyAlias(_, ref generics)
| ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. })
| ItemKind::OpaqueTy(OpaqueTy {
ref generics, origin: OpaqueTyOrigin::TyAlias, ..
})
| ItemKind::Enum(_, ref generics)
| ItemKind::Struct(_, ref generics)
| ItemKind::Union(_, ref generics)

2
compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs
View file

@ -107,7 +107,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
kind:
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
bounds,
origin: hir::OpaqueTyOrigin::AsyncFn,
origin: hir::OpaqueTyOrigin::AsyncFn(..),
..
}),
..

40
compiler/rustc_infer/src/infer/opaque_types.rs
View file

@ -276,7 +276,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
debug!(?concrete_ty);
let first_own_region = match opaque_defn.origin {
hir::OpaqueTyOrigin::FnReturn | hir::OpaqueTyOrigin::AsyncFn => {
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => {
// We lower
//
// fn foo<'l0..'ln>() -> impl Trait<'l0..'lm>
@ -461,35 +461,29 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
if let Some(def_id) = def_id.as_local() {
let opaque_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let parent_def_id = self.infcx.defining_use_anchor;
let (in_definition_scope, origin) = match tcx.hir().expect_item(def_id).kind
{
let item_kind = &tcx.hir().expect_item(def_id).kind;
let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item_kind else {
span_bug!(
self.value_span,
"weird opaque type: {:#?}, {:#?}",
ty.kind(),
item_kind
)
};
let in_definition_scope = match *origin {
// Async `impl Trait`
hir::OpaqueTyOrigin::AsyncFn(parent) => parent == parent_def_id,
// Anonymous `impl Trait`
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
impl_trait_fn: Some(parent),
origin,
..
}) => (parent == parent_def_id.to_def_id(), origin),
hir::OpaqueTyOrigin::FnReturn(parent) => parent == parent_def_id,
// Named `type Foo = impl Bar;`
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
impl_trait_fn: None,
origin,
..
}) => {
(may_define_opaque_type(tcx, parent_def_id, opaque_hir_id), origin)
}
ref itemkind => {
span_bug!(
self.value_span,
"weird opaque type: {:#?}, {:#?}",
ty.kind(),
itemkind
)
hir::OpaqueTyOrigin::TyAlias => {
may_define_opaque_type(tcx, parent_def_id, opaque_hir_id)
}
};
if in_definition_scope {
let opaque_type_key =
OpaqueTypeKey { def_id: def_id.to_def_id(), substs };
return self.fold_opaque_ty(ty, opaque_type_key, origin);
return self.fold_opaque_ty(ty, opaque_type_key, *origin);
}
debug!(

18
compiler/rustc_middle/src/ty/mod.rs
View file

@ -2055,13 +2055,17 @@ impl<'tcx> TyCtxt<'tcx> {
}
}
/// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
if let Some(def_id) = def_id.as_local() {
if let Node::Item(item) = tcx.hir().get(tcx.hir().local_def_id_to_hir_id(def_id)) {
if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
return opaque_ty.impl_trait_fn;
}
/// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
let def_id = def_id.as_local()?;
if let Node::Item(item) = tcx.hir().get(tcx.hir().local_def_id_to_hir_id(def_id)) {
if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
return match opaque_ty.origin {
hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
Some(parent)
}
hir::OpaqueTyOrigin::TyAlias => None,
};
}
}
None

15
compiler/rustc_resolve/src/late/lifetimes.rs
View file

@ -968,7 +968,10 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
let (generics, bounds) = match opaque_ty.kind {
// Named opaque `impl Trait` types are reached via `TyKind::Path`.
// This arm is for `impl Trait` in the types of statics, constants and locals.
hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: None, .. }) => {
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
origin: hir::OpaqueTyOrigin::TyAlias,
..
}) => {
intravisit::walk_ty(self, ty);
// Elided lifetimes are not allowed in non-return
@ -985,7 +988,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
}
// RPIT (return position impl trait)
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
impl_trait_fn: Some(_),
origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..),
ref generics,
bounds,
..
@ -1695,7 +1698,11 @@ fn compute_object_lifetime_defaults(
hir::ItemKind::Struct(_, ref generics)
| hir::ItemKind::Union(_, ref generics)
| hir::ItemKind::Enum(_, ref generics)
| hir::ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, impl_trait_fn: None, .. })
| hir::ItemKind::OpaqueTy(hir::OpaqueTy {
ref generics,
origin: hir::OpaqueTyOrigin::TyAlias,
..
})
| hir::ItemKind::TyAlias(_, ref generics)
| hir::ItemKind::Trait(_, _, ref generics, ..) => {
let result = object_lifetime_defaults_for_item(tcx, generics);
@ -2067,7 +2074,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
..
}) = self.tcx.hir().get(parent_hir_id)
{
if opaque.origin != hir::OpaqueTyOrigin::AsyncFn {
if !matches!(opaque.origin, hir::OpaqueTyOrigin::AsyncFn(..)) {
continue 'lifetimes;
}
// We want to do this only if the liftime identifier is already defined

4
compiler/rustc_ty_utils/src/ty.rs
View file

@ -248,7 +248,7 @@ fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
// The param_env of an impl Trait type is its defining function's param_env
if let Some(parent) = ty::is_impl_trait_defn(tcx, def_id) {
return param_env(tcx, parent);
return param_env(tcx, parent.to_def_id());
}
// Compute the bounds on Self and the type parameters.
@ -313,7 +313,7 @@ fn well_formed_types_in_env<'tcx>(
// The environment of an impl Trait type is its defining function's environment.
if let Some(parent) = ty::is_impl_trait_defn(tcx, def_id) {
return well_formed_types_in_env(tcx, parent);
return well_formed_types_in_env(tcx, parent.to_def_id());
}
// Compute the bounds on `Self` and the type parameters.

13
compiler/rustc_typeck/src/astconv/mod.rs
View file

@ -2336,9 +2336,16 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
let def_id = item_id.def_id.to_def_id();
match opaque_ty.kind {
hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => {
self.impl_trait_ty_to_ty(def_id, lifetimes, impl_trait_fn.is_some())
}
hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => self
.impl_trait_ty_to_ty(
def_id,
lifetimes,
matches!(
origin,
hir::OpaqueTyOrigin::FnReturn(..)
| hir::OpaqueTyOrigin::AsyncFn(..)
),
),
ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
}
}

8
compiler/rustc_typeck/src/check/check.rs
View file

@ -541,7 +541,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes(
}
if let ItemKind::OpaqueTy(hir::OpaqueTy {
origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn,
origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
..
}) = item.kind
{
@ -567,7 +567,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes(
visitor.visit_item(&item);
let is_async = match item.kind {
ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
matches!(origin, hir::OpaqueTyOrigin::AsyncFn)
matches!(origin, hir::OpaqueTyOrigin::AsyncFn(..))
}
_ => unreachable!(),
};
@ -604,7 +604,7 @@ pub(super) fn check_opaque_for_cycles<'tcx>(
) -> Result<(), ErrorReported> {
if tcx.try_expand_impl_trait_type(def_id.to_def_id(), substs).is_err() {
match origin {
hir::OpaqueTyOrigin::AsyncFn => async_opaque_type_cycle_error(tcx, span),
hir::OpaqueTyOrigin::AsyncFn(..) => async_opaque_type_cycle_error(tcx, span),
_ => opaque_type_cycle_error(tcx, def_id, span),
}
Err(ErrorReported)
@ -635,7 +635,7 @@ fn check_opaque_meets_bounds<'tcx>(
) {
match origin {
// Checked when type checking the function containing them.
hir::OpaqueTyOrigin::FnReturn | hir::OpaqueTyOrigin::AsyncFn => return,
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => return,
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {}
}

81
compiler/rustc_typeck/src/collect.rs
View file

@ -594,7 +594,11 @@ fn type_param_predicates(
ItemKind::Fn(.., ref generics, _)
| ItemKind::Impl(hir::Impl { ref generics, .. })
| ItemKind::TyAlias(_, ref generics)
| ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. })
| ItemKind::OpaqueTy(OpaqueTy {
ref generics,
origin: hir::OpaqueTyOrigin::TyAlias,
..
})
| ItemKind::Enum(_, ref generics)
| ItemKind::Struct(_, ref generics)
| ItemKind::Union(_, ref generics) => generics,
@ -793,7 +797,10 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
}
// Desugared from `impl Trait`, so visited by the function's return type.
hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {}
hir::ItemKind::OpaqueTy(hir::OpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..),
..
}) => {}
// Don't call `type_of` on opaque types, since that depends on type
// checking function bodies. `check_item_type` ensures that it's called
@ -1488,15 +1495,18 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
Some(tcx.typeck_root_def_id(def_id))
}
Node::Item(item) => match item.kind {
ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => {
impl_trait_fn.or_else(|| {
let parent_id = tcx.hir().get_parent_item(hir_id);
assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID);
debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
// Opaque types are always nested within another item, and
// inherit the generics of the item.
Some(tcx.hir().local_def_id(parent_id).to_def_id())
})
ItemKind::OpaqueTy(hir::OpaqueTy {
origin:
hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
..
}) => Some(fn_def_id.to_def_id()),
ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
let parent_id = tcx.hir().get_parent_item(hir_id);
assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID);
debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
// Opaque types are always nested within another item, and
// inherit the generics of the item.
Some(tcx.hir().local_def_id(parent_id).to_def_id())
}
_ => None,
},
@ -2051,31 +2061,32 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
generics
}
ItemKind::OpaqueTy(OpaqueTy {
bounds: _,
impl_trait_fn,
ref generics,
origin: _,
origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
..
}) => {
if impl_trait_fn.is_some() {
// return-position impl trait
//
// We don't inherit predicates from the parent here:
// If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
// then the return type is `f::<'static, T>::{{opaque}}`.
//
// If we inherited the predicates of `f` then we would
// require that `T: 'static` to show that the return
// type is well-formed.
//
// The only way to have something with this opaque type
// is from the return type of the containing function,
// which will ensure that the function's predicates
// hold.
return ty::GenericPredicates { parent: None, predicates: &[] };
} else {
// type-alias impl trait
generics
}
// return-position impl trait
//
// We don't inherit predicates from the parent here:
// If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
// then the return type is `f::<'static, T>::{{opaque}}`.
//
// If we inherited the predicates of `f` then we would
// require that `T: 'static` to show that the return
// type is well-formed.
//
// The only way to have something with this opaque type
// is from the return type of the containing function,
// which will ensure that the function's predicates
// hold.
return ty::GenericPredicates { parent: None, predicates: &[] };
}
ItemKind::OpaqueTy(OpaqueTy {
ref generics,
origin: hir::OpaqueTyOrigin::TyAlias,
..
}) => {
// type-alias impl trait
generics
}
_ => NO_GENERICS,

8
compiler/rustc_typeck/src/collect/type_of.rs
View file

@ -394,13 +394,13 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
tcx.mk_adt(def, substs)
}
ItemKind::OpaqueTy(OpaqueTy { impl_trait_fn: None, .. }) => {
ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
find_opaque_ty_constraints(tcx, def_id)
}
// Opaque types desugared from `impl Trait`.
ItemKind::OpaqueTy(OpaqueTy { impl_trait_fn: Some(owner), .. }) => {
ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner), .. }) => {
let concrete_ty = tcx
.mir_borrowck(owner.expect_local())
.mir_borrowck(owner)
.concrete_opaque_types
.get_value_matching(|(key, _)| key.def_id == def_id.to_def_id())
.copied()
@ -413,7 +413,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
),
);
if let Some(ErrorReported) =
tcx.typeck(owner.expect_local()).tainted_by_errors
tcx.typeck(owner).tainted_by_errors
{
// Some error in the
// owner fn prevented us from populating

11
src/test/ui/async-await/generics-and-bounds.rs
View file

@ -2,6 +2,8 @@
// edition:2018
// compile-flags: --crate-type lib
#![feature(in_band_lifetimes)]
use std::future::Future;
pub async fn simple_generic<T>() {}
@ -71,6 +73,10 @@ pub fn call_with_ref_block<'a>(f: &'a (impl Foo + 'a)) -> impl Future<Output = (
async move { f.foo() }
}
pub fn call_with_ref_block_in_band(f: &'a (impl Foo + 'a)) -> impl Future<Output = ()> + 'a {
async move { f.foo() }
}
pub fn async_block_with_same_generic_params_unifies() {
let mut a = call_generic_bound_block(FooType);
a = call_generic_bound_block(FooType);
@ -85,4 +91,9 @@ pub fn async_block_with_same_generic_params_unifies() {
let f_two = FooType;
let mut d = call_with_ref_block(&f_one);
d = call_with_ref_block(&f_two);
let f_one = FooType;
let f_two = FooType;
let mut d = call_with_ref_block_in_band(&f_one);
d = call_with_ref_block_in_band(&f_two);
}