diff options
Diffstat (limited to 'compiler/rustc_ast_lowering/src/lib.rs')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 281 |
1 files changed, 111 insertions, 170 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 2b3a538772e..77738b2c5cc 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -32,7 +32,6 @@ #![feature(crate_visibility_modifier)] #![feature(box_patterns)] -#![feature(iter_zip)] #![feature(never_type)] #![recursion_limit = "256"] @@ -47,20 +46,18 @@ use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::sorted_map::SortedMap; use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; use rustc_data_structures::sync::Lrc; -use rustc_errors::{struct_span_err, Applicability}; +use rustc_errors::struct_span_err; use rustc_hir as hir; use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res}; use rustc_hir::def_id::{DefId, DefPathHash, LocalDefId, CRATE_DEF_ID}; use rustc_hir::definitions::{DefKey, DefPathData, Definitions}; use rustc_hir::intravisit; -use rustc_hir::{ConstArg, GenericArg, InferKind, ParamName}; +use rustc_hir::{ConstArg, GenericArg, ParamName}; use rustc_index::vec::{Idx, IndexVec}; use rustc_query_system::ich::StableHashingContext; -use rustc_session::lint::builtin::BARE_TRAIT_OBJECTS; -use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer}; +use rustc_session::lint::LintBuffer; use rustc_session::utils::{FlattenNonterminals, NtToTokenstream}; use rustc_session::Session; -use rustc_span::edition::Edition; use rustc_span::hygiene::ExpnId; use rustc_span::source_map::{respan, DesugaringKind}; use rustc_span::symbol::{kw, sym, Ident, Symbol}; @@ -70,10 +67,9 @@ use smallvec::SmallVec; use tracing::{debug, trace}; macro_rules! arena_vec { - ($this:expr; $($x:expr),*) => ({ - let a = [$($x),*]; - $this.arena.alloc_from_iter(std::array::IntoIter::new(a)) - }); + ($this:expr; $($x:expr),*) => ( + $this.arena.alloc_from_iter([$($x),*]) + ); } mod asm; @@ -162,6 +158,7 @@ struct LoweringContext<'a, 'hir: 'a> { allow_try_trait: Option<Lrc<[Symbol]>>, allow_gen_future: Option<Lrc<[Symbol]>>, + allow_into_future: Option<Lrc<[Symbol]>>, } pub trait ResolverAstLowering { @@ -228,7 +225,7 @@ 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, }, @@ -320,6 +317,7 @@ pub fn lower_crate<'a, 'hir>( in_scope_lifetimes: Vec::new(), allow_try_trait: Some([sym::try_trait_v2][..].into()), allow_gen_future: Some([sym::gen_future][..].into()), + allow_into_future: Some([sym::into_future][..].into()), } .lower_crate(krate) } @@ -645,31 +643,16 @@ 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; - - self.anonymous_lifetime_mode = anonymous_lifetime_mode; - self.is_collecting_in_band_lifetimes = true; - - 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); + 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(); - 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(); + let res = f(self); - (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. @@ -784,27 +767,39 @@ 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) @@ -1116,7 +1111,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { return GenericArg::Infer(hir::InferArg { hir_id: self.lower_node_id(ty.id), span: self.lower_span(ty.span), - kind: InferKind::Type, }); } // We parse const arguments as path types as we cannot distinguish them during @@ -1188,11 +1182,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { ) -> hir::Ty<'hir> { let id = self.lower_node_id(t.id); let qpath = self.lower_qpath(t.id, qself, path, param_mode, itctx); - let ty = self.ty_path(id, t.span, qpath); - if let hir::TyKind::TraitObject(..) = ty.kind { - self.maybe_lint_bare_trait(t.span, t.id, qself.is_none() && path.is_global()); - } - ty + self.ty_path(id, t.span, qpath) } fn ty(&mut self, span: Span, kind: hir::TyKind<'hir>) -> hir::Ty<'hir> { @@ -1289,9 +1279,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { lifetime_bound.unwrap_or_else(|| this.elided_dyn_bound(t.span)); (bounds, lifetime_bound) }); - if kind != TraitObjectSyntax::Dyn { - self.maybe_lint_bare_trait(t.span, t.id, false); - } hir::TyKind::TraitObject(bounds, lifetime_bound, kind) } TyKind::ImplTrait(def_node_id, ref bounds) => { @@ -1379,7 +1366,7 @@ 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>>, @@ -1451,7 +1438,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { span: lctx.lower_span(span), }, bounds: hir_bounds, - impl_trait_fn: fn_def_id, origin, }; @@ -1521,7 +1507,7 @@ 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> { @@ -1579,7 +1565,7 @@ 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(), @@ -1634,7 +1620,7 @@ 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!( @@ -1688,18 +1674,29 @@ 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. + + 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. // - // 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(); + // `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 @@ -1709,34 +1706,26 @@ 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 { @@ -1746,8 +1735,7 @@ 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); @@ -1770,25 +1758,14 @@ 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, - }))); - 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 @@ -1804,7 +1781,7 @@ 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. @@ -1815,7 +1792,7 @@ 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) } @@ -1927,7 +1904,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }); let param_name = match lt.name { hir::LifetimeName::Param(param_name) => param_name, - hir::LifetimeName::Implicit + hir::LifetimeName::Implicit(_) | hir::LifetimeName::Underscore | hir::LifetimeName::Static => hir::ParamName::Plain(lt.name.ident()), hir::LifetimeName::ImplicitObjectLifetimeDefault => { @@ -2139,21 +2116,21 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn pat_cf_continue(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { let field = self.single_pat_field(span, pat); - self.pat_lang_item_variant(span, hir::LangItem::ControlFlowContinue, field) + self.pat_lang_item_variant(span, hir::LangItem::ControlFlowContinue, field, None) } fn pat_cf_break(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { let field = self.single_pat_field(span, pat); - self.pat_lang_item_variant(span, hir::LangItem::ControlFlowBreak, field) + self.pat_lang_item_variant(span, hir::LangItem::ControlFlowBreak, field, None) } fn pat_some(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { let field = self.single_pat_field(span, pat); - self.pat_lang_item_variant(span, hir::LangItem::OptionSome, field) + self.pat_lang_item_variant(span, hir::LangItem::OptionSome, field, None) } fn pat_none(&mut self, span: Span) -> &'hir hir::Pat<'hir> { - self.pat_lang_item_variant(span, hir::LangItem::OptionNone, &[]) + self.pat_lang_item_variant(span, hir::LangItem::OptionNone, &[], None) } fn single_pat_field( @@ -2176,8 +2153,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { span: Span, lang_item: hir::LangItem, fields: &'hir [hir::PatField<'hir>], + hir_id: Option<hir::HirId>, ) -> &'hir hir::Pat<'hir> { - let qpath = hir::QPath::LangItem(lang_item, self.lower_span(span)); + let qpath = hir::QPath::LangItem(lang_item, self.lower_span(span), hir_id); self.pat(span, hir::PatKind::Struct(qpath, fields, false)) } @@ -2290,7 +2268,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { AnonymousLifetimeMode::ReportError => self.new_error_lifetime(None, span), - AnonymousLifetimeMode::PassThrough => self.new_implicit_lifetime(span), + AnonymousLifetimeMode::PassThrough => self.new_implicit_lifetime(span, false), } } @@ -2322,11 +2300,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { &'s mut self, span: Span, count: usize, + param_mode: ParamMode, ) -> impl Iterator<Item = hir::Lifetime> + Captures<'a> + Captures<'s> + Captures<'hir> { - (0..count).map(move |_| self.elided_path_lifetime(span)) + (0..count).map(move |_| self.elided_path_lifetime(span, param_mode)) } - fn elided_path_lifetime(&mut self, span: Span) -> hir::Lifetime { + fn elided_path_lifetime(&mut self, span: Span, param_mode: ParamMode) -> hir::Lifetime { match self.anonymous_lifetime_mode { AnonymousLifetimeMode::CreateParameter => { // We should have emitted E0726 when processing this path above @@ -2342,7 +2321,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // lifetime. Instead, we simply create an implicit lifetime, which will be checked // later, at which point a suitable error will be emitted. AnonymousLifetimeMode::PassThrough | AnonymousLifetimeMode::ReportError => { - self.new_implicit_lifetime(span) + self.new_implicit_lifetime(span, param_mode == ParamMode::Explicit) } } } @@ -2385,44 +2364,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { r } - fn new_implicit_lifetime(&mut self, span: Span) -> hir::Lifetime { + fn new_implicit_lifetime(&mut self, span: Span, missing: bool) -> hir::Lifetime { hir::Lifetime { hir_id: self.next_id(), span: self.lower_span(span), - name: hir::LifetimeName::Implicit, - } - } - - fn maybe_lint_bare_trait(&mut self, span: Span, id: NodeId, is_global: bool) { - // FIXME(davidtwco): This is a hack to detect macros which produce spans of the - // call site which do not have a macro backtrace. See #61963. - let is_macro_callsite = self - .sess - .source_map() - .span_to_snippet(span) - .map(|snippet| snippet.starts_with("#[")) - .unwrap_or(true); - if !is_macro_callsite { - if span.edition() < Edition::Edition2021 { - self.resolver.lint_buffer().buffer_lint_with_diagnostic( - BARE_TRAIT_OBJECTS, - id, - span, - "trait objects without an explicit `dyn` are deprecated", - BuiltinLintDiagnostics::BareTraitObject(span, is_global), - ) - } else { - let msg = "trait objects must include the `dyn` keyword"; - let label = "add `dyn` keyword before this trait"; - let mut err = struct_span_err!(self.sess, span, E0782, "{}", msg,); - err.span_suggestion_verbose( - span.shrink_to_lo(), - label, - String::from("dyn "), - Applicability::MachineApplicable, - ); - err.emit(); - } + name: hir::LifetimeName::Implicit(missing), } } } @@ -2451,17 +2397,12 @@ 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>`. @@ -2536,7 +2477,7 @@ fn lifetimes_from_impl_trait_bounds( fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) { let name = match lifetime.name { - hir::LifetimeName::Implicit | hir::LifetimeName::Underscore => { + hir::LifetimeName::Implicit(_) | hir::LifetimeName::Underscore => { if self.collect_elided_lifetimes { // Use `'_` for both implicit and underscore lifetimes in // `type Foo<'_> = impl SomeTrait<'_>;`. |