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041b39d2 XL |
1 | //! Lowers the AST to the HIR. |
2 | //! | |
3 | //! Since the AST and HIR are fairly similar, this is mostly a simple procedure, | |
4 | //! much like a fold. Where lowering involves a bit more work things get more | |
5 | //! interesting and there are some invariants you should know about. These mostly | |
9fa01778 | 6 | //! concern spans and IDs. |
041b39d2 XL |
7 | //! |
8 | //! Spans are assigned to AST nodes during parsing and then are modified during | |
9 | //! expansion to indicate the origin of a node and the process it went through | |
9fa01778 | 10 | //! being expanded. IDs are assigned to AST nodes just before lowering. |
041b39d2 | 11 | //! |
9fa01778 | 12 | //! For the simpler lowering steps, IDs and spans should be preserved. Unlike |
041b39d2 XL |
13 | //! expansion we do not preserve the process of lowering in the spans, so spans |
14 | //! should not be modified here. When creating a new node (as opposed to | |
9fa01778 | 15 | //! 'folding' an existing one), then you create a new ID using `next_id()`. |
041b39d2 | 16 | //! |
9fa01778 | 17 | //! You must ensure that IDs are unique. That means that you should only use the |
dc9dc135 | 18 | //! ID from an AST node in a single HIR node (you can assume that AST node-IDs |
9fa01778 XL |
19 | //! are unique). Every new node must have a unique ID. Avoid cloning HIR nodes. |
20 | //! If you do, you must then set the new node's ID to a fresh one. | |
041b39d2 XL |
21 | //! |
22 | //! Spans are used for error messages and for tools to map semantics back to | |
9fa01778 | 23 | //! source code. It is therefore not as important with spans as IDs to be strict |
041b39d2 XL |
24 | //! about use (you can't break the compiler by screwing up a span). Obviously, a |
25 | //! HIR node can only have a single span. But multiple nodes can have the same | |
26 | //! span and spans don't need to be kept in order, etc. Where code is preserved | |
27 | //! by lowering, it should have the same span as in the AST. Where HIR nodes are | |
28 | //! new it is probably best to give a span for the whole AST node being lowered. | |
29 | //! All nodes should have real spans, don't use dummy spans. Tools are likely to | |
30 | //! get confused if the spans from leaf AST nodes occur in multiple places | |
31 | //! in the HIR, especially for multiple identifiers. | |
e9174d1e | 32 | |
dfeec247 XL |
33 | #![feature(array_value_iter)] |
34 | #![feature(crate_visibility_modifier)] | |
ba9703b0 XL |
35 | #![feature(marker_trait_attr)] |
36 | #![feature(specialization)] | |
37 | #![feature(or_patterns)] | |
74b04a01 | 38 | #![recursion_limit = "256"] |
416331ca | 39 | |
74b04a01 XL |
40 | use rustc_ast::ast; |
41 | use rustc_ast::ast::*; | |
42 | use rustc_ast::attr; | |
43 | use rustc_ast::node_id::NodeMap; | |
44 | use rustc_ast::token::{self, Nonterminal, Token}; | |
45 | use rustc_ast::tokenstream::{TokenStream, TokenTree}; | |
46 | use rustc_ast::visit::{self, AssocCtxt, Visitor}; | |
47 | use rustc_ast::walk_list; | |
48 | use rustc_ast_pretty::pprust; | |
dfeec247 | 49 | use rustc_data_structures::captures::Captures; |
b7449926 | 50 | use rustc_data_structures::fx::FxHashSet; |
dc9dc135 | 51 | use rustc_data_structures::sync::Lrc; |
dfeec247 XL |
52 | use rustc_errors::struct_span_err; |
53 | use rustc_hir as hir; | |
54 | use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res}; | |
ba9703b0 XL |
55 | use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX}; |
56 | use rustc_hir::definitions::{DefKey, DefPathData, Definitions}; | |
dfeec247 XL |
57 | use rustc_hir::intravisit; |
58 | use rustc_hir::{ConstArg, GenericArg, ParamName}; | |
59 | use rustc_index::vec::IndexVec; | |
60 | use rustc_session::config::nightly_options; | |
74b04a01 XL |
61 | use rustc_session::lint::{builtin::BARE_TRAIT_OBJECTS, BuiltinLintDiagnostics, LintBuffer}; |
62 | use rustc_session::parse::ParseSess; | |
dfeec247 XL |
63 | use rustc_session::Session; |
64 | use rustc_span::hygiene::ExpnId; | |
65 | use rustc_span::source_map::{respan, DesugaringKind, ExpnData, ExpnKind}; | |
66 | use rustc_span::symbol::{kw, sym, Symbol}; | |
67 | use rustc_span::Span; | |
b039eaaf | 68 | |
dfeec247 XL |
69 | use log::{debug, trace}; |
70 | use smallvec::{smallvec, SmallVec}; | |
71 | use std::collections::BTreeMap; | |
72 | use std::mem; | |
73 | ||
74 | macro_rules! arena_vec { | |
75 | ($this:expr; $($x:expr),*) => ({ | |
76 | let a = [$($x),*]; | |
77 | $this.arena.alloc_from_iter(std::array::IntoIter::new(a)) | |
78 | }); | |
79 | } | |
80 | ||
81 | mod expr; | |
82 | mod item; | |
83 | mod pat; | |
84 | mod path; | |
60c5eb7d | 85 | |
cc61c64b XL |
86 | const HIR_ID_COUNTER_LOCKED: u32 = 0xFFFFFFFF; |
87 | ||
ba9703b0 XL |
88 | rustc_hir::arena_types!(::arena::declare_arena, [], 'tcx); |
89 | ||
dfeec247 | 90 | struct LoweringContext<'a, 'hir: 'a> { |
48663c56 | 91 | crate_root: Option<Symbol>, |
041b39d2 | 92 | |
e1599b0c | 93 | /// Used to assign IDs to HIR nodes that do not directly correspond to AST nodes. |
9e0c209e | 94 | sess: &'a Session, |
041b39d2 | 95 | |
8faf50e0 | 96 | resolver: &'a mut dyn Resolver, |
476ff2be | 97 | |
e74abb32 XL |
98 | /// HACK(Centril): there is a cyclic dependency between the parser and lowering |
99 | /// if we don't have this function pointer. To avoid that dependency so that | |
ba9703b0 | 100 | /// librustc_middle is independent of the parser, we use dynamic dispatch here. |
e74abb32 XL |
101 | nt_to_tokenstream: NtToTokenstream, |
102 | ||
dfeec247 XL |
103 | /// Used to allocate HIR nodes |
104 | arena: &'hir Arena<'hir>, | |
105 | ||
476ff2be | 106 | /// The items being lowered are collected here. |
dfeec247 | 107 | items: BTreeMap<hir::HirId, hir::Item<'hir>>, |
476ff2be | 108 | |
dfeec247 XL |
109 | trait_items: BTreeMap<hir::TraitItemId, hir::TraitItem<'hir>>, |
110 | impl_items: BTreeMap<hir::ImplItemId, hir::ImplItem<'hir>>, | |
111 | bodies: BTreeMap<hir::BodyId, hir::Body<'hir>>, | |
112 | exported_macros: Vec<hir::MacroDef<'hir>>, | |
416331ca | 113 | non_exported_macro_attrs: Vec<ast::Attribute>, |
8bb4bdeb | 114 | |
532ac7d7 | 115 | trait_impls: BTreeMap<DefId, Vec<hir::HirId>>, |
8bb4bdeb | 116 | |
e74abb32 | 117 | modules: BTreeMap<hir::HirId, hir::ModuleItems>, |
0731742a | 118 | |
dc9dc135 | 119 | generator_kind: Option<hir::GeneratorKind>, |
48663c56 | 120 | |
ba9703b0 XL |
121 | /// When inside an `async` context, this is the `HirId` of the |
122 | /// `task_context` local bound to the resume argument of the generator. | |
123 | task_context: Option<hir::HirId>, | |
124 | ||
48663c56 XL |
125 | /// Used to get the current `fn`'s def span to point to when using `await` |
126 | /// outside of an `async fn`. | |
127 | current_item: Option<Span>, | |
ea8adc8c | 128 | |
cc61c64b | 129 | catch_scopes: Vec<NodeId>, |
8bb4bdeb XL |
130 | loop_scopes: Vec<NodeId>, |
131 | is_in_loop_condition: bool, | |
abe05a73 | 132 | is_in_trait_impl: bool, |
dc9dc135 | 133 | is_in_dyn_type: bool, |
32a655c1 | 134 | |
0531ce1d XL |
135 | /// What to do when we encounter either an "anonymous lifetime |
136 | /// reference". The term "anonymous" is meant to encompass both | |
137 | /// `'_` lifetimes as well as fully elided cases where nothing is | |
138 | /// written at all (e.g., `&T` or `std::cell::Ref<T>`). | |
139 | anonymous_lifetime_mode: AnonymousLifetimeMode, | |
140 | ||
532ac7d7 XL |
141 | /// Used to create lifetime definitions from in-band lifetime usages. |
142 | /// e.g., `fn foo(x: &'x u8) -> &'x u8` to `fn foo<'x>(x: &'x u8) -> &'x u8` | |
143 | /// When a named lifetime is encountered in a function or impl header and | |
144 | /// has not been defined | |
145 | /// (i.e., it doesn't appear in the in_scope_lifetimes list), it is added | |
146 | /// to this list. The results of this list are then added to the list of | |
147 | /// lifetime definitions in the corresponding impl or function generics. | |
8faf50e0 | 148 | lifetimes_to_define: Vec<(Span, ParamName)>, |
0531ce1d | 149 | |
e1599b0c | 150 | /// `true` if in-band lifetimes are being collected. This is used to |
532ac7d7 XL |
151 | /// indicate whether or not we're in a place where new lifetimes will result |
152 | /// in in-band lifetime definitions, such a function or an impl header, | |
153 | /// including implicit lifetimes from `impl_header_lifetime_elision`. | |
ff7c6d11 | 154 | is_collecting_in_band_lifetimes: bool, |
0531ce1d | 155 | |
532ac7d7 XL |
156 | /// Currently in-scope lifetimes defined in impl headers, fn headers, or HRTB. |
157 | /// When `is_collectin_in_band_lifetimes` is true, each lifetime is checked | |
158 | /// against this list to see if it is already in-scope, or if a definition | |
159 | /// needs to be created for it. | |
e1599b0c | 160 | /// |
ba9703b0 | 161 | /// We always store a `normalize_to_macros_2_0()` version of the param-name in this |
e1599b0c XL |
162 | /// vector. |
163 | in_scope_lifetimes: Vec<ParamName>, | |
ff7c6d11 | 164 | |
e74abb32 | 165 | current_module: hir::HirId, |
0731742a | 166 | |
32a655c1 | 167 | type_def_lifetime_params: DefIdMap<usize>, |
cc61c64b | 168 | |
ba9703b0 | 169 | current_hir_id_owner: Vec<(LocalDefId, u32)>, |
cc61c64b | 170 | item_local_id_counters: NodeMap<u32>, |
ba9703b0 | 171 | node_id_to_hir_id: IndexVec<NodeId, Option<hir::HirId>>, |
dc9dc135 XL |
172 | |
173 | allow_try_trait: Option<Lrc<[Symbol]>>, | |
174 | allow_gen_future: Option<Lrc<[Symbol]>>, | |
b039eaaf SL |
175 | } |
176 | ||
a7813a04 | 177 | pub trait Resolver { |
dfeec247 XL |
178 | fn def_key(&mut self, id: DefId) -> DefKey; |
179 | ||
180 | fn item_generics_num_lifetimes(&self, def: DefId, sess: &Session) -> usize; | |
e74abb32 | 181 | |
e1599b0c | 182 | /// Obtains resolution for a `NodeId` with a single resolution. |
48663c56 XL |
183 | fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes>; |
184 | ||
e1599b0c | 185 | /// Obtains per-namespace resolutions for `use` statement with the given `NodeId`. |
48663c56 | 186 | fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res<NodeId>>>; |
a7813a04 | 187 | |
e1599b0c | 188 | /// Obtains resolution for a label with the given `NodeId`. |
48663c56 | 189 | fn get_label_res(&mut self, id: NodeId) -> Option<NodeId>; |
94b46f34 | 190 | |
041b39d2 XL |
191 | /// We must keep the set of definitions up to date as we add nodes that weren't in the AST. |
192 | /// This should only return `None` during testing. | |
9e0c209e | 193 | fn definitions(&mut self) -> &mut Definitions; |
2c00a5a8 | 194 | |
dc9dc135 | 195 | /// Given suffix `["b", "c", "d"]`, creates an AST path for `[::crate_root]::b::c::d` and |
0731742a | 196 | /// resolves it based on `is_value`. |
0531ce1d XL |
197 | fn resolve_str_path( |
198 | &mut self, | |
199 | span: Span, | |
48663c56 XL |
200 | crate_root: Option<Symbol>, |
201 | components: &[Symbol], | |
416331ca | 202 | ns: Namespace, |
dc9dc135 | 203 | ) -> (ast::Path, Res<NodeId>); |
416331ca | 204 | |
dfeec247 | 205 | fn lint_buffer(&mut self) -> &mut LintBuffer; |
60c5eb7d XL |
206 | |
207 | fn next_node_id(&mut self) -> NodeId; | |
a7813a04 | 208 | } |
b039eaaf | 209 | |
e74abb32 XL |
210 | type NtToTokenstream = fn(&Nonterminal, &ParseSess, Span) -> TokenStream; |
211 | ||
dc9dc135 XL |
212 | /// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree, |
213 | /// and if so, what meaning it has. | |
8faf50e0 | 214 | #[derive(Debug)] |
dfeec247 | 215 | enum ImplTraitContext<'b, 'a> { |
abe05a73 XL |
216 | /// Treat `impl Trait` as shorthand for a new universal generic parameter. |
217 | /// Example: `fn foo(x: impl Debug)`, where `impl Debug` is conceptually | |
218 | /// equivalent to a fresh universal parameter like `fn foo<T: Debug>(x: T)`. | |
219 | /// | |
0bf4aa26 | 220 | /// Newly generated parameters should be inserted into the given `Vec`. |
dfeec247 | 221 | Universal(&'b mut Vec<hir::GenericParam<'a>>), |
abe05a73 | 222 | |
416331ca | 223 | /// Treat `impl Trait` as shorthand for a new opaque type. |
abe05a73 | 224 | /// Example: `fn foo() -> impl Debug`, where `impl Debug` is conceptually |
416331ca | 225 | /// equivalent to a new opaque type like `type T = impl Debug; fn foo() -> T`. |
94b46f34 | 226 | /// |
0bf4aa26 | 227 | /// We optionally store a `DefId` for the parent item here so we can look up necessary |
dc9dc135 XL |
228 | /// information later. It is `None` when no information about the context should be stored |
229 | /// (e.g., for consts and statics). | |
74b04a01 | 230 | OpaqueTy(Option<DefId> /* fn def-ID */, hir::OpaqueTyOrigin), |
abe05a73 XL |
231 | |
232 | /// `impl Trait` is not accepted in this position. | |
0bf4aa26 XL |
233 | Disallowed(ImplTraitPosition), |
234 | } | |
235 | ||
dc9dc135 | 236 | /// Position in which `impl Trait` is disallowed. |
0bf4aa26 XL |
237 | #[derive(Debug, Copy, Clone, PartialEq, Eq)] |
238 | enum ImplTraitPosition { | |
dc9dc135 | 239 | /// Disallowed in `let` / `const` / `static` bindings. |
0bf4aa26 | 240 | Binding, |
dc9dc135 XL |
241 | |
242 | /// All other posiitons. | |
0bf4aa26 | 243 | Other, |
abe05a73 XL |
244 | } |
245 | ||
dfeec247 | 246 | impl<'a> ImplTraitContext<'_, 'a> { |
0bf4aa26 XL |
247 | #[inline] |
248 | fn disallowed() -> Self { | |
249 | ImplTraitContext::Disallowed(ImplTraitPosition::Other) | |
250 | } | |
251 | ||
dfeec247 | 252 | fn reborrow<'this>(&'this mut self) -> ImplTraitContext<'this, 'a> { |
8faf50e0 XL |
253 | use self::ImplTraitContext::*; |
254 | match self { | |
255 | Universal(params) => Universal(params), | |
74b04a01 | 256 | OpaqueTy(fn_def_id, origin) => OpaqueTy(*fn_def_id, *origin), |
0bf4aa26 | 257 | Disallowed(pos) => Disallowed(*pos), |
8faf50e0 XL |
258 | } |
259 | } | |
260 | } | |
261 | ||
dfeec247 XL |
262 | pub fn lower_crate<'a, 'hir>( |
263 | sess: &'a Session, | |
dfeec247 XL |
264 | krate: &'a Crate, |
265 | resolver: &'a mut dyn Resolver, | |
e74abb32 | 266 | nt_to_tokenstream: NtToTokenstream, |
dfeec247 XL |
267 | arena: &'hir Arena<'hir>, |
268 | ) -> hir::Crate<'hir> { | |
dfeec247 | 269 | let _prof_timer = sess.prof.verbose_generic_activity("hir_lowering"); |
e74abb32 | 270 | |
a7813a04 | 271 | LoweringContext { |
416331ca | 272 | crate_root: sess.parse_sess.injected_crate_name.try_get().copied(), |
041b39d2 | 273 | sess, |
041b39d2 | 274 | resolver, |
e74abb32 | 275 | nt_to_tokenstream, |
dfeec247 | 276 | arena, |
476ff2be | 277 | items: BTreeMap::new(), |
32a655c1 | 278 | trait_items: BTreeMap::new(), |
476ff2be | 279 | impl_items: BTreeMap::new(), |
8bb4bdeb XL |
280 | bodies: BTreeMap::new(), |
281 | trait_impls: BTreeMap::new(), | |
0731742a | 282 | modules: BTreeMap::new(), |
8bb4bdeb | 283 | exported_macros: Vec::new(), |
416331ca | 284 | non_exported_macro_attrs: Vec::new(), |
cc61c64b | 285 | catch_scopes: Vec::new(), |
8bb4bdeb XL |
286 | loop_scopes: Vec::new(), |
287 | is_in_loop_condition: false, | |
dc9dc135 XL |
288 | is_in_trait_impl: false, |
289 | is_in_dyn_type: false, | |
0531ce1d | 290 | anonymous_lifetime_mode: AnonymousLifetimeMode::PassThrough, |
a1dfa0c6 | 291 | type_def_lifetime_params: Default::default(), |
e74abb32 | 292 | current_module: hir::CRATE_HIR_ID, |
ba9703b0 | 293 | current_hir_id_owner: vec![(LocalDefId { local_def_index: CRATE_DEF_INDEX }, 0)], |
a1dfa0c6 | 294 | item_local_id_counters: Default::default(), |
cc61c64b | 295 | node_id_to_hir_id: IndexVec::new(), |
dc9dc135 | 296 | generator_kind: None, |
ba9703b0 | 297 | task_context: None, |
48663c56 | 298 | current_item: None, |
ff7c6d11 XL |
299 | lifetimes_to_define: Vec::new(), |
300 | is_collecting_in_band_lifetimes: false, | |
301 | in_scope_lifetimes: Vec::new(), | |
dc9dc135 XL |
302 | allow_try_trait: Some([sym::try_trait][..].into()), |
303 | allow_gen_future: Some([sym::gen_future][..].into()), | |
dfeec247 XL |
304 | } |
305 | .lower_crate(krate) | |
a7813a04 XL |
306 | } |
307 | ||
8faf50e0 | 308 | #[derive(Copy, Clone, PartialEq)] |
476ff2be SL |
309 | enum ParamMode { |
310 | /// Any path in a type context. | |
311 | Explicit, | |
dc9dc135 XL |
312 | /// Path in a type definition, where the anonymous lifetime `'_` is not allowed. |
313 | ExplicitNamed, | |
476ff2be | 314 | /// The `module::Type` in `module::Type::method` in an expression. |
0531ce1d | 315 | Optional, |
476ff2be SL |
316 | } |
317 | ||
3b2f2976 XL |
318 | enum ParenthesizedGenericArgs { |
319 | Ok, | |
3b2f2976 XL |
320 | Err, |
321 | } | |
322 | ||
0531ce1d | 323 | /// What to do when we encounter an **anonymous** lifetime |
9fa01778 | 324 | /// reference. Anonymous lifetime references come in two flavors. You |
0531ce1d XL |
325 | /// have implicit, or fully elided, references to lifetimes, like the |
326 | /// one in `&T` or `Ref<T>`, and you have `'_` lifetimes, like `&'_ T` | |
9fa01778 | 327 | /// or `Ref<'_, T>`. These often behave the same, but not always: |
0531ce1d XL |
328 | /// |
329 | /// - certain usages of implicit references are deprecated, like | |
330 | /// `Ref<T>`, and we sometimes just give hard errors in those cases | |
331 | /// as well. | |
332 | /// - for object bounds there is a difference: `Box<dyn Foo>` is not | |
333 | /// the same as `Box<dyn Foo + '_>`. | |
334 | /// | |
335 | /// We describe the effects of the various modes in terms of three cases: | |
336 | /// | |
337 | /// - **Modern** -- includes all uses of `'_`, but also the lifetime arg | |
338 | /// of a `&` (e.g., the missing lifetime in something like `&T`) | |
339 | /// - **Dyn Bound** -- if you have something like `Box<dyn Foo>`, | |
340 | /// there is an elided lifetime bound (`Box<dyn Foo + 'X>`). These | |
341 | /// elided bounds follow special rules. Note that this only covers | |
342 | /// cases where *nothing* is written; the `'_` in `Box<dyn Foo + | |
343 | /// '_>` is a case of "modern" elision. | |
344 | /// - **Deprecated** -- this coverse cases like `Ref<T>`, where the lifetime | |
345 | /// parameter to ref is completely elided. `Ref<'_, T>` would be the modern, | |
346 | /// non-deprecated equivalent. | |
347 | /// | |
348 | /// Currently, the handling of lifetime elision is somewhat spread out | |
349 | /// between HIR lowering and -- as described below -- the | |
350 | /// `resolve_lifetime` module. Often we "fallthrough" to that code by generating | |
351 | /// an "elided" or "underscore" lifetime name. In the future, we probably want to move | |
352 | /// everything into HIR lowering. | |
e1599b0c | 353 | #[derive(Copy, Clone, Debug)] |
0531ce1d XL |
354 | enum AnonymousLifetimeMode { |
355 | /// For **Modern** cases, create a new anonymous region parameter | |
356 | /// and reference that. | |
357 | /// | |
358 | /// For **Dyn Bound** cases, pass responsibility to | |
359 | /// `resolve_lifetime` code. | |
360 | /// | |
361 | /// For **Deprecated** cases, report an error. | |
362 | CreateParameter, | |
363 | ||
0bf4aa26 XL |
364 | /// Give a hard error when either `&` or `'_` is written. Used to |
365 | /// rule out things like `where T: Foo<'_>`. Does not imply an | |
366 | /// error on default object bounds (e.g., `Box<dyn Foo>`). | |
367 | ReportError, | |
368 | ||
0531ce1d XL |
369 | /// Pass responsibility to `resolve_lifetime` code for all cases. |
370 | PassThrough, | |
371 | } | |
372 | ||
dfeec247 XL |
373 | struct ImplTraitTypeIdVisitor<'a> { |
374 | ids: &'a mut SmallVec<[NodeId; 1]>, | |
375 | } | |
0bf4aa26 | 376 | |
dfeec247 XL |
377 | impl Visitor<'_> for ImplTraitTypeIdVisitor<'_> { |
378 | fn visit_ty(&mut self, ty: &Ty) { | |
e74abb32 | 379 | match ty.kind { |
dfeec247 | 380 | TyKind::Typeof(_) | TyKind::BareFn(_) => return, |
0bf4aa26 | 381 | |
532ac7d7 | 382 | TyKind::ImplTrait(id, _) => self.ids.push(id), |
dfeec247 | 383 | _ => {} |
0bf4aa26 XL |
384 | } |
385 | visit::walk_ty(self, ty); | |
386 | } | |
387 | ||
dfeec247 | 388 | fn visit_path_segment(&mut self, path_span: Span, path_segment: &PathSegment) { |
0bf4aa26 XL |
389 | if let Some(ref p) = path_segment.args { |
390 | if let GenericArgs::Parenthesized(_) = **p { | |
391 | return; | |
392 | } | |
393 | } | |
394 | visit::walk_path_segment(self, path_span, path_segment) | |
395 | } | |
396 | } | |
397 | ||
dfeec247 XL |
398 | impl<'a, 'hir> LoweringContext<'a, 'hir> { |
399 | fn lower_crate(mut self, c: &Crate) -> hir::Crate<'hir> { | |
32a655c1 SL |
400 | /// Full-crate AST visitor that inserts into a fresh |
401 | /// `LoweringContext` any information that may be | |
0731742a XL |
402 | /// needed from arbitrary locations in the crate, |
403 | /// e.g., the number of lifetime generic parameters | |
32a655c1 | 404 | /// declared for every type and trait definition. |
dfeec247 XL |
405 | struct MiscCollector<'tcx, 'lowering, 'hir> { |
406 | lctx: &'tcx mut LoweringContext<'lowering, 'hir>, | |
48663c56 | 407 | hir_id_owner: Option<NodeId>, |
32a655c1 | 408 | } |
476ff2be | 409 | |
dfeec247 | 410 | impl MiscCollector<'_, '_, '_> { |
ba9703b0 | 411 | fn allocate_use_tree_hir_id_counters(&mut self, tree: &UseTree, owner: LocalDefId) { |
532ac7d7 XL |
412 | match tree.kind { |
413 | UseTreeKind::Simple(_, id1, id2) => { | |
414 | for &id in &[id1, id2] { | |
415 | self.lctx.resolver.definitions().create_def_with_parent( | |
416 | owner, | |
417 | id, | |
418 | DefPathData::Misc, | |
416331ca | 419 | ExpnId::root(), |
532ac7d7 XL |
420 | tree.prefix.span, |
421 | ); | |
422 | self.lctx.allocate_hir_id_counter(id); | |
423 | } | |
424 | } | |
425 | UseTreeKind::Glob => (), | |
426 | UseTreeKind::Nested(ref trees) => { | |
427 | for &(ref use_tree, id) in trees { | |
48663c56 | 428 | let hir_id = self.lctx.allocate_hir_id_counter(id); |
532ac7d7 XL |
429 | self.allocate_use_tree_hir_id_counters(use_tree, hir_id.owner); |
430 | } | |
431 | } | |
432 | } | |
433 | } | |
48663c56 | 434 | |
dfeec247 XL |
435 | fn with_hir_id_owner<T>( |
436 | &mut self, | |
437 | owner: Option<NodeId>, | |
438 | f: impl FnOnce(&mut Self) -> T, | |
439 | ) -> T { | |
48663c56 XL |
440 | let old = mem::replace(&mut self.hir_id_owner, owner); |
441 | let r = f(self); | |
442 | self.hir_id_owner = old; | |
443 | r | |
444 | } | |
532ac7d7 XL |
445 | } |
446 | ||
dfeec247 | 447 | impl<'tcx> Visitor<'tcx> for MiscCollector<'tcx, '_, '_> { |
dc9dc135 | 448 | fn visit_pat(&mut self, p: &'tcx Pat) { |
e74abb32 | 449 | if let PatKind::Paren(..) | PatKind::Rest = p.kind { |
48663c56 | 450 | // Doesn't generate a HIR node |
e1599b0c XL |
451 | } else if let Some(owner) = self.hir_id_owner { |
452 | self.lctx.lower_node_id_with_owner(p.id, owner); | |
453 | } | |
48663c56 XL |
454 | |
455 | visit::walk_pat(self, p) | |
456 | } | |
457 | ||
dc9dc135 | 458 | fn visit_item(&mut self, item: &'tcx Item) { |
48663c56 | 459 | let hir_id = self.lctx.allocate_hir_id_counter(item.id); |
cc61c64b | 460 | |
e74abb32 | 461 | match item.kind { |
0531ce1d XL |
462 | ItemKind::Struct(_, ref generics) |
463 | | ItemKind::Union(_, ref generics) | |
464 | | ItemKind::Enum(_, ref generics) | |
74b04a01 | 465 | | ItemKind::TyAlias(_, ref generics, ..) |
0531ce1d | 466 | | ItemKind::Trait(_, _, ref generics, ..) => { |
32a655c1 | 467 | let def_id = self.lctx.resolver.definitions().local_def_id(item.id); |
0531ce1d XL |
468 | let count = generics |
469 | .params | |
470 | .iter() | |
8faf50e0 XL |
471 | .filter(|param| match param.kind { |
472 | ast::GenericParamKind::Lifetime { .. } => true, | |
473 | _ => false, | |
474 | }) | |
ff7c6d11 | 475 | .count(); |
ba9703b0 | 476 | self.lctx.type_def_lifetime_params.insert(def_id.to_def_id(), count); |
32a655c1 | 477 | } |
532ac7d7 XL |
478 | ItemKind::Use(ref use_tree) => { |
479 | self.allocate_use_tree_hir_id_counters(use_tree, hir_id.owner); | |
480 | } | |
32a655c1 SL |
481 | _ => {} |
482 | } | |
48663c56 XL |
483 | |
484 | self.with_hir_id_owner(Some(item.id), |this| { | |
485 | visit::walk_item(this, item); | |
486 | }); | |
32a655c1 | 487 | } |
cc61c64b | 488 | |
74b04a01 | 489 | fn visit_assoc_item(&mut self, item: &'tcx AssocItem, ctxt: AssocCtxt) { |
532ac7d7 | 490 | self.lctx.allocate_hir_id_counter(item.id); |
74b04a01 XL |
491 | let owner = match (&item.kind, ctxt) { |
492 | // Ignore patterns in trait methods without bodies. | |
493 | (AssocItemKind::Fn(_, _, _, None), AssocCtxt::Trait) => None, | |
494 | _ => Some(item.id), | |
495 | }; | |
496 | self.with_hir_id_owner(owner, |this| visit::walk_assoc_item(this, item, ctxt)); | |
48663c56 XL |
497 | } |
498 | ||
dc9dc135 | 499 | fn visit_foreign_item(&mut self, i: &'tcx ForeignItem) { |
48663c56 | 500 | // Ignore patterns in foreign items |
dfeec247 | 501 | self.with_hir_id_owner(None, |this| visit::walk_foreign_item(this, i)); |
48663c56 XL |
502 | } |
503 | ||
dc9dc135 | 504 | fn visit_ty(&mut self, t: &'tcx Ty) { |
e74abb32 | 505 | match t.kind { |
48663c56 XL |
506 | // Mirrors the case in visit::walk_ty |
507 | TyKind::BareFn(ref f) => { | |
dfeec247 | 508 | walk_list!(self, visit_generic_param, &f.generic_params); |
48663c56 | 509 | // Mirrors visit::walk_fn_decl |
e1599b0c | 510 | for parameter in &f.decl.inputs { |
48663c56 XL |
511 | // We don't lower the ids of argument patterns |
512 | self.with_hir_id_owner(None, |this| { | |
e1599b0c | 513 | this.visit_pat(¶meter.pat); |
48663c56 | 514 | }); |
e1599b0c | 515 | self.visit_ty(¶meter.ty) |
48663c56 XL |
516 | } |
517 | self.visit_fn_ret_ty(&f.decl.output) | |
518 | } | |
519 | _ => visit::walk_ty(self, t), | |
520 | } | |
cc61c64b | 521 | } |
476ff2be | 522 | } |
476ff2be | 523 | |
cc61c64b | 524 | self.lower_node_id(CRATE_NODE_ID); |
ba9703b0 | 525 | debug_assert!(self.node_id_to_hir_id[CRATE_NODE_ID] == Some(hir::CRATE_HIR_ID)); |
cc61c64b | 526 | |
48663c56 | 527 | visit::walk_crate(&mut MiscCollector { lctx: &mut self, hir_id_owner: None }, c); |
416331ca | 528 | visit::walk_crate(&mut item::ItemLowerer { lctx: &mut self }, c); |
32a655c1 SL |
529 | |
530 | let module = self.lower_mod(&c.module); | |
531 | let attrs = self.lower_attrs(&c.attrs); | |
8bb4bdeb | 532 | let body_ids = body_ids(&self.bodies); |
ba9703b0 XL |
533 | let proc_macros = |
534 | c.proc_macros.iter().map(|id| self.node_id_to_hir_id[*id].unwrap()).collect(); | |
32a655c1 | 535 | |
dfeec247 | 536 | self.resolver.definitions().init_node_id_to_hir_id_mapping(self.node_id_to_hir_id); |
cc61c64b | 537 | |
32a655c1 | 538 | hir::Crate { |
ba9703b0 | 539 | item: hir::CrateItem { module, attrs, span: c.span }, |
dfeec247 XL |
540 | exported_macros: self.arena.alloc_from_iter(self.exported_macros), |
541 | non_exported_macro_attrs: self.arena.alloc_from_iter(self.non_exported_macro_attrs), | |
32a655c1 SL |
542 | items: self.items, |
543 | trait_items: self.trait_items, | |
544 | impl_items: self.impl_items, | |
545 | bodies: self.bodies, | |
041b39d2 | 546 | body_ids, |
8bb4bdeb | 547 | trait_impls: self.trait_impls, |
0731742a | 548 | modules: self.modules, |
74b04a01 | 549 | proc_macros, |
32a655c1 | 550 | } |
476ff2be | 551 | } |
a7813a04 | 552 | |
dfeec247 | 553 | fn insert_item(&mut self, item: hir::Item<'hir>) { |
532ac7d7 | 554 | let id = item.hir_id; |
dc9dc135 | 555 | // FIXME: Use `debug_asset-rt`. |
532ac7d7 | 556 | assert_eq!(id.local_id, hir::ItemLocalId::from_u32(0)); |
0731742a XL |
557 | self.items.insert(id, item); |
558 | self.modules.get_mut(&self.current_module).unwrap().items.insert(id); | |
559 | } | |
560 | ||
48663c56 | 561 | fn allocate_hir_id_counter(&mut self, owner: NodeId) -> hir::HirId { |
dc9dc135 | 562 | // Set up the counter if needed. |
532ac7d7 | 563 | self.item_local_id_counters.entry(owner).or_insert(0); |
0731742a | 564 | // Always allocate the first `HirId` for the owner itself. |
532ac7d7 | 565 | let lowered = self.lower_node_id_with_owner(owner, owner); |
48663c56 | 566 | debug_assert_eq!(lowered.local_id.as_u32(), 0); |
532ac7d7 | 567 | lowered |
cc61c64b XL |
568 | } |
569 | ||
dfeec247 XL |
570 | fn lower_node_id_generic( |
571 | &mut self, | |
572 | ast_node_id: NodeId, | |
573 | alloc_hir_id: impl FnOnce(&mut Self) -> hir::HirId, | |
574 | ) -> hir::HirId { | |
ba9703b0 | 575 | assert_ne!(ast_node_id, DUMMY_NODE_ID); |
cc61c64b XL |
576 | |
577 | let min_size = ast_node_id.as_usize() + 1; | |
578 | ||
579 | if min_size > self.node_id_to_hir_id.len() { | |
ba9703b0 | 580 | self.node_id_to_hir_id.resize(min_size, None); |
cc61c64b XL |
581 | } |
582 | ||
ba9703b0 XL |
583 | if let Some(existing_hir_id) = self.node_id_to_hir_id[ast_node_id] { |
584 | existing_hir_id | |
585 | } else { | |
0731742a | 586 | // Generate a new `HirId`. |
3b2f2976 | 587 | let hir_id = alloc_hir_id(self); |
ba9703b0 | 588 | self.node_id_to_hir_id[ast_node_id] = Some(hir_id); |
48663c56 XL |
589 | |
590 | hir_id | |
cc61c64b | 591 | } |
cc61c64b XL |
592 | } |
593 | ||
dfeec247 XL |
594 | fn with_hir_id_owner<T>(&mut self, owner: NodeId, f: impl FnOnce(&mut Self) -> T) -> T { |
595 | let counter = self | |
596 | .item_local_id_counters | |
0531ce1d | 597 | .insert(owner, HIR_ID_COUNTER_LOCKED) |
dc9dc135 | 598 | .unwrap_or_else(|| panic!("no `item_local_id_counters` entry for {:?}", owner)); |
ba9703b0 XL |
599 | let def_id = self.resolver.definitions().local_def_id(owner); |
600 | self.current_hir_id_owner.push((def_id, counter)); | |
94b46f34 | 601 | let ret = f(self); |
ba9703b0 | 602 | let (new_def_id, new_counter) = self.current_hir_id_owner.pop().unwrap(); |
cc61c64b | 603 | |
ba9703b0 | 604 | debug_assert!(def_id == new_def_id); |
cc61c64b XL |
605 | debug_assert!(new_counter >= counter); |
606 | ||
dfeec247 | 607 | let prev = self.item_local_id_counters.insert(owner, new_counter).unwrap(); |
cc61c64b | 608 | debug_assert!(prev == HIR_ID_COUNTER_LOCKED); |
94b46f34 | 609 | ret |
cc61c64b XL |
610 | } |
611 | ||
0731742a XL |
612 | /// This method allocates a new `HirId` for the given `NodeId` and stores it in |
613 | /// the `LoweringContext`'s `NodeId => HirId` map. | |
614 | /// Take care not to call this method if the resulting `HirId` is then not | |
cc61c64b | 615 | /// actually used in the HIR, as that would trigger an assertion in the |
0731742a XL |
616 | /// `HirIdValidator` later on, which makes sure that all `NodeId`s got mapped |
617 | /// properly. Calling the method twice with the same `NodeId` is fine though. | |
48663c56 | 618 | fn lower_node_id(&mut self, ast_node_id: NodeId) -> hir::HirId { |
cc61c64b | 619 | self.lower_node_id_generic(ast_node_id, |this| { |
ba9703b0 | 620 | let &mut (owner, ref mut local_id_counter) = |
0531ce1d | 621 | this.current_hir_id_owner.last_mut().unwrap(); |
cc61c64b XL |
622 | let local_id = *local_id_counter; |
623 | *local_id_counter += 1; | |
ba9703b0 | 624 | hir::HirId { owner, local_id: hir::ItemLocalId::from_u32(local_id) } |
cc61c64b XL |
625 | }) |
626 | } | |
627 | ||
48663c56 | 628 | fn lower_node_id_with_owner(&mut self, ast_node_id: NodeId, owner: NodeId) -> hir::HirId { |
cc61c64b | 629 | self.lower_node_id_generic(ast_node_id, |this| { |
94b46f34 XL |
630 | let local_id_counter = this |
631 | .item_local_id_counters | |
632 | .get_mut(&owner) | |
dc9dc135 | 633 | .expect("called `lower_node_id_with_owner` before `allocate_hir_id_counter`"); |
cc61c64b XL |
634 | let local_id = *local_id_counter; |
635 | ||
636 | // We want to be sure not to modify the counter in the map while it | |
637 | // is also on the stack. Otherwise we'll get lost updates when writing | |
638 | // back from the stack to the map. | |
639 | debug_assert!(local_id != HIR_ID_COUNTER_LOCKED); | |
640 | ||
641 | *local_id_counter += 1; | |
ba9703b0 | 642 | let owner = this.resolver.definitions().opt_local_def_id(owner).expect( |
dfeec247 | 643 | "you forgot to call `create_def_with_parent` or are lowering node-IDs \ |
ba9703b0 | 644 | that do not belong to the current owner", |
dfeec247 XL |
645 | ); |
646 | ||
ba9703b0 | 647 | hir::HirId { owner, local_id: hir::ItemLocalId::from_u32(local_id) } |
cc61c64b XL |
648 | }) |
649 | } | |
650 | ||
48663c56 | 651 | fn next_id(&mut self) -> hir::HirId { |
60c5eb7d XL |
652 | let node_id = self.resolver.next_node_id(); |
653 | self.lower_node_id(node_id) | |
3157f602 XL |
654 | } |
655 | ||
48663c56 XL |
656 | fn lower_res(&mut self, res: Res<NodeId>) -> Res { |
657 | res.map_id(|id| { | |
658 | self.lower_node_id_generic(id, |_| { | |
e1599b0c | 659 | panic!("expected `NodeId` to be lowered already for res {:#?}", res); |
48663c56 | 660 | }) |
476ff2be SL |
661 | }) |
662 | } | |
663 | ||
48663c56 XL |
664 | fn expect_full_res(&mut self, id: NodeId) -> Res<NodeId> { |
665 | self.resolver.get_partial_res(id).map_or(Res::Err, |pr| { | |
94b46f34 | 666 | if pr.unresolved_segments() != 0 { |
ba9703b0 | 667 | panic!("path not fully resolved: {:?}", pr); |
94b46f34 | 668 | } |
48663c56 | 669 | pr.base_res() |
94b46f34 XL |
670 | }) |
671 | } | |
672 | ||
48663c56 XL |
673 | fn expect_full_res_from_use(&mut self, id: NodeId) -> impl Iterator<Item = Res<NodeId>> { |
674 | self.resolver.get_import_res(id).present_items() | |
54a0048b | 675 | } |
e9174d1e | 676 | |
dfeec247 | 677 | fn diagnostic(&self) -> &rustc_errors::Handler { |
48663c56 | 678 | self.sess.diagnostic() |
a7813a04 | 679 | } |
7453a54e | 680 | |
dc9dc135 XL |
681 | /// Reuses the span but adds information like the kind of the desugaring and features that are |
682 | /// allowed inside this span. | |
683 | fn mark_span_with_reason( | |
684 | &self, | |
416331ca | 685 | reason: DesugaringKind, |
dc9dc135 XL |
686 | span: Span, |
687 | allow_internal_unstable: Option<Lrc<[Symbol]>>, | |
688 | ) -> Span { | |
e1599b0c | 689 | span.fresh_expansion(ExpnData { |
dc9dc135 | 690 | allow_internal_unstable, |
e1599b0c | 691 | ..ExpnData::default(ExpnKind::Desugaring(reason), span, self.sess.edition()) |
416331ca | 692 | }) |
dc9dc135 XL |
693 | } |
694 | ||
94b46f34 XL |
695 | fn with_anonymous_lifetime_mode<R>( |
696 | &mut self, | |
697 | anonymous_lifetime_mode: AnonymousLifetimeMode, | |
698 | op: impl FnOnce(&mut Self) -> R, | |
699 | ) -> R { | |
e1599b0c XL |
700 | debug!( |
701 | "with_anonymous_lifetime_mode(anonymous_lifetime_mode={:?})", | |
702 | anonymous_lifetime_mode, | |
703 | ); | |
94b46f34 XL |
704 | let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode; |
705 | self.anonymous_lifetime_mode = anonymous_lifetime_mode; | |
706 | let result = op(self); | |
707 | self.anonymous_lifetime_mode = old_anonymous_lifetime_mode; | |
dfeec247 XL |
708 | debug!( |
709 | "with_anonymous_lifetime_mode: restoring anonymous_lifetime_mode={:?}", | |
710 | old_anonymous_lifetime_mode | |
711 | ); | |
94b46f34 XL |
712 | result |
713 | } | |
714 | ||
dc9dc135 | 715 | /// Creates a new `hir::GenericParam` for every new lifetime and |
0531ce1d XL |
716 | /// type parameter encountered while evaluating `f`. Definitions |
717 | /// are created with the parent provided. If no `parent_id` is | |
718 | /// provided, no definitions will be returned. | |
719 | /// | |
720 | /// Presuming that in-band lifetimes are enabled, then | |
721 | /// `self.anonymous_lifetime_mode` will be updated to match the | |
e1599b0c | 722 | /// parameter while `f` is running (and restored afterwards). |
dfeec247 | 723 | fn collect_in_band_defs<T>( |
ff7c6d11 | 724 | &mut self, |
ba9703b0 | 725 | parent_def_id: LocalDefId, |
0531ce1d | 726 | anonymous_lifetime_mode: AnonymousLifetimeMode, |
dfeec247 XL |
727 | f: impl FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T), |
728 | ) -> (Vec<hir::GenericParam<'hir>>, T) { | |
ff7c6d11 XL |
729 | assert!(!self.is_collecting_in_band_lifetimes); |
730 | assert!(self.lifetimes_to_define.is_empty()); | |
0531ce1d | 731 | let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode; |
ff7c6d11 | 732 | |
0bf4aa26 XL |
733 | self.anonymous_lifetime_mode = anonymous_lifetime_mode; |
734 | self.is_collecting_in_band_lifetimes = true; | |
ff7c6d11 | 735 | |
8faf50e0 | 736 | let (in_band_ty_params, res) = f(self); |
ff7c6d11 XL |
737 | |
738 | self.is_collecting_in_band_lifetimes = false; | |
0531ce1d | 739 | self.anonymous_lifetime_mode = old_anonymous_lifetime_mode; |
ff7c6d11 | 740 | |
ff7c6d11 XL |
741 | let lifetimes_to_define = self.lifetimes_to_define.split_off(0); |
742 | ||
0531ce1d XL |
743 | let params = lifetimes_to_define |
744 | .into_iter() | |
ba9703b0 | 745 | .map(|(span, hir_name)| self.lifetime_to_generic_param(span, hir_name, parent_def_id)) |
8faf50e0 | 746 | .chain(in_band_ty_params.into_iter()) |
0531ce1d | 747 | .collect(); |
ff7c6d11 XL |
748 | |
749 | (params, res) | |
750 | } | |
751 | ||
532ac7d7 XL |
752 | /// Converts a lifetime into a new generic parameter. |
753 | fn lifetime_to_generic_param( | |
754 | &mut self, | |
755 | span: Span, | |
756 | hir_name: ParamName, | |
ba9703b0 | 757 | parent_def_id: LocalDefId, |
dfeec247 | 758 | ) -> hir::GenericParam<'hir> { |
60c5eb7d | 759 | let node_id = self.resolver.next_node_id(); |
532ac7d7 XL |
760 | |
761 | // Get the name we'll use to make the def-path. Note | |
762 | // that collisions are ok here and this shouldn't | |
763 | // really show up for end-user. | |
764 | let (str_name, kind) = match hir_name { | |
dfeec247 XL |
765 | ParamName::Plain(ident) => (ident.name, hir::LifetimeParamKind::InBand), |
766 | ParamName::Fresh(_) => (kw::UnderscoreLifetime, hir::LifetimeParamKind::Elided), | |
767 | ParamName::Error => (kw::UnderscoreLifetime, hir::LifetimeParamKind::Error), | |
532ac7d7 XL |
768 | }; |
769 | ||
770 | // Add a definition for the in-band lifetime def. | |
771 | self.resolver.definitions().create_def_with_parent( | |
ba9703b0 | 772 | parent_def_id, |
532ac7d7 | 773 | node_id, |
48663c56 | 774 | DefPathData::LifetimeNs(str_name), |
416331ca | 775 | ExpnId::root(), |
532ac7d7 XL |
776 | span, |
777 | ); | |
778 | ||
779 | hir::GenericParam { | |
48663c56 | 780 | hir_id: self.lower_node_id(node_id), |
532ac7d7 | 781 | name: hir_name, |
dfeec247 XL |
782 | attrs: &[], |
783 | bounds: &[], | |
532ac7d7 XL |
784 | span, |
785 | pure_wrt_drop: false, | |
dfeec247 | 786 | kind: hir::GenericParamKind::Lifetime { kind }, |
532ac7d7 XL |
787 | } |
788 | } | |
789 | ||
0531ce1d XL |
790 | /// When there is a reference to some lifetime `'a`, and in-band |
791 | /// lifetimes are enabled, then we want to push that lifetime into | |
792 | /// the vector of names to define later. In that case, it will get | |
793 | /// added to the appropriate generics. | |
8faf50e0 | 794 | fn maybe_collect_in_band_lifetime(&mut self, ident: Ident) { |
0531ce1d XL |
795 | if !self.is_collecting_in_band_lifetimes { |
796 | return; | |
797 | } | |
798 | ||
b7449926 XL |
799 | if !self.sess.features_untracked().in_band_lifetimes { |
800 | return; | |
801 | } | |
802 | ||
ba9703b0 | 803 | if self.in_scope_lifetimes.contains(&ParamName::Plain(ident.normalize_to_macros_2_0())) { |
0531ce1d XL |
804 | return; |
805 | } | |
806 | ||
8faf50e0 | 807 | let hir_name = ParamName::Plain(ident); |
0531ce1d | 808 | |
ba9703b0 XL |
809 | if self.lifetimes_to_define.iter().any(|(_, lt_name)| { |
810 | lt_name.normalize_to_macros_2_0() == hir_name.normalize_to_macros_2_0() | |
811 | }) { | |
0531ce1d XL |
812 | return; |
813 | } | |
814 | ||
8faf50e0 | 815 | self.lifetimes_to_define.push((ident.span, hir_name)); |
0531ce1d XL |
816 | } |
817 | ||
818 | /// When we have either an elided or `'_` lifetime in an impl | |
0bf4aa26 | 819 | /// header, we convert it to an in-band lifetime. |
8faf50e0 | 820 | fn collect_fresh_in_band_lifetime(&mut self, span: Span) -> ParamName { |
0531ce1d | 821 | assert!(self.is_collecting_in_band_lifetimes); |
e1599b0c | 822 | let index = self.lifetimes_to_define.len() + self.in_scope_lifetimes.len(); |
8faf50e0 | 823 | let hir_name = ParamName::Fresh(index); |
0531ce1d XL |
824 | self.lifetimes_to_define.push((span, hir_name)); |
825 | hir_name | |
826 | } | |
827 | ||
8faf50e0 | 828 | // Evaluates `f` with the lifetimes in `params` in-scope. |
ff7c6d11 XL |
829 | // This is used to track which lifetimes have already been defined, and |
830 | // which are new in-band lifetimes that need to have a definition created | |
831 | // for them. | |
dfeec247 XL |
832 | fn with_in_scope_lifetime_defs<T>( |
833 | &mut self, | |
834 | params: &[GenericParam], | |
835 | f: impl FnOnce(&mut Self) -> T, | |
836 | ) -> T { | |
ff7c6d11 | 837 | let old_len = self.in_scope_lifetimes.len(); |
8faf50e0 | 838 | let lt_def_names = params.iter().filter_map(|param| match param.kind { |
ba9703b0 XL |
839 | GenericParamKind::Lifetime { .. } => { |
840 | Some(ParamName::Plain(param.ident.normalize_to_macros_2_0())) | |
841 | } | |
8faf50e0 XL |
842 | _ => None, |
843 | }); | |
ff7c6d11 XL |
844 | self.in_scope_lifetimes.extend(lt_def_names); |
845 | ||
846 | let res = f(self); | |
847 | ||
848 | self.in_scope_lifetimes.truncate(old_len); | |
849 | res | |
850 | } | |
851 | ||
0531ce1d XL |
852 | /// Appends in-band lifetime defs and argument-position `impl |
853 | /// Trait` defs to the existing set of generics. | |
854 | /// | |
855 | /// Presuming that in-band lifetimes are enabled, then | |
856 | /// `self.anonymous_lifetime_mode` will be updated to match the | |
e1599b0c | 857 | /// parameter while `f` is running (and restored afterwards). |
dfeec247 | 858 | fn add_in_band_defs<T>( |
ff7c6d11 XL |
859 | &mut self, |
860 | generics: &Generics, | |
ba9703b0 | 861 | parent_def_id: LocalDefId, |
0531ce1d | 862 | anonymous_lifetime_mode: AnonymousLifetimeMode, |
dfeec247 XL |
863 | f: impl FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T, |
864 | ) -> (hir::Generics<'hir>, T) { | |
865 | let (in_band_defs, (mut lowered_generics, res)) = | |
866 | self.with_in_scope_lifetime_defs(&generics.params, |this| { | |
ba9703b0 | 867 | this.collect_in_band_defs(parent_def_id, anonymous_lifetime_mode, |this| { |
8faf50e0 | 868 | let mut params = Vec::new(); |
532ac7d7 XL |
869 | // Note: it is necessary to lower generics *before* calling `f`. |
870 | // When lowering `async fn`, there's a final step when lowering | |
871 | // the return type that assumes that all in-scope lifetimes have | |
872 | // already been added to either `in_scope_lifetimes` or | |
873 | // `lifetimes_to_define`. If we swapped the order of these two, | |
874 | // in-band-lifetimes introduced by generics or where-clauses | |
875 | // wouldn't have been added yet. | |
dfeec247 XL |
876 | let generics = |
877 | this.lower_generics_mut(generics, ImplTraitContext::Universal(&mut params)); | |
8faf50e0 XL |
878 | let res = f(this, &mut params); |
879 | (params, (generics, res)) | |
0531ce1d | 880 | }) |
dfeec247 | 881 | }); |
ff7c6d11 | 882 | |
dfeec247 XL |
883 | let mut lowered_params: Vec<_> = |
884 | lowered_generics.params.into_iter().chain(in_band_defs).collect(); | |
ff7c6d11 | 885 | |
dc9dc135 XL |
886 | // FIXME(const_generics): the compiler doesn't always cope with |
887 | // unsorted generic parameters at the moment, so we make sure | |
888 | // that they're ordered correctly here for now. (When we chain | |
889 | // the `in_band_defs`, we might make the order unsorted.) | |
dfeec247 XL |
890 | lowered_params.sort_by_key(|param| match param.kind { |
891 | hir::GenericParamKind::Lifetime { .. } => ParamKindOrd::Lifetime, | |
892 | hir::GenericParamKind::Type { .. } => ParamKindOrd::Type, | |
893 | hir::GenericParamKind::Const { .. } => ParamKindOrd::Const, | |
dc9dc135 XL |
894 | }); |
895 | ||
416331ca | 896 | lowered_generics.params = lowered_params.into(); |
8bb4bdeb | 897 | |
dfeec247 | 898 | let lowered_generics = lowered_generics.into_generics(self.arena); |
416331ca | 899 | (lowered_generics, res) |
8bb4bdeb XL |
900 | } |
901 | ||
dfeec247 | 902 | fn with_dyn_type_scope<T>(&mut self, in_scope: bool, f: impl FnOnce(&mut Self) -> T) -> T { |
dc9dc135 XL |
903 | let was_in_dyn_type = self.is_in_dyn_type; |
904 | self.is_in_dyn_type = in_scope; | |
905 | ||
906 | let result = f(self); | |
907 | ||
908 | self.is_in_dyn_type = was_in_dyn_type; | |
909 | ||
910 | result | |
911 | } | |
912 | ||
dfeec247 | 913 | fn with_new_scopes<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T { |
8bb4bdeb XL |
914 | let was_in_loop_condition = self.is_in_loop_condition; |
915 | self.is_in_loop_condition = false; | |
916 | ||
416331ca XL |
917 | let catch_scopes = mem::take(&mut self.catch_scopes); |
918 | let loop_scopes = mem::take(&mut self.loop_scopes); | |
0bf4aa26 | 919 | let ret = f(self); |
cc61c64b XL |
920 | self.catch_scopes = catch_scopes; |
921 | self.loop_scopes = loop_scopes; | |
8bb4bdeb XL |
922 | |
923 | self.is_in_loop_condition = was_in_loop_condition; | |
924 | ||
0bf4aa26 | 925 | ret |
8bb4bdeb XL |
926 | } |
927 | ||
dfeec247 XL |
928 | fn lower_attrs(&mut self, attrs: &[Attribute]) -> &'hir [Attribute] { |
929 | self.arena.alloc_from_iter(attrs.iter().map(|a| self.lower_attr(a))) | |
416331ca XL |
930 | } |
931 | ||
ea8adc8c | 932 | fn lower_attr(&mut self, attr: &Attribute) -> Attribute { |
13cf67c4 XL |
933 | // Note that we explicitly do not walk the path. Since we don't really |
934 | // lower attributes (we use the AST version) there is nowhere to keep | |
0731742a | 935 | // the `HirId`s. We don't actually need HIR version of attributes anyway. |
60c5eb7d | 936 | let kind = match attr.kind { |
dfeec247 XL |
937 | AttrKind::Normal(ref item) => AttrKind::Normal(AttrItem { |
938 | path: item.path.clone(), | |
939 | args: self.lower_mac_args(&item.args), | |
940 | }), | |
941 | AttrKind::DocComment(comment) => AttrKind::DocComment(comment), | |
60c5eb7d XL |
942 | }; |
943 | ||
dfeec247 | 944 | Attribute { kind, id: attr.id, style: attr.style, span: attr.span } |
ea8adc8c XL |
945 | } |
946 | ||
60c5eb7d XL |
947 | fn lower_mac_args(&mut self, args: &MacArgs) -> MacArgs { |
948 | match *args { | |
949 | MacArgs::Empty => MacArgs::Empty, | |
dfeec247 XL |
950 | MacArgs::Delimited(dspan, delim, ref tokens) => { |
951 | MacArgs::Delimited(dspan, delim, self.lower_token_stream(tokens.clone())) | |
952 | } | |
953 | MacArgs::Eq(eq_span, ref tokens) => { | |
954 | MacArgs::Eq(eq_span, self.lower_token_stream(tokens.clone())) | |
955 | } | |
60c5eb7d XL |
956 | } |
957 | } | |
958 | ||
ea8adc8c | 959 | fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream { |
dfeec247 | 960 | tokens.into_trees().flat_map(|tree| self.lower_token_tree(tree).into_trees()).collect() |
ea8adc8c XL |
961 | } |
962 | ||
963 | fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream { | |
964 | match tree { | |
dc9dc135 | 965 | TokenTree::Token(token) => self.lower_token(token), |
dfeec247 XL |
966 | TokenTree::Delimited(span, delim, tts) => { |
967 | TokenTree::Delimited(span, delim, self.lower_token_stream(tts)).into() | |
968 | } | |
ea8adc8c XL |
969 | } |
970 | } | |
971 | ||
dc9dc135 XL |
972 | fn lower_token(&mut self, token: Token) -> TokenStream { |
973 | match token.kind { | |
974 | token::Interpolated(nt) => { | |
e74abb32 | 975 | let tts = (self.nt_to_tokenstream)(&nt, &self.sess.parse_sess, token.span); |
9fa01778 XL |
976 | self.lower_token_stream(tts) |
977 | } | |
dc9dc135 | 978 | _ => TokenTree::Token(token).into(), |
ea8adc8c | 979 | } |
7453a54e | 980 | } |
7453a54e | 981 | |
dc9dc135 XL |
982 | /// Given an associated type constraint like one of these: |
983 | /// | |
984 | /// ``` | |
985 | /// T: Iterator<Item: Debug> | |
986 | /// ^^^^^^^^^^^ | |
987 | /// T: Iterator<Item = Debug> | |
988 | /// ^^^^^^^^^^^^ | |
989 | /// ``` | |
990 | /// | |
991 | /// returns a `hir::TypeBinding` representing `Item`. | |
e1599b0c XL |
992 | fn lower_assoc_ty_constraint( |
993 | &mut self, | |
994 | constraint: &AssocTyConstraint, | |
dfeec247 XL |
995 | itctx: ImplTraitContext<'_, 'hir>, |
996 | ) -> hir::TypeBinding<'hir> { | |
e1599b0c | 997 | debug!("lower_assoc_ty_constraint(constraint={:?}, itctx={:?})", constraint, itctx); |
dc9dc135 | 998 | |
e1599b0c | 999 | let kind = match constraint.kind { |
dfeec247 XL |
1000 | AssocTyConstraintKind::Equality { ref ty } => { |
1001 | hir::TypeBindingKind::Equality { ty: self.lower_ty(ty, itctx) } | |
1002 | } | |
dc9dc135 XL |
1003 | AssocTyConstraintKind::Bound { ref bounds } => { |
1004 | // Piggy-back on the `impl Trait` context to figure out the correct behavior. | |
1005 | let (desugar_to_impl_trait, itctx) = match itctx { | |
1006 | // We are in the return position: | |
1007 | // | |
1008 | // fn foo() -> impl Iterator<Item: Debug> | |
1009 | // | |
1010 | // so desugar to | |
1011 | // | |
1012 | // fn foo() -> impl Iterator<Item = impl Debug> | |
74b04a01 | 1013 | ImplTraitContext::OpaqueTy(..) => (true, itctx), |
dc9dc135 XL |
1014 | |
1015 | // We are in the argument position, but within a dyn type: | |
1016 | // | |
1017 | // fn foo(x: dyn Iterator<Item: Debug>) | |
1018 | // | |
1019 | // so desugar to | |
1020 | // | |
1021 | // fn foo(x: dyn Iterator<Item = impl Debug>) | |
74b04a01 | 1022 | ImplTraitContext::Universal(..) if self.is_in_dyn_type => (true, itctx), |
dc9dc135 XL |
1023 | |
1024 | // In `type Foo = dyn Iterator<Item: Debug>` we desugar to | |
1025 | // `type Foo = dyn Iterator<Item = impl Debug>` but we have to override the | |
1026 | // "impl trait context" to permit `impl Debug` in this position (it desugars | |
416331ca | 1027 | // then to an opaque type). |
dc9dc135 XL |
1028 | // |
1029 | // FIXME: this is only needed until `impl Trait` is allowed in type aliases. | |
dfeec247 | 1030 | ImplTraitContext::Disallowed(_) if self.is_in_dyn_type => { |
74b04a01 | 1031 | (true, ImplTraitContext::OpaqueTy(None, hir::OpaqueTyOrigin::Misc)) |
dfeec247 | 1032 | } |
dc9dc135 | 1033 | |
e1599b0c | 1034 | // We are in the parameter position, but not within a dyn type: |
dc9dc135 XL |
1035 | // |
1036 | // fn foo(x: impl Iterator<Item: Debug>) | |
1037 | // | |
1038 | // so we leave it as is and this gets expanded in astconv to a bound like | |
1039 | // `<T as Iterator>::Item: Debug` where `T` is the type parameter for the | |
1040 | // `impl Iterator`. | |
1041 | _ => (false, itctx), | |
1042 | }; | |
1043 | ||
1044 | if desugar_to_impl_trait { | |
1045 | // Desugar `AssocTy: Bounds` into `AssocTy = impl Bounds`. We do this by | |
1046 | // constructing the HIR for `impl bounds...` and then lowering that. | |
1047 | ||
60c5eb7d | 1048 | let impl_trait_node_id = self.resolver.next_node_id(); |
ba9703b0 | 1049 | let parent_def_id = self.current_hir_id_owner.last().unwrap().0; |
dc9dc135 | 1050 | self.resolver.definitions().create_def_with_parent( |
ba9703b0 | 1051 | parent_def_id, |
dc9dc135 XL |
1052 | impl_trait_node_id, |
1053 | DefPathData::ImplTrait, | |
416331ca | 1054 | ExpnId::root(), |
e1599b0c | 1055 | constraint.span, |
dc9dc135 XL |
1056 | ); |
1057 | ||
1058 | self.with_dyn_type_scope(false, |this| { | |
60c5eb7d | 1059 | let node_id = this.resolver.next_node_id(); |
dc9dc135 XL |
1060 | let ty = this.lower_ty( |
1061 | &Ty { | |
60c5eb7d | 1062 | id: node_id, |
e74abb32 | 1063 | kind: TyKind::ImplTrait(impl_trait_node_id, bounds.clone()), |
e1599b0c | 1064 | span: constraint.span, |
dc9dc135 XL |
1065 | }, |
1066 | itctx, | |
1067 | ); | |
1068 | ||
dfeec247 | 1069 | hir::TypeBindingKind::Equality { ty } |
dc9dc135 XL |
1070 | }) |
1071 | } else { | |
1072 | // Desugar `AssocTy: Bounds` into a type binding where the | |
1073 | // later desugars into a trait predicate. | |
1074 | let bounds = self.lower_param_bounds(bounds, itctx); | |
1075 | ||
dfeec247 | 1076 | hir::TypeBindingKind::Constraint { bounds } |
dc9dc135 XL |
1077 | } |
1078 | } | |
1079 | }; | |
1080 | ||
a7813a04 | 1081 | hir::TypeBinding { |
e1599b0c XL |
1082 | hir_id: self.lower_node_id(constraint.id), |
1083 | ident: constraint.ident, | |
dc9dc135 | 1084 | kind, |
e1599b0c | 1085 | span: constraint.span, |
a7813a04 | 1086 | } |
92a42be0 | 1087 | } |
e9174d1e | 1088 | |
60c5eb7d XL |
1089 | fn lower_generic_arg( |
1090 | &mut self, | |
1091 | arg: &ast::GenericArg, | |
dfeec247 XL |
1092 | itctx: ImplTraitContext<'_, 'hir>, |
1093 | ) -> hir::GenericArg<'hir> { | |
8faf50e0 XL |
1094 | match arg { |
1095 | ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(<)), | |
60c5eb7d | 1096 | ast::GenericArg::Type(ty) => { |
74b04a01 | 1097 | // We parse const arguments as path types as we cannot distinguish them during |
60c5eb7d XL |
1098 | // parsing. We try to resolve that ambiguity by attempting resolution in both the |
1099 | // type and value namespaces. If we resolved the path in the value namespace, we | |
1100 | // transform it into a generic const argument. | |
1101 | if let TyKind::Path(ref qself, ref path) = ty.kind { | |
1102 | if let Some(partial_res) = self.resolver.get_partial_res(ty.id) { | |
1103 | let res = partial_res.base_res(); | |
1104 | if !res.matches_ns(Namespace::TypeNS) { | |
1105 | debug!( | |
1106 | "lower_generic_arg: Lowering type argument as const argument: {:?}", | |
1107 | ty, | |
1108 | ); | |
1109 | ||
1110 | // Construct a AnonConst where the expr is the "ty"'s path. | |
1111 | ||
ba9703b0 | 1112 | let parent_def_id = self.current_hir_id_owner.last().unwrap().0; |
60c5eb7d XL |
1113 | let node_id = self.resolver.next_node_id(); |
1114 | ||
1115 | // Add a definition for the in-band const def. | |
1116 | self.resolver.definitions().create_def_with_parent( | |
ba9703b0 | 1117 | parent_def_id, |
60c5eb7d XL |
1118 | node_id, |
1119 | DefPathData::AnonConst, | |
1120 | ExpnId::root(), | |
1121 | ty.span, | |
1122 | ); | |
1123 | ||
1124 | let path_expr = Expr { | |
1125 | id: ty.id, | |
1126 | kind: ExprKind::Path(qself.clone(), path.clone()), | |
1127 | span: ty.span, | |
dfeec247 | 1128 | attrs: AttrVec::new(), |
60c5eb7d XL |
1129 | }; |
1130 | ||
dfeec247 XL |
1131 | let ct = self.with_new_scopes(|this| hir::AnonConst { |
1132 | hir_id: this.lower_node_id(node_id), | |
1133 | body: this.lower_const_body(path_expr.span, Some(&path_expr)), | |
60c5eb7d | 1134 | }); |
dfeec247 | 1135 | return GenericArg::Const(ConstArg { value: ct, span: ty.span }); |
60c5eb7d XL |
1136 | } |
1137 | } | |
1138 | } | |
1139 | GenericArg::Type(self.lower_ty_direct(&ty, itctx)) | |
1140 | } | |
dfeec247 XL |
1141 | ast::GenericArg::Const(ct) => GenericArg::Const(ConstArg { |
1142 | value: self.lower_anon_const(&ct), | |
1143 | span: ct.value.span, | |
1144 | }), | |
8faf50e0 XL |
1145 | } |
1146 | } | |
1147 | ||
dfeec247 XL |
1148 | fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext<'_, 'hir>) -> &'hir hir::Ty<'hir> { |
1149 | self.arena.alloc(self.lower_ty_direct(t, itctx)) | |
8faf50e0 XL |
1150 | } |
1151 | ||
dc9dc135 XL |
1152 | fn lower_path_ty( |
1153 | &mut self, | |
1154 | t: &Ty, | |
1155 | qself: &Option<QSelf>, | |
1156 | path: &Path, | |
1157 | param_mode: ParamMode, | |
dfeec247 XL |
1158 | itctx: ImplTraitContext<'_, 'hir>, |
1159 | ) -> hir::Ty<'hir> { | |
dc9dc135 XL |
1160 | let id = self.lower_node_id(t.id); |
1161 | let qpath = self.lower_qpath(t.id, qself, path, param_mode, itctx); | |
1162 | let ty = self.ty_path(id, t.span, qpath); | |
e74abb32 | 1163 | if let hir::TyKind::TraitObject(..) = ty.kind { |
dc9dc135 XL |
1164 | self.maybe_lint_bare_trait(t.span, t.id, qself.is_none() && path.is_global()); |
1165 | } | |
1166 | ty | |
1167 | } | |
1168 | ||
dfeec247 XL |
1169 | fn ty(&mut self, span: Span, kind: hir::TyKind<'hir>) -> hir::Ty<'hir> { |
1170 | hir::Ty { hir_id: self.next_id(), kind, span } | |
1171 | } | |
1172 | ||
1173 | fn ty_tup(&mut self, span: Span, tys: &'hir [hir::Ty<'hir>]) -> hir::Ty<'hir> { | |
1174 | self.ty(span, hir::TyKind::Tup(tys)) | |
1175 | } | |
1176 | ||
1177 | fn lower_ty_direct(&mut self, t: &Ty, mut itctx: ImplTraitContext<'_, 'hir>) -> hir::Ty<'hir> { | |
e74abb32 | 1178 | let kind = match t.kind { |
8faf50e0 XL |
1179 | TyKind::Infer => hir::TyKind::Infer, |
1180 | TyKind::Err => hir::TyKind::Err, | |
1181 | TyKind::Slice(ref ty) => hir::TyKind::Slice(self.lower_ty(ty, itctx)), | |
1182 | TyKind::Ptr(ref mt) => hir::TyKind::Ptr(self.lower_mt(mt, itctx)), | |
cc61c64b | 1183 | TyKind::Rptr(ref region, ref mt) => { |
0bf4aa26 | 1184 | let span = self.sess.source_map().next_point(t.span.shrink_to_lo()); |
cc61c64b XL |
1185 | let lifetime = match *region { |
1186 | Some(ref lt) => self.lower_lifetime(lt), | |
0531ce1d | 1187 | None => self.elided_ref_lifetime(span), |
cc61c64b | 1188 | }; |
8faf50e0 | 1189 | hir::TyKind::Rptr(lifetime, self.lower_mt(mt, itctx)) |
cc61c64b | 1190 | } |
dfeec247 XL |
1191 | TyKind::BareFn(ref f) => self.with_in_scope_lifetime_defs(&f.generic_params, |this| { |
1192 | this.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| { | |
1193 | hir::TyKind::BareFn(this.arena.alloc(hir::BareFnTy { | |
1194 | generic_params: this.lower_generic_params( | |
1195 | &f.generic_params, | |
1196 | &NodeMap::default(), | |
1197 | ImplTraitContext::disallowed(), | |
1198 | ), | |
74b04a01 | 1199 | unsafety: this.lower_unsafety(f.unsafety), |
dfeec247 XL |
1200 | abi: this.lower_extern(f.ext), |
1201 | decl: this.lower_fn_decl(&f.decl, None, false, None), | |
1202 | param_names: this.lower_fn_params_to_names(&f.decl), | |
1203 | })) | |
1204 | }) | |
1205 | }), | |
8faf50e0 | 1206 | TyKind::Never => hir::TyKind::Never, |
cc61c64b | 1207 | TyKind::Tup(ref tys) => { |
dfeec247 XL |
1208 | hir::TyKind::Tup(self.arena.alloc_from_iter( |
1209 | tys.iter().map(|ty| self.lower_ty_direct(ty, itctx.reborrow())), | |
1210 | )) | |
cc61c64b XL |
1211 | } |
1212 | TyKind::Paren(ref ty) => { | |
8faf50e0 | 1213 | return self.lower_ty_direct(ty, itctx); |
cc61c64b XL |
1214 | } |
1215 | TyKind::Path(ref qself, ref path) => { | |
dc9dc135 | 1216 | return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx); |
cc61c64b | 1217 | } |
48663c56 XL |
1218 | TyKind::ImplicitSelf => { |
1219 | let res = self.expect_full_res(t.id); | |
1220 | let res = self.lower_res(res); | |
1221 | hir::TyKind::Path(hir::QPath::Resolved( | |
1222 | None, | |
dfeec247 | 1223 | self.arena.alloc(hir::Path { |
48663c56 | 1224 | res, |
dfeec247 | 1225 | segments: arena_vec![self; hir::PathSegment::from_ident( |
e1599b0c | 1226 | Ident::with_dummy_span(kw::SelfUpper) |
48663c56 XL |
1227 | )], |
1228 | span: t.span, | |
1229 | }), | |
1230 | )) | |
dfeec247 | 1231 | } |
cc61c64b | 1232 | TyKind::Array(ref ty, ref length) => { |
8faf50e0 | 1233 | hir::TyKind::Array(self.lower_ty(ty, itctx), self.lower_anon_const(length)) |
cc61c64b | 1234 | } |
dfeec247 | 1235 | TyKind::Typeof(ref expr) => hir::TyKind::Typeof(self.lower_anon_const(expr)), |
0531ce1d | 1236 | TyKind::TraitObject(ref bounds, kind) => { |
cc61c64b | 1237 | let mut lifetime_bound = None; |
dc9dc135 | 1238 | let (bounds, lifetime_bound) = self.with_dyn_type_scope(true, |this| { |
dfeec247 XL |
1239 | let bounds = |
1240 | this.arena.alloc_from_iter(bounds.iter().filter_map( | |
1241 | |bound| match *bound { | |
ba9703b0 XL |
1242 | GenericBound::Trait( |
1243 | ref ty, | |
1244 | TraitBoundModifier::None | TraitBoundModifier::MaybeConst, | |
1245 | ) => Some(this.lower_poly_trait_ref(ty, itctx.reborrow())), | |
dfeec247 XL |
1246 | // `?const ?Bound` will cause an error during AST validation |
1247 | // anyways, so treat it like `?Bound` as compilation proceeds. | |
ba9703b0 XL |
1248 | GenericBound::Trait( |
1249 | _, | |
1250 | TraitBoundModifier::Maybe | TraitBoundModifier::MaybeConstMaybe, | |
1251 | ) => None, | |
dfeec247 XL |
1252 | GenericBound::Outlives(ref lifetime) => { |
1253 | if lifetime_bound.is_none() { | |
1254 | lifetime_bound = Some(this.lower_lifetime(lifetime)); | |
1255 | } | |
1256 | None | |
1257 | } | |
1258 | }, | |
1259 | )); | |
dc9dc135 XL |
1260 | let lifetime_bound = |
1261 | lifetime_bound.unwrap_or_else(|| this.elided_dyn_bound(t.span)); | |
1262 | (bounds, lifetime_bound) | |
1263 | }); | |
0531ce1d XL |
1264 | if kind != TraitObjectSyntax::Dyn { |
1265 | self.maybe_lint_bare_trait(t.span, t.id, false); | |
1266 | } | |
8faf50e0 | 1267 | hir::TyKind::TraitObject(bounds, lifetime_bound) |
cc61c64b | 1268 | } |
8faf50e0 | 1269 | TyKind::ImplTrait(def_node_id, ref bounds) => { |
ff7c6d11 | 1270 | let span = t.span; |
abe05a73 | 1271 | match itctx { |
74b04a01 XL |
1272 | ImplTraitContext::OpaqueTy(fn_def_id, origin) => { |
1273 | self.lower_opaque_impl_trait(span, fn_def_id, origin, def_node_id, |this| { | |
dfeec247 XL |
1274 | this.lower_param_bounds(bounds, itctx) |
1275 | }) | |
8faf50e0 XL |
1276 | } |
1277 | ImplTraitContext::Universal(in_band_ty_params) => { | |
0731742a | 1278 | // Add a definition for the in-band `Param`. |
ba9703b0 | 1279 | let def_id = self.resolver.definitions().local_def_id(def_node_id); |
ff7c6d11 | 1280 | |
8faf50e0 XL |
1281 | let hir_bounds = self.lower_param_bounds( |
1282 | bounds, | |
1283 | ImplTraitContext::Universal(in_band_ty_params), | |
ff7c6d11 | 1284 | ); |
0731742a | 1285 | // Set the name to `impl Bound1 + Bound2`. |
e1599b0c | 1286 | let ident = Ident::from_str_and_span(&pprust::ty_to_string(t), span); |
8faf50e0 | 1287 | in_band_ty_params.push(hir::GenericParam { |
48663c56 | 1288 | hir_id: self.lower_node_id(def_node_id), |
8faf50e0 XL |
1289 | name: ParamName::Plain(ident), |
1290 | pure_wrt_drop: false, | |
dfeec247 | 1291 | attrs: &[], |
ff7c6d11 | 1292 | bounds: hir_bounds, |
ff7c6d11 | 1293 | span, |
8faf50e0 XL |
1294 | kind: hir::GenericParamKind::Type { |
1295 | default: None, | |
1296 | synthetic: Some(hir::SyntheticTyParamKind::ImplTrait), | |
dfeec247 | 1297 | }, |
ff7c6d11 XL |
1298 | }); |
1299 | ||
8faf50e0 | 1300 | hir::TyKind::Path(hir::QPath::Resolved( |
0531ce1d | 1301 | None, |
dfeec247 | 1302 | self.arena.alloc(hir::Path { |
0531ce1d | 1303 | span, |
ba9703b0 | 1304 | res: Res::Def(DefKind::TyParam, def_id.to_def_id()), |
dfeec247 | 1305 | segments: arena_vec![self; hir::PathSegment::from_ident(ident)], |
0531ce1d XL |
1306 | }), |
1307 | )) | |
1308 | } | |
0bf4aa26 | 1309 | ImplTraitContext::Disallowed(pos) => { |
dfeec247 | 1310 | let allowed_in = if self.sess.features_untracked().impl_trait_in_bindings { |
0bf4aa26 XL |
1311 | "bindings or function and inherent method return types" |
1312 | } else { | |
1313 | "function and inherent method return types" | |
1314 | }; | |
1315 | let mut err = struct_span_err!( | |
0531ce1d XL |
1316 | self.sess, |
1317 | t.span, | |
1318 | E0562, | |
0bf4aa26 XL |
1319 | "`impl Trait` not allowed outside of {}", |
1320 | allowed_in, | |
0531ce1d | 1321 | ); |
dfeec247 XL |
1322 | if pos == ImplTraitPosition::Binding && nightly_options::is_nightly_build() |
1323 | { | |
1324 | err.help( | |
1325 | "add `#![feature(impl_trait_in_bindings)]` to the crate \ | |
1326 | attributes to enable", | |
1327 | ); | |
0bf4aa26 XL |
1328 | } |
1329 | err.emit(); | |
8faf50e0 | 1330 | hir::TyKind::Err |
abe05a73 XL |
1331 | } |
1332 | } | |
cc61c64b | 1333 | } |
ba9703b0 | 1334 | TyKind::MacCall(_) => panic!("`TyKind::MacCall` should have been expanded by now"), |
dfeec247 XL |
1335 | TyKind::CVarArgs => { |
1336 | self.sess.delay_span_bug( | |
1337 | t.span, | |
1338 | "`TyKind::CVarArgs` should have been handled elsewhere", | |
1339 | ); | |
1340 | hir::TyKind::Err | |
1341 | } | |
cc61c64b XL |
1342 | }; |
1343 | ||
dfeec247 | 1344 | hir::Ty { kind, span: t.span, hir_id: self.lower_node_id(t.id) } |
8faf50e0 XL |
1345 | } |
1346 | ||
416331ca | 1347 | fn lower_opaque_impl_trait( |
8faf50e0 XL |
1348 | &mut self, |
1349 | span: Span, | |
0bf4aa26 | 1350 | fn_def_id: Option<DefId>, |
74b04a01 | 1351 | origin: hir::OpaqueTyOrigin, |
416331ca | 1352 | opaque_ty_node_id: NodeId, |
dfeec247 XL |
1353 | lower_bounds: impl FnOnce(&mut Self) -> hir::GenericBounds<'hir>, |
1354 | ) -> hir::TyKind<'hir> { | |
e1599b0c XL |
1355 | debug!( |
1356 | "lower_opaque_impl_trait(fn_def_id={:?}, opaque_ty_node_id={:?}, span={:?})", | |
dfeec247 | 1357 | fn_def_id, opaque_ty_node_id, span, |
e1599b0c XL |
1358 | ); |
1359 | ||
8faf50e0 XL |
1360 | // Make sure we know that some funky desugaring has been going on here. |
1361 | // This is a first: there is code in other places like for loop | |
1362 | // desugaring that explicitly states that we don't want to track that. | |
dc9dc135 | 1363 | // Not tracking it makes lints in rustc and clippy very fragile, as |
8faf50e0 | 1364 | // frequently opened issues show. |
dfeec247 | 1365 | let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::OpaqueTy, span, None); |
8faf50e0 | 1366 | |
ba9703b0 | 1367 | let opaque_ty_def_id = self.resolver.definitions().local_def_id(opaque_ty_node_id); |
8faf50e0 | 1368 | |
416331ca | 1369 | self.allocate_hir_id_counter(opaque_ty_node_id); |
8faf50e0 | 1370 | |
416331ca | 1371 | let hir_bounds = self.with_hir_id_owner(opaque_ty_node_id, lower_bounds); |
8faf50e0 | 1372 | |
ba9703b0 XL |
1373 | let (lifetimes, lifetime_defs) = |
1374 | self.lifetimes_from_impl_trait_bounds(opaque_ty_node_id, opaque_ty_def_id, &hir_bounds); | |
8faf50e0 | 1375 | |
dfeec247 | 1376 | debug!("lower_opaque_impl_trait: lifetimes={:#?}", lifetimes,); |
e1599b0c | 1377 | |
dfeec247 | 1378 | debug!("lower_opaque_impl_trait: lifetime_defs={:#?}", lifetime_defs,); |
e1599b0c | 1379 | |
dfeec247 | 1380 | self.with_hir_id_owner(opaque_ty_node_id, move |lctx| { |
416331ca | 1381 | let opaque_ty_item = hir::OpaqueTy { |
8faf50e0 XL |
1382 | generics: hir::Generics { |
1383 | params: lifetime_defs, | |
dfeec247 | 1384 | where_clause: hir::WhereClause { predicates: &[], span }, |
8faf50e0 XL |
1385 | span, |
1386 | }, | |
1387 | bounds: hir_bounds, | |
0bf4aa26 | 1388 | impl_trait_fn: fn_def_id, |
74b04a01 | 1389 | origin, |
8faf50e0 XL |
1390 | }; |
1391 | ||
ba9703b0 | 1392 | trace!("lower_opaque_impl_trait: {:#?}", opaque_ty_def_id); |
dfeec247 XL |
1393 | let opaque_ty_id = |
1394 | lctx.generate_opaque_type(opaque_ty_node_id, opaque_ty_item, span, opaque_ty_span); | |
8faf50e0 | 1395 | |
0731742a | 1396 | // `impl Trait` now just becomes `Foo<'a, 'b, ..>`. |
416331ca | 1397 | hir::TyKind::Def(hir::ItemId { id: opaque_ty_id }, lifetimes) |
a7813a04 XL |
1398 | }) |
1399 | } | |
e9174d1e | 1400 | |
416331ca XL |
1401 | /// Registers a new opaque type with the proper `NodeId`s and |
1402 | /// returns the lowered node-ID for the opaque type. | |
1403 | fn generate_opaque_type( | |
532ac7d7 | 1404 | &mut self, |
416331ca | 1405 | opaque_ty_node_id: NodeId, |
dfeec247 | 1406 | opaque_ty_item: hir::OpaqueTy<'hir>, |
532ac7d7 | 1407 | span: Span, |
416331ca | 1408 | opaque_ty_span: Span, |
48663c56 | 1409 | ) -> hir::HirId { |
416331ca XL |
1410 | let opaque_ty_item_kind = hir::ItemKind::OpaqueTy(opaque_ty_item); |
1411 | let opaque_ty_id = self.lower_node_id(opaque_ty_node_id); | |
1412 | // Generate an `type Foo = impl Trait;` declaration. | |
1413 | trace!("registering opaque type with id {:#?}", opaque_ty_id); | |
1414 | let opaque_ty_item = hir::Item { | |
1415 | hir_id: opaque_ty_id, | |
dc9dc135 | 1416 | ident: Ident::invalid(), |
532ac7d7 | 1417 | attrs: Default::default(), |
e74abb32 | 1418 | kind: opaque_ty_item_kind, |
532ac7d7 | 1419 | vis: respan(span.shrink_to_lo(), hir::VisibilityKind::Inherited), |
416331ca | 1420 | span: opaque_ty_span, |
532ac7d7 XL |
1421 | }; |
1422 | ||
1423 | // Insert the item into the global item list. This usually happens | |
416331ca | 1424 | // automatically for all AST items. But this opaque type item |
532ac7d7 | 1425 | // does not actually exist in the AST. |
416331ca XL |
1426 | self.insert_item(opaque_ty_item); |
1427 | opaque_ty_id | |
532ac7d7 XL |
1428 | } |
1429 | ||
ff7c6d11 XL |
1430 | fn lifetimes_from_impl_trait_bounds( |
1431 | &mut self, | |
416331ca | 1432 | opaque_ty_id: NodeId, |
ba9703b0 | 1433 | parent_def_id: LocalDefId, |
dfeec247 XL |
1434 | bounds: hir::GenericBounds<'hir>, |
1435 | ) -> (&'hir [hir::GenericArg<'hir>], &'hir [hir::GenericParam<'hir>]) { | |
e1599b0c XL |
1436 | debug!( |
1437 | "lifetimes_from_impl_trait_bounds(opaque_ty_id={:?}, \ | |
ba9703b0 | 1438 | parent_def_id={:?}, \ |
e1599b0c | 1439 | bounds={:#?})", |
ba9703b0 | 1440 | opaque_ty_id, parent_def_id, bounds, |
e1599b0c XL |
1441 | ); |
1442 | ||
dc9dc135 | 1443 | // This visitor walks over `impl Trait` bounds and creates defs for all lifetimes that |
ff7c6d11 | 1444 | // appear in the bounds, excluding lifetimes that are created within the bounds. |
0731742a | 1445 | // E.g., `'a`, `'b`, but not `'c` in `impl for<'c> SomeTrait<'a, 'b, 'c>`. |
dfeec247 XL |
1446 | struct ImplTraitLifetimeCollector<'r, 'a, 'hir> { |
1447 | context: &'r mut LoweringContext<'a, 'hir>, | |
ba9703b0 | 1448 | parent: LocalDefId, |
416331ca | 1449 | opaque_ty_id: NodeId, |
ff7c6d11 XL |
1450 | collect_elided_lifetimes: bool, |
1451 | currently_bound_lifetimes: Vec<hir::LifetimeName>, | |
b7449926 | 1452 | already_defined_lifetimes: FxHashSet<hir::LifetimeName>, |
dfeec247 XL |
1453 | output_lifetimes: Vec<hir::GenericArg<'hir>>, |
1454 | output_lifetime_params: Vec<hir::GenericParam<'hir>>, | |
ff7c6d11 XL |
1455 | } |
1456 | ||
dfeec247 | 1457 | impl<'r, 'a, 'v, 'hir> intravisit::Visitor<'v> for ImplTraitLifetimeCollector<'r, 'a, 'hir> { |
ba9703b0 | 1458 | type Map = intravisit::ErasedMap<'v>; |
dfeec247 | 1459 | |
ba9703b0 | 1460 | fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { |
dfeec247 | 1461 | intravisit::NestedVisitorMap::None |
ff7c6d11 XL |
1462 | } |
1463 | ||
dfeec247 | 1464 | fn visit_generic_args(&mut self, span: Span, parameters: &'v hir::GenericArgs<'v>) { |
ff7c6d11 XL |
1465 | // Don't collect elided lifetimes used inside of `Fn()` syntax. |
1466 | if parameters.parenthesized { | |
1467 | let old_collect_elided_lifetimes = self.collect_elided_lifetimes; | |
1468 | self.collect_elided_lifetimes = false; | |
dfeec247 | 1469 | intravisit::walk_generic_args(self, span, parameters); |
ff7c6d11 XL |
1470 | self.collect_elided_lifetimes = old_collect_elided_lifetimes; |
1471 | } else { | |
dfeec247 | 1472 | intravisit::walk_generic_args(self, span, parameters); |
ff7c6d11 XL |
1473 | } |
1474 | } | |
1475 | ||
dfeec247 | 1476 | fn visit_ty(&mut self, t: &'v hir::Ty<'v>) { |
0731742a | 1477 | // Don't collect elided lifetimes used inside of `fn()` syntax. |
e74abb32 | 1478 | if let hir::TyKind::BareFn(_) = t.kind { |
ff7c6d11 XL |
1479 | let old_collect_elided_lifetimes = self.collect_elided_lifetimes; |
1480 | self.collect_elided_lifetimes = false; | |
94b46f34 XL |
1481 | |
1482 | // Record the "stack height" of `for<'a>` lifetime bindings | |
1483 | // to be able to later fully undo their introduction. | |
1484 | let old_len = self.currently_bound_lifetimes.len(); | |
dfeec247 | 1485 | intravisit::walk_ty(self, t); |
94b46f34 XL |
1486 | self.currently_bound_lifetimes.truncate(old_len); |
1487 | ||
ff7c6d11 XL |
1488 | self.collect_elided_lifetimes = old_collect_elided_lifetimes; |
1489 | } else { | |
dfeec247 | 1490 | intravisit::walk_ty(self, t) |
ff7c6d11 XL |
1491 | } |
1492 | } | |
1493 | ||
0531ce1d XL |
1494 | fn visit_poly_trait_ref( |
1495 | &mut self, | |
dfeec247 | 1496 | trait_ref: &'v hir::PolyTraitRef<'v>, |
94b46f34 | 1497 | modifier: hir::TraitBoundModifier, |
0531ce1d | 1498 | ) { |
94b46f34 XL |
1499 | // Record the "stack height" of `for<'a>` lifetime bindings |
1500 | // to be able to later fully undo their introduction. | |
ff7c6d11 | 1501 | let old_len = self.currently_bound_lifetimes.len(); |
dfeec247 | 1502 | intravisit::walk_poly_trait_ref(self, trait_ref, modifier); |
94b46f34 XL |
1503 | self.currently_bound_lifetimes.truncate(old_len); |
1504 | } | |
ff7c6d11 | 1505 | |
dfeec247 | 1506 | fn visit_generic_param(&mut self, param: &'v hir::GenericParam<'v>) { |
0731742a | 1507 | // Record the introduction of 'a in `for<'a> ...`. |
8faf50e0 | 1508 | if let hir::GenericParamKind::Lifetime { .. } = param.kind { |
94b46f34 | 1509 | // Introduce lifetimes one at a time so that we can handle |
0731742a | 1510 | // cases like `fn foo<'d>() -> impl for<'a, 'b: 'a, 'c: 'b + 'd>`. |
8faf50e0 XL |
1511 | let lt_name = hir::LifetimeName::Param(param.name); |
1512 | self.currently_bound_lifetimes.push(lt_name); | |
ff7c6d11 XL |
1513 | } |
1514 | ||
dfeec247 | 1515 | intravisit::walk_generic_param(self, param); |
ff7c6d11 XL |
1516 | } |
1517 | ||
1518 | fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) { | |
1519 | let name = match lifetime.name { | |
0531ce1d | 1520 | hir::LifetimeName::Implicit | hir::LifetimeName::Underscore => { |
ff7c6d11 XL |
1521 | if self.collect_elided_lifetimes { |
1522 | // Use `'_` for both implicit and underscore lifetimes in | |
416331ca | 1523 | // `type Foo<'_> = impl SomeTrait<'_>;`. |
ff7c6d11 XL |
1524 | hir::LifetimeName::Underscore |
1525 | } else { | |
0531ce1d | 1526 | return; |
ff7c6d11 | 1527 | } |
0531ce1d | 1528 | } |
8faf50e0 | 1529 | hir::LifetimeName::Param(_) => lifetime.name, |
e1599b0c XL |
1530 | |
1531 | // Refers to some other lifetime that is "in | |
1532 | // scope" within the type. | |
1533 | hir::LifetimeName::ImplicitObjectLifetimeDefault => return, | |
1534 | ||
0bf4aa26 | 1535 | hir::LifetimeName::Error | hir::LifetimeName::Static => return, |
ff7c6d11 XL |
1536 | }; |
1537 | ||
0531ce1d | 1538 | if !self.currently_bound_lifetimes.contains(&name) |
dfeec247 XL |
1539 | && !self.already_defined_lifetimes.contains(&name) |
1540 | { | |
ff7c6d11 XL |
1541 | self.already_defined_lifetimes.insert(name); |
1542 | ||
8faf50e0 | 1543 | self.output_lifetimes.push(hir::GenericArg::Lifetime(hir::Lifetime { |
48663c56 | 1544 | hir_id: self.context.next_id(), |
ff7c6d11 XL |
1545 | span: lifetime.span, |
1546 | name, | |
8faf50e0 | 1547 | })); |
ff7c6d11 | 1548 | |
60c5eb7d | 1549 | let def_node_id = self.context.resolver.next_node_id(); |
48663c56 | 1550 | let hir_id = |
416331ca | 1551 | self.context.lower_node_id_with_owner(def_node_id, self.opaque_ty_id); |
ff7c6d11 XL |
1552 | self.context.resolver.definitions().create_def_with_parent( |
1553 | self.parent, | |
1554 | def_node_id, | |
e74abb32 | 1555 | DefPathData::LifetimeNs(name.ident().name), |
416331ca | 1556 | ExpnId::root(), |
dfeec247 XL |
1557 | lifetime.span, |
1558 | ); | |
8faf50e0 | 1559 | |
0bf4aa26 XL |
1560 | let (name, kind) = match name { |
1561 | hir::LifetimeName::Underscore => ( | |
e1599b0c | 1562 | hir::ParamName::Plain(Ident::with_dummy_span(kw::UnderscoreLifetime)), |
0bf4aa26 XL |
1563 | hir::LifetimeParamKind::Elided, |
1564 | ), | |
dfeec247 XL |
1565 | hir::LifetimeName::Param(param_name) => { |
1566 | (param_name, hir::LifetimeParamKind::Explicit) | |
1567 | } | |
ba9703b0 | 1568 | _ => panic!("expected `LifetimeName::Param` or `ParamName::Plain`"), |
8faf50e0 XL |
1569 | }; |
1570 | ||
1571 | self.output_lifetime_params.push(hir::GenericParam { | |
9fa01778 | 1572 | hir_id, |
94b46f34 | 1573 | name, |
8faf50e0 XL |
1574 | span: lifetime.span, |
1575 | pure_wrt_drop: false, | |
dfeec247 XL |
1576 | attrs: &[], |
1577 | bounds: &[], | |
1578 | kind: hir::GenericParamKind::Lifetime { kind }, | |
8faf50e0 | 1579 | }); |
ff7c6d11 XL |
1580 | } |
1581 | } | |
1582 | } | |
1583 | ||
1584 | let mut lifetime_collector = ImplTraitLifetimeCollector { | |
1585 | context: self, | |
ba9703b0 | 1586 | parent: parent_def_id, |
416331ca | 1587 | opaque_ty_id, |
ff7c6d11 XL |
1588 | collect_elided_lifetimes: true, |
1589 | currently_bound_lifetimes: Vec::new(), | |
b7449926 | 1590 | already_defined_lifetimes: FxHashSet::default(), |
ff7c6d11 XL |
1591 | output_lifetimes: Vec::new(), |
1592 | output_lifetime_params: Vec::new(), | |
1593 | }; | |
1594 | ||
1595 | for bound in bounds { | |
dfeec247 | 1596 | intravisit::walk_param_bound(&mut lifetime_collector, &bound); |
ff7c6d11 XL |
1597 | } |
1598 | ||
dfeec247 XL |
1599 | let ImplTraitLifetimeCollector { output_lifetimes, output_lifetime_params, .. } = |
1600 | lifetime_collector; | |
32a655c1 | 1601 | |
dc9dc135 | 1602 | ( |
dfeec247 XL |
1603 | self.arena.alloc_from_iter(output_lifetimes), |
1604 | self.arena.alloc_from_iter(output_lifetime_params), | |
0531ce1d | 1605 | ) |
e9174d1e | 1606 | } |
e9174d1e | 1607 | |
dfeec247 | 1608 | fn lower_local(&mut self, l: &Local) -> (hir::Local<'hir>, SmallVec<[NodeId; 1]>) { |
532ac7d7 | 1609 | let mut ids = SmallVec::<[NodeId; 1]>::new(); |
0bf4aa26 XL |
1610 | if self.sess.features_untracked().impl_trait_in_bindings { |
1611 | if let Some(ref ty) = l.ty { | |
1612 | let mut visitor = ImplTraitTypeIdVisitor { ids: &mut ids }; | |
1613 | visitor.visit_ty(ty); | |
1614 | } | |
1615 | } | |
ba9703b0 | 1616 | let parent_def_id = self.current_hir_id_owner.last().unwrap().0; |
dfeec247 XL |
1617 | let ty = l.ty.as_ref().map(|t| { |
1618 | self.lower_ty( | |
1619 | t, | |
1620 | if self.sess.features_untracked().impl_trait_in_bindings { | |
ba9703b0 XL |
1621 | ImplTraitContext::OpaqueTy( |
1622 | Some(parent_def_id.to_def_id()), | |
1623 | hir::OpaqueTyOrigin::Misc, | |
1624 | ) | |
dfeec247 XL |
1625 | } else { |
1626 | ImplTraitContext::Disallowed(ImplTraitPosition::Binding) | |
1627 | }, | |
1628 | ) | |
1629 | }); | |
1630 | let init = l.init.as_ref().map(|e| self.lower_expr(e)); | |
1631 | ( | |
1632 | hir::Local { | |
1633 | hir_id: self.lower_node_id(l.id), | |
1634 | ty, | |
1635 | pat: self.lower_pat(&l.pat), | |
1636 | init, | |
1637 | span: l.span, | |
1638 | attrs: l.attrs.clone(), | |
1639 | source: hir::LocalSource::Normal, | |
1640 | }, | |
1641 | ids, | |
1642 | ) | |
a7813a04 | 1643 | } |
e9174d1e | 1644 | |
dfeec247 | 1645 | fn lower_fn_params_to_names(&mut self, decl: &FnDecl) -> &'hir [Ident] { |
e74abb32 XL |
1646 | // Skip the `...` (`CVarArgs`) trailing arguments from the AST, |
1647 | // as they are not explicit in HIR/Ty function signatures. | |
1648 | // (instead, the `c_variadic` flag is set to `true`) | |
1649 | let mut inputs = &decl.inputs[..]; | |
1650 | if decl.c_variadic() { | |
1651 | inputs = &inputs[..inputs.len() - 1]; | |
1652 | } | |
dfeec247 XL |
1653 | self.arena.alloc_from_iter(inputs.iter().map(|param| match param.pat.kind { |
1654 | PatKind::Ident(_, ident, _) => ident, | |
1655 | _ => Ident::new(kw::Invalid, param.pat.span), | |
1656 | })) | |
32a655c1 SL |
1657 | } |
1658 | ||
8faf50e0 XL |
1659 | // Lowers a function declaration. |
1660 | // | |
dc9dc135 XL |
1661 | // `decl`: the unlowered (AST) function declaration. |
1662 | // `fn_def_id`: if `Some`, impl Trait arguments are lowered into generic parameters on the | |
8faf50e0 | 1663 | // given DefId, otherwise impl Trait is disallowed. Must be `Some` if |
dc9dc135 XL |
1664 | // `make_ret_async` is also `Some`. |
1665 | // `impl_trait_return_allow`: determines whether `impl Trait` can be used in return position. | |
1666 | // This guards against trait declarations and implementations where `impl Trait` is | |
8faf50e0 | 1667 | // disallowed. |
dc9dc135 XL |
1668 | // `make_ret_async`: if `Some`, converts `-> T` into `-> impl Future<Output = T>` in the |
1669 | // return type. This is used for `async fn` declarations. The `NodeId` is the ID of the | |
1670 | // return type `impl Trait` item. | |
0531ce1d XL |
1671 | fn lower_fn_decl( |
1672 | &mut self, | |
1673 | decl: &FnDecl, | |
dfeec247 | 1674 | mut in_band_ty_params: Option<(DefId, &mut Vec<hir::GenericParam<'hir>>)>, |
0531ce1d | 1675 | impl_trait_return_allow: bool, |
8faf50e0 | 1676 | make_ret_async: Option<NodeId>, |
dfeec247 XL |
1677 | ) -> &'hir hir::FnDecl<'hir> { |
1678 | debug!( | |
1679 | "lower_fn_decl(\ | |
60c5eb7d XL |
1680 | fn_decl: {:?}, \ |
1681 | in_band_ty_params: {:?}, \ | |
1682 | impl_trait_return_allow: {}, \ | |
1683 | make_ret_async: {:?})", | |
dfeec247 | 1684 | decl, in_band_ty_params, impl_trait_return_allow, make_ret_async, |
60c5eb7d | 1685 | ); |
532ac7d7 XL |
1686 | let lt_mode = if make_ret_async.is_some() { |
1687 | // In `async fn`, argument-position elided lifetimes | |
1688 | // must be transformed into fresh generic parameters so that | |
416331ca | 1689 | // they can be applied to the opaque `impl Trait` return type. |
532ac7d7 XL |
1690 | AnonymousLifetimeMode::CreateParameter |
1691 | } else { | |
1692 | self.anonymous_lifetime_mode | |
1693 | }; | |
1694 | ||
e74abb32 XL |
1695 | let c_variadic = decl.c_variadic(); |
1696 | ||
532ac7d7 XL |
1697 | // Remember how many lifetimes were already around so that we can |
1698 | // only look at the lifetime parameters introduced by the arguments. | |
532ac7d7 | 1699 | let inputs = self.with_anonymous_lifetime_mode(lt_mode, |this| { |
e74abb32 XL |
1700 | // Skip the `...` (`CVarArgs`) trailing arguments from the AST, |
1701 | // as they are not explicit in HIR/Ty function signatures. | |
1702 | // (instead, the `c_variadic` flag is set to `true`) | |
1703 | let mut inputs = &decl.inputs[..]; | |
1704 | if c_variadic { | |
1705 | inputs = &inputs[..inputs.len() - 1]; | |
1706 | } | |
dfeec247 XL |
1707 | this.arena.alloc_from_iter(inputs.iter().map(|param| { |
1708 | if let Some((_, ibty)) = &mut in_band_ty_params { | |
1709 | this.lower_ty_direct(¶m.ty, ImplTraitContext::Universal(ibty)) | |
1710 | } else { | |
1711 | this.lower_ty_direct(¶m.ty, ImplTraitContext::disallowed()) | |
1712 | } | |
1713 | })) | |
532ac7d7 | 1714 | }); |
8faf50e0 XL |
1715 | |
1716 | let output = if let Some(ret_id) = make_ret_async { | |
1717 | self.lower_async_fn_ret_ty( | |
8faf50e0 | 1718 | &decl.output, |
dc9dc135 | 1719 | in_band_ty_params.expect("`make_ret_async` but no `fn_def_id`").0, |
8faf50e0 XL |
1720 | ret_id, |
1721 | ) | |
1722 | } else { | |
1723 | match decl.output { | |
74b04a01 XL |
1724 | FnRetTy::Ty(ref ty) => { |
1725 | let context = match in_band_ty_params { | |
1726 | Some((def_id, _)) if impl_trait_return_allow => { | |
1727 | ImplTraitContext::OpaqueTy(Some(def_id), hir::OpaqueTyOrigin::FnReturn) | |
1728 | } | |
1729 | _ => ImplTraitContext::disallowed(), | |
1730 | }; | |
1731 | hir::FnRetTy::Return(self.lower_ty(ty, context)) | |
1732 | } | |
1733 | FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(span), | |
8faf50e0 XL |
1734 | } |
1735 | }; | |
1736 | ||
dfeec247 | 1737 | self.arena.alloc(hir::FnDecl { |
8faf50e0 XL |
1738 | inputs, |
1739 | output, | |
e74abb32 | 1740 | c_variadic, |
dfeec247 XL |
1741 | implicit_self: decl.inputs.get(0).map_or(hir::ImplicitSelfKind::None, |arg| { |
1742 | let is_mutable_pat = match arg.pat.kind { | |
ba9703b0 XL |
1743 | PatKind::Ident(BindingMode::ByValue(mt) | BindingMode::ByRef(mt), _, _) => { |
1744 | mt == Mutability::Mut | |
1745 | } | |
dfeec247 XL |
1746 | _ => false, |
1747 | }; | |
0bf4aa26 | 1748 | |
dfeec247 XL |
1749 | match arg.ty.kind { |
1750 | TyKind::ImplicitSelf if is_mutable_pat => hir::ImplicitSelfKind::Mut, | |
1751 | TyKind::ImplicitSelf => hir::ImplicitSelfKind::Imm, | |
1752 | // Given we are only considering `ImplicitSelf` types, we needn't consider | |
1753 | // the case where we have a mutable pattern to a reference as that would | |
1754 | // no longer be an `ImplicitSelf`. | |
1755 | TyKind::Rptr(_, ref mt) | |
1756 | if mt.ty.kind.is_implicit_self() && mt.mutbl == ast::Mutability::Mut => | |
1757 | { | |
1758 | hir::ImplicitSelfKind::MutRef | |
0bf4aa26 | 1759 | } |
dfeec247 XL |
1760 | TyKind::Rptr(_, ref mt) if mt.ty.kind.is_implicit_self() => { |
1761 | hir::ImplicitSelfKind::ImmRef | |
1762 | } | |
1763 | _ => hir::ImplicitSelfKind::None, | |
1764 | } | |
1765 | }), | |
a7813a04 | 1766 | }) |
b039eaaf | 1767 | } |
e9174d1e | 1768 | |
416331ca XL |
1769 | // Transforms `-> T` for `async fn` into `-> OpaqueTy { .. }` |
1770 | // combined with the following definition of `OpaqueTy`: | |
532ac7d7 | 1771 | // |
416331ca | 1772 | // type OpaqueTy<generics_from_parent_fn> = impl Future<Output = T>; |
8faf50e0 | 1773 | // |
e1599b0c | 1774 | // `inputs`: lowered types of parameters to the function (used to collect lifetimes) |
dc9dc135 XL |
1775 | // `output`: unlowered output type (`T` in `-> T`) |
1776 | // `fn_def_id`: `DefId` of the parent function (used to create child impl trait definition) | |
416331ca | 1777 | // `opaque_ty_node_id`: `NodeId` of the opaque `impl Trait` type that should be created |
dc9dc135 | 1778 | // `elided_lt_replacement`: replacement for elided lifetimes in the return type |
8faf50e0 | 1779 | fn lower_async_fn_ret_ty( |
0531ce1d | 1780 | &mut self, |
74b04a01 | 1781 | output: &FnRetTy, |
8faf50e0 | 1782 | fn_def_id: DefId, |
416331ca | 1783 | opaque_ty_node_id: NodeId, |
74b04a01 | 1784 | ) -> hir::FnRetTy<'hir> { |
e1599b0c XL |
1785 | debug!( |
1786 | "lower_async_fn_ret_ty(\ | |
1787 | output={:?}, \ | |
1788 | fn_def_id={:?}, \ | |
1789 | opaque_ty_node_id={:?})", | |
1790 | output, fn_def_id, opaque_ty_node_id, | |
1791 | ); | |
1792 | ||
532ac7d7 | 1793 | let span = output.span(); |
8faf50e0 | 1794 | |
dfeec247 | 1795 | let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, span, None); |
8faf50e0 | 1796 | |
ba9703b0 | 1797 | let opaque_ty_def_id = self.resolver.definitions().local_def_id(opaque_ty_node_id); |
8faf50e0 | 1798 | |
416331ca | 1799 | self.allocate_hir_id_counter(opaque_ty_node_id); |
8faf50e0 | 1800 | |
e1599b0c XL |
1801 | // When we create the opaque type for this async fn, it is going to have |
1802 | // to capture all the lifetimes involved in the signature (including in the | |
1803 | // return type). This is done by introducing lifetime parameters for: | |
1804 | // | |
1805 | // - all the explicitly declared lifetimes from the impl and function itself; | |
1806 | // - all the elided lifetimes in the fn arguments; | |
1807 | // - all the elided lifetimes in the return type. | |
1808 | // | |
1809 | // So for example in this snippet: | |
1810 | // | |
1811 | // ```rust | |
1812 | // impl<'a> Foo<'a> { | |
1813 | // async fn bar<'b>(&self, x: &'b Vec<f64>, y: &str) -> &u32 { | |
1814 | // // ^ '0 ^ '1 ^ '2 | |
1815 | // // elided lifetimes used below | |
1816 | // } | |
1817 | // } | |
1818 | // ``` | |
1819 | // | |
1820 | // we would create an opaque type like: | |
1821 | // | |
1822 | // ``` | |
1823 | // type Bar<'a, 'b, '0, '1, '2> = impl Future<Output = &'2 u32>; | |
1824 | // ``` | |
1825 | // | |
1826 | // and we would then desugar `bar` to the equivalent of: | |
1827 | // | |
1828 | // ```rust | |
1829 | // impl<'a> Foo<'a> { | |
1830 | // fn bar<'b, '0, '1>(&'0 self, x: &'b Vec<f64>, y: &'1 str) -> Bar<'a, 'b, '0, '1, '_> | |
1831 | // } | |
1832 | // ``` | |
1833 | // | |
1834 | // Note that the final parameter to `Bar` is `'_`, not `'2` -- | |
1835 | // this is because the elided lifetimes from the return type | |
1836 | // should be figured out using the ordinary elision rules, and | |
1837 | // this desugaring achieves that. | |
1838 | // | |
1839 | // The variable `input_lifetimes_count` tracks the number of | |
1840 | // lifetime parameters to the opaque type *not counting* those | |
1841 | // lifetimes elided in the return type. This includes those | |
1842 | // that are explicitly declared (`in_scope_lifetimes`) and | |
1843 | // those elided lifetimes we found in the arguments (current | |
1844 | // content of `lifetimes_to_define`). Next, we will process | |
1845 | // the return type, which will cause `lifetimes_to_define` to | |
1846 | // grow. | |
1847 | let input_lifetimes_count = self.in_scope_lifetimes.len() + self.lifetimes_to_define.len(); | |
1848 | ||
416331ca | 1849 | let (opaque_ty_id, lifetime_params) = self.with_hir_id_owner(opaque_ty_node_id, |this| { |
e1599b0c XL |
1850 | // We have to be careful to get elision right here. The |
1851 | // idea is that we create a lifetime parameter for each | |
1852 | // lifetime in the return type. So, given a return type | |
1853 | // like `async fn foo(..) -> &[&u32]`, we lower to `impl | |
1854 | // Future<Output = &'1 [ &'2 u32 ]>`. | |
1855 | // | |
1856 | // Then, we will create `fn foo(..) -> Foo<'_, '_>`, and | |
1857 | // hence the elision takes place at the fn site. | |
dfeec247 XL |
1858 | let future_bound = this |
1859 | .with_anonymous_lifetime_mode(AnonymousLifetimeMode::CreateParameter, |this| { | |
1860 | this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span) | |
1861 | }); | |
8faf50e0 | 1862 | |
e1599b0c XL |
1863 | debug!("lower_async_fn_ret_ty: future_bound={:#?}", future_bound); |
1864 | ||
532ac7d7 | 1865 | // Calculate all the lifetimes that should be captured |
416331ca | 1866 | // by the opaque type. This should include all in-scope |
532ac7d7 XL |
1867 | // lifetime parameters, including those defined in-band. |
1868 | // | |
1869 | // Note: this must be done after lowering the output type, | |
1870 | // as the output type may introduce new in-band lifetimes. | |
dfeec247 XL |
1871 | let lifetime_params: Vec<(Span, ParamName)> = this |
1872 | .in_scope_lifetimes | |
1873 | .iter() | |
1874 | .cloned() | |
1875 | .map(|name| (name.ident().span, name)) | |
1876 | .chain(this.lifetimes_to_define.iter().cloned()) | |
1877 | .collect(); | |
8faf50e0 | 1878 | |
e1599b0c XL |
1879 | debug!("lower_async_fn_ret_ty: in_scope_lifetimes={:#?}", this.in_scope_lifetimes); |
1880 | debug!("lower_async_fn_ret_ty: lifetimes_to_define={:#?}", this.lifetimes_to_define); | |
1881 | debug!("lower_async_fn_ret_ty: lifetime_params={:#?}", lifetime_params); | |
1882 | ||
532ac7d7 | 1883 | let generic_params = |
dfeec247 | 1884 | this.arena.alloc_from_iter(lifetime_params.iter().map(|(span, hir_name)| { |
ba9703b0 | 1885 | this.lifetime_to_generic_param(*span, *hir_name, opaque_ty_def_id) |
dfeec247 | 1886 | })); |
8faf50e0 | 1887 | |
416331ca | 1888 | let opaque_ty_item = hir::OpaqueTy { |
532ac7d7 XL |
1889 | generics: hir::Generics { |
1890 | params: generic_params, | |
dfeec247 | 1891 | where_clause: hir::WhereClause { predicates: &[], span }, |
532ac7d7 XL |
1892 | span, |
1893 | }, | |
dfeec247 | 1894 | bounds: arena_vec![this; future_bound], |
532ac7d7 | 1895 | impl_trait_fn: Some(fn_def_id), |
416331ca | 1896 | origin: hir::OpaqueTyOrigin::AsyncFn, |
8faf50e0 XL |
1897 | }; |
1898 | ||
ba9703b0 | 1899 | trace!("exist ty from async fn def id: {:#?}", opaque_ty_def_id); |
dfeec247 XL |
1900 | let opaque_ty_id = |
1901 | this.generate_opaque_type(opaque_ty_node_id, opaque_ty_item, span, opaque_ty_span); | |
8faf50e0 | 1902 | |
416331ca | 1903 | (opaque_ty_id, lifetime_params) |
532ac7d7 | 1904 | }); |
8faf50e0 | 1905 | |
e1599b0c XL |
1906 | // As documented above on the variable |
1907 | // `input_lifetimes_count`, we need to create the lifetime | |
1908 | // arguments to our opaque type. Continuing with our example, | |
1909 | // we're creating the type arguments for the return type: | |
1910 | // | |
1911 | // ``` | |
1912 | // Bar<'a, 'b, '0, '1, '_> | |
1913 | // ``` | |
1914 | // | |
1915 | // For the "input" lifetime parameters, we wish to create | |
1916 | // references to the parameters themselves, including the | |
1917 | // "implicit" ones created from parameter types (`'a`, `'b`, | |
1918 | // '`0`, `'1`). | |
1919 | // | |
1920 | // For the "output" lifetime parameters, we just want to | |
1921 | // generate `'_`. | |
dfeec247 | 1922 | let mut generic_args: Vec<_> = lifetime_params[..input_lifetimes_count] |
e1599b0c XL |
1923 | .iter() |
1924 | .map(|&(span, hir_name)| { | |
1925 | // Input lifetime like `'a` or `'1`: | |
1926 | GenericArg::Lifetime(hir::Lifetime { | |
1927 | hir_id: self.next_id(), | |
1928 | span, | |
1929 | name: hir::LifetimeName::Param(hir_name), | |
532ac7d7 | 1930 | }) |
e1599b0c XL |
1931 | }) |
1932 | .collect(); | |
dfeec247 XL |
1933 | generic_args.extend(lifetime_params[input_lifetimes_count..].iter().map(|&(span, _)| |
1934 | // Output lifetime like `'_`. | |
1935 | GenericArg::Lifetime(hir::Lifetime { | |
1936 | hir_id: self.next_id(), | |
1937 | span, | |
1938 | name: hir::LifetimeName::Implicit, | |
1939 | }))); | |
1940 | let generic_args = self.arena.alloc_from_iter(generic_args); | |
8faf50e0 | 1941 | |
dfeec247 | 1942 | // Create the `Foo<...>` reference itself. Note that the `type |
e1599b0c XL |
1943 | // Foo = impl Trait` is, internally, created as a child of the |
1944 | // async fn, so the *type parameters* are inherited. It's | |
1945 | // only the lifetime parameters that we must supply. | |
dfeec247 XL |
1946 | let opaque_ty_ref = hir::TyKind::Def(hir::ItemId { id: opaque_ty_id }, generic_args); |
1947 | let opaque_ty = self.ty(opaque_ty_span, opaque_ty_ref); | |
74b04a01 | 1948 | hir::FnRetTy::Return(self.arena.alloc(opaque_ty)) |
532ac7d7 | 1949 | } |
8faf50e0 | 1950 | |
dc9dc135 | 1951 | /// Transforms `-> T` into `Future<Output = T>` |
532ac7d7 XL |
1952 | fn lower_async_fn_output_type_to_future_bound( |
1953 | &mut self, | |
74b04a01 | 1954 | output: &FnRetTy, |
532ac7d7 XL |
1955 | fn_def_id: DefId, |
1956 | span: Span, | |
dfeec247 | 1957 | ) -> hir::GenericBound<'hir> { |
532ac7d7 XL |
1958 | // Compute the `T` in `Future<Output = T>` from the return type. |
1959 | let output_ty = match output { | |
74b04a01 XL |
1960 | FnRetTy::Ty(ty) => { |
1961 | // Not `OpaqueTyOrigin::AsyncFn`: that's only used for the | |
1962 | // `impl Future` opaque type that `async fn` implicitly | |
1963 | // generates. | |
1964 | let context = | |
1965 | ImplTraitContext::OpaqueTy(Some(fn_def_id), hir::OpaqueTyOrigin::FnReturn); | |
1966 | self.lower_ty(ty, context) | |
1967 | } | |
1968 | FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])), | |
532ac7d7 | 1969 | }; |
8faf50e0 | 1970 | |
532ac7d7 | 1971 | // "<Output = T>" |
dfeec247 XL |
1972 | let future_params = self.arena.alloc(hir::GenericArgs { |
1973 | args: &[], | |
1974 | bindings: arena_vec![self; self.output_ty_binding(span, output_ty)], | |
532ac7d7 | 1975 | parenthesized: false, |
8faf50e0 XL |
1976 | }); |
1977 | ||
532ac7d7 XL |
1978 | // ::std::future::Future<future_params> |
1979 | let future_path = | |
dfeec247 | 1980 | self.std_path(span, &[sym::future, sym::Future], Some(future_params), false); |
8faf50e0 | 1981 | |
532ac7d7 XL |
1982 | hir::GenericBound::Trait( |
1983 | hir::PolyTraitRef { | |
dfeec247 XL |
1984 | trait_ref: hir::TraitRef { path: future_path, hir_ref_id: self.next_id() }, |
1985 | bound_generic_params: &[], | |
532ac7d7 XL |
1986 | span, |
1987 | }, | |
1988 | hir::TraitBoundModifier::None, | |
1989 | ) | |
b039eaaf | 1990 | } |
e9174d1e | 1991 | |
8faf50e0 | 1992 | fn lower_param_bound( |
0531ce1d | 1993 | &mut self, |
8faf50e0 | 1994 | tpb: &GenericBound, |
dfeec247 XL |
1995 | itctx: ImplTraitContext<'_, 'hir>, |
1996 | ) -> hir::GenericBound<'hir> { | |
8faf50e0 | 1997 | match *tpb { |
dfeec247 XL |
1998 | GenericBound::Trait(ref ty, modifier) => hir::GenericBound::Trait( |
1999 | self.lower_poly_trait_ref(ty, itctx), | |
2000 | self.lower_trait_bound_modifier(modifier), | |
2001 | ), | |
8faf50e0 XL |
2002 | GenericBound::Outlives(ref lifetime) => { |
2003 | hir::GenericBound::Outlives(self.lower_lifetime(lifetime)) | |
2004 | } | |
e9174d1e | 2005 | } |
e9174d1e | 2006 | } |
e9174d1e | 2007 | |
a7813a04 | 2008 | fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime { |
83c7162d | 2009 | let span = l.ident.span; |
8faf50e0 | 2010 | match l.ident { |
dfeec247 XL |
2011 | ident if ident.name == kw::StaticLifetime => { |
2012 | self.new_named_lifetime(l.id, span, hir::LifetimeName::Static) | |
2013 | } | |
2014 | ident if ident.name == kw::UnderscoreLifetime => match self.anonymous_lifetime_mode { | |
2015 | AnonymousLifetimeMode::CreateParameter => { | |
2016 | let fresh_name = self.collect_fresh_in_band_lifetime(span); | |
2017 | self.new_named_lifetime(l.id, span, hir::LifetimeName::Param(fresh_name)) | |
2018 | } | |
ff7c6d11 | 2019 | |
dfeec247 XL |
2020 | AnonymousLifetimeMode::PassThrough => { |
2021 | self.new_named_lifetime(l.id, span, hir::LifetimeName::Underscore) | |
2022 | } | |
0bf4aa26 | 2023 | |
dfeec247 XL |
2024 | AnonymousLifetimeMode::ReportError => self.new_error_lifetime(Some(l.id), span), |
2025 | }, | |
8faf50e0 XL |
2026 | ident => { |
2027 | self.maybe_collect_in_band_lifetime(ident); | |
2028 | let param_name = ParamName::Plain(ident); | |
2029 | self.new_named_lifetime(l.id, span, hir::LifetimeName::Param(param_name)) | |
ff7c6d11 | 2030 | } |
0531ce1d XL |
2031 | } |
2032 | } | |
ff7c6d11 | 2033 | |
0531ce1d XL |
2034 | fn new_named_lifetime( |
2035 | &mut self, | |
2036 | id: NodeId, | |
2037 | span: Span, | |
2038 | name: hir::LifetimeName, | |
2039 | ) -> hir::Lifetime { | |
dfeec247 XL |
2040 | hir::Lifetime { hir_id: self.lower_node_id(id), span, name } |
2041 | } | |
2042 | ||
2043 | fn lower_generic_params_mut<'s>( | |
2044 | &'s mut self, | |
2045 | params: &'s [GenericParam], | |
2046 | add_bounds: &'s NodeMap<Vec<GenericBound>>, | |
2047 | mut itctx: ImplTraitContext<'s, 'hir>, | |
2048 | ) -> impl Iterator<Item = hir::GenericParam<'hir>> + Captures<'a> + Captures<'s> { | |
2049 | params | |
2050 | .iter() | |
2051 | .map(move |param| self.lower_generic_param(param, add_bounds, itctx.reborrow())) | |
b039eaaf | 2052 | } |
e9174d1e | 2053 | |
8faf50e0 XL |
2054 | fn lower_generic_params( |
2055 | &mut self, | |
2056 | params: &[GenericParam], | |
2057 | add_bounds: &NodeMap<Vec<GenericBound>>, | |
dfeec247 XL |
2058 | itctx: ImplTraitContext<'_, 'hir>, |
2059 | ) -> &'hir [hir::GenericParam<'hir>] { | |
2060 | self.arena.alloc_from_iter(self.lower_generic_params_mut(params, add_bounds, itctx)) | |
2061 | } | |
2062 | ||
2063 | fn lower_generic_param( | |
2064 | &mut self, | |
2065 | param: &GenericParam, | |
2066 | add_bounds: &NodeMap<Vec<GenericBound>>, | |
2067 | mut itctx: ImplTraitContext<'_, 'hir>, | |
2068 | ) -> hir::GenericParam<'hir> { | |
2069 | let mut bounds: Vec<_> = self | |
2070 | .with_anonymous_lifetime_mode(AnonymousLifetimeMode::ReportError, |this| { | |
2071 | this.lower_param_bounds_mut(¶m.bounds, itctx.reborrow()).collect() | |
2072 | }); | |
0bf4aa26 | 2073 | |
9fa01778 | 2074 | let (name, kind) = match param.kind { |
8faf50e0 XL |
2075 | GenericParamKind::Lifetime => { |
2076 | let was_collecting_in_band = self.is_collecting_in_band_lifetimes; | |
2077 | self.is_collecting_in_band_lifetimes = false; | |
2078 | ||
dfeec247 XL |
2079 | let lt = self |
2080 | .with_anonymous_lifetime_mode(AnonymousLifetimeMode::ReportError, |this| { | |
2081 | this.lower_lifetime(&Lifetime { id: param.id, ident: param.ident }) | |
2082 | }); | |
8faf50e0 XL |
2083 | let param_name = match lt.name { |
2084 | hir::LifetimeName::Param(param_name) => param_name, | |
0bf4aa26 | 2085 | hir::LifetimeName::Implicit |
dfeec247 XL |
2086 | | hir::LifetimeName::Underscore |
2087 | | hir::LifetimeName::Static => hir::ParamName::Plain(lt.name.ident()), | |
e1599b0c | 2088 | hir::LifetimeName::ImplicitObjectLifetimeDefault => { |
ba9703b0 | 2089 | self.sess.diagnostic().span_bug( |
e1599b0c XL |
2090 | param.ident.span, |
2091 | "object-lifetime-default should not occur here", | |
2092 | ); | |
2093 | } | |
0bf4aa26 | 2094 | hir::LifetimeName::Error => ParamName::Error, |
8faf50e0 | 2095 | }; |
9fa01778 | 2096 | |
dfeec247 XL |
2097 | let kind = |
2098 | hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }; | |
ff7c6d11 | 2099 | |
8faf50e0 | 2100 | self.is_collecting_in_band_lifetimes = was_collecting_in_band; |
ff7c6d11 | 2101 | |
9fa01778 | 2102 | (param_name, kind) |
8faf50e0 XL |
2103 | } |
2104 | GenericParamKind::Type { ref default, .. } => { | |
8faf50e0 XL |
2105 | let add_bounds = add_bounds.get(¶m.id).map_or(&[][..], |x| &x); |
2106 | if !add_bounds.is_empty() { | |
dfeec247 XL |
2107 | let params = self.lower_param_bounds_mut(add_bounds, itctx.reborrow()); |
2108 | bounds.extend(params); | |
8faf50e0 | 2109 | } |
e9174d1e | 2110 | |
9fa01778 | 2111 | let kind = hir::GenericParamKind::Type { |
74b04a01 XL |
2112 | default: default.as_ref().map(|x| { |
2113 | self.lower_ty( | |
2114 | x, | |
2115 | ImplTraitContext::OpaqueTy(None, hir::OpaqueTyOrigin::Misc), | |
2116 | ) | |
2117 | }), | |
dfeec247 XL |
2118 | synthetic: param |
2119 | .attrs | |
2120 | .iter() | |
2121 | .filter(|attr| attr.check_name(sym::rustc_synthetic)) | |
2122 | .map(|_| hir::SyntheticTyParamKind::ImplTrait) | |
2123 | .next(), | |
9fa01778 XL |
2124 | }; |
2125 | ||
e1599b0c | 2126 | (hir::ParamName::Plain(param.ident), kind) |
8faf50e0 | 2127 | } |
9fa01778 | 2128 | GenericParamKind::Const { ref ty } => { |
dfeec247 XL |
2129 | let ty = self |
2130 | .with_anonymous_lifetime_mode(AnonymousLifetimeMode::ReportError, |this| { | |
2131 | this.lower_ty(&ty, ImplTraitContext::disallowed()) | |
2132 | }); | |
2133 | ||
2134 | (hir::ParamName::Plain(param.ident), hir::GenericParamKind::Const { ty }) | |
9fa01778 XL |
2135 | } |
2136 | }; | |
2137 | ||
9fa01778 | 2138 | hir::GenericParam { |
48663c56 | 2139 | hir_id: self.lower_node_id(param.id), |
9fa01778 XL |
2140 | name, |
2141 | span: param.ident.span, | |
48663c56 | 2142 | pure_wrt_drop: attr::contains_name(¶m.attrs, sym::may_dangle), |
9fa01778 | 2143 | attrs: self.lower_attrs(¶m.attrs), |
dfeec247 | 2144 | bounds: self.arena.alloc_from_iter(bounds), |
9fa01778 | 2145 | kind, |
8faf50e0 | 2146 | } |
e9174d1e | 2147 | } |
e9174d1e | 2148 | |
dfeec247 XL |
2149 | fn lower_trait_ref( |
2150 | &mut self, | |
2151 | p: &TraitRef, | |
2152 | itctx: ImplTraitContext<'_, 'hir>, | |
2153 | ) -> hir::TraitRef<'hir> { | |
abe05a73 | 2154 | let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) { |
416331ca | 2155 | hir::QPath::Resolved(None, path) => path, |
ba9703b0 | 2156 | qpath => panic!("lower_trait_ref: unexpected QPath `{:?}`", qpath), |
32a655c1 | 2157 | }; |
dfeec247 | 2158 | hir::TraitRef { path, hir_ref_id: self.lower_node_id(p.ref_id) } |
e9174d1e | 2159 | } |
e9174d1e | 2160 | |
0531ce1d XL |
2161 | fn lower_poly_trait_ref( |
2162 | &mut self, | |
2163 | p: &PolyTraitRef, | |
dfeec247 XL |
2164 | mut itctx: ImplTraitContext<'_, 'hir>, |
2165 | ) -> hir::PolyTraitRef<'hir> { | |
a1dfa0c6 XL |
2166 | let bound_generic_params = self.lower_generic_params( |
2167 | &p.bound_generic_params, | |
2168 | &NodeMap::default(), | |
2169 | itctx.reborrow(), | |
2170 | ); | |
dfeec247 XL |
2171 | let trait_ref = self.with_in_scope_lifetime_defs(&p.bound_generic_params, |this| { |
2172 | this.lower_trait_ref(&p.trait_ref, itctx) | |
2173 | }); | |
ff7c6d11 | 2174 | |
dfeec247 | 2175 | hir::PolyTraitRef { bound_generic_params, trait_ref, span: p.span } |
b039eaaf | 2176 | } |
e9174d1e | 2177 | |
dfeec247 XL |
2178 | fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext<'_, 'hir>) -> hir::MutTy<'hir> { |
2179 | hir::MutTy { ty: self.lower_ty(&mt.ty, itctx), mutbl: mt.mutbl } | |
2180 | } | |
2181 | ||
2182 | fn lower_param_bounds( | |
2183 | &mut self, | |
2184 | bounds: &[GenericBound], | |
2185 | itctx: ImplTraitContext<'_, 'hir>, | |
2186 | ) -> hir::GenericBounds<'hir> { | |
2187 | self.arena.alloc_from_iter(self.lower_param_bounds_mut(bounds, itctx)) | |
a7813a04 | 2188 | } |
e9174d1e | 2189 | |
dfeec247 XL |
2190 | fn lower_param_bounds_mut<'s>( |
2191 | &'s mut self, | |
2192 | bounds: &'s [GenericBound], | |
2193 | mut itctx: ImplTraitContext<'s, 'hir>, | |
2194 | ) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> { | |
2195 | bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx.reborrow())) | |
a7813a04 | 2196 | } |
e9174d1e | 2197 | |
dfeec247 XL |
2198 | fn lower_block(&mut self, b: &Block, targeted_by_break: bool) -> &'hir hir::Block<'hir> { |
2199 | self.arena.alloc(self.lower_block_noalloc(b, targeted_by_break)) | |
2200 | } | |
2201 | ||
2202 | fn lower_block_noalloc(&mut self, b: &Block, targeted_by_break: bool) -> hir::Block<'hir> { | |
e1599b0c | 2203 | let mut stmts = vec![]; |
dfeec247 | 2204 | let mut expr: Option<&'hir _> = None; |
3157f602 | 2205 | |
cc61c64b XL |
2206 | for (index, stmt) in b.stmts.iter().enumerate() { |
2207 | if index == b.stmts.len() - 1 { | |
e74abb32 | 2208 | if let StmtKind::Expr(ref e) = stmt.kind { |
dfeec247 | 2209 | expr = Some(self.lower_expr(e)); |
cc61c64b XL |
2210 | } else { |
2211 | stmts.extend(self.lower_stmt(stmt)); | |
2212 | } | |
3157f602 | 2213 | } else { |
cc61c64b | 2214 | stmts.extend(self.lower_stmt(stmt)); |
3157f602 XL |
2215 | } |
2216 | } | |
2217 | ||
dfeec247 | 2218 | hir::Block { |
48663c56 | 2219 | hir_id: self.lower_node_id(b.id), |
dfeec247 | 2220 | stmts: self.arena.alloc_from_iter(stmts), |
041b39d2 | 2221 | expr, |
a7813a04 XL |
2222 | rules: self.lower_block_check_mode(&b.rules), |
2223 | span: b.span, | |
041b39d2 | 2224 | targeted_by_break, |
dfeec247 | 2225 | } |
e9174d1e | 2226 | } |
e9174d1e | 2227 | |
e1599b0c XL |
2228 | /// Lowers a block directly to an expression, presuming that it |
2229 | /// has no attributes and is not targeted by a `break`. | |
dfeec247 | 2230 | fn lower_block_expr(&mut self, b: &Block) -> hir::Expr<'hir> { |
e1599b0c | 2231 | let block = self.lower_block(b, false); |
dfeec247 | 2232 | self.expr_block(block, AttrVec::new()) |
a7813a04 | 2233 | } |
b039eaaf | 2234 | |
416331ca | 2235 | fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst { |
dfeec247 XL |
2236 | self.with_new_scopes(|this| hir::AnonConst { |
2237 | hir_id: this.lower_node_id(c.id), | |
2238 | body: this.lower_const_body(c.value.span, Some(&c.value)), | |
416331ca XL |
2239 | }) |
2240 | } | |
2241 | ||
dfeec247 | 2242 | fn lower_stmt(&mut self, s: &Stmt) -> SmallVec<[hir::Stmt<'hir>; 1]> { |
e74abb32 | 2243 | let kind = match s.kind { |
0bf4aa26 XL |
2244 | StmtKind::Local(ref l) => { |
2245 | let (l, item_ids) = self.lower_local(l); | |
dfeec247 | 2246 | let mut ids: SmallVec<[hir::Stmt<'hir>; 1]> = item_ids |
0bf4aa26 | 2247 | .into_iter() |
9fa01778 | 2248 | .map(|item_id| { |
48663c56 XL |
2249 | let item_id = hir::ItemId { id: self.lower_node_id(item_id) }; |
2250 | self.stmt(s.span, hir::StmtKind::Item(item_id)) | |
0bf4aa26 XL |
2251 | }) |
2252 | .collect(); | |
9fa01778 | 2253 | ids.push({ |
9fa01778 | 2254 | hir::Stmt { |
48663c56 | 2255 | hir_id: self.lower_node_id(s.id), |
dfeec247 | 2256 | kind: hir::StmtKind::Local(self.arena.alloc(l)), |
9fa01778 XL |
2257 | span: s.span, |
2258 | } | |
0bf4aa26 XL |
2259 | }); |
2260 | return ids; | |
dfeec247 | 2261 | } |
476ff2be SL |
2262 | StmtKind::Item(ref it) => { |
2263 | // Can only use the ID once. | |
2264 | let mut id = Some(s.id); | |
dfeec247 XL |
2265 | return self |
2266 | .lower_item_id(it) | |
0531ce1d | 2267 | .into_iter() |
9fa01778 | 2268 | .map(|item_id| { |
dfeec247 XL |
2269 | let hir_id = id |
2270 | .take() | |
2271 | .map(|id| self.lower_node_id(id)) | |
2272 | .unwrap_or_else(|| self.next_id()); | |
2273 | ||
2274 | hir::Stmt { hir_id, kind: hir::StmtKind::Item(item_id), span: s.span } | |
0531ce1d XL |
2275 | }) |
2276 | .collect(); | |
92a42be0 | 2277 | } |
dfeec247 XL |
2278 | StmtKind::Expr(ref e) => hir::StmtKind::Expr(self.lower_expr(e)), |
2279 | StmtKind::Semi(ref e) => hir::StmtKind::Semi(self.lower_expr(e)), | |
74b04a01 | 2280 | StmtKind::Empty => return smallvec![], |
ba9703b0 | 2281 | StmtKind::MacCall(..) => panic!("shouldn't exist here"), |
8faf50e0 | 2282 | }; |
dfeec247 | 2283 | smallvec![hir::Stmt { hir_id: self.lower_node_id(s.id), kind, span: s.span }] |
e9174d1e | 2284 | } |
e9174d1e | 2285 | |
a7813a04 XL |
2286 | fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode { |
2287 | match *b { | |
dfeec247 XL |
2288 | BlockCheckMode::Default => hir::BlockCheckMode::DefaultBlock, |
2289 | BlockCheckMode::Unsafe(u) => { | |
2290 | hir::BlockCheckMode::UnsafeBlock(self.lower_unsafe_source(u)) | |
2291 | } | |
a7813a04 | 2292 | } |
e9174d1e | 2293 | } |
e9174d1e | 2294 | |
a7813a04 XL |
2295 | fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource { |
2296 | match u { | |
dfeec247 XL |
2297 | CompilerGenerated => hir::UnsafeSource::CompilerGenerated, |
2298 | UserProvided => hir::UnsafeSource::UserProvided, | |
a7813a04 | 2299 | } |
e9174d1e | 2300 | } |
e9174d1e | 2301 | |
a7813a04 XL |
2302 | fn lower_trait_bound_modifier(&mut self, f: TraitBoundModifier) -> hir::TraitBoundModifier { |
2303 | match f { | |
2304 | TraitBoundModifier::None => hir::TraitBoundModifier::None, | |
dfeec247 XL |
2305 | TraitBoundModifier::MaybeConst => hir::TraitBoundModifier::MaybeConst, |
2306 | ||
2307 | // `MaybeConstMaybe` will cause an error during AST validation, but we need to pick a | |
2308 | // placeholder for compilation to proceed. | |
2309 | TraitBoundModifier::MaybeConstMaybe | TraitBoundModifier::Maybe => { | |
2310 | hir::TraitBoundModifier::Maybe | |
2311 | } | |
a7813a04 | 2312 | } |
e9174d1e | 2313 | } |
e9174d1e | 2314 | |
a7813a04 | 2315 | // Helper methods for building HIR. |
b039eaaf | 2316 | |
dfeec247 | 2317 | fn stmt(&mut self, span: Span, kind: hir::StmtKind<'hir>) -> hir::Stmt<'hir> { |
e74abb32 | 2318 | hir::Stmt { span, kind, hir_id: self.next_id() } |
48663c56 XL |
2319 | } |
2320 | ||
dfeec247 XL |
2321 | fn stmt_expr(&mut self, span: Span, expr: hir::Expr<'hir>) -> hir::Stmt<'hir> { |
2322 | self.stmt(span, hir::StmtKind::Expr(self.arena.alloc(expr))) | |
416331ca XL |
2323 | } |
2324 | ||
0531ce1d XL |
2325 | fn stmt_let_pat( |
2326 | &mut self, | |
dfeec247 | 2327 | attrs: AttrVec, |
48663c56 | 2328 | span: Span, |
dfeec247 XL |
2329 | init: Option<&'hir hir::Expr<'hir>>, |
2330 | pat: &'hir hir::Pat<'hir>, | |
0531ce1d | 2331 | source: hir::LocalSource, |
dfeec247 XL |
2332 | ) -> hir::Stmt<'hir> { |
2333 | let local = hir::Local { attrs, hir_id: self.next_id(), init, pat, source, span, ty: None }; | |
2334 | self.stmt(span, hir::StmtKind::Local(self.arena.alloc(local))) | |
7cac9316 XL |
2335 | } |
2336 | ||
dfeec247 XL |
2337 | fn block_expr(&mut self, expr: &'hir hir::Expr<'hir>) -> &'hir hir::Block<'hir> { |
2338 | self.block_all(expr.span, &[], Some(expr)) | |
a7813a04 | 2339 | } |
b039eaaf | 2340 | |
0531ce1d XL |
2341 | fn block_all( |
2342 | &mut self, | |
2343 | span: Span, | |
dfeec247 XL |
2344 | stmts: &'hir [hir::Stmt<'hir>], |
2345 | expr: Option<&'hir hir::Expr<'hir>>, | |
2346 | ) -> &'hir hir::Block<'hir> { | |
2347 | let blk = hir::Block { | |
041b39d2 XL |
2348 | stmts, |
2349 | expr, | |
48663c56 | 2350 | hir_id: self.next_id(), |
dfeec247 | 2351 | rules: hir::BlockCheckMode::DefaultBlock, |
041b39d2 | 2352 | span, |
cc61c64b | 2353 | targeted_by_break: false, |
dfeec247 XL |
2354 | }; |
2355 | self.arena.alloc(blk) | |
a7813a04 | 2356 | } |
b039eaaf | 2357 | |
48663c56 | 2358 | /// Constructs a `true` or `false` literal pattern. |
dfeec247 | 2359 | fn pat_bool(&mut self, span: Span, val: bool) -> &'hir hir::Pat<'hir> { |
dc9dc135 | 2360 | let expr = self.expr_bool(span, val); |
dfeec247 | 2361 | self.pat(span, hir::PatKind::Lit(expr)) |
48663c56 XL |
2362 | } |
2363 | ||
dfeec247 XL |
2364 | fn pat_ok(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { |
2365 | self.pat_std_enum(span, &[sym::result, sym::Result, sym::Ok], arena_vec![self; pat]) | |
a7813a04 | 2366 | } |
b039eaaf | 2367 | |
dfeec247 XL |
2368 | fn pat_err(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { |
2369 | self.pat_std_enum(span, &[sym::result, sym::Result, sym::Err], arena_vec![self; pat]) | |
a7813a04 | 2370 | } |
b039eaaf | 2371 | |
dfeec247 XL |
2372 | fn pat_some(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> { |
2373 | self.pat_std_enum(span, &[sym::option, sym::Option, sym::Some], arena_vec![self; pat]) | |
a7813a04 | 2374 | } |
b039eaaf | 2375 | |
dfeec247 XL |
2376 | fn pat_none(&mut self, span: Span) -> &'hir hir::Pat<'hir> { |
2377 | self.pat_std_enum(span, &[sym::option, sym::Option, sym::None], &[]) | |
a7813a04 | 2378 | } |
b039eaaf | 2379 | |
0531ce1d XL |
2380 | fn pat_std_enum( |
2381 | &mut self, | |
2382 | span: Span, | |
48663c56 | 2383 | components: &[Symbol], |
dfeec247 XL |
2384 | subpats: &'hir [&'hir hir::Pat<'hir>], |
2385 | ) -> &'hir hir::Pat<'hir> { | |
8faf50e0 | 2386 | let path = self.std_path(span, components, None, true); |
dfeec247 | 2387 | let qpath = hir::QPath::Resolved(None, path); |
a7813a04 | 2388 | let pt = if subpats.is_empty() { |
476ff2be | 2389 | hir::PatKind::Path(qpath) |
a7813a04 | 2390 | } else { |
476ff2be | 2391 | hir::PatKind::TupleStruct(qpath, subpats, None) |
a7813a04 | 2392 | }; |
476ff2be | 2393 | self.pat(span, pt) |
e9174d1e | 2394 | } |
e9174d1e | 2395 | |
dfeec247 | 2396 | fn pat_ident(&mut self, span: Span, ident: Ident) -> (&'hir hir::Pat<'hir>, hir::HirId) { |
8faf50e0 | 2397 | self.pat_ident_binding_mode(span, ident, hir::BindingAnnotation::Unannotated) |
e9174d1e | 2398 | } |
e9174d1e | 2399 | |
0531ce1d XL |
2400 | fn pat_ident_binding_mode( |
2401 | &mut self, | |
2402 | span: Span, | |
8faf50e0 | 2403 | ident: Ident, |
0531ce1d | 2404 | bm: hir::BindingAnnotation, |
dfeec247 | 2405 | ) -> (&'hir hir::Pat<'hir>, hir::HirId) { |
48663c56 | 2406 | let hir_id = self.next_id(); |
b039eaaf | 2407 | |
532ac7d7 | 2408 | ( |
dfeec247 | 2409 | self.arena.alloc(hir::Pat { |
532ac7d7 | 2410 | hir_id, |
e74abb32 | 2411 | kind: hir::PatKind::Binding(bm, hir_id, ident.with_span_pos(span), None), |
532ac7d7 XL |
2412 | span, |
2413 | }), | |
dfeec247 | 2414 | hir_id, |
532ac7d7 | 2415 | ) |
a7813a04 | 2416 | } |
b039eaaf | 2417 | |
dfeec247 | 2418 | fn pat_wild(&mut self, span: Span) -> &'hir hir::Pat<'hir> { |
a7813a04 XL |
2419 | self.pat(span, hir::PatKind::Wild) |
2420 | } | |
b039eaaf | 2421 | |
dfeec247 XL |
2422 | fn pat(&mut self, span: Span, kind: hir::PatKind<'hir>) -> &'hir hir::Pat<'hir> { |
2423 | self.arena.alloc(hir::Pat { hir_id: self.next_id(), kind, span }) | |
b039eaaf SL |
2424 | } |
2425 | ||
dc9dc135 | 2426 | /// Given a suffix `["b", "c", "d"]`, returns path `::std::b::c::d` when |
476ff2be SL |
2427 | /// `fld.cx.use_std`, and `::core::b::c::d` otherwise. |
2428 | /// The path is also resolved according to `is_value`. | |
8faf50e0 XL |
2429 | fn std_path( |
2430 | &mut self, | |
2431 | span: Span, | |
48663c56 | 2432 | components: &[Symbol], |
dfeec247 | 2433 | params: Option<&'hir hir::GenericArgs<'hir>>, |
48663c56 | 2434 | is_value: bool, |
dfeec247 | 2435 | ) -> &'hir hir::Path<'hir> { |
416331ca XL |
2436 | let ns = if is_value { Namespace::ValueNS } else { Namespace::TypeNS }; |
2437 | let (path, res) = self.resolver.resolve_str_path(span, self.crate_root, components, ns); | |
13cf67c4 | 2438 | |
dfeec247 XL |
2439 | let mut segments: Vec<_> = path |
2440 | .segments | |
2441 | .iter() | |
2442 | .map(|segment| { | |
2443 | let res = self.expect_full_res(segment.id); | |
2444 | hir::PathSegment { | |
2445 | ident: segment.ident, | |
2446 | hir_id: Some(self.lower_node_id(segment.id)), | |
2447 | res: Some(self.lower_res(res)), | |
2448 | infer_args: true, | |
2449 | args: None, | |
2450 | } | |
2451 | }) | |
2452 | .collect(); | |
dc9dc135 XL |
2453 | segments.last_mut().unwrap().args = params; |
2454 | ||
dfeec247 | 2455 | self.arena.alloc(hir::Path { |
dc9dc135 | 2456 | span, |
e1599b0c | 2457 | res: res.map_id(|_| panic!("unexpected `NodeId`")), |
dfeec247 XL |
2458 | segments: self.arena.alloc_from_iter(segments), |
2459 | }) | |
a7813a04 XL |
2460 | } |
2461 | ||
dfeec247 XL |
2462 | fn ty_path( |
2463 | &mut self, | |
2464 | mut hir_id: hir::HirId, | |
2465 | span: Span, | |
2466 | qpath: hir::QPath<'hir>, | |
2467 | ) -> hir::Ty<'hir> { | |
e74abb32 | 2468 | let kind = match qpath { |
32a655c1 | 2469 | hir::QPath::Resolved(None, path) => { |
8faf50e0 | 2470 | // Turn trait object paths into `TyKind::TraitObject` instead. |
48663c56 | 2471 | match path.res { |
ba9703b0 | 2472 | Res::Def(DefKind::Trait | DefKind::TraitAlias, _) => { |
a1dfa0c6 | 2473 | let principal = hir::PolyTraitRef { |
dfeec247 XL |
2474 | bound_generic_params: &[], |
2475 | trait_ref: hir::TraitRef { path, hir_ref_id: hir_id }, | |
a1dfa0c6 XL |
2476 | span, |
2477 | }; | |
32a655c1 | 2478 | |
a1dfa0c6 XL |
2479 | // The original ID is taken by the `PolyTraitRef`, |
2480 | // so the `Ty` itself needs a different one. | |
48663c56 | 2481 | hir_id = self.next_id(); |
dfeec247 XL |
2482 | hir::TyKind::TraitObject( |
2483 | arena_vec![self; principal], | |
2484 | self.elided_dyn_bound(span), | |
2485 | ) | |
a1dfa0c6 XL |
2486 | } |
2487 | _ => hir::TyKind::Path(hir::QPath::Resolved(None, path)), | |
32a655c1 SL |
2488 | } |
2489 | } | |
8faf50e0 | 2490 | _ => hir::TyKind::Path(qpath), |
32a655c1 | 2491 | }; |
e74abb32 | 2492 | |
dfeec247 | 2493 | hir::Ty { hir_id, kind, span } |
0531ce1d XL |
2494 | } |
2495 | ||
2496 | /// Invoked to create the lifetime argument for a type `&T` | |
2497 | /// with no explicit lifetime. | |
2498 | fn elided_ref_lifetime(&mut self, span: Span) -> hir::Lifetime { | |
2499 | match self.anonymous_lifetime_mode { | |
532ac7d7 XL |
2500 | // Intercept when we are in an impl header or async fn and introduce an in-band |
2501 | // lifetime. | |
0531ce1d XL |
2502 | // Hence `impl Foo for &u32` becomes `impl<'f> Foo for &'f u32` for some fresh |
2503 | // `'f`. | |
2504 | AnonymousLifetimeMode::CreateParameter => { | |
2505 | let fresh_name = self.collect_fresh_in_band_lifetime(span); | |
2506 | hir::Lifetime { | |
48663c56 | 2507 | hir_id: self.next_id(), |
0531ce1d | 2508 | span, |
8faf50e0 | 2509 | name: hir::LifetimeName::Param(fresh_name), |
0531ce1d XL |
2510 | } |
2511 | } | |
2512 | ||
0bf4aa26 XL |
2513 | AnonymousLifetimeMode::ReportError => self.new_error_lifetime(None, span), |
2514 | ||
0531ce1d XL |
2515 | AnonymousLifetimeMode::PassThrough => self.new_implicit_lifetime(span), |
2516 | } | |
2517 | } | |
2518 | ||
0bf4aa26 XL |
2519 | /// Report an error on illegal use of `'_` or a `&T` with no explicit lifetime; |
2520 | /// return a "error lifetime". | |
2521 | fn new_error_lifetime(&mut self, id: Option<NodeId>, span: Span) -> hir::Lifetime { | |
2522 | let (id, msg, label) = match id { | |
2523 | Some(id) => (id, "`'_` cannot be used here", "`'_` is a reserved lifetime name"), | |
2524 | ||
2525 | None => ( | |
60c5eb7d | 2526 | self.resolver.next_node_id(), |
0bf4aa26 XL |
2527 | "`&` without an explicit lifetime name cannot be used here", |
2528 | "explicit lifetime name needed here", | |
2529 | ), | |
2530 | }; | |
2531 | ||
dfeec247 | 2532 | let mut err = struct_span_err!(self.sess, span, E0637, "{}", msg,); |
0bf4aa26 XL |
2533 | err.span_label(span, label); |
2534 | err.emit(); | |
2535 | ||
2536 | self.new_named_lifetime(id, span, hir::LifetimeName::Error) | |
2537 | } | |
2538 | ||
0531ce1d XL |
2539 | /// Invoked to create the lifetime argument(s) for a path like |
2540 | /// `std::cell::Ref<T>`; note that implicit lifetimes in these | |
2541 | /// sorts of cases are deprecated. This may therefore report a warning or an | |
2542 | /// error, depending on the mode. | |
dfeec247 XL |
2543 | fn elided_path_lifetimes<'s>( |
2544 | &'s mut self, | |
2545 | span: Span, | |
2546 | count: usize, | |
2547 | ) -> impl Iterator<Item = hir::Lifetime> + Captures<'a> + Captures<'s> + Captures<'hir> { | |
2548 | (0..count).map(move |_| self.elided_path_lifetime(span)) | |
532ac7d7 XL |
2549 | } |
2550 | ||
2551 | fn elided_path_lifetime(&mut self, span: Span) -> hir::Lifetime { | |
0531ce1d | 2552 | match self.anonymous_lifetime_mode { |
48663c56 XL |
2553 | AnonymousLifetimeMode::CreateParameter => { |
2554 | // We should have emitted E0726 when processing this path above | |
dfeec247 XL |
2555 | self.sess |
2556 | .delay_span_bug(span, "expected 'implicit elided lifetime not allowed' error"); | |
60c5eb7d | 2557 | let id = self.resolver.next_node_id(); |
48663c56 XL |
2558 | self.new_named_lifetime(id, span, hir::LifetimeName::Error) |
2559 | } | |
e74abb32 XL |
2560 | // `PassThrough` is the normal case. |
2561 | // `new_error_lifetime`, which would usually be used in the case of `ReportError`, | |
2562 | // is unsuitable here, as these can occur from missing lifetime parameters in a | |
2563 | // `PathSegment`, for which there is no associated `'_` or `&T` with no explicit | |
2564 | // lifetime. Instead, we simply create an implicit lifetime, which will be checked | |
2565 | // later, at which point a suitable error will be emitted. | |
dfeec247 XL |
2566 | AnonymousLifetimeMode::PassThrough | AnonymousLifetimeMode::ReportError => { |
2567 | self.new_implicit_lifetime(span) | |
2568 | } | |
0531ce1d | 2569 | } |
0531ce1d XL |
2570 | } |
2571 | ||
2572 | /// Invoked to create the lifetime argument(s) for an elided trait object | |
2573 | /// bound, like the bound in `Box<dyn Debug>`. This method is not invoked | |
2574 | /// when the bound is written, even if it is written with `'_` like in | |
2575 | /// `Box<dyn Debug + '_>`. In those cases, `lower_lifetime` is invoked. | |
2576 | fn elided_dyn_bound(&mut self, span: Span) -> hir::Lifetime { | |
2577 | match self.anonymous_lifetime_mode { | |
2578 | // NB. We intentionally ignore the create-parameter mode here. | |
2579 | // and instead "pass through" to resolve-lifetimes, which will apply | |
2580 | // the object-lifetime-defaulting rules. Elided object lifetime defaults | |
2581 | // do not act like other elided lifetimes. In other words, given this: | |
2582 | // | |
2583 | // impl Foo for Box<dyn Debug> | |
2584 | // | |
2585 | // we do not introduce a fresh `'_` to serve as the bound, but instead | |
2586 | // ultimately translate to the equivalent of: | |
2587 | // | |
2588 | // impl Foo for Box<dyn Debug + 'static> | |
2589 | // | |
2590 | // `resolve_lifetime` has the code to make that happen. | |
2591 | AnonymousLifetimeMode::CreateParameter => {} | |
2592 | ||
0bf4aa26 XL |
2593 | AnonymousLifetimeMode::ReportError => { |
2594 | // ReportError applies to explicit use of `'_`. | |
2595 | } | |
2596 | ||
0531ce1d XL |
2597 | // This is the normal case. |
2598 | AnonymousLifetimeMode::PassThrough => {} | |
2599 | } | |
2600 | ||
e1599b0c XL |
2601 | let r = hir::Lifetime { |
2602 | hir_id: self.next_id(), | |
2603 | span, | |
2604 | name: hir::LifetimeName::ImplicitObjectLifetimeDefault, | |
2605 | }; | |
2606 | debug!("elided_dyn_bound: r={:?}", r); | |
2607 | r | |
532ac7d7 XL |
2608 | } |
2609 | ||
0531ce1d | 2610 | fn new_implicit_lifetime(&mut self, span: Span) -> hir::Lifetime { |
dfeec247 | 2611 | hir::Lifetime { hir_id: self.next_id(), span, name: hir::LifetimeName::Implicit } |
9e0c209e | 2612 | } |
0531ce1d | 2613 | |
e74abb32 | 2614 | fn maybe_lint_bare_trait(&mut self, span: Span, id: NodeId, is_global: bool) { |
416331ca XL |
2615 | // FIXME(davidtwco): This is a hack to detect macros which produce spans of the |
2616 | // call site which do not have a macro backtrace. See #61963. | |
dfeec247 XL |
2617 | let is_macro_callsite = self |
2618 | .sess | |
2619 | .source_map() | |
416331ca XL |
2620 | .span_to_snippet(span) |
2621 | .map(|snippet| snippet.starts_with("#[")) | |
2622 | .unwrap_or(true); | |
2623 | if !is_macro_callsite { | |
e74abb32 | 2624 | self.resolver.lint_buffer().buffer_lint_with_diagnostic( |
74b04a01 | 2625 | BARE_TRAIT_OBJECTS, |
416331ca | 2626 | id, |
48663c56 | 2627 | span, |
416331ca | 2628 | "trait objects without an explicit `dyn` are deprecated", |
dfeec247 | 2629 | BuiltinLintDiagnostics::BareTraitObject(span, is_global), |
416331ca XL |
2630 | ) |
2631 | } | |
48663c56 | 2632 | } |
e9174d1e | 2633 | } |
8bb4bdeb | 2634 | |
dfeec247 | 2635 | fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body<'_>>) -> Vec<hir::BodyId> { |
8bb4bdeb XL |
2636 | // Sorting by span ensures that we get things in order within a |
2637 | // file, and also puts the files in a sensible order. | |
2638 | let mut body_ids: Vec<_> = bodies.keys().cloned().collect(); | |
2639 | body_ids.sort_by_key(|b| bodies[b].value.span); | |
2640 | body_ids | |
2641 | } | |
48663c56 | 2642 | |
dfeec247 XL |
2643 | /// Helper struct for delayed construction of GenericArgs. |
2644 | struct GenericArgsCtor<'hir> { | |
2645 | args: SmallVec<[hir::GenericArg<'hir>; 4]>, | |
2646 | bindings: &'hir [hir::TypeBinding<'hir>], | |
2647 | parenthesized: bool, | |
2648 | } | |
48663c56 | 2649 | |
dfeec247 XL |
2650 | impl<'hir> GenericArgsCtor<'hir> { |
2651 | fn is_empty(&self) -> bool { | |
2652 | self.args.is_empty() && self.bindings.is_empty() && !self.parenthesized | |
2653 | } | |
48663c56 | 2654 | |
dfeec247 XL |
2655 | fn into_generic_args(self, arena: &'hir Arena<'hir>) -> hir::GenericArgs<'hir> { |
2656 | hir::GenericArgs { | |
2657 | args: arena.alloc_from_iter(self.args), | |
2658 | bindings: self.bindings, | |
2659 | parenthesized: self.parenthesized, | |
48663c56 | 2660 | } |
48663c56 | 2661 | } |
48663c56 | 2662 | } |