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1b1a35ee XL |
1 | /*! |
2 | ||
3 | # typeck: check phase | |
4 | ||
5 | Within the check phase of type check, we check each item one at a time | |
6 | (bodies of function expressions are checked as part of the containing | |
7 | function). Inference is used to supply types wherever they are unknown. | |
8 | ||
9 | By far the most complex case is checking the body of a function. This | |
10 | can be broken down into several distinct phases: | |
11 | ||
12 | - gather: creates type variables to represent the type of each local | |
13 | variable and pattern binding. | |
14 | ||
15 | - main: the main pass does the lion's share of the work: it | |
16 | determines the types of all expressions, resolves | |
17 | methods, checks for most invalid conditions, and so forth. In | |
18 | some cases, where a type is unknown, it may create a type or region | |
19 | variable and use that as the type of an expression. | |
20 | ||
21 | In the process of checking, various constraints will be placed on | |
22 | these type variables through the subtyping relationships requested | |
23 | through the `demand` module. The `infer` module is in charge | |
24 | of resolving those constraints. | |
25 | ||
26 | - regionck: after main is complete, the regionck pass goes over all | |
27 | types looking for regions and making sure that they did not escape | |
28 | into places they are not in scope. This may also influence the | |
29 | final assignments of the various region variables if there is some | |
30 | flexibility. | |
31 | ||
32 | - writeback: writes the final types within a function body, replacing | |
33 | type variables with their final inferred types. These final types | |
34 | are written into the `tcx.node_types` table, which should *never* contain | |
35 | any reference to a type variable. | |
36 | ||
37 | ## Intermediate types | |
38 | ||
39 | While type checking a function, the intermediate types for the | |
40 | expressions, blocks, and so forth contained within the function are | |
41 | stored in `fcx.node_types` and `fcx.node_substs`. These types | |
42 | may contain unresolved type variables. After type checking is | |
43 | complete, the functions in the writeback module are used to take the | |
44 | types from this table, resolve them, and then write them into their | |
45 | permanent home in the type context `tcx`. | |
46 | ||
47 | This means that during inferencing you should use `fcx.write_ty()` | |
48 | and `fcx.expr_ty()` / `fcx.node_ty()` to write/obtain the types of | |
49 | nodes within the function. | |
50 | ||
51 | The types of top-level items, which never contain unbound type | |
52 | variables, are stored directly into the `tcx` typeck_results. | |
53 | ||
54 | N.B., a type variable is not the same thing as a type parameter. A | |
5869c6ff XL |
55 | type variable is an instance of a type parameter. That is, |
56 | given a generic function `fn foo<T>(t: T)`, while checking the | |
1b1a35ee | 57 | function `foo`, the type `ty_param(0)` refers to the type `T`, which |
5869c6ff | 58 | is treated in abstract. However, when `foo()` is called, `T` will be |
1b1a35ee XL |
59 | substituted for a fresh type variable `N`. This variable will |
60 | eventually be resolved to some concrete type (which might itself be | |
5869c6ff | 61 | a type parameter). |
1b1a35ee XL |
62 | |
63 | */ | |
64 | ||
65 | pub mod _match; | |
66 | mod autoderef; | |
67 | mod callee; | |
68 | pub mod cast; | |
69 | mod check; | |
70 | mod closure; | |
71 | pub mod coercion; | |
72 | mod compare_method; | |
73 | pub mod demand; | |
74 | mod diverges; | |
75 | pub mod dropck; | |
76 | mod expectation; | |
77 | mod expr; | |
78 | mod fn_ctxt; | |
79 | mod gather_locals; | |
80 | mod generator_interior; | |
81 | mod inherited; | |
82 | pub mod intrinsic; | |
83 | pub mod method; | |
84 | mod op; | |
85 | mod pat; | |
86 | mod place_op; | |
87 | mod regionck; | |
88 | mod upvar; | |
89 | mod wfcheck; | |
90 | pub mod writeback; | |
91 | ||
92 | use check::{ | |
93 | check_abi, check_fn, check_impl_item_well_formed, check_item_well_formed, check_mod_item_types, | |
94 | check_trait_item_well_formed, | |
95 | }; | |
96 | pub use check::{check_item_type, check_wf_new}; | |
97 | pub use diverges::Diverges; | |
98 | pub use expectation::Expectation; | |
29967ef6 | 99 | pub use fn_ctxt::*; |
1b1a35ee XL |
100 | pub use inherited::{Inherited, InheritedBuilder}; |
101 | ||
102 | use crate::astconv::AstConv; | |
103 | use crate::check::gather_locals::GatherLocalsVisitor; | |
104 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; | |
105 | use rustc_errors::{pluralize, struct_span_err, Applicability}; | |
106 | use rustc_hir as hir; | |
107 | use rustc_hir::def::Res; | |
17df50a5 | 108 | use rustc_hir::def_id::{DefId, LocalDefId}; |
1b1a35ee XL |
109 | use rustc_hir::intravisit::Visitor; |
110 | use rustc_hir::itemlikevisit::ItemLikeVisitor; | |
fc512014 | 111 | use rustc_hir::{HirIdMap, ImplicitSelfKind, Node}; |
1b1a35ee XL |
112 | use rustc_index::bit_set::BitSet; |
113 | use rustc_index::vec::Idx; | |
29967ef6 | 114 | use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; |
1b1a35ee XL |
115 | use rustc_middle::ty::fold::{TypeFoldable, TypeFolder}; |
116 | use rustc_middle::ty::query::Providers; | |
117 | use rustc_middle::ty::subst::GenericArgKind; | |
118 | use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef}; | |
1b1a35ee XL |
119 | use rustc_middle::ty::{self, RegionKind, Ty, TyCtxt, UserType}; |
120 | use rustc_session::config; | |
121 | use rustc_session::parse::feature_err; | |
122 | use rustc_session::Session; | |
1b1a35ee XL |
123 | use rustc_span::symbol::{kw, Ident}; |
124 | use rustc_span::{self, BytePos, MultiSpan, Span}; | |
6a06907d | 125 | use rustc_span::{source_map::DUMMY_SP, sym}; |
1b1a35ee XL |
126 | use rustc_target::abi::VariantIdx; |
127 | use rustc_target::spec::abi::Abi; | |
128 | use rustc_trait_selection::traits; | |
129 | use rustc_trait_selection::traits::error_reporting::recursive_type_with_infinite_size_error; | |
130 | use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor; | |
131 | ||
132 | use std::cell::{Ref, RefCell, RefMut}; | |
133 | ||
134 | use crate::require_c_abi_if_c_variadic; | |
135 | use crate::util::common::indenter; | |
136 | ||
137 | use self::coercion::DynamicCoerceMany; | |
138 | pub use self::Expectation::*; | |
139 | ||
140 | #[macro_export] | |
141 | macro_rules! type_error_struct { | |
142 | ($session:expr, $span:expr, $typ:expr, $code:ident, $($message:tt)*) => ({ | |
143 | if $typ.references_error() { | |
144 | $session.diagnostic().struct_dummy() | |
145 | } else { | |
146 | rustc_errors::struct_span_err!($session, $span, $code, $($message)*) | |
147 | } | |
148 | }) | |
149 | } | |
150 | ||
151 | /// The type of a local binding, including the revealed type for anon types. | |
152 | #[derive(Copy, Clone, Debug)] | |
153 | pub struct LocalTy<'tcx> { | |
154 | decl_ty: Ty<'tcx>, | |
155 | revealed_ty: Ty<'tcx>, | |
156 | } | |
157 | ||
158 | #[derive(Copy, Clone, Debug, PartialEq, Eq)] | |
159 | pub enum Needs { | |
160 | MutPlace, | |
161 | None, | |
162 | } | |
163 | ||
164 | impl Needs { | |
165 | fn maybe_mut_place(m: hir::Mutability) -> Self { | |
166 | match m { | |
167 | hir::Mutability::Mut => Needs::MutPlace, | |
168 | hir::Mutability::Not => Needs::None, | |
169 | } | |
170 | } | |
171 | } | |
172 | ||
173 | #[derive(Copy, Clone)] | |
174 | pub struct UnsafetyState { | |
175 | pub def: hir::HirId, | |
176 | pub unsafety: hir::Unsafety, | |
177 | pub unsafe_push_count: u32, | |
178 | from_fn: bool, | |
179 | } | |
180 | ||
181 | impl UnsafetyState { | |
182 | pub fn function(unsafety: hir::Unsafety, def: hir::HirId) -> UnsafetyState { | |
183 | UnsafetyState { def, unsafety, unsafe_push_count: 0, from_fn: true } | |
184 | } | |
185 | ||
5869c6ff | 186 | pub fn recurse(self, blk: &hir::Block<'_>) -> UnsafetyState { |
1b1a35ee XL |
187 | use hir::BlockCheckMode; |
188 | match self.unsafety { | |
189 | // If this unsafe, then if the outer function was already marked as | |
190 | // unsafe we shouldn't attribute the unsafe'ness to the block. This | |
191 | // way the block can be warned about instead of ignoring this | |
192 | // extraneous block (functions are never warned about). | |
5869c6ff | 193 | hir::Unsafety::Unsafe if self.from_fn => self, |
1b1a35ee XL |
194 | |
195 | unsafety => { | |
196 | let (unsafety, def, count) = match blk.rules { | |
197 | BlockCheckMode::PushUnsafeBlock(..) => { | |
198 | (unsafety, blk.hir_id, self.unsafe_push_count.checked_add(1).unwrap()) | |
199 | } | |
200 | BlockCheckMode::PopUnsafeBlock(..) => { | |
201 | (unsafety, blk.hir_id, self.unsafe_push_count.checked_sub(1).unwrap()) | |
202 | } | |
203 | BlockCheckMode::UnsafeBlock(..) => { | |
204 | (hir::Unsafety::Unsafe, blk.hir_id, self.unsafe_push_count) | |
205 | } | |
206 | BlockCheckMode::DefaultBlock => (unsafety, self.def, self.unsafe_push_count), | |
207 | }; | |
208 | UnsafetyState { def, unsafety, unsafe_push_count: count, from_fn: false } | |
209 | } | |
210 | } | |
211 | } | |
212 | } | |
213 | ||
214 | #[derive(Debug, Copy, Clone)] | |
215 | pub enum PlaceOp { | |
216 | Deref, | |
217 | Index, | |
218 | } | |
219 | ||
220 | pub struct BreakableCtxt<'tcx> { | |
221 | may_break: bool, | |
222 | ||
223 | // this is `null` for loops where break with a value is illegal, | |
224 | // such as `while`, `for`, and `while let` | |
225 | coerce: Option<DynamicCoerceMany<'tcx>>, | |
226 | } | |
227 | ||
228 | pub struct EnclosingBreakables<'tcx> { | |
229 | stack: Vec<BreakableCtxt<'tcx>>, | |
230 | by_id: HirIdMap<usize>, | |
231 | } | |
232 | ||
233 | impl<'tcx> EnclosingBreakables<'tcx> { | |
234 | fn find_breakable(&mut self, target_id: hir::HirId) -> &mut BreakableCtxt<'tcx> { | |
235 | self.opt_find_breakable(target_id).unwrap_or_else(|| { | |
236 | bug!("could not find enclosing breakable with id {}", target_id); | |
237 | }) | |
238 | } | |
239 | ||
240 | fn opt_find_breakable(&mut self, target_id: hir::HirId) -> Option<&mut BreakableCtxt<'tcx>> { | |
241 | match self.by_id.get(&target_id) { | |
242 | Some(ix) => Some(&mut self.stack[*ix]), | |
243 | None => None, | |
244 | } | |
245 | } | |
246 | } | |
247 | ||
248 | pub fn provide(providers: &mut Providers) { | |
249 | method::provide(providers); | |
250 | *providers = Providers { | |
251 | typeck_item_bodies, | |
252 | typeck_const_arg, | |
253 | typeck, | |
254 | diagnostic_only_typeck, | |
255 | has_typeck_results, | |
256 | adt_destructor, | |
257 | used_trait_imports, | |
258 | check_item_well_formed, | |
259 | check_trait_item_well_formed, | |
260 | check_impl_item_well_formed, | |
261 | check_mod_item_types, | |
262 | ..*providers | |
263 | }; | |
264 | } | |
265 | ||
266 | fn adt_destructor(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::Destructor> { | |
29967ef6 | 267 | tcx.calculate_dtor(def_id, dropck::check_drop_impl) |
1b1a35ee XL |
268 | } |
269 | ||
270 | /// If this `DefId` is a "primary tables entry", returns | |
271 | /// `Some((body_id, header, decl))` with information about | |
fc512014 | 272 | /// its body-id, fn-header and fn-decl (if any). Otherwise, |
1b1a35ee XL |
273 | /// returns `None`. |
274 | /// | |
275 | /// If this function returns `Some`, then `typeck_results(def_id)` will | |
276 | /// succeed; if it returns `None`, then `typeck_results(def_id)` may or | |
277 | /// may not succeed. In some cases where this function returns `None` | |
278 | /// (notably closures), `typeck_results(def_id)` would wind up | |
279 | /// redirecting to the owning function. | |
280 | fn primary_body_of( | |
281 | tcx: TyCtxt<'_>, | |
282 | id: hir::HirId, | |
283 | ) -> Option<(hir::BodyId, Option<&hir::Ty<'_>>, Option<&hir::FnHeader>, Option<&hir::FnDecl<'_>>)> { | |
284 | match tcx.hir().get(id) { | |
285 | Node::Item(item) => match item.kind { | |
286 | hir::ItemKind::Const(ref ty, body) | hir::ItemKind::Static(ref ty, _, body) => { | |
287 | Some((body, Some(ty), None, None)) | |
288 | } | |
289 | hir::ItemKind::Fn(ref sig, .., body) => { | |
290 | Some((body, None, Some(&sig.header), Some(&sig.decl))) | |
291 | } | |
292 | _ => None, | |
293 | }, | |
294 | Node::TraitItem(item) => match item.kind { | |
295 | hir::TraitItemKind::Const(ref ty, Some(body)) => Some((body, Some(ty), None, None)), | |
296 | hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => { | |
297 | Some((body, None, Some(&sig.header), Some(&sig.decl))) | |
298 | } | |
299 | _ => None, | |
300 | }, | |
301 | Node::ImplItem(item) => match item.kind { | |
302 | hir::ImplItemKind::Const(ref ty, body) => Some((body, Some(ty), None, None)), | |
303 | hir::ImplItemKind::Fn(ref sig, body) => { | |
304 | Some((body, None, Some(&sig.header), Some(&sig.decl))) | |
305 | } | |
306 | _ => None, | |
307 | }, | |
308 | Node::AnonConst(constant) => Some((constant.body, None, None, None)), | |
309 | _ => None, | |
310 | } | |
311 | } | |
312 | ||
313 | fn has_typeck_results(tcx: TyCtxt<'_>, def_id: DefId) -> bool { | |
314 | // Closures' typeck results come from their outermost function, | |
315 | // as they are part of the same "inference environment". | |
316 | let outer_def_id = tcx.closure_base_def_id(def_id); | |
317 | if outer_def_id != def_id { | |
318 | return tcx.has_typeck_results(outer_def_id); | |
319 | } | |
320 | ||
321 | if let Some(def_id) = def_id.as_local() { | |
322 | let id = tcx.hir().local_def_id_to_hir_id(def_id); | |
323 | primary_body_of(tcx, id).is_some() | |
324 | } else { | |
325 | false | |
326 | } | |
327 | } | |
328 | ||
329 | fn used_trait_imports(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &FxHashSet<LocalDefId> { | |
330 | &*tcx.typeck(def_id).used_trait_imports | |
331 | } | |
332 | ||
333 | /// Inspects the substs of opaque types, replacing any inference variables | |
334 | /// with proper generic parameter from the identity substs. | |
335 | /// | |
336 | /// This is run after we normalize the function signature, to fix any inference | |
337 | /// variables introduced by the projection of associated types. This ensures that | |
338 | /// any opaque types used in the signature continue to refer to generic parameters, | |
339 | /// allowing them to be considered for defining uses in the function body | |
340 | /// | |
341 | /// For example, consider this code. | |
342 | /// | |
343 | /// ```rust | |
344 | /// trait MyTrait { | |
345 | /// type MyItem; | |
346 | /// fn use_it(self) -> Self::MyItem | |
347 | /// } | |
348 | /// impl<T, I> MyTrait for T where T: Iterator<Item = I> { | |
349 | /// type MyItem = impl Iterator<Item = I>; | |
350 | /// fn use_it(self) -> Self::MyItem { | |
351 | /// self | |
352 | /// } | |
353 | /// } | |
354 | /// ``` | |
355 | /// | |
356 | /// When we normalize the signature of `use_it` from the impl block, | |
357 | /// we will normalize `Self::MyItem` to the opaque type `impl Iterator<Item = I>` | |
358 | /// However, this projection result may contain inference variables, due | |
359 | /// to the way that projection works. We didn't have any inference variables | |
360 | /// in the signature to begin with - leaving them in will cause us to incorrectly | |
361 | /// conclude that we don't have a defining use of `MyItem`. By mapping inference | |
362 | /// variables back to the actual generic parameters, we will correctly see that | |
363 | /// we have a defining use of `MyItem` | |
fc512014 | 364 | fn fixup_opaque_types<'tcx, T>(tcx: TyCtxt<'tcx>, val: T) -> T |
1b1a35ee XL |
365 | where |
366 | T: TypeFoldable<'tcx>, | |
367 | { | |
368 | struct FixupFolder<'tcx> { | |
369 | tcx: TyCtxt<'tcx>, | |
370 | } | |
371 | ||
372 | impl<'tcx> TypeFolder<'tcx> for FixupFolder<'tcx> { | |
373 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { | |
374 | self.tcx | |
375 | } | |
376 | ||
377 | fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
378 | match *ty.kind() { | |
379 | ty::Opaque(def_id, substs) => { | |
380 | debug!("fixup_opaque_types: found type {:?}", ty); | |
381 | // Here, we replace any inference variables that occur within | |
382 | // the substs of an opaque type. By definition, any type occurring | |
383 | // in the substs has a corresponding generic parameter, which is what | |
384 | // we replace it with. | |
385 | // This replacement is only run on the function signature, so any | |
386 | // inference variables that we come across must be the rust of projection | |
387 | // (there's no other way for a user to get inference variables into | |
388 | // a function signature). | |
389 | if ty.needs_infer() { | |
390 | let new_substs = InternalSubsts::for_item(self.tcx, def_id, |param, _| { | |
391 | let old_param = substs[param.index as usize]; | |
392 | match old_param.unpack() { | |
393 | GenericArgKind::Type(old_ty) => { | |
394 | if let ty::Infer(_) = old_ty.kind() { | |
395 | // Replace inference type with a generic parameter | |
396 | self.tcx.mk_param_from_def(param) | |
397 | } else { | |
398 | old_param.fold_with(self) | |
399 | } | |
400 | } | |
401 | GenericArgKind::Const(old_const) => { | |
402 | if let ty::ConstKind::Infer(_) = old_const.val { | |
403 | // This should never happen - we currently do not support | |
404 | // 'const projections', e.g.: | |
405 | // `impl<T: SomeTrait> MyTrait for T where <T as SomeTrait>::MyConst == 25` | |
406 | // which should be the only way for us to end up with a const inference | |
407 | // variable after projection. If Rust ever gains support for this kind | |
408 | // of projection, this should *probably* be changed to | |
409 | // `self.tcx.mk_param_from_def(param)` | |
410 | bug!( | |
411 | "Found infer const: `{:?}` in opaque type: {:?}", | |
412 | old_const, | |
413 | ty | |
414 | ); | |
415 | } else { | |
416 | old_param.fold_with(self) | |
417 | } | |
418 | } | |
419 | GenericArgKind::Lifetime(old_region) => { | |
420 | if let RegionKind::ReVar(_) = old_region { | |
421 | self.tcx.mk_param_from_def(param) | |
422 | } else { | |
423 | old_param.fold_with(self) | |
424 | } | |
425 | } | |
426 | } | |
427 | }); | |
428 | let new_ty = self.tcx.mk_opaque(def_id, new_substs); | |
429 | debug!("fixup_opaque_types: new type: {:?}", new_ty); | |
430 | new_ty | |
431 | } else { | |
432 | ty | |
433 | } | |
434 | } | |
435 | _ => ty.super_fold_with(self), | |
436 | } | |
437 | } | |
438 | } | |
439 | ||
440 | debug!("fixup_opaque_types({:?})", val); | |
441 | val.fold_with(&mut FixupFolder { tcx }) | |
442 | } | |
443 | ||
444 | fn typeck_const_arg<'tcx>( | |
445 | tcx: TyCtxt<'tcx>, | |
446 | (did, param_did): (LocalDefId, DefId), | |
447 | ) -> &ty::TypeckResults<'tcx> { | |
448 | let fallback = move || tcx.type_of(param_did); | |
449 | typeck_with_fallback(tcx, did, fallback) | |
450 | } | |
451 | ||
452 | fn typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::TypeckResults<'tcx> { | |
453 | if let Some(param_did) = tcx.opt_const_param_of(def_id) { | |
454 | tcx.typeck_const_arg((def_id, param_did)) | |
455 | } else { | |
456 | let fallback = move || tcx.type_of(def_id.to_def_id()); | |
457 | typeck_with_fallback(tcx, def_id, fallback) | |
458 | } | |
459 | } | |
460 | ||
461 | /// Used only to get `TypeckResults` for type inference during error recovery. | |
462 | /// Currently only used for type inference of `static`s and `const`s to avoid type cycle errors. | |
463 | fn diagnostic_only_typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::TypeckResults<'tcx> { | |
464 | let fallback = move || { | |
465 | let span = tcx.hir().span(tcx.hir().local_def_id_to_hir_id(def_id)); | |
466 | tcx.ty_error_with_message(span, "diagnostic only typeck table used") | |
467 | }; | |
468 | typeck_with_fallback(tcx, def_id, fallback) | |
469 | } | |
470 | ||
471 | fn typeck_with_fallback<'tcx>( | |
472 | tcx: TyCtxt<'tcx>, | |
473 | def_id: LocalDefId, | |
474 | fallback: impl Fn() -> Ty<'tcx> + 'tcx, | |
475 | ) -> &'tcx ty::TypeckResults<'tcx> { | |
476 | // Closures' typeck results come from their outermost function, | |
477 | // as they are part of the same "inference environment". | |
478 | let outer_def_id = tcx.closure_base_def_id(def_id.to_def_id()).expect_local(); | |
479 | if outer_def_id != def_id { | |
480 | return tcx.typeck(outer_def_id); | |
481 | } | |
482 | ||
483 | let id = tcx.hir().local_def_id_to_hir_id(def_id); | |
484 | let span = tcx.hir().span(id); | |
485 | ||
486 | // Figure out what primary body this item has. | |
487 | let (body_id, body_ty, fn_header, fn_decl) = primary_body_of(tcx, id).unwrap_or_else(|| { | |
488 | span_bug!(span, "can't type-check body of {:?}", def_id); | |
489 | }); | |
490 | let body = tcx.hir().body(body_id); | |
491 | ||
492 | let typeck_results = Inherited::build(tcx, def_id).enter(|inh| { | |
493 | let param_env = tcx.param_env(def_id); | |
494 | let fcx = if let (Some(header), Some(decl)) = (fn_header, fn_decl) { | |
495 | let fn_sig = if crate::collect::get_infer_ret_ty(&decl.output).is_some() { | |
496 | let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id); | |
6a06907d | 497 | <dyn AstConv<'_>>::ty_of_fn( |
1b1a35ee | 498 | &fcx, |
cdc7bbd5 | 499 | id, |
1b1a35ee XL |
500 | header.unsafety, |
501 | header.abi, | |
502 | decl, | |
503 | &hir::Generics::empty(), | |
504 | None, | |
6a06907d | 505 | None, |
1b1a35ee XL |
506 | ) |
507 | } else { | |
508 | tcx.fn_sig(def_id) | |
509 | }; | |
510 | ||
511 | check_abi(tcx, span, fn_sig.abi()); | |
512 | ||
513 | // Compute the fty from point of view of inside the fn. | |
fc512014 | 514 | let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig); |
1b1a35ee XL |
515 | let fn_sig = inh.normalize_associated_types_in( |
516 | body.value.span, | |
517 | body_id.hir_id, | |
518 | param_env, | |
fc512014 | 519 | fn_sig, |
1b1a35ee XL |
520 | ); |
521 | ||
fc512014 | 522 | let fn_sig = fixup_opaque_types(tcx, fn_sig); |
1b1a35ee XL |
523 | |
524 | let fcx = check_fn(&inh, param_env, fn_sig, decl, id, body, None).0; | |
525 | fcx | |
526 | } else { | |
527 | let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id); | |
528 | let expected_type = body_ty | |
529 | .and_then(|ty| match ty.kind { | |
6a06907d | 530 | hir::TyKind::Infer => Some(<dyn AstConv<'_>>::ast_ty_to_ty(&fcx, ty)), |
1b1a35ee XL |
531 | _ => None, |
532 | }) | |
29967ef6 XL |
533 | .unwrap_or_else(|| match tcx.hir().get(id) { |
534 | Node::AnonConst(_) => match tcx.hir().get(tcx.hir().get_parent_node(id)) { | |
535 | Node::Expr(&hir::Expr { | |
536 | kind: hir::ExprKind::ConstBlock(ref anon_const), | |
537 | .. | |
538 | }) if anon_const.hir_id == id => fcx.next_ty_var(TypeVariableOrigin { | |
539 | kind: TypeVariableOriginKind::TypeInference, | |
540 | span, | |
541 | }), | |
cdc7bbd5 XL |
542 | Node::Ty(&hir::Ty { |
543 | kind: hir::TyKind::Typeof(ref anon_const), .. | |
544 | }) if anon_const.hir_id == id => fcx.next_ty_var(TypeVariableOrigin { | |
545 | kind: TypeVariableOriginKind::TypeInference, | |
546 | span, | |
547 | }), | |
17df50a5 XL |
548 | Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(asm), .. }) |
549 | | Node::Item(&hir::Item { kind: hir::ItemKind::GlobalAsm(asm), .. }) | |
550 | if asm.operands.iter().any(|(op, _op_sp)| match op { | |
cdc7bbd5 XL |
551 | hir::InlineAsmOperand::Const { anon_const } => { |
552 | anon_const.hir_id == id | |
553 | } | |
554 | _ => false, | |
555 | }) => | |
556 | { | |
17df50a5 XL |
557 | // Inline assembly constants must be integers. |
558 | fcx.next_int_var() | |
cdc7bbd5 | 559 | } |
29967ef6 XL |
560 | _ => fallback(), |
561 | }, | |
562 | _ => fallback(), | |
563 | }); | |
564 | ||
fc512014 | 565 | let expected_type = fcx.normalize_associated_types_in(body.value.span, expected_type); |
1b1a35ee XL |
566 | fcx.require_type_is_sized(expected_type, body.value.span, traits::ConstSized); |
567 | ||
6a06907d XL |
568 | let revealed_ty = fcx.instantiate_opaque_types_from_value( |
569 | id, | |
570 | expected_type, | |
571 | body.value.span, | |
572 | Some(sym::impl_trait_in_bindings), | |
573 | ); | |
1b1a35ee XL |
574 | |
575 | // Gather locals in statics (because of block expressions). | |
576 | GatherLocalsVisitor::new(&fcx, id).visit_body(body); | |
577 | ||
578 | fcx.check_expr_coercable_to_type(&body.value, revealed_ty, None); | |
579 | ||
580 | fcx.write_ty(id, revealed_ty); | |
581 | ||
582 | fcx | |
583 | }; | |
584 | ||
585 | // All type checking constraints were added, try to fallback unsolved variables. | |
586 | fcx.select_obligations_where_possible(false, |_| {}); | |
587 | let mut fallback_has_occurred = false; | |
588 | ||
589 | // We do fallback in two passes, to try to generate | |
590 | // better error messages. | |
591 | // The first time, we do *not* replace opaque types. | |
592 | for ty in &fcx.unsolved_variables() { | |
593 | fallback_has_occurred |= fcx.fallback_if_possible(ty, FallbackMode::NoOpaque); | |
594 | } | |
595 | // We now see if we can make progress. This might | |
596 | // cause us to unify inference variables for opaque types, | |
597 | // since we may have unified some other type variables | |
598 | // during the first phase of fallback. | |
599 | // This means that we only replace inference variables with their underlying | |
600 | // opaque types as a last resort. | |
601 | // | |
602 | // In code like this: | |
603 | // | |
604 | // ```rust | |
605 | // type MyType = impl Copy; | |
606 | // fn produce() -> MyType { true } | |
607 | // fn bad_produce() -> MyType { panic!() } | |
608 | // ``` | |
609 | // | |
610 | // we want to unify the opaque inference variable in `bad_produce` | |
611 | // with the diverging fallback for `panic!` (e.g. `()` or `!`). | |
612 | // This will produce a nice error message about conflicting concrete | |
613 | // types for `MyType`. | |
614 | // | |
615 | // If we had tried to fallback the opaque inference variable to `MyType`, | |
616 | // we will generate a confusing type-check error that does not explicitly | |
617 | // refer to opaque types. | |
618 | fcx.select_obligations_where_possible(fallback_has_occurred, |_| {}); | |
619 | ||
620 | // We now run fallback again, but this time we allow it to replace | |
621 | // unconstrained opaque type variables, in addition to performing | |
622 | // other kinds of fallback. | |
623 | for ty in &fcx.unsolved_variables() { | |
624 | fallback_has_occurred |= fcx.fallback_if_possible(ty, FallbackMode::All); | |
625 | } | |
626 | ||
627 | // See if we can make any more progress. | |
628 | fcx.select_obligations_where_possible(fallback_has_occurred, |_| {}); | |
629 | ||
630 | // Even though coercion casts provide type hints, we check casts after fallback for | |
631 | // backwards compatibility. This makes fallback a stronger type hint than a cast coercion. | |
632 | fcx.check_casts(); | |
633 | ||
634 | // Closure and generator analysis may run after fallback | |
635 | // because they don't constrain other type variables. | |
636 | fcx.closure_analyze(body); | |
637 | assert!(fcx.deferred_call_resolutions.borrow().is_empty()); | |
638 | fcx.resolve_generator_interiors(def_id.to_def_id()); | |
639 | ||
640 | for (ty, span, code) in fcx.deferred_sized_obligations.borrow_mut().drain(..) { | |
641 | let ty = fcx.normalize_ty(span, ty); | |
642 | fcx.require_type_is_sized(ty, span, code); | |
643 | } | |
644 | ||
645 | fcx.select_all_obligations_or_error(); | |
646 | ||
647 | if fn_decl.is_some() { | |
648 | fcx.regionck_fn(id, body); | |
649 | } else { | |
650 | fcx.regionck_expr(body); | |
651 | } | |
652 | ||
653 | fcx.resolve_type_vars_in_body(body) | |
654 | }); | |
655 | ||
656 | // Consistency check our TypeckResults instance can hold all ItemLocalIds | |
657 | // it will need to hold. | |
658 | assert_eq!(typeck_results.hir_owner, id.owner); | |
659 | ||
660 | typeck_results | |
661 | } | |
662 | ||
663 | /// When `check_fn` is invoked on a generator (i.e., a body that | |
664 | /// includes yield), it returns back some information about the yield | |
665 | /// points. | |
666 | struct GeneratorTypes<'tcx> { | |
667 | /// Type of generator argument / values returned by `yield`. | |
668 | resume_ty: Ty<'tcx>, | |
669 | ||
670 | /// Type of value that is yielded. | |
671 | yield_ty: Ty<'tcx>, | |
672 | ||
673 | /// Types that are captured (see `GeneratorInterior` for more). | |
674 | interior: Ty<'tcx>, | |
675 | ||
676 | /// Indicates if the generator is movable or static (immovable). | |
677 | movability: hir::Movability, | |
678 | } | |
679 | ||
680 | /// Given a `DefId` for an opaque type in return position, find its parent item's return | |
681 | /// expressions. | |
682 | fn get_owner_return_paths( | |
683 | tcx: TyCtxt<'tcx>, | |
684 | def_id: LocalDefId, | |
685 | ) -> Option<(hir::HirId, ReturnsVisitor<'tcx>)> { | |
686 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); | |
687 | let id = tcx.hir().get_parent_item(hir_id); | |
688 | tcx.hir() | |
689 | .find(id) | |
690 | .map(|n| (id, n)) | |
691 | .and_then(|(hir_id, node)| node.body_id().map(|b| (hir_id, b))) | |
692 | .map(|(hir_id, body_id)| { | |
693 | let body = tcx.hir().body(body_id); | |
694 | let mut visitor = ReturnsVisitor::default(); | |
695 | visitor.visit_body(body); | |
696 | (hir_id, visitor) | |
697 | }) | |
698 | } | |
699 | ||
700 | /// Emit an error for recursive opaque types in a `let` binding. | |
701 | fn binding_opaque_type_cycle_error( | |
702 | tcx: TyCtxt<'tcx>, | |
703 | def_id: LocalDefId, | |
704 | span: Span, | |
705 | partially_expanded_type: Ty<'tcx>, | |
706 | ) { | |
707 | let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type"); | |
708 | err.span_label(span, "cannot resolve opaque type"); | |
709 | // Find the owner that declared this `impl Trait` type. | |
710 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); | |
711 | let mut prev_hir_id = hir_id; | |
712 | let mut hir_id = tcx.hir().get_parent_node(hir_id); | |
713 | while let Some(node) = tcx.hir().find(hir_id) { | |
714 | match node { | |
715 | hir::Node::Local(hir::Local { | |
716 | pat, | |
717 | init: None, | |
718 | ty: Some(ty), | |
719 | source: hir::LocalSource::Normal, | |
720 | .. | |
721 | }) => { | |
722 | err.span_label(pat.span, "this binding might not have a concrete type"); | |
723 | err.span_suggestion_verbose( | |
724 | ty.span.shrink_to_hi(), | |
725 | "set the binding to a value for a concrete type to be resolved", | |
726 | " = /* value */".to_string(), | |
727 | Applicability::HasPlaceholders, | |
728 | ); | |
729 | } | |
730 | hir::Node::Local(hir::Local { | |
731 | init: Some(expr), | |
732 | source: hir::LocalSource::Normal, | |
733 | .. | |
734 | }) => { | |
735 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); | |
736 | let typeck_results = | |
737 | tcx.typeck(tcx.hir().local_def_id(tcx.hir().get_parent_item(hir_id))); | |
738 | if let Some(ty) = typeck_results.node_type_opt(expr.hir_id) { | |
739 | err.span_label( | |
740 | expr.span, | |
741 | &format!( | |
742 | "this is of type `{}`, which doesn't constrain \ | |
743 | `{}` enough to arrive to a concrete type", | |
744 | ty, partially_expanded_type | |
745 | ), | |
746 | ); | |
747 | } | |
748 | } | |
749 | _ => {} | |
750 | } | |
751 | if prev_hir_id == hir_id { | |
752 | break; | |
753 | } | |
754 | prev_hir_id = hir_id; | |
755 | hir_id = tcx.hir().get_parent_node(hir_id); | |
756 | } | |
757 | err.emit(); | |
758 | } | |
759 | ||
760 | // Forbid defining intrinsics in Rust code, | |
761 | // as they must always be defined by the compiler. | |
762 | fn fn_maybe_err(tcx: TyCtxt<'_>, sp: Span, abi: Abi) { | |
763 | if let Abi::RustIntrinsic | Abi::PlatformIntrinsic = abi { | |
764 | tcx.sess.span_err(sp, "intrinsic must be in `extern \"rust-intrinsic\" { ... }` block"); | |
765 | } | |
766 | } | |
767 | ||
768 | fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId, span: Span) { | |
769 | // Only restricted on wasm32 target for now | |
770 | if !tcx.sess.opts.target_triple.triple().starts_with("wasm32") { | |
771 | return; | |
772 | } | |
773 | ||
774 | // If `#[link_section]` is missing, then nothing to verify | |
775 | let attrs = tcx.codegen_fn_attrs(id); | |
776 | if attrs.link_section.is_none() { | |
777 | return; | |
778 | } | |
779 | ||
780 | // For the wasm32 target statics with `#[link_section]` are placed into custom | |
781 | // sections of the final output file, but this isn't link custom sections of | |
782 | // other executable formats. Namely we can only embed a list of bytes, | |
783 | // nothing with pointers to anything else or relocations. If any relocation | |
784 | // show up, reject them here. | |
785 | // `#[link_section]` may contain arbitrary, or even undefined bytes, but it is | |
786 | // the consumer's responsibility to ensure all bytes that have been read | |
787 | // have defined values. | |
788 | match tcx.eval_static_initializer(id.to_def_id()) { | |
789 | Ok(alloc) => { | |
790 | if alloc.relocations().len() != 0 { | |
791 | let msg = "statics with a custom `#[link_section]` must be a \ | |
792 | simple list of bytes on the wasm target with no \ | |
793 | extra levels of indirection such as references"; | |
794 | tcx.sess.span_err(span, msg); | |
795 | } | |
796 | } | |
797 | Err(_) => {} | |
798 | } | |
799 | } | |
800 | ||
801 | fn report_forbidden_specialization( | |
802 | tcx: TyCtxt<'_>, | |
803 | impl_item: &hir::ImplItem<'_>, | |
804 | parent_impl: DefId, | |
805 | ) { | |
806 | let mut err = struct_span_err!( | |
807 | tcx.sess, | |
808 | impl_item.span, | |
809 | E0520, | |
810 | "`{}` specializes an item from a parent `impl`, but \ | |
811 | that item is not marked `default`", | |
812 | impl_item.ident | |
813 | ); | |
814 | err.span_label(impl_item.span, format!("cannot specialize default item `{}`", impl_item.ident)); | |
815 | ||
816 | match tcx.span_of_impl(parent_impl) { | |
817 | Ok(span) => { | |
818 | err.span_label(span, "parent `impl` is here"); | |
819 | err.note(&format!( | |
820 | "to specialize, `{}` in the parent `impl` must be marked `default`", | |
821 | impl_item.ident | |
822 | )); | |
823 | } | |
824 | Err(cname) => { | |
825 | err.note(&format!("parent implementation is in crate `{}`", cname)); | |
826 | } | |
827 | } | |
828 | ||
829 | err.emit(); | |
830 | } | |
831 | ||
832 | fn missing_items_err( | |
833 | tcx: TyCtxt<'_>, | |
834 | impl_span: Span, | |
835 | missing_items: &[ty::AssocItem], | |
836 | full_impl_span: Span, | |
837 | ) { | |
838 | let missing_items_msg = missing_items | |
839 | .iter() | |
840 | .map(|trait_item| trait_item.ident.to_string()) | |
841 | .collect::<Vec<_>>() | |
842 | .join("`, `"); | |
843 | ||
844 | let mut err = struct_span_err!( | |
845 | tcx.sess, | |
846 | impl_span, | |
847 | E0046, | |
848 | "not all trait items implemented, missing: `{}`", | |
849 | missing_items_msg | |
850 | ); | |
851 | err.span_label(impl_span, format!("missing `{}` in implementation", missing_items_msg)); | |
852 | ||
853 | // `Span` before impl block closing brace. | |
854 | let hi = full_impl_span.hi() - BytePos(1); | |
855 | // Point at the place right before the closing brace of the relevant `impl` to suggest | |
856 | // adding the associated item at the end of its body. | |
857 | let sugg_sp = full_impl_span.with_lo(hi).with_hi(hi); | |
858 | // Obtain the level of indentation ending in `sugg_sp`. | |
859 | let indentation = tcx.sess.source_map().span_to_margin(sugg_sp).unwrap_or(0); | |
860 | // Make the whitespace that will make the suggestion have the right indentation. | |
6a06907d | 861 | let padding: String = std::iter::repeat(" ").take(indentation).collect(); |
1b1a35ee XL |
862 | |
863 | for trait_item in missing_items { | |
864 | let snippet = suggestion_signature(&trait_item, tcx); | |
865 | let code = format!("{}{}\n{}", padding, snippet, padding); | |
866 | let msg = format!("implement the missing item: `{}`", snippet); | |
867 | let appl = Applicability::HasPlaceholders; | |
868 | if let Some(span) = tcx.hir().span_if_local(trait_item.def_id) { | |
869 | err.span_label(span, format!("`{}` from trait", trait_item.ident)); | |
870 | err.tool_only_span_suggestion(sugg_sp, &msg, code, appl); | |
871 | } else { | |
872 | err.span_suggestion_hidden(sugg_sp, &msg, code, appl); | |
873 | } | |
874 | } | |
875 | err.emit(); | |
876 | } | |
877 | ||
878 | /// Resugar `ty::GenericPredicates` in a way suitable to be used in structured suggestions. | |
879 | fn bounds_from_generic_predicates<'tcx>( | |
880 | tcx: TyCtxt<'tcx>, | |
881 | predicates: ty::GenericPredicates<'tcx>, | |
882 | ) -> (String, String) { | |
883 | let mut types: FxHashMap<Ty<'tcx>, Vec<DefId>> = FxHashMap::default(); | |
884 | let mut projections = vec![]; | |
885 | for (predicate, _) in predicates.predicates { | |
886 | debug!("predicate {:?}", predicate); | |
5869c6ff | 887 | let bound_predicate = predicate.kind(); |
29967ef6 | 888 | match bound_predicate.skip_binder() { |
5869c6ff | 889 | ty::PredicateKind::Trait(trait_predicate, _) => { |
1b1a35ee XL |
890 | let entry = types.entry(trait_predicate.self_ty()).or_default(); |
891 | let def_id = trait_predicate.def_id(); | |
892 | if Some(def_id) != tcx.lang_items().sized_trait() { | |
893 | // Type params are `Sized` by default, do not add that restriction to the list | |
894 | // if it is a positive requirement. | |
895 | entry.push(trait_predicate.def_id()); | |
896 | } | |
897 | } | |
5869c6ff | 898 | ty::PredicateKind::Projection(projection_pred) => { |
29967ef6 | 899 | projections.push(bound_predicate.rebind(projection_pred)); |
1b1a35ee XL |
900 | } |
901 | _ => {} | |
902 | } | |
903 | } | |
904 | let generics = if types.is_empty() { | |
905 | "".to_string() | |
906 | } else { | |
907 | format!( | |
908 | "<{}>", | |
909 | types | |
910 | .keys() | |
911 | .filter_map(|t| match t.kind() { | |
912 | ty::Param(_) => Some(t.to_string()), | |
913 | // Avoid suggesting the following: | |
914 | // fn foo<T, <T as Trait>::Bar>(_: T) where T: Trait, <T as Trait>::Bar: Other {} | |
915 | _ => None, | |
916 | }) | |
917 | .collect::<Vec<_>>() | |
918 | .join(", ") | |
919 | ) | |
920 | }; | |
921 | let mut where_clauses = vec![]; | |
922 | for (ty, bounds) in types { | |
923 | for bound in &bounds { | |
924 | where_clauses.push(format!("{}: {}", ty, tcx.def_path_str(*bound))); | |
925 | } | |
926 | } | |
927 | for projection in &projections { | |
928 | let p = projection.skip_binder(); | |
929 | // FIXME: this is not currently supported syntax, we should be looking at the `types` and | |
930 | // insert the associated types where they correspond, but for now let's be "lazy" and | |
931 | // propose this instead of the following valid resugaring: | |
932 | // `T: Trait, Trait::Assoc = K` → `T: Trait<Assoc = K>` | |
933 | where_clauses.push(format!("{} = {}", tcx.def_path_str(p.projection_ty.item_def_id), p.ty)); | |
934 | } | |
935 | let where_clauses = if where_clauses.is_empty() { | |
936 | String::new() | |
937 | } else { | |
938 | format!(" where {}", where_clauses.join(", ")) | |
939 | }; | |
940 | (generics, where_clauses) | |
941 | } | |
942 | ||
943 | /// Return placeholder code for the given function. | |
944 | fn fn_sig_suggestion<'tcx>( | |
945 | tcx: TyCtxt<'tcx>, | |
946 | sig: ty::FnSig<'tcx>, | |
947 | ident: Ident, | |
948 | predicates: ty::GenericPredicates<'tcx>, | |
949 | assoc: &ty::AssocItem, | |
950 | ) -> String { | |
951 | let args = sig | |
952 | .inputs() | |
953 | .iter() | |
954 | .enumerate() | |
955 | .map(|(i, ty)| { | |
956 | Some(match ty.kind() { | |
957 | ty::Param(_) if assoc.fn_has_self_parameter && i == 0 => "self".to_string(), | |
958 | ty::Ref(reg, ref_ty, mutability) if i == 0 => { | |
959 | let reg = match &format!("{}", reg)[..] { | |
960 | "'_" | "" => String::new(), | |
961 | reg => format!("{} ", reg), | |
962 | }; | |
963 | if assoc.fn_has_self_parameter { | |
964 | match ref_ty.kind() { | |
965 | ty::Param(param) if param.name == kw::SelfUpper => { | |
966 | format!("&{}{}self", reg, mutability.prefix_str()) | |
967 | } | |
968 | ||
969 | _ => format!("self: {}", ty), | |
970 | } | |
971 | } else { | |
972 | format!("_: {}", ty) | |
973 | } | |
974 | } | |
975 | _ => { | |
976 | if assoc.fn_has_self_parameter && i == 0 { | |
977 | format!("self: {}", ty) | |
978 | } else { | |
979 | format!("_: {}", ty) | |
980 | } | |
981 | } | |
982 | }) | |
983 | }) | |
984 | .chain(std::iter::once(if sig.c_variadic { Some("...".to_string()) } else { None })) | |
985 | .filter_map(|arg| arg) | |
986 | .collect::<Vec<String>>() | |
987 | .join(", "); | |
988 | let output = sig.output(); | |
989 | let output = if !output.is_unit() { format!(" -> {}", output) } else { String::new() }; | |
990 | ||
991 | let unsafety = sig.unsafety.prefix_str(); | |
992 | let (generics, where_clauses) = bounds_from_generic_predicates(tcx, predicates); | |
993 | ||
994 | // FIXME: this is not entirely correct, as the lifetimes from borrowed params will | |
995 | // not be present in the `fn` definition, not will we account for renamed | |
996 | // lifetimes between the `impl` and the `trait`, but this should be good enough to | |
997 | // fill in a significant portion of the missing code, and other subsequent | |
998 | // suggestions can help the user fix the code. | |
999 | format!( | |
1000 | "{}fn {}{}({}){}{} {{ todo!() }}", | |
1001 | unsafety, ident, generics, args, output, where_clauses | |
1002 | ) | |
1003 | } | |
1004 | ||
1005 | /// Return placeholder code for the given associated item. | |
1006 | /// Similar to `ty::AssocItem::suggestion`, but appropriate for use as the code snippet of a | |
1007 | /// structured suggestion. | |
1008 | fn suggestion_signature(assoc: &ty::AssocItem, tcx: TyCtxt<'_>) -> String { | |
1009 | match assoc.kind { | |
1010 | ty::AssocKind::Fn => { | |
1011 | // We skip the binder here because the binder would deanonymize all | |
1012 | // late-bound regions, and we don't want method signatures to show up | |
1013 | // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound | |
1014 | // regions just fine, showing `fn(&MyType)`. | |
1015 | fn_sig_suggestion( | |
1016 | tcx, | |
1017 | tcx.fn_sig(assoc.def_id).skip_binder(), | |
1018 | assoc.ident, | |
1019 | tcx.predicates_of(assoc.def_id), | |
1020 | assoc, | |
1021 | ) | |
1022 | } | |
1023 | ty::AssocKind::Type => format!("type {} = Type;", assoc.ident), | |
1024 | ty::AssocKind::Const => { | |
1025 | let ty = tcx.type_of(assoc.def_id); | |
1026 | let val = expr::ty_kind_suggestion(ty).unwrap_or("value"); | |
1027 | format!("const {}: {} = {};", assoc.ident, ty, val) | |
1028 | } | |
1029 | } | |
1030 | } | |
1031 | ||
1032 | /// Emit an error when encountering more or less than one variant in a transparent enum. | |
1033 | fn bad_variant_count<'tcx>(tcx: TyCtxt<'tcx>, adt: &'tcx ty::AdtDef, sp: Span, did: DefId) { | |
1034 | let variant_spans: Vec<_> = adt | |
1035 | .variants | |
1036 | .iter() | |
1037 | .map(|variant| tcx.hir().span_if_local(variant.def_id).unwrap()) | |
1038 | .collect(); | |
1039 | let msg = format!("needs exactly one variant, but has {}", adt.variants.len(),); | |
1040 | let mut err = struct_span_err!(tcx.sess, sp, E0731, "transparent enum {}", msg); | |
1041 | err.span_label(sp, &msg); | |
1042 | if let [start @ .., end] = &*variant_spans { | |
1043 | for variant_span in start { | |
1044 | err.span_label(*variant_span, ""); | |
1045 | } | |
1046 | err.span_label(*end, &format!("too many variants in `{}`", tcx.def_path_str(did))); | |
1047 | } | |
1048 | err.emit(); | |
1049 | } | |
1050 | ||
1051 | /// Emit an error when encountering more or less than one non-zero-sized field in a transparent | |
1052 | /// enum. | |
1053 | fn bad_non_zero_sized_fields<'tcx>( | |
1054 | tcx: TyCtxt<'tcx>, | |
1055 | adt: &'tcx ty::AdtDef, | |
1056 | field_count: usize, | |
1057 | field_spans: impl Iterator<Item = Span>, | |
1058 | sp: Span, | |
1059 | ) { | |
1060 | let msg = format!("needs exactly one non-zero-sized field, but has {}", field_count); | |
1061 | let mut err = struct_span_err!( | |
1062 | tcx.sess, | |
1063 | sp, | |
1064 | E0690, | |
1065 | "{}transparent {} {}", | |
1066 | if adt.is_enum() { "the variant of a " } else { "" }, | |
1067 | adt.descr(), | |
1068 | msg, | |
1069 | ); | |
1070 | err.span_label(sp, &msg); | |
1071 | for sp in field_spans { | |
1072 | err.span_label(sp, "this field is non-zero-sized"); | |
1073 | } | |
1074 | err.emit(); | |
1075 | } | |
1076 | ||
1077 | fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span) { | |
1078 | struct_span_err!( | |
1079 | tcx.sess, | |
1080 | span, | |
1081 | E0533, | |
1082 | "expected unit struct, unit variant or constant, found {}{}", | |
1083 | res.descr(), | |
6a06907d XL |
1084 | tcx.sess |
1085 | .source_map() | |
1086 | .span_to_snippet(span) | |
1087 | .map_or_else(|_| String::new(), |s| format!(" `{}`", s)), | |
1b1a35ee XL |
1088 | ) |
1089 | .emit(); | |
1090 | } | |
1091 | ||
1092 | /// Controls whether the arguments are tupled. This is used for the call | |
1093 | /// operator. | |
1094 | /// | |
1095 | /// Tupling means that all call-side arguments are packed into a tuple and | |
1096 | /// passed as a single parameter. For example, if tupling is enabled, this | |
1097 | /// function: | |
1098 | /// | |
1099 | /// fn f(x: (isize, isize)) | |
1100 | /// | |
1101 | /// Can be called as: | |
1102 | /// | |
1103 | /// f(1, 2); | |
1104 | /// | |
1105 | /// Instead of: | |
1106 | /// | |
1107 | /// f((1, 2)); | |
1108 | #[derive(Clone, Eq, PartialEq)] | |
1109 | enum TupleArgumentsFlag { | |
1110 | DontTupleArguments, | |
1111 | TupleArguments, | |
1112 | } | |
1113 | ||
1114 | /// Controls how we perform fallback for unconstrained | |
1115 | /// type variables. | |
1116 | enum FallbackMode { | |
1117 | /// Do not fallback type variables to opaque types. | |
1118 | NoOpaque, | |
1119 | /// Perform all possible kinds of fallback, including | |
1120 | /// turning type variables to opaque types. | |
1121 | All, | |
1122 | } | |
1123 | ||
1124 | /// A wrapper for `InferCtxt`'s `in_progress_typeck_results` field. | |
1125 | #[derive(Copy, Clone)] | |
1126 | struct MaybeInProgressTables<'a, 'tcx> { | |
1127 | maybe_typeck_results: Option<&'a RefCell<ty::TypeckResults<'tcx>>>, | |
1128 | } | |
1129 | ||
1130 | impl<'a, 'tcx> MaybeInProgressTables<'a, 'tcx> { | |
1131 | fn borrow(self) -> Ref<'a, ty::TypeckResults<'tcx>> { | |
1132 | match self.maybe_typeck_results { | |
1133 | Some(typeck_results) => typeck_results.borrow(), | |
1134 | None => bug!( | |
1135 | "MaybeInProgressTables: inh/fcx.typeck_results.borrow() with no typeck results" | |
1136 | ), | |
1137 | } | |
1138 | } | |
1139 | ||
1140 | fn borrow_mut(self) -> RefMut<'a, ty::TypeckResults<'tcx>> { | |
1141 | match self.maybe_typeck_results { | |
1142 | Some(typeck_results) => typeck_results.borrow_mut(), | |
1143 | None => bug!( | |
1144 | "MaybeInProgressTables: inh/fcx.typeck_results.borrow_mut() with no typeck results" | |
1145 | ), | |
1146 | } | |
1147 | } | |
1148 | } | |
1149 | ||
1150 | struct CheckItemTypesVisitor<'tcx> { | |
1151 | tcx: TyCtxt<'tcx>, | |
1152 | } | |
1153 | ||
1154 | impl ItemLikeVisitor<'tcx> for CheckItemTypesVisitor<'tcx> { | |
1155 | fn visit_item(&mut self, i: &'tcx hir::Item<'tcx>) { | |
1156 | check_item_type(self.tcx, i); | |
1157 | } | |
1158 | fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem<'tcx>) {} | |
1159 | fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem<'tcx>) {} | |
fc512014 | 1160 | fn visit_foreign_item(&mut self, _: &'tcx hir::ForeignItem<'tcx>) {} |
1b1a35ee XL |
1161 | } |
1162 | ||
17df50a5 | 1163 | fn typeck_item_bodies(tcx: TyCtxt<'_>, (): ()) { |
1b1a35ee XL |
1164 | tcx.par_body_owners(|body_owner_def_id| { |
1165 | tcx.ensure().typeck(body_owner_def_id); | |
1166 | }); | |
1167 | } | |
1168 | ||
1169 | fn fatally_break_rust(sess: &Session) { | |
1170 | let handler = sess.diagnostic(); | |
1171 | handler.span_bug_no_panic( | |
1172 | MultiSpan::new(), | |
1173 | "It looks like you're trying to break rust; would you like some ICE?", | |
1174 | ); | |
1175 | handler.note_without_error("the compiler expectedly panicked. this is a feature."); | |
1176 | handler.note_without_error( | |
1177 | "we would appreciate a joke overview: \ | |
1178 | https://github.com/rust-lang/rust/issues/43162#issuecomment-320764675", | |
1179 | ); | |
1180 | handler.note_without_error(&format!( | |
1181 | "rustc {} running on {}", | |
1182 | option_env!("CFG_VERSION").unwrap_or("unknown_version"), | |
1183 | config::host_triple(), | |
1184 | )); | |
1185 | } | |
1186 | ||
1187 | fn potentially_plural_count(count: usize, word: &str) -> String { | |
1188 | format!("{} {}{}", count, word, pluralize!(count)) | |
1189 | } | |
17df50a5 XL |
1190 | |
1191 | fn has_expected_num_generic_args<'tcx>( | |
1192 | tcx: TyCtxt<'tcx>, | |
1193 | trait_did: Option<DefId>, | |
1194 | expected: usize, | |
1195 | ) -> bool { | |
1196 | trait_did.map_or(true, |trait_did| { | |
1197 | let generics = tcx.generics_of(trait_did); | |
1198 | generics.count() == expected + if generics.has_self { 1 } else { 0 } | |
1199 | }) | |
1200 | } |