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Commit | Line | Data |
---|---|---|
ba9703b0 | 1 | use rustc_data_structures::fx::FxHashSet; |
1b1a35ee | 2 | use rustc_errors::{Applicability, ErrorReported, StashKey}; |
74b04a01 XL |
3 | use rustc_hir as hir; |
4 | use rustc_hir::def::{DefKind, Res}; | |
f9f354fc | 5 | use rustc_hir::def_id::{DefId, LocalDefId}; |
74b04a01 XL |
6 | use rustc_hir::intravisit; |
7 | use rustc_hir::intravisit::Visitor; | |
5869c6ff | 8 | use rustc_hir::{HirId, Node}; |
ba9703b0 XL |
9 | use rustc_middle::hir::map::Map; |
10 | use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts}; | |
11 | use rustc_middle::ty::util::IntTypeExt; | |
12 | use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt, TypeFoldable}; | |
f035d41b | 13 | use rustc_span::symbol::Ident; |
74b04a01 XL |
14 | use rustc_span::{Span, DUMMY_SP}; |
15 | ||
16 | use super::ItemCtxt; | |
17 | use super::{bad_placeholder_type, is_suggestable_infer_ty}; | |
18 | ||
3dfed10e XL |
19 | /// Computes the relevant generic parameter for a potential generic const argument. |
20 | /// | |
21 | /// This should be called using the query `tcx.opt_const_param_of`. | |
22 | pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<DefId> { | |
23 | use hir::*; | |
3dfed10e XL |
24 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
25 | ||
26 | if let Node::AnonConst(_) = tcx.hir().get(hir_id) { | |
27 | let parent_node_id = tcx.hir().get_parent_node(hir_id); | |
28 | let parent_node = tcx.hir().get(parent_node_id); | |
29 | ||
30 | match parent_node { | |
6a06907d XL |
31 | // This match arm is for when the def_id appears in a GAT whose |
32 | // path can't be resolved without typechecking e.g. | |
33 | // | |
34 | // trait Foo { | |
35 | // type Assoc<const N: usize>; | |
36 | // fn foo() -> Self::Assoc<3>; | |
37 | // } | |
38 | // | |
39 | // In the above code we would call this query with the def_id of 3 and | |
40 | // the parent_node we match on would be the hir node for Self::Assoc<3> | |
41 | // | |
42 | // `Self::Assoc<3>` cant be resolved without typchecking here as we | |
43 | // didnt write <Self as Foo>::Assoc<3>. If we did then another match | |
44 | // arm would handle this. | |
45 | // | |
46 | // I believe this match arm is only needed for GAT but I am not 100% sure - BoxyUwU | |
47 | Node::Ty(hir_ty @ Ty { kind: TyKind::Path(QPath::TypeRelative(_, segment)), .. }) => { | |
48 | // Find the Item containing the associated type so we can create an ItemCtxt. | |
49 | // Using the ItemCtxt convert the HIR for the unresolved assoc type into a | |
50 | // ty which is a fully resolved projection. | |
51 | // For the code example above, this would mean converting Self::Assoc<3> | |
52 | // into a ty::Projection(<Self as Foo>::Assoc<3>) | |
53 | let item_hir_id = tcx | |
54 | .hir() | |
55 | .parent_iter(hir_id) | |
56 | .filter(|(_, node)| matches!(node, Node::Item(_))) | |
57 | .map(|(id, _)| id) | |
58 | .next() | |
59 | .unwrap(); | |
60 | let item_did = tcx.hir().local_def_id(item_hir_id).to_def_id(); | |
61 | let item_ctxt = &ItemCtxt::new(tcx, item_did) as &dyn crate::astconv::AstConv<'_>; | |
62 | let ty = item_ctxt.ast_ty_to_ty(hir_ty); | |
63 | ||
64 | // Iterate through the generics of the projection to find the one that corresponds to | |
65 | // the def_id that this query was called with. We filter to only const args here as a | |
66 | // precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't | |
67 | // but it can't hurt to be safe ^^ | |
68 | if let ty::Projection(projection) = ty.kind() { | |
69 | let generics = tcx.generics_of(projection.item_def_id); | |
70 | ||
71 | let arg_index = segment | |
72 | .args | |
73 | .and_then(|args| { | |
74 | args.args | |
75 | .iter() | |
76 | .filter(|arg| arg.is_const()) | |
77 | .position(|arg| arg.id() == hir_id) | |
78 | }) | |
79 | .unwrap_or_else(|| { | |
80 | bug!("no arg matching AnonConst in segment"); | |
81 | }); | |
82 | ||
83 | return generics | |
84 | .params | |
85 | .iter() | |
86 | .filter(|param| matches!(param.kind, ty::GenericParamDefKind::Const)) | |
87 | .nth(arg_index) | |
88 | .map(|param| param.def_id); | |
89 | } | |
90 | ||
91 | // I dont think it's possible to reach this but I'm not 100% sure - BoxyUwU | |
92 | tcx.sess.delay_span_bug( | |
93 | tcx.def_span(def_id), | |
94 | "unexpected non-GAT usage of an anon const", | |
95 | ); | |
96 | return None; | |
97 | } | |
3dfed10e XL |
98 | Node::Expr(&Expr { |
99 | kind: | |
100 | ExprKind::MethodCall(segment, ..) | ExprKind::Path(QPath::TypeRelative(_, segment)), | |
101 | .. | |
102 | }) => { | |
103 | let body_owner = tcx.hir().local_def_id(tcx.hir().enclosing_body_owner(hir_id)); | |
104 | let tables = tcx.typeck(body_owner); | |
105 | // This may fail in case the method/path does not actually exist. | |
106 | // As there is no relevant param for `def_id`, we simply return | |
107 | // `None` here. | |
108 | let type_dependent_def = tables.type_dependent_def_id(parent_node_id)?; | |
109 | let idx = segment | |
110 | .args | |
111 | .and_then(|args| { | |
112 | args.args | |
113 | .iter() | |
114 | .filter(|arg| arg.is_const()) | |
115 | .position(|arg| arg.id() == hir_id) | |
116 | }) | |
117 | .unwrap_or_else(|| { | |
118 | bug!("no arg matching AnonConst in segment"); | |
119 | }); | |
120 | ||
121 | tcx.generics_of(type_dependent_def) | |
122 | .params | |
123 | .iter() | |
124 | .filter(|param| matches!(param.kind, ty::GenericParamDefKind::Const)) | |
125 | .nth(idx) | |
126 | .map(|param| param.def_id) | |
127 | } | |
128 | ||
129 | Node::Ty(&Ty { kind: TyKind::Path(_), .. }) | |
5869c6ff XL |
130 | | Node::Expr(&Expr { kind: ExprKind::Path(_) | ExprKind::Struct(..), .. }) |
131 | | Node::TraitRef(..) | |
132 | | Node::Pat(_) => { | |
3dfed10e XL |
133 | let path = match parent_node { |
134 | Node::Ty(&Ty { kind: TyKind::Path(QPath::Resolved(_, path)), .. }) | |
135 | | Node::TraitRef(&TraitRef { path, .. }) => &*path, | |
136 | Node::Expr(&Expr { | |
137 | kind: | |
138 | ExprKind::Path(QPath::Resolved(_, path)) | |
139 | | ExprKind::Struct(&QPath::Resolved(_, path), ..), | |
140 | .. | |
141 | }) => { | |
142 | let body_owner = | |
143 | tcx.hir().local_def_id(tcx.hir().enclosing_body_owner(hir_id)); | |
144 | let _tables = tcx.typeck(body_owner); | |
145 | &*path | |
146 | } | |
5869c6ff XL |
147 | Node::Pat(pat) => { |
148 | if let Some(path) = get_path_containing_arg_in_pat(pat, hir_id) { | |
149 | path | |
150 | } else { | |
151 | tcx.sess.delay_span_bug( | |
152 | tcx.def_span(def_id), | |
153 | &format!( | |
154 | "unable to find const parent for {} in pat {:?}", | |
155 | hir_id, pat | |
156 | ), | |
157 | ); | |
158 | return None; | |
159 | } | |
160 | } | |
1b1a35ee XL |
161 | _ => { |
162 | tcx.sess.delay_span_bug( | |
163 | tcx.def_span(def_id), | |
164 | &format!("unexpected const parent path {:?}", parent_node), | |
165 | ); | |
166 | return None; | |
167 | } | |
3dfed10e XL |
168 | }; |
169 | ||
170 | // We've encountered an `AnonConst` in some path, so we need to | |
171 | // figure out which generic parameter it corresponds to and return | |
172 | // the relevant type. | |
3dfed10e XL |
173 | let (arg_index, segment) = path |
174 | .segments | |
175 | .iter() | |
176 | .filter_map(|seg| seg.args.map(|args| (args.args, seg))) | |
177 | .find_map(|(args, seg)| { | |
178 | args.iter() | |
179 | .filter(|arg| arg.is_const()) | |
180 | .position(|arg| arg.id() == hir_id) | |
181 | .map(|index| (index, seg)) | |
182 | }) | |
183 | .unwrap_or_else(|| { | |
184 | bug!("no arg matching AnonConst in path"); | |
185 | }); | |
186 | ||
187 | // Try to use the segment resolution if it is valid, otherwise we | |
188 | // default to the path resolution. | |
189 | let res = segment.res.filter(|&r| r != Res::Err).unwrap_or(path.res); | |
190 | let generics = match res { | |
191 | Res::Def(DefKind::Ctor(..), def_id) => { | |
192 | tcx.generics_of(tcx.parent(def_id).unwrap()) | |
193 | } | |
194 | Res::Def(_, def_id) => tcx.generics_of(def_id), | |
195 | Res::Err => { | |
196 | tcx.sess.delay_span_bug(tcx.def_span(def_id), "anon const with Res::Err"); | |
197 | return None; | |
198 | } | |
29967ef6 XL |
199 | _ => { |
200 | // If the user tries to specify generics on a type that does not take them, | |
201 | // e.g. `usize<T>`, we may hit this branch, in which case we treat it as if | |
202 | // no arguments have been passed. An error should already have been emitted. | |
203 | tcx.sess.delay_span_bug( | |
204 | tcx.def_span(def_id), | |
205 | &format!("unexpected anon const res {:?} in path: {:?}", res, path), | |
206 | ); | |
207 | return None; | |
208 | } | |
3dfed10e XL |
209 | }; |
210 | ||
211 | generics | |
212 | .params | |
213 | .iter() | |
214 | .filter(|param| matches!(param.kind, ty::GenericParamDefKind::Const)) | |
215 | .nth(arg_index) | |
216 | .map(|param| param.def_id) | |
217 | } | |
218 | _ => None, | |
219 | } | |
220 | } else { | |
221 | None | |
222 | } | |
223 | } | |
224 | ||
5869c6ff XL |
225 | fn get_path_containing_arg_in_pat<'hir>( |
226 | pat: &'hir hir::Pat<'hir>, | |
227 | arg_id: HirId, | |
228 | ) -> Option<&'hir hir::Path<'hir>> { | |
229 | use hir::*; | |
230 | ||
231 | let is_arg_in_path = |p: &hir::Path<'_>| { | |
232 | p.segments | |
233 | .iter() | |
234 | .filter_map(|seg| seg.args) | |
235 | .flat_map(|args| args.args) | |
236 | .any(|arg| arg.id() == arg_id) | |
237 | }; | |
238 | let mut arg_path = None; | |
239 | pat.walk(|pat| match pat.kind { | |
240 | PatKind::Struct(QPath::Resolved(_, path), _, _) | |
241 | | PatKind::TupleStruct(QPath::Resolved(_, path), _, _) | |
242 | | PatKind::Path(QPath::Resolved(_, path)) | |
243 | if is_arg_in_path(path) => | |
244 | { | |
245 | arg_path = Some(path); | |
246 | false | |
247 | } | |
248 | _ => true, | |
249 | }); | |
250 | arg_path | |
251 | } | |
252 | ||
74b04a01 | 253 | pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> { |
3dfed10e | 254 | let def_id = def_id.expect_local(); |
74b04a01 XL |
255 | use rustc_hir::*; |
256 | ||
3dfed10e | 257 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
74b04a01 | 258 | |
3dfed10e | 259 | let icx = ItemCtxt::new(tcx, def_id.to_def_id()); |
74b04a01 XL |
260 | |
261 | match tcx.hir().get(hir_id) { | |
262 | Node::TraitItem(item) => match item.kind { | |
ba9703b0 | 263 | TraitItemKind::Fn(..) => { |
3dfed10e XL |
264 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
265 | tcx.mk_fn_def(def_id.to_def_id(), substs) | |
74b04a01 XL |
266 | } |
267 | TraitItemKind::Const(ref ty, body_id) => body_id | |
268 | .and_then(|body_id| { | |
269 | if is_suggestable_infer_ty(ty) { | |
3dfed10e | 270 | Some(infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident)) |
74b04a01 XL |
271 | } else { |
272 | None | |
273 | } | |
274 | }) | |
275 | .unwrap_or_else(|| icx.to_ty(ty)), | |
276 | TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty), | |
277 | TraitItemKind::Type(_, None) => { | |
278 | span_bug!(item.span, "associated type missing default"); | |
279 | } | |
280 | }, | |
281 | ||
282 | Node::ImplItem(item) => match item.kind { | |
ba9703b0 | 283 | ImplItemKind::Fn(..) => { |
3dfed10e XL |
284 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
285 | tcx.mk_fn_def(def_id.to_def_id(), substs) | |
74b04a01 XL |
286 | } |
287 | ImplItemKind::Const(ref ty, body_id) => { | |
288 | if is_suggestable_infer_ty(ty) { | |
3dfed10e | 289 | infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident) |
74b04a01 XL |
290 | } else { |
291 | icx.to_ty(ty) | |
292 | } | |
293 | } | |
74b04a01 | 294 | ImplItemKind::TyAlias(ref ty) => { |
ba9703b0 | 295 | if tcx.impl_trait_ref(tcx.hir().get_parent_did(hir_id).to_def_id()).is_none() { |
6a06907d | 296 | check_feature_inherent_assoc_ty(tcx, item.span); |
74b04a01 XL |
297 | } |
298 | ||
299 | icx.to_ty(ty) | |
300 | } | |
301 | }, | |
302 | ||
303 | Node::Item(item) => { | |
304 | match item.kind { | |
305 | ItemKind::Static(ref ty, .., body_id) | ItemKind::Const(ref ty, body_id) => { | |
306 | if is_suggestable_infer_ty(ty) { | |
3dfed10e | 307 | infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident) |
74b04a01 XL |
308 | } else { |
309 | icx.to_ty(ty) | |
310 | } | |
311 | } | |
5869c6ff XL |
312 | ItemKind::TyAlias(ref self_ty, _) |
313 | | ItemKind::Impl(hir::Impl { ref self_ty, .. }) => icx.to_ty(self_ty), | |
74b04a01 | 314 | ItemKind::Fn(..) => { |
3dfed10e XL |
315 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
316 | tcx.mk_fn_def(def_id.to_def_id(), substs) | |
74b04a01 XL |
317 | } |
318 | ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) => { | |
319 | let def = tcx.adt_def(def_id); | |
3dfed10e | 320 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
74b04a01 XL |
321 | tcx.mk_adt(def, substs) |
322 | } | |
f035d41b | 323 | ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::Binding, .. }) => { |
3dfed10e | 324 | let_position_impl_trait_type(tcx, def_id) |
f035d41b | 325 | } |
74b04a01 | 326 | ItemKind::OpaqueTy(OpaqueTy { impl_trait_fn: None, .. }) => { |
3dfed10e | 327 | find_opaque_ty_constraints(tcx, def_id) |
74b04a01 XL |
328 | } |
329 | // Opaque types desugared from `impl Trait`. | |
f035d41b XL |
330 | ItemKind::OpaqueTy(OpaqueTy { impl_trait_fn: Some(owner), .. }) => { |
331 | let concrete_ty = tcx | |
332 | .mir_borrowck(owner.expect_local()) | |
333 | .concrete_opaque_types | |
3dfed10e | 334 | .get(&def_id.to_def_id()) |
74b04a01 XL |
335 | .map(|opaque| opaque.concrete_type) |
336 | .unwrap_or_else(|| { | |
337 | tcx.sess.delay_span_bug( | |
338 | DUMMY_SP, | |
339 | &format!( | |
3dfed10e | 340 | "owner {:?} has no opaque type for {:?} in its typeck results", |
74b04a01 XL |
341 | owner, def_id, |
342 | ), | |
343 | ); | |
ba9703b0 | 344 | if let Some(ErrorReported) = |
3dfed10e | 345 | tcx.typeck(owner.expect_local()).tainted_by_errors |
ba9703b0 | 346 | { |
74b04a01 XL |
347 | // Some error in the |
348 | // owner fn prevented us from populating | |
349 | // the `concrete_opaque_types` table. | |
f035d41b | 350 | tcx.ty_error() |
74b04a01 XL |
351 | } else { |
352 | // We failed to resolve the opaque type or it | |
353 | // resolves to itself. Return the non-revealed | |
354 | // type, which should result in E0720. | |
355 | tcx.mk_opaque( | |
3dfed10e XL |
356 | def_id.to_def_id(), |
357 | InternalSubsts::identity_for_item(tcx, def_id.to_def_id()), | |
74b04a01 XL |
358 | ) |
359 | } | |
360 | }); | |
361 | debug!("concrete_ty = {:?}", concrete_ty); | |
74b04a01 XL |
362 | concrete_ty |
363 | } | |
364 | ItemKind::Trait(..) | |
365 | | ItemKind::TraitAlias(..) | |
366 | | ItemKind::Mod(..) | |
fc512014 | 367 | | ItemKind::ForeignMod { .. } |
74b04a01 XL |
368 | | ItemKind::GlobalAsm(..) |
369 | | ItemKind::ExternCrate(..) | |
370 | | ItemKind::Use(..) => { | |
371 | span_bug!( | |
372 | item.span, | |
373 | "compute_type_of_item: unexpected item type: {:?}", | |
374 | item.kind | |
375 | ); | |
376 | } | |
377 | } | |
378 | } | |
379 | ||
380 | Node::ForeignItem(foreign_item) => match foreign_item.kind { | |
381 | ForeignItemKind::Fn(..) => { | |
3dfed10e XL |
382 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
383 | tcx.mk_fn_def(def_id.to_def_id(), substs) | |
74b04a01 XL |
384 | } |
385 | ForeignItemKind::Static(ref t, _) => icx.to_ty(t), | |
3dfed10e | 386 | ForeignItemKind::Type => tcx.mk_foreign(def_id.to_def_id()), |
74b04a01 XL |
387 | }, |
388 | ||
389 | Node::Ctor(&ref def) | Node::Variant(Variant { data: ref def, .. }) => match *def { | |
390 | VariantData::Unit(..) | VariantData::Struct(..) => { | |
ba9703b0 | 391 | tcx.type_of(tcx.hir().get_parent_did(hir_id).to_def_id()) |
74b04a01 XL |
392 | } |
393 | VariantData::Tuple(..) => { | |
3dfed10e XL |
394 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
395 | tcx.mk_fn_def(def_id.to_def_id(), substs) | |
74b04a01 XL |
396 | } |
397 | }, | |
398 | ||
399 | Node::Field(field) => icx.to_ty(&field.ty), | |
400 | ||
401 | Node::Expr(&Expr { kind: ExprKind::Closure(.., gen), .. }) => { | |
3dfed10e | 402 | let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
ba9703b0 | 403 | if let Some(movability) = gen { |
3dfed10e | 404 | tcx.mk_generator(def_id.to_def_id(), substs, movability) |
ba9703b0 | 405 | } else { |
3dfed10e | 406 | tcx.mk_closure(def_id.to_def_id(), substs) |
ba9703b0 | 407 | } |
74b04a01 XL |
408 | } |
409 | ||
410 | Node::AnonConst(_) => { | |
3dfed10e XL |
411 | if let Some(param) = tcx.opt_const_param_of(def_id) { |
412 | // We defer to `type_of` of the corresponding parameter | |
413 | // for generic arguments. | |
414 | return tcx.type_of(param); | |
415 | } | |
416 | ||
74b04a01 XL |
417 | let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id)); |
418 | match parent_node { | |
419 | Node::Ty(&Ty { kind: TyKind::Array(_, ref constant), .. }) | |
420 | | Node::Ty(&Ty { kind: TyKind::Typeof(ref constant), .. }) | |
421 | | Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. }) | |
422 | if constant.hir_id == hir_id => | |
423 | { | |
424 | tcx.types.usize | |
425 | } | |
426 | ||
29967ef6 XL |
427 | Node::Expr(&Expr { kind: ExprKind::ConstBlock(ref anon_const), .. }) |
428 | if anon_const.hir_id == hir_id => | |
429 | { | |
430 | tcx.typeck(def_id).node_type(anon_const.hir_id) | |
431 | } | |
432 | ||
ba9703b0 XL |
433 | Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => tcx |
434 | .adt_def(tcx.hir().get_parent_did(hir_id).to_def_id()) | |
435 | .repr | |
436 | .discr_type() | |
437 | .to_ty(tcx), | |
74b04a01 | 438 | |
f035d41b XL |
439 | x => tcx.ty_error_with_message( |
440 | DUMMY_SP, | |
441 | &format!("unexpected const parent in type_of_def_id(): {:?}", x), | |
442 | ), | |
74b04a01 XL |
443 | } |
444 | } | |
445 | ||
446 | Node::GenericParam(param) => match ¶m.kind { | |
3dfed10e XL |
447 | GenericParamKind::Type { default: Some(ty), .. } |
448 | | GenericParamKind::Const { ty, .. } => icx.to_ty(ty), | |
74b04a01 XL |
449 | x => bug!("unexpected non-type Node::GenericParam: {:?}", x), |
450 | }, | |
451 | ||
452 | x => { | |
453 | bug!("unexpected sort of node in type_of_def_id(): {:?}", x); | |
454 | } | |
455 | } | |
456 | } | |
457 | ||
f9f354fc | 458 | fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> { |
74b04a01 XL |
459 | use rustc_hir::{Expr, ImplItem, Item, TraitItem}; |
460 | ||
461 | debug!("find_opaque_ty_constraints({:?})", def_id); | |
462 | ||
463 | struct ConstraintLocator<'tcx> { | |
464 | tcx: TyCtxt<'tcx>, | |
465 | def_id: DefId, | |
ba9703b0 XL |
466 | // (first found type span, actual type) |
467 | found: Option<(Span, Ty<'tcx>)>, | |
74b04a01 XL |
468 | } |
469 | ||
470 | impl ConstraintLocator<'_> { | |
f9f354fc | 471 | fn check(&mut self, def_id: LocalDefId) { |
74b04a01 | 472 | // Don't try to check items that cannot possibly constrain the type. |
3dfed10e | 473 | if !self.tcx.has_typeck_results(def_id) { |
74b04a01 | 474 | debug!( |
3dfed10e | 475 | "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`: no typeck results", |
74b04a01 XL |
476 | self.def_id, def_id, |
477 | ); | |
478 | return; | |
479 | } | |
480 | // Calling `mir_borrowck` can lead to cycle errors through | |
481 | // const-checking, avoid calling it if we don't have to. | |
3dfed10e | 482 | if !self.tcx.typeck(def_id).concrete_opaque_types.contains_key(&self.def_id) { |
74b04a01 XL |
483 | debug!( |
484 | "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`", | |
485 | self.def_id, def_id, | |
486 | ); | |
487 | return; | |
488 | } | |
489 | // Use borrowck to get the type with unerased regions. | |
490 | let ty = self.tcx.mir_borrowck(def_id).concrete_opaque_types.get(&self.def_id); | |
491 | if let Some(ty::ResolvedOpaqueTy { concrete_type, substs }) = ty { | |
492 | debug!( | |
493 | "find_opaque_ty_constraints: found constraint for `{:?}` at `{:?}`: {:?}", | |
494 | self.def_id, def_id, ty, | |
495 | ); | |
496 | ||
497 | // FIXME(oli-obk): trace the actual span from inference to improve errors. | |
498 | let span = self.tcx.def_span(def_id); | |
ba9703b0 XL |
499 | |
500 | // HACK(eddyb) this check shouldn't be needed, as `wfcheck` | |
501 | // performs the same checks, in theory, but I've kept it here | |
502 | // using `delay_span_bug`, just in case `wfcheck` slips up. | |
503 | let opaque_generics = self.tcx.generics_of(self.def_id); | |
504 | let mut used_params: FxHashSet<_> = FxHashSet::default(); | |
505 | for (i, arg) in substs.iter().enumerate() { | |
506 | let arg_is_param = match arg.unpack() { | |
1b1a35ee | 507 | GenericArgKind::Type(ty) => matches!(ty.kind(), ty::Param(_)), |
ba9703b0 XL |
508 | GenericArgKind::Lifetime(lt) => { |
509 | matches!(lt, ty::ReEarlyBound(_) | ty::ReFree(_)) | |
510 | } | |
511 | GenericArgKind::Const(ct) => matches!(ct.val, ty::ConstKind::Param(_)), | |
512 | }; | |
513 | ||
514 | if arg_is_param { | |
515 | if !used_params.insert(arg) { | |
516 | // There was already an entry for `arg`, meaning a generic parameter | |
517 | // was used twice. | |
74b04a01 XL |
518 | self.tcx.sess.delay_span_bug( |
519 | span, | |
520 | &format!( | |
ba9703b0 XL |
521 | "defining opaque type use restricts opaque \ |
522 | type by using the generic parameter `{}` twice", | |
523 | arg, | |
74b04a01 XL |
524 | ), |
525 | ); | |
526 | } | |
ba9703b0 XL |
527 | } else { |
528 | let param = opaque_generics.param_at(i, self.tcx); | |
529 | self.tcx.sess.delay_span_bug( | |
74b04a01 XL |
530 | span, |
531 | &format!( | |
532 | "defining opaque type use does not fully define opaque type: \ | |
ba9703b0 XL |
533 | generic parameter `{}` is specified as concrete {} `{}`", |
534 | param.name, | |
535 | param.kind.descr(), | |
536 | arg, | |
74b04a01 XL |
537 | ), |
538 | ); | |
539 | } | |
ba9703b0 XL |
540 | } |
541 | ||
542 | if let Some((prev_span, prev_ty)) = self.found { | |
543 | if *concrete_type != prev_ty { | |
74b04a01 XL |
544 | debug!("find_opaque_ty_constraints: span={:?}", span); |
545 | // Found different concrete types for the opaque type. | |
546 | let mut err = self.tcx.sess.struct_span_err( | |
547 | span, | |
548 | "concrete type differs from previous defining opaque type use", | |
549 | ); | |
550 | err.span_label( | |
551 | span, | |
552 | format!("expected `{}`, got `{}`", prev_ty, concrete_type), | |
553 | ); | |
554 | err.span_note(prev_span, "previous use here"); | |
555 | err.emit(); | |
74b04a01 XL |
556 | } |
557 | } else { | |
ba9703b0 | 558 | self.found = Some((span, concrete_type)); |
74b04a01 XL |
559 | } |
560 | } else { | |
561 | debug!( | |
562 | "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`", | |
563 | self.def_id, def_id, | |
564 | ); | |
565 | } | |
566 | } | |
567 | } | |
568 | ||
569 | impl<'tcx> intravisit::Visitor<'tcx> for ConstraintLocator<'tcx> { | |
570 | type Map = Map<'tcx>; | |
571 | ||
ba9703b0 XL |
572 | fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { |
573 | intravisit::NestedVisitorMap::All(self.tcx.hir()) | |
74b04a01 XL |
574 | } |
575 | fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { | |
576 | if let hir::ExprKind::Closure(..) = ex.kind { | |
577 | let def_id = self.tcx.hir().local_def_id(ex.hir_id); | |
578 | self.check(def_id); | |
579 | } | |
580 | intravisit::walk_expr(self, ex); | |
581 | } | |
582 | fn visit_item(&mut self, it: &'tcx Item<'tcx>) { | |
583 | debug!("find_existential_constraints: visiting {:?}", it); | |
74b04a01 | 584 | // The opaque type itself or its children are not within its reveal scope. |
6a06907d XL |
585 | if it.def_id.to_def_id() != self.def_id { |
586 | self.check(it.def_id); | |
74b04a01 XL |
587 | intravisit::walk_item(self, it); |
588 | } | |
589 | } | |
590 | fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) { | |
591 | debug!("find_existential_constraints: visiting {:?}", it); | |
74b04a01 | 592 | // The opaque type itself or its children are not within its reveal scope. |
6a06907d XL |
593 | if it.def_id.to_def_id() != self.def_id { |
594 | self.check(it.def_id); | |
74b04a01 XL |
595 | intravisit::walk_impl_item(self, it); |
596 | } | |
597 | } | |
598 | fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) { | |
599 | debug!("find_existential_constraints: visiting {:?}", it); | |
6a06907d | 600 | self.check(it.def_id); |
74b04a01 XL |
601 | intravisit::walk_trait_item(self, it); |
602 | } | |
603 | } | |
604 | ||
3dfed10e | 605 | let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
74b04a01 | 606 | let scope = tcx.hir().get_defining_scope(hir_id); |
f9f354fc | 607 | let mut locator = ConstraintLocator { def_id: def_id.to_def_id(), tcx, found: None }; |
74b04a01 XL |
608 | |
609 | debug!("find_opaque_ty_constraints: scope={:?}", scope); | |
610 | ||
611 | if scope == hir::CRATE_HIR_ID { | |
612 | intravisit::walk_crate(&mut locator, tcx.hir().krate()); | |
613 | } else { | |
614 | debug!("find_opaque_ty_constraints: scope={:?}", tcx.hir().get(scope)); | |
615 | match tcx.hir().get(scope) { | |
616 | // We explicitly call `visit_*` methods, instead of using `intravisit::walk_*` methods | |
617 | // This allows our visitor to process the defining item itself, causing | |
618 | // it to pick up any 'sibling' defining uses. | |
619 | // | |
620 | // For example, this code: | |
621 | // ``` | |
622 | // fn foo() { | |
623 | // type Blah = impl Debug; | |
624 | // let my_closure = || -> Blah { true }; | |
625 | // } | |
626 | // ``` | |
627 | // | |
628 | // requires us to explicitly process `foo()` in order | |
629 | // to notice the defining usage of `Blah`. | |
630 | Node::Item(ref it) => locator.visit_item(it), | |
631 | Node::ImplItem(ref it) => locator.visit_impl_item(it), | |
632 | Node::TraitItem(ref it) => locator.visit_trait_item(it), | |
633 | other => bug!("{:?} is not a valid scope for an opaque type item", other), | |
634 | } | |
635 | } | |
636 | ||
637 | match locator.found { | |
ba9703b0 | 638 | Some((_, ty)) => ty, |
74b04a01 XL |
639 | None => { |
640 | let span = tcx.def_span(def_id); | |
641 | tcx.sess.span_err(span, "could not find defining uses"); | |
f035d41b | 642 | tcx.ty_error() |
74b04a01 XL |
643 | } |
644 | } | |
645 | } | |
646 | ||
f035d41b XL |
647 | /// Retrieve the inferred concrete type for let position impl trait. |
648 | /// | |
649 | /// This is different to other kinds of impl trait because: | |
650 | /// | |
651 | /// 1. We know which function contains the defining use (the function that | |
652 | /// contains the let statement) | |
653 | /// 2. We do not currently allow (free) lifetimes in the return type. `let` | |
654 | /// statements in some statically unreachable code are removed from the MIR | |
655 | /// by the time we borrow check, and it's not clear how we should handle | |
656 | /// those. | |
657 | fn let_position_impl_trait_type(tcx: TyCtxt<'_>, opaque_ty_id: LocalDefId) -> Ty<'_> { | |
3dfed10e | 658 | let scope = tcx.hir().get_defining_scope(tcx.hir().local_def_id_to_hir_id(opaque_ty_id)); |
f035d41b XL |
659 | let scope_def_id = tcx.hir().local_def_id(scope); |
660 | ||
661 | let opaque_ty_def_id = opaque_ty_id.to_def_id(); | |
662 | ||
3dfed10e XL |
663 | let owner_typeck_results = tcx.typeck(scope_def_id); |
664 | let concrete_ty = owner_typeck_results | |
f035d41b XL |
665 | .concrete_opaque_types |
666 | .get(&opaque_ty_def_id) | |
667 | .map(|opaque| opaque.concrete_type) | |
668 | .unwrap_or_else(|| { | |
669 | tcx.sess.delay_span_bug( | |
670 | DUMMY_SP, | |
671 | &format!( | |
3dfed10e | 672 | "owner {:?} has no opaque type for {:?} in its typeck results", |
f035d41b XL |
673 | scope_def_id, opaque_ty_id |
674 | ), | |
675 | ); | |
3dfed10e | 676 | if let Some(ErrorReported) = owner_typeck_results.tainted_by_errors { |
f035d41b XL |
677 | // Some error in the owner fn prevented us from populating the |
678 | // `concrete_opaque_types` table. | |
679 | tcx.ty_error() | |
680 | } else { | |
681 | // We failed to resolve the opaque type or it resolves to | |
682 | // itself. Return the non-revealed type, which should result in | |
683 | // E0720. | |
684 | tcx.mk_opaque( | |
685 | opaque_ty_def_id, | |
686 | InternalSubsts::identity_for_item(tcx, opaque_ty_def_id), | |
687 | ) | |
688 | } | |
689 | }); | |
690 | debug!("concrete_ty = {:?}", concrete_ty); | |
691 | if concrete_ty.has_erased_regions() { | |
692 | // FIXME(impl_trait_in_bindings) Handle this case. | |
693 | tcx.sess.span_fatal( | |
3dfed10e | 694 | tcx.hir().span(tcx.hir().local_def_id_to_hir_id(opaque_ty_id)), |
f035d41b XL |
695 | "lifetimes in impl Trait types in bindings are not currently supported", |
696 | ); | |
697 | } | |
698 | concrete_ty | |
699 | } | |
700 | ||
74b04a01 XL |
701 | fn infer_placeholder_type( |
702 | tcx: TyCtxt<'_>, | |
f9f354fc | 703 | def_id: LocalDefId, |
74b04a01 XL |
704 | body_id: hir::BodyId, |
705 | span: Span, | |
706 | item_ident: Ident, | |
707 | ) -> Ty<'_> { | |
3dfed10e | 708 | let ty = tcx.diagnostic_only_typeck(def_id).node_type(body_id.hir_id); |
74b04a01 XL |
709 | |
710 | // If this came from a free `const` or `static mut?` item, | |
711 | // then the user may have written e.g. `const A = 42;`. | |
712 | // In this case, the parser has stashed a diagnostic for | |
713 | // us to improve in typeck so we do that now. | |
714 | match tcx.sess.diagnostic().steal_diagnostic(span, StashKey::ItemNoType) { | |
715 | Some(mut err) => { | |
716 | // The parser provided a sub-optimal `HasPlaceholders` suggestion for the type. | |
717 | // We are typeck and have the real type, so remove that and suggest the actual type. | |
718 | err.suggestions.clear(); | |
719 | err.span_suggestion( | |
720 | span, | |
721 | "provide a type for the item", | |
722 | format!("{}: {}", item_ident, ty), | |
723 | Applicability::MachineApplicable, | |
724 | ) | |
6a06907d | 725 | .emit_unless(ty.references_error()); |
74b04a01 XL |
726 | } |
727 | None => { | |
728 | let mut diag = bad_placeholder_type(tcx, vec![span]); | |
6a06907d XL |
729 | |
730 | if !ty.references_error() { | |
74b04a01 XL |
731 | diag.span_suggestion( |
732 | span, | |
733 | "replace `_` with the correct type", | |
734 | ty.to_string(), | |
735 | Applicability::MaybeIncorrect, | |
736 | ); | |
737 | } | |
6a06907d | 738 | |
74b04a01 XL |
739 | diag.emit(); |
740 | } | |
741 | } | |
742 | ||
ba9703b0 | 743 | // Typeck doesn't expect erased regions to be returned from `type_of`. |
fc512014 | 744 | tcx.fold_regions(ty, &mut false, |r, _| match r { |
ba9703b0 XL |
745 | ty::ReErased => tcx.lifetimes.re_static, |
746 | _ => r, | |
747 | }) | |
74b04a01 XL |
748 | } |
749 | ||
6a06907d XL |
750 | fn check_feature_inherent_assoc_ty(tcx: TyCtxt<'_>, span: Span) { |
751 | if !tcx.features().inherent_associated_types { | |
752 | use rustc_session::parse::feature_err; | |
753 | use rustc_span::symbol::sym; | |
754 | feature_err( | |
755 | &tcx.sess.parse_sess, | |
756 | sym::inherent_associated_types, | |
757 | span, | |
758 | "inherent associated types are unstable", | |
759 | ) | |
760 | .emit(); | |
761 | } | |
74b04a01 | 762 | } |