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Commit | Line | Data |
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e74abb32 | 1 | use crate::ty::subst::{GenericArg, Subst}; |
dfeec247 | 2 | use crate::ty::{self, DefIdTree, Ty, TyCtxt}; |
532ac7d7 XL |
3 | |
4 | use rustc_data_structures::fx::FxHashSet; | |
dfeec247 | 5 | use rustc_hir::def_id::{CrateNum, DefId}; |
ba9703b0 | 6 | use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData}; |
532ac7d7 XL |
7 | |
8 | // `pretty` is a separate module only for organization. | |
9 | mod pretty; | |
10 | pub use self::pretty::*; | |
11 | ||
dc9dc135 XL |
12 | pub mod obsolete; |
13 | ||
14 | // FIXME(eddyb) false positive, the lifetime parameters are used with `P: Printer<...>`. | |
15 | #[allow(unused_lifetimes)] | |
16 | pub trait Print<'tcx, P> { | |
532ac7d7 XL |
17 | type Output; |
18 | type Error; | |
19 | ||
20 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error>; | |
21 | } | |
22 | ||
23 | /// Interface for outputting user-facing "type-system entities" | |
24 | /// (paths, types, lifetimes, constants, etc.) as a side-effect | |
25 | /// (e.g. formatting, like `PrettyPrinter` implementors do) or by | |
26 | /// constructing some alternative representation (e.g. an AST), | |
27 | /// which the associated types allow passing through the methods. | |
28 | /// | |
29 | /// For pretty-printing/formatting in particular, see `PrettyPrinter`. | |
e1599b0c XL |
30 | // |
31 | // FIXME(eddyb) find a better name; this is more general than "printing". | |
dc9dc135 | 32 | pub trait Printer<'tcx>: Sized { |
532ac7d7 XL |
33 | type Error; |
34 | ||
35 | type Path; | |
36 | type Region; | |
37 | type Type; | |
38 | type DynExistential; | |
dc9dc135 | 39 | type Const; |
532ac7d7 | 40 | |
dc9dc135 | 41 | fn tcx(&'a self) -> TyCtxt<'tcx>; |
532ac7d7 XL |
42 | |
43 | fn print_def_path( | |
44 | self, | |
45 | def_id: DefId, | |
e74abb32 | 46 | substs: &'tcx [GenericArg<'tcx>], |
532ac7d7 XL |
47 | ) -> Result<Self::Path, Self::Error> { |
48 | self.default_print_def_path(def_id, substs) | |
49 | } | |
e1599b0c | 50 | |
532ac7d7 XL |
51 | fn print_impl_path( |
52 | self, | |
53 | impl_def_id: DefId, | |
e74abb32 | 54 | substs: &'tcx [GenericArg<'tcx>], |
532ac7d7 XL |
55 | self_ty: Ty<'tcx>, |
56 | trait_ref: Option<ty::TraitRef<'tcx>>, | |
57 | ) -> Result<Self::Path, Self::Error> { | |
58 | self.default_print_impl_path(impl_def_id, substs, self_ty, trait_ref) | |
59 | } | |
60 | ||
dfeec247 | 61 | fn print_region(self, region: ty::Region<'_>) -> Result<Self::Region, Self::Error>; |
532ac7d7 | 62 | |
dfeec247 | 63 | fn print_type(self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error>; |
532ac7d7 XL |
64 | |
65 | fn print_dyn_existential( | |
66 | self, | |
67 | predicates: &'tcx ty::List<ty::ExistentialPredicate<'tcx>>, | |
68 | ) -> Result<Self::DynExistential, Self::Error>; | |
69 | ||
dfeec247 | 70 | fn print_const(self, ct: &'tcx ty::Const<'tcx>) -> Result<Self::Const, Self::Error>; |
dc9dc135 | 71 | |
dfeec247 | 72 | fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error>; |
e1599b0c | 73 | |
532ac7d7 XL |
74 | fn path_qualified( |
75 | self, | |
76 | self_ty: Ty<'tcx>, | |
77 | trait_ref: Option<ty::TraitRef<'tcx>>, | |
78 | ) -> Result<Self::Path, Self::Error>; | |
79 | ||
80 | fn path_append_impl( | |
81 | self, | |
82 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
83 | disambiguated_data: &DisambiguatedDefPathData, | |
84 | self_ty: Ty<'tcx>, | |
85 | trait_ref: Option<ty::TraitRef<'tcx>>, | |
86 | ) -> Result<Self::Path, Self::Error>; | |
e1599b0c | 87 | |
532ac7d7 XL |
88 | fn path_append( |
89 | self, | |
90 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
91 | disambiguated_data: &DisambiguatedDefPathData, | |
92 | ) -> Result<Self::Path, Self::Error>; | |
e1599b0c | 93 | |
532ac7d7 XL |
94 | fn path_generic_args( |
95 | self, | |
96 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
e74abb32 | 97 | args: &[GenericArg<'tcx>], |
532ac7d7 XL |
98 | ) -> Result<Self::Path, Self::Error>; |
99 | ||
74b04a01 | 100 | // Defaults (should not be overridden): |
532ac7d7 XL |
101 | |
102 | fn default_print_def_path( | |
103 | self, | |
104 | def_id: DefId, | |
e74abb32 | 105 | substs: &'tcx [GenericArg<'tcx>], |
532ac7d7 XL |
106 | ) -> Result<Self::Path, Self::Error> { |
107 | debug!("default_print_def_path: def_id={:?}, substs={:?}", def_id, substs); | |
108 | let key = self.tcx().def_key(def_id); | |
109 | debug!("default_print_def_path: key={:?}", key); | |
110 | ||
111 | match key.disambiguated_data.data { | |
112 | DefPathData::CrateRoot => { | |
113 | assert!(key.parent.is_none()); | |
114 | self.path_crate(def_id.krate) | |
115 | } | |
116 | ||
117 | DefPathData::Impl => { | |
118 | let generics = self.tcx().generics_of(def_id); | |
119 | let mut self_ty = self.tcx().type_of(def_id); | |
120 | let mut impl_trait_ref = self.tcx().impl_trait_ref(def_id); | |
121 | if substs.len() >= generics.count() { | |
122 | self_ty = self_ty.subst(self.tcx(), substs); | |
123 | impl_trait_ref = impl_trait_ref.subst(self.tcx(), substs); | |
124 | } | |
125 | self.print_impl_path(def_id, substs, self_ty, impl_trait_ref) | |
126 | } | |
127 | ||
128 | _ => { | |
129 | let parent_def_id = DefId { index: key.parent.unwrap(), ..def_id }; | |
130 | ||
131 | let mut parent_substs = substs; | |
132 | let mut trait_qualify_parent = false; | |
133 | if !substs.is_empty() { | |
134 | let generics = self.tcx().generics_of(def_id); | |
135 | parent_substs = &substs[..generics.parent_count.min(substs.len())]; | |
136 | ||
137 | match key.disambiguated_data.data { | |
138 | // Closures' own generics are only captures, don't print them. | |
139 | DefPathData::ClosureExpr => {} | |
140 | ||
141 | // If we have any generic arguments to print, we do that | |
142 | // on top of the same path, but without its own generics. | |
dfeec247 XL |
143 | _ => { |
144 | if !generics.params.is_empty() && substs.len() >= generics.count() { | |
145 | let args = self.generic_args_to_print(generics, substs); | |
146 | return self.path_generic_args( | |
147 | |cx| cx.print_def_path(def_id, parent_substs), | |
148 | args, | |
149 | ); | |
150 | } | |
532ac7d7 XL |
151 | } |
152 | } | |
153 | ||
154 | // FIXME(eddyb) try to move this into the parent's printing | |
155 | // logic, instead of doing it when printing the child. | |
dfeec247 XL |
156 | trait_qualify_parent = generics.has_self |
157 | && generics.parent == Some(parent_def_id) | |
158 | && parent_substs.len() == generics.parent_count | |
159 | && self.tcx().generics_of(parent_def_id).parent_count == 0; | |
532ac7d7 XL |
160 | } |
161 | ||
162 | self.path_append( | |
dfeec247 XL |
163 | |cx: Self| { |
164 | if trait_qualify_parent { | |
165 | let trait_ref = ty::TraitRef::new( | |
166 | parent_def_id, | |
167 | cx.tcx().intern_substs(parent_substs), | |
168 | ); | |
169 | cx.path_qualified(trait_ref.self_ty(), Some(trait_ref)) | |
170 | } else { | |
171 | cx.print_def_path(parent_def_id, parent_substs) | |
172 | } | |
532ac7d7 XL |
173 | }, |
174 | &key.disambiguated_data, | |
175 | ) | |
176 | } | |
177 | } | |
178 | } | |
179 | ||
180 | fn generic_args_to_print( | |
181 | &self, | |
182 | generics: &'tcx ty::Generics, | |
e74abb32 XL |
183 | substs: &'tcx [GenericArg<'tcx>], |
184 | ) -> &'tcx [GenericArg<'tcx>] { | |
532ac7d7 XL |
185 | let mut own_params = generics.parent_count..generics.count(); |
186 | ||
187 | // Don't print args for `Self` parameters (of traits). | |
188 | if generics.has_self && own_params.start == 0 { | |
189 | own_params.start = 1; | |
190 | } | |
191 | ||
192 | // Don't print args that are the defaults of their respective parameters. | |
dfeec247 XL |
193 | own_params.end -= generics |
194 | .params | |
195 | .iter() | |
196 | .rev() | |
197 | .take_while(|param| { | |
198 | match param.kind { | |
199 | ty::GenericParamDefKind::Lifetime => false, | |
200 | ty::GenericParamDefKind::Type { has_default, .. } => { | |
201 | has_default | |
202 | && substs[param.index as usize] | |
203 | == GenericArg::from( | |
204 | self.tcx().type_of(param.def_id).subst(self.tcx(), substs), | |
205 | ) | |
206 | } | |
207 | ty::GenericParamDefKind::Const => false, // FIXME(const_generics:defaults) | |
532ac7d7 | 208 | } |
dfeec247 XL |
209 | }) |
210 | .count(); | |
532ac7d7 XL |
211 | |
212 | &substs[own_params] | |
213 | } | |
214 | ||
215 | fn default_print_impl_path( | |
216 | self, | |
217 | impl_def_id: DefId, | |
e74abb32 | 218 | _substs: &'tcx [GenericArg<'tcx>], |
532ac7d7 XL |
219 | self_ty: Ty<'tcx>, |
220 | impl_trait_ref: Option<ty::TraitRef<'tcx>>, | |
221 | ) -> Result<Self::Path, Self::Error> { | |
dfeec247 XL |
222 | debug!( |
223 | "default_print_impl_path: impl_def_id={:?}, self_ty={}, impl_trait_ref={:?}", | |
224 | impl_def_id, self_ty, impl_trait_ref | |
225 | ); | |
532ac7d7 XL |
226 | |
227 | let key = self.tcx().def_key(impl_def_id); | |
228 | let parent_def_id = DefId { index: key.parent.unwrap(), ..impl_def_id }; | |
229 | ||
230 | // Decide whether to print the parent path for the impl. | |
231 | // Logically, since impls are global, it's never needed, but | |
232 | // users may find it useful. Currently, we omit the parent if | |
233 | // the impl is either in the same module as the self-type or | |
234 | // as the trait. | |
235 | let in_self_mod = match characteristic_def_id_of_type(self_ty) { | |
236 | None => false, | |
237 | Some(ty_def_id) => self.tcx().parent(ty_def_id) == Some(parent_def_id), | |
238 | }; | |
239 | let in_trait_mod = match impl_trait_ref { | |
240 | None => false, | |
241 | Some(trait_ref) => self.tcx().parent(trait_ref.def_id) == Some(parent_def_id), | |
242 | }; | |
243 | ||
244 | if !in_self_mod && !in_trait_mod { | |
245 | // If the impl is not co-located with either self-type or | |
246 | // trait-type, then fallback to a format that identifies | |
247 | // the module more clearly. | |
248 | self.path_append_impl( | |
249 | |cx| cx.print_def_path(parent_def_id, &[]), | |
250 | &key.disambiguated_data, | |
251 | self_ty, | |
252 | impl_trait_ref, | |
253 | ) | |
254 | } else { | |
255 | // Otherwise, try to give a good form that would be valid language | |
256 | // syntax. Preferably using associated item notation. | |
257 | self.path_qualified(self_ty, impl_trait_ref) | |
258 | } | |
259 | } | |
260 | } | |
261 | ||
262 | /// As a heuristic, when we see an impl, if we see that the | |
263 | /// 'self type' is a type defined in the same module as the impl, | |
264 | /// we can omit including the path to the impl itself. This | |
265 | /// function tries to find a "characteristic `DefId`" for a | |
266 | /// type. It's just a heuristic so it makes some questionable | |
267 | /// decisions and we may want to adjust it later. | |
268 | pub fn characteristic_def_id_of_type(ty: Ty<'_>) -> Option<DefId> { | |
e74abb32 | 269 | match ty.kind { |
532ac7d7 XL |
270 | ty::Adt(adt_def, _) => Some(adt_def.did), |
271 | ||
272 | ty::Dynamic(data, ..) => data.principal_def_id(), | |
273 | ||
dfeec247 | 274 | ty::Array(subty, _) | ty::Slice(subty) => characteristic_def_id_of_type(subty), |
532ac7d7 XL |
275 | |
276 | ty::RawPtr(mt) => characteristic_def_id_of_type(mt.ty), | |
277 | ||
278 | ty::Ref(_, ty, _) => characteristic_def_id_of_type(ty), | |
279 | ||
dfeec247 | 280 | ty::Tuple(ref tys) => { |
f9f354fc | 281 | tys.iter().find_map(|ty| characteristic_def_id_of_type(ty.expect_ty())) |
dfeec247 XL |
282 | } |
283 | ||
284 | ty::FnDef(def_id, _) | |
285 | | ty::Closure(def_id, _) | |
286 | | ty::Generator(def_id, _, _) | |
287 | | ty::Foreign(def_id) => Some(def_id), | |
288 | ||
289 | ty::Bool | |
290 | | ty::Char | |
291 | | ty::Int(_) | |
292 | | ty::Uint(_) | |
293 | | ty::Str | |
294 | | ty::FnPtr(_) | |
295 | | ty::Projection(_) | |
296 | | ty::Placeholder(..) | |
dfeec247 XL |
297 | | ty::Param(_) |
298 | | ty::Opaque(..) | |
299 | | ty::Infer(_) | |
300 | | ty::Bound(..) | |
f035d41b | 301 | | ty::Error(_) |
dfeec247 XL |
302 | | ty::GeneratorWitness(..) |
303 | | ty::Never | |
304 | | ty::Float(_) => None, | |
532ac7d7 XL |
305 | } |
306 | } | |
307 | ||
dc9dc135 | 308 | impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::RegionKind { |
532ac7d7 XL |
309 | type Output = P::Region; |
310 | type Error = P::Error; | |
311 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error> { | |
312 | cx.print_region(self) | |
313 | } | |
314 | } | |
315 | ||
dc9dc135 | 316 | impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::Region<'_> { |
532ac7d7 XL |
317 | type Output = P::Region; |
318 | type Error = P::Error; | |
319 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error> { | |
320 | cx.print_region(self) | |
321 | } | |
322 | } | |
323 | ||
dc9dc135 | 324 | impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for Ty<'tcx> { |
532ac7d7 XL |
325 | type Output = P::Type; |
326 | type Error = P::Error; | |
327 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error> { | |
328 | cx.print_type(self) | |
329 | } | |
330 | } | |
331 | ||
dc9dc135 | 332 | impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for &'tcx ty::List<ty::ExistentialPredicate<'tcx>> { |
532ac7d7 XL |
333 | type Output = P::DynExistential; |
334 | type Error = P::Error; | |
335 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error> { | |
336 | cx.print_dyn_existential(self) | |
337 | } | |
338 | } | |
dc9dc135 XL |
339 | |
340 | impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for &'tcx ty::Const<'tcx> { | |
341 | type Output = P::Const; | |
342 | type Error = P::Error; | |
343 | fn print(&self, cx: P) -> Result<Self::Output, Self::Error> { | |
344 | cx.print_const(self) | |
345 | } | |
346 | } |