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85aaf69f | 1 | // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT |
1a4d82fc JJ |
2 | // file at the top-level directory of this distribution and at |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | /* | |
12 | ||
13 | # check.rs | |
14 | ||
15 | Within the check phase of type check, we check each item one at a time | |
16 | (bodies of function expressions are checked as part of the containing | |
17 | function). Inference is used to supply types wherever they are | |
18 | unknown. | |
19 | ||
20 | By far the most complex case is checking the body of a function. This | |
21 | can be broken down into several distinct phases: | |
22 | ||
23 | - gather: creates type variables to represent the type of each local | |
24 | variable and pattern binding. | |
25 | ||
26 | - main: the main pass does the lion's share of the work: it | |
27 | determines the types of all expressions, resolves | |
28 | methods, checks for most invalid conditions, and so forth. In | |
29 | some cases, where a type is unknown, it may create a type or region | |
30 | variable and use that as the type of an expression. | |
31 | ||
32 | In the process of checking, various constraints will be placed on | |
33 | these type variables through the subtyping relationships requested | |
34 | through the `demand` module. The `infer` module is in charge | |
35 | of resolving those constraints. | |
36 | ||
37 | - regionck: after main is complete, the regionck pass goes over all | |
38 | types looking for regions and making sure that they did not escape | |
39 | into places they are not in scope. This may also influence the | |
40 | final assignments of the various region variables if there is some | |
41 | flexibility. | |
42 | ||
43 | - vtable: find and records the impls to use for each trait bound that | |
44 | appears on a type parameter. | |
45 | ||
46 | - writeback: writes the final types within a function body, replacing | |
47 | type variables with their final inferred types. These final types | |
48 | are written into the `tcx.node_types` table, which should *never* contain | |
49 | any reference to a type variable. | |
50 | ||
51 | ## Intermediate types | |
52 | ||
53 | While type checking a function, the intermediate types for the | |
54 | expressions, blocks, and so forth contained within the function are | |
55 | stored in `fcx.node_types` and `fcx.item_substs`. These types | |
56 | may contain unresolved type variables. After type checking is | |
57 | complete, the functions in the writeback module are used to take the | |
58 | types from this table, resolve them, and then write them into their | |
59 | permanent home in the type context `ccx.tcx`. | |
60 | ||
61 | This means that during inferencing you should use `fcx.write_ty()` | |
62 | and `fcx.expr_ty()` / `fcx.node_ty()` to write/obtain the types of | |
63 | nodes within the function. | |
64 | ||
65 | The types of top-level items, which never contain unbound type | |
66 | variables, are stored directly into the `tcx` tables. | |
67 | ||
68 | n.b.: A type variable is not the same thing as a type parameter. A | |
69 | type variable is rather an "instance" of a type parameter: that is, | |
70 | given a generic function `fn foo<T>(t: T)`: while checking the | |
71 | function `foo`, the type `ty_param(0)` refers to the type `T`, which | |
72 | is treated in abstract. When `foo()` is called, however, `T` will be | |
73 | substituted for a fresh type variable `N`. This variable will | |
74 | eventually be resolved to some concrete type (which might itself be | |
75 | type parameter). | |
76 | ||
77 | */ | |
78 | ||
1a4d82fc | 79 | pub use self::Expectation::*; |
d9579d0f | 80 | pub use self::compare_method::{compare_impl_method, compare_const_impl}; |
1a4d82fc JJ |
81 | use self::TupleArgumentsFlag::*; |
82 | ||
a7813a04 XL |
83 | use astconv::{AstConv, ast_region_to_region, PathParamMode}; |
84 | use check::_match::PatCtxt; | |
9cc50fc6 | 85 | use dep_graph::DepNode; |
85aaf69f | 86 | use fmt_macros::{Parser, Piece, Position}; |
92a42be0 | 87 | use middle::cstore::LOCAL_CRATE; |
54a0048b SL |
88 | use hir::def::{self, Def}; |
89 | use hir::def_id::DefId; | |
a7813a04 | 90 | use rustc::infer::{self, InferCtxt, InferOk, TypeOrigin, TypeTrace, type_variable}; |
54a0048b SL |
91 | use hir::pat_util::{self, pat_id_map}; |
92 | use rustc::ty::subst::{self, Subst, Substs, VecPerParamSpace, ParamSpace}; | |
a7813a04 | 93 | use rustc::traits::{self, ProjectionMode}; |
54a0048b SL |
94 | use rustc::ty::{GenericPredicates, TypeScheme}; |
95 | use rustc::ty::{ParamTy, ParameterEnvironment}; | |
96 | use rustc::ty::{LvaluePreference, NoPreference, PreferMutLvalue}; | |
97 | use rustc::ty::{self, ToPolyTraitRef, Ty, TyCtxt, Visibility}; | |
98 | use rustc::ty::{MethodCall, MethodCallee}; | |
99 | use rustc::ty::adjustment; | |
a7813a04 | 100 | use rustc::ty::fold::TypeFoldable; |
54a0048b | 101 | use rustc::ty::util::{Representability, IntTypeExt}; |
c1a9b12d SL |
102 | use require_c_abi_if_variadic; |
103 | use rscope::{ElisionFailureInfo, RegionScope}; | |
7453a54e | 104 | use session::{Session, CompileResult}; |
e9174d1e | 105 | use {CrateCtxt, lookup_full_def}; |
1a4d82fc | 106 | use TypeAndSubsts; |
1a4d82fc | 107 | use lint; |
c34b1796 | 108 | use util::common::{block_query, ErrorReported, indenter, loop_query}; |
1a4d82fc JJ |
109 | use util::nodemap::{DefIdMap, FnvHashMap, NodeMap}; |
110 | ||
111 | use std::cell::{Cell, Ref, RefCell}; | |
e9174d1e | 112 | use std::collections::{HashSet}; |
1a4d82fc | 113 | use std::mem::replace; |
a7813a04 | 114 | use std::ops::Deref; |
7453a54e | 115 | use syntax::abi::Abi; |
e9174d1e | 116 | use syntax::ast; |
b039eaaf SL |
117 | use syntax::attr; |
118 | use syntax::attr::AttrMetaMethods; | |
119 | use syntax::codemap::{self, Span, Spanned}; | |
9cc50fc6 | 120 | use syntax::errors::DiagnosticBuilder; |
a7813a04 | 121 | use syntax::parse::token::{self, InternedString, keywords}; |
1a4d82fc | 122 | use syntax::ptr::P; |
9cc50fc6 | 123 | use syntax::util::lev_distance::find_best_match_for_name; |
e9174d1e | 124 | |
54a0048b SL |
125 | use rustc::hir::intravisit::{self, Visitor}; |
126 | use rustc::hir::{self, PatKind}; | |
127 | use rustc::hir::print as pprust; | |
b039eaaf | 128 | use rustc_back::slice; |
54a0048b | 129 | use rustc_const_eval::eval_repeat_count; |
1a4d82fc JJ |
130 | |
131 | mod assoc; | |
85aaf69f | 132 | pub mod dropck; |
1a4d82fc | 133 | pub mod _match; |
1a4d82fc | 134 | pub mod writeback; |
1a4d82fc | 135 | pub mod regionck; |
85aaf69f | 136 | pub mod coercion; |
1a4d82fc JJ |
137 | pub mod demand; |
138 | pub mod method; | |
139 | mod upvar; | |
e9174d1e | 140 | mod wfcheck; |
9346a6ac | 141 | mod cast; |
1a4d82fc JJ |
142 | mod closure; |
143 | mod callee; | |
85aaf69f | 144 | mod compare_method; |
e9174d1e | 145 | mod intrinsic; |
c34b1796 | 146 | mod op; |
1a4d82fc | 147 | |
1a4d82fc JJ |
148 | /// closures defined within the function. For example: |
149 | /// | |
150 | /// fn foo() { | |
151 | /// bar(move|| { ... }) | |
152 | /// } | |
153 | /// | |
154 | /// Here, the function `foo()` and the closure passed to | |
155 | /// `bar()` will each have their own `FnCtxt`, but they will | |
156 | /// share the inherited fields. | |
a7813a04 XL |
157 | pub struct Inherited<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { |
158 | ccx: &'a CrateCtxt<'a, 'gcx>, | |
159 | infcx: InferCtxt<'a, 'gcx, 'tcx>, | |
1a4d82fc | 160 | locals: RefCell<NodeMap<Ty<'tcx>>>, |
1a4d82fc | 161 | |
7453a54e SL |
162 | fulfillment_cx: RefCell<traits::FulfillmentContext<'tcx>>, |
163 | ||
85aaf69f SL |
164 | // When we process a call like `c()` where `c` is a closure type, |
165 | // we may not have decided yet whether `c` is a `Fn`, `FnMut`, or | |
166 | // `FnOnce` closure. In that case, we defer full resolution of the | |
167 | // call until upvar inference can kick in and make the | |
168 | // decision. We keep these deferred resolutions grouped by the | |
169 | // def-id of the closure, so that once we decide, we can easily go | |
170 | // back and process them. | |
a7813a04 | 171 | deferred_call_resolutions: RefCell<DefIdMap<Vec<DeferredCallResolutionHandler<'gcx, 'tcx>>>>, |
c34b1796 | 172 | |
9346a6ac | 173 | deferred_cast_checks: RefCell<Vec<cast::CastCheck<'tcx>>>, |
85aaf69f SL |
174 | } |
175 | ||
a7813a04 XL |
176 | impl<'a, 'gcx, 'tcx> Deref for Inherited<'a, 'gcx, 'tcx> { |
177 | type Target = InferCtxt<'a, 'gcx, 'tcx>; | |
178 | fn deref(&self) -> &Self::Target { | |
179 | &self.infcx | |
180 | } | |
181 | } | |
182 | ||
183 | trait DeferredCallResolution<'gcx, 'tcx> { | |
184 | fn resolve<'a>(&mut self, fcx: &FnCtxt<'a, 'gcx, 'tcx>); | |
1a4d82fc JJ |
185 | } |
186 | ||
a7813a04 | 187 | type DeferredCallResolutionHandler<'gcx, 'tcx> = Box<DeferredCallResolution<'gcx, 'tcx>+'tcx>; |
85aaf69f | 188 | |
1a4d82fc JJ |
189 | /// When type-checking an expression, we propagate downward |
190 | /// whatever type hint we are able in the form of an `Expectation`. | |
62682a34 | 191 | #[derive(Copy, Clone, Debug)] |
c34b1796 | 192 | pub enum Expectation<'tcx> { |
1a4d82fc JJ |
193 | /// We know nothing about what type this expression should have. |
194 | NoExpectation, | |
195 | ||
196 | /// This expression should have the type given (or some subtype) | |
197 | ExpectHasType(Ty<'tcx>), | |
198 | ||
199 | /// This expression will be cast to the `Ty` | |
200 | ExpectCastableToType(Ty<'tcx>), | |
201 | ||
202 | /// This rvalue expression will be wrapped in `&` or `Box` and coerced | |
203 | /// to `&Ty` or `Box<Ty>`, respectively. `Ty` is `[A]` or `Trait`. | |
204 | ExpectRvalueLikeUnsized(Ty<'tcx>), | |
205 | } | |
206 | ||
a7813a04 | 207 | impl<'a, 'gcx, 'tcx> Expectation<'tcx> { |
1a4d82fc JJ |
208 | // Disregard "castable to" expectations because they |
209 | // can lead us astray. Consider for example `if cond | |
210 | // {22} else {c} as u8` -- if we propagate the | |
211 | // "castable to u8" constraint to 22, it will pick the | |
212 | // type 22u8, which is overly constrained (c might not | |
213 | // be a u8). In effect, the problem is that the | |
214 | // "castable to" expectation is not the tightest thing | |
215 | // we can say, so we want to drop it in this case. | |
216 | // The tightest thing we can say is "must unify with | |
217 | // else branch". Note that in the case of a "has type" | |
218 | // constraint, this limitation does not hold. | |
219 | ||
220 | // If the expected type is just a type variable, then don't use | |
221 | // an expected type. Otherwise, we might write parts of the type | |
222 | // when checking the 'then' block which are incompatible with the | |
223 | // 'else' branch. | |
a7813a04 | 224 | fn adjust_for_branches(&self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Expectation<'tcx> { |
1a4d82fc JJ |
225 | match *self { |
226 | ExpectHasType(ety) => { | |
a7813a04 | 227 | let ety = fcx.shallow_resolve(ety); |
c1a9b12d | 228 | if !ety.is_ty_var() { |
1a4d82fc JJ |
229 | ExpectHasType(ety) |
230 | } else { | |
231 | NoExpectation | |
232 | } | |
233 | } | |
234 | ExpectRvalueLikeUnsized(ety) => { | |
235 | ExpectRvalueLikeUnsized(ety) | |
236 | } | |
237 | _ => NoExpectation | |
238 | } | |
239 | } | |
a7813a04 XL |
240 | |
241 | /// Provide an expectation for an rvalue expression given an *optional* | |
242 | /// hint, which is not required for type safety (the resulting type might | |
243 | /// be checked higher up, as is the case with `&expr` and `box expr`), but | |
244 | /// is useful in determining the concrete type. | |
245 | /// | |
246 | /// The primary use case is where the expected type is a fat pointer, | |
247 | /// like `&[isize]`. For example, consider the following statement: | |
248 | /// | |
249 | /// let x: &[isize] = &[1, 2, 3]; | |
250 | /// | |
251 | /// In this case, the expected type for the `&[1, 2, 3]` expression is | |
252 | /// `&[isize]`. If however we were to say that `[1, 2, 3]` has the | |
253 | /// expectation `ExpectHasType([isize])`, that would be too strong -- | |
254 | /// `[1, 2, 3]` does not have the type `[isize]` but rather `[isize; 3]`. | |
255 | /// It is only the `&[1, 2, 3]` expression as a whole that can be coerced | |
256 | /// to the type `&[isize]`. Therefore, we propagate this more limited hint, | |
257 | /// which still is useful, because it informs integer literals and the like. | |
258 | /// See the test case `test/run-pass/coerce-expect-unsized.rs` and #20169 | |
259 | /// for examples of where this comes up,. | |
260 | fn rvalue_hint(fcx: &FnCtxt<'a, 'gcx, 'tcx>, ty: Ty<'tcx>) -> Expectation<'tcx> { | |
261 | match fcx.tcx.struct_tail(ty).sty { | |
262 | ty::TySlice(_) | ty::TyStr | ty::TyTrait(..) => { | |
263 | ExpectRvalueLikeUnsized(ty) | |
264 | } | |
265 | _ => ExpectHasType(ty) | |
266 | } | |
267 | } | |
268 | ||
269 | // Resolves `expected` by a single level if it is a variable. If | |
270 | // there is no expected type or resolution is not possible (e.g., | |
271 | // no constraints yet present), just returns `None`. | |
272 | fn resolve(self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Expectation<'tcx> { | |
273 | match self { | |
274 | NoExpectation => { | |
275 | NoExpectation | |
276 | } | |
277 | ExpectCastableToType(t) => { | |
278 | ExpectCastableToType(fcx.resolve_type_vars_if_possible(&t)) | |
279 | } | |
280 | ExpectHasType(t) => { | |
281 | ExpectHasType(fcx.resolve_type_vars_if_possible(&t)) | |
282 | } | |
283 | ExpectRvalueLikeUnsized(t) => { | |
284 | ExpectRvalueLikeUnsized(fcx.resolve_type_vars_if_possible(&t)) | |
285 | } | |
286 | } | |
287 | } | |
288 | ||
289 | fn to_option(self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Option<Ty<'tcx>> { | |
290 | match self.resolve(fcx) { | |
291 | NoExpectation => None, | |
292 | ExpectCastableToType(ty) | | |
293 | ExpectHasType(ty) | | |
294 | ExpectRvalueLikeUnsized(ty) => Some(ty), | |
295 | } | |
296 | } | |
297 | ||
298 | fn only_has_type(self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Option<Ty<'tcx>> { | |
299 | match self.resolve(fcx) { | |
300 | ExpectHasType(ty) => Some(ty), | |
301 | _ => None | |
302 | } | |
303 | } | |
1a4d82fc JJ |
304 | } |
305 | ||
306 | #[derive(Copy, Clone)] | |
307 | pub struct UnsafetyState { | |
308 | pub def: ast::NodeId, | |
e9174d1e | 309 | pub unsafety: hir::Unsafety, |
c1a9b12d | 310 | pub unsafe_push_count: u32, |
1a4d82fc JJ |
311 | from_fn: bool |
312 | } | |
313 | ||
314 | impl UnsafetyState { | |
e9174d1e | 315 | pub fn function(unsafety: hir::Unsafety, def: ast::NodeId) -> UnsafetyState { |
c1a9b12d | 316 | UnsafetyState { def: def, unsafety: unsafety, unsafe_push_count: 0, from_fn: true } |
1a4d82fc JJ |
317 | } |
318 | ||
e9174d1e | 319 | pub fn recurse(&mut self, blk: &hir::Block) -> UnsafetyState { |
1a4d82fc JJ |
320 | match self.unsafety { |
321 | // If this unsafe, then if the outer function was already marked as | |
322 | // unsafe we shouldn't attribute the unsafe'ness to the block. This | |
323 | // way the block can be warned about instead of ignoring this | |
324 | // extraneous block (functions are never warned about). | |
e9174d1e | 325 | hir::Unsafety::Unsafe if self.from_fn => *self, |
1a4d82fc JJ |
326 | |
327 | unsafety => { | |
c1a9b12d | 328 | let (unsafety, def, count) = match blk.rules { |
e9174d1e | 329 | hir::PushUnsafeBlock(..) => |
c1a9b12d | 330 | (unsafety, blk.id, self.unsafe_push_count.checked_add(1).unwrap()), |
e9174d1e | 331 | hir::PopUnsafeBlock(..) => |
c1a9b12d | 332 | (unsafety, blk.id, self.unsafe_push_count.checked_sub(1).unwrap()), |
e9174d1e SL |
333 | hir::UnsafeBlock(..) => |
334 | (hir::Unsafety::Unsafe, blk.id, self.unsafe_push_count), | |
b039eaaf | 335 | hir::DefaultBlock | hir::PushUnstableBlock | hir:: PopUnstableBlock => |
c1a9b12d | 336 | (unsafety, self.def, self.unsafe_push_count), |
1a4d82fc JJ |
337 | }; |
338 | UnsafetyState{ def: def, | |
c1a9b12d SL |
339 | unsafety: unsafety, |
340 | unsafe_push_count: count, | |
341 | from_fn: false } | |
1a4d82fc JJ |
342 | } |
343 | } | |
344 | } | |
345 | } | |
346 | ||
1a4d82fc | 347 | #[derive(Clone)] |
a7813a04 XL |
348 | pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { |
349 | ast_ty_to_ty_cache: RefCell<NodeMap<Ty<'tcx>>>, | |
350 | ||
1a4d82fc JJ |
351 | body_id: ast::NodeId, |
352 | ||
353 | // This flag is set to true if, during the writeback phase, we encounter | |
354 | // a type error in this function. | |
355 | writeback_errors: Cell<bool>, | |
356 | ||
357 | // Number of errors that had been reported when we started | |
358 | // checking this function. On exit, if we find that *more* errors | |
359 | // have been reported, we will skip regionck and other work that | |
360 | // expects the types within the function to be consistent. | |
c34b1796 | 361 | err_count_on_creation: usize, |
1a4d82fc JJ |
362 | |
363 | ret_ty: ty::FnOutput<'tcx>, | |
364 | ||
365 | ps: RefCell<UnsafetyState>, | |
366 | ||
a7813a04 XL |
367 | inh: &'a Inherited<'a, 'gcx, 'tcx>, |
368 | } | |
369 | ||
370 | impl<'a, 'gcx, 'tcx> Deref for FnCtxt<'a, 'gcx, 'tcx> { | |
371 | type Target = Inherited<'a, 'gcx, 'tcx>; | |
372 | fn deref(&self) -> &Self::Target { | |
373 | &self.inh | |
374 | } | |
375 | } | |
1a4d82fc | 376 | |
a7813a04 XL |
377 | /// Helper type of a temporary returned by ccx.inherited(...). |
378 | /// Necessary because we can't write the following bound: | |
379 | /// F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(Inherited<'b, 'gcx, 'tcx>). | |
380 | pub struct InheritedBuilder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { | |
381 | ccx: &'a CrateCtxt<'a, 'gcx>, | |
382 | infcx: infer::InferCtxtBuilder<'a, 'gcx, 'tcx> | |
1a4d82fc JJ |
383 | } |
384 | ||
a7813a04 XL |
385 | impl<'a, 'gcx, 'tcx> CrateCtxt<'a, 'gcx> { |
386 | pub fn inherited(&'a self, param_env: Option<ty::ParameterEnvironment<'gcx>>) | |
387 | -> InheritedBuilder<'a, 'gcx, 'tcx> { | |
388 | InheritedBuilder { | |
389 | ccx: self, | |
390 | infcx: self.tcx.infer_ctxt(Some(ty::Tables::empty()), | |
391 | param_env, | |
392 | ProjectionMode::AnyFinal) | |
1a4d82fc JJ |
393 | } |
394 | } | |
a7813a04 XL |
395 | } |
396 | ||
397 | impl<'a, 'gcx, 'tcx> InheritedBuilder<'a, 'gcx, 'tcx> { | |
398 | fn enter<F, R>(&'tcx mut self, f: F) -> R | |
399 | where F: for<'b> FnOnce(Inherited<'b, 'gcx, 'tcx>) -> R | |
400 | { | |
401 | let ccx = self.ccx; | |
402 | self.infcx.enter(|infcx| { | |
403 | f(Inherited { | |
404 | ccx: ccx, | |
405 | infcx: infcx, | |
406 | fulfillment_cx: RefCell::new(traits::FulfillmentContext::new()), | |
407 | locals: RefCell::new(NodeMap()), | |
408 | deferred_call_resolutions: RefCell::new(DefIdMap()), | |
409 | deferred_cast_checks: RefCell::new(Vec::new()), | |
410 | }) | |
411 | }) | |
412 | } | |
413 | } | |
1a4d82fc | 414 | |
a7813a04 | 415 | impl<'a, 'gcx, 'tcx> Inherited<'a, 'gcx, 'tcx> { |
1a4d82fc | 416 | fn normalize_associated_types_in<T>(&self, |
1a4d82fc JJ |
417 | span: Span, |
418 | body_id: ast::NodeId, | |
419 | value: &T) | |
420 | -> T | |
9cc50fc6 | 421 | where T : TypeFoldable<'tcx> |
1a4d82fc | 422 | { |
a7813a04 | 423 | assoc::normalize_associated_types_in(self, |
7453a54e | 424 | &mut self.fulfillment_cx.borrow_mut(), |
c1a9b12d | 425 | span, |
1a4d82fc JJ |
426 | body_id, |
427 | value) | |
428 | } | |
429 | ||
430 | } | |
431 | ||
1a4d82fc | 432 | struct CheckItemTypesVisitor<'a, 'tcx: 'a> { ccx: &'a CrateCtxt<'a, 'tcx> } |
9346a6ac | 433 | struct CheckItemBodiesVisitor<'a, 'tcx: 'a> { ccx: &'a CrateCtxt<'a, 'tcx> } |
1a4d82fc | 434 | |
85aaf69f | 435 | impl<'a, 'tcx> Visitor<'tcx> for CheckItemTypesVisitor<'a, 'tcx> { |
e9174d1e | 436 | fn visit_item(&mut self, i: &'tcx hir::Item) { |
9346a6ac | 437 | check_item_type(self.ccx, i); |
92a42be0 | 438 | intravisit::walk_item(self, i); |
1a4d82fc JJ |
439 | } |
440 | ||
e9174d1e | 441 | fn visit_ty(&mut self, t: &'tcx hir::Ty) { |
1a4d82fc | 442 | match t.node { |
e9174d1e | 443 | hir::TyFixedLengthVec(_, ref expr) => { |
7453a54e | 444 | check_const_in_type(self.ccx, &expr, self.ccx.tcx.types.usize); |
1a4d82fc JJ |
445 | } |
446 | _ => {} | |
447 | } | |
448 | ||
92a42be0 | 449 | intravisit::walk_ty(self, t); |
1a4d82fc JJ |
450 | } |
451 | } | |
452 | ||
9346a6ac | 453 | impl<'a, 'tcx> Visitor<'tcx> for CheckItemBodiesVisitor<'a, 'tcx> { |
e9174d1e | 454 | fn visit_item(&mut self, i: &'tcx hir::Item) { |
9346a6ac | 455 | check_item_body(self.ccx, i); |
9346a6ac AL |
456 | } |
457 | } | |
458 | ||
7453a54e SL |
459 | pub fn check_wf_new(ccx: &CrateCtxt) -> CompileResult { |
460 | ccx.tcx.sess.track_errors(|| { | |
9cc50fc6 SL |
461 | let mut visit = wfcheck::CheckTypeWellFormedVisitor::new(ccx); |
462 | ccx.tcx.visit_all_items_in_krate(DepNode::WfCheck, &mut visit); | |
7453a54e | 463 | }) |
e9174d1e | 464 | } |
c34b1796 | 465 | |
7453a54e SL |
466 | pub fn check_item_types(ccx: &CrateCtxt) -> CompileResult { |
467 | ccx.tcx.sess.track_errors(|| { | |
9cc50fc6 SL |
468 | let mut visit = CheckItemTypesVisitor { ccx: ccx }; |
469 | ccx.tcx.visit_all_items_in_krate(DepNode::TypeckItemType, &mut visit); | |
7453a54e | 470 | }) |
e9174d1e SL |
471 | } |
472 | ||
7453a54e SL |
473 | pub fn check_item_bodies(ccx: &CrateCtxt) -> CompileResult { |
474 | ccx.tcx.sess.track_errors(|| { | |
9cc50fc6 SL |
475 | let mut visit = CheckItemBodiesVisitor { ccx: ccx }; |
476 | ccx.tcx.visit_all_items_in_krate(DepNode::TypeckItemBody, &mut visit); | |
7453a54e | 477 | }) |
e9174d1e | 478 | } |
9346a6ac | 479 | |
7453a54e SL |
480 | pub fn check_drop_impls(ccx: &CrateCtxt) -> CompileResult { |
481 | ccx.tcx.sess.track_errors(|| { | |
9cc50fc6 SL |
482 | let _task = ccx.tcx.dep_graph.in_task(DepNode::Dropck); |
483 | let drop_trait = match ccx.tcx.lang_items.drop_trait() { | |
484 | Some(id) => ccx.tcx.lookup_trait_def(id), None => { return } | |
485 | }; | |
486 | drop_trait.for_each_impl(ccx.tcx, |drop_impl_did| { | |
487 | let _task = ccx.tcx.dep_graph.in_task(DepNode::DropckImpl(drop_impl_did)); | |
488 | if drop_impl_did.is_local() { | |
a7813a04 | 489 | match dropck::check_drop_impl(ccx, drop_impl_did) { |
9cc50fc6 SL |
490 | Ok(()) => {} |
491 | Err(()) => { | |
492 | assert!(ccx.tcx.sess.has_errors()); | |
493 | } | |
c34b1796 AL |
494 | } |
495 | } | |
9cc50fc6 | 496 | }); |
7453a54e | 497 | }) |
1a4d82fc JJ |
498 | } |
499 | ||
500 | fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, | |
e9174d1e SL |
501 | decl: &'tcx hir::FnDecl, |
502 | body: &'tcx hir::Block, | |
85aaf69f SL |
503 | fn_id: ast::NodeId, |
504 | fn_span: Span, | |
1a4d82fc | 505 | raw_fty: Ty<'tcx>, |
a7813a04 | 506 | param_env: ty::ParameterEnvironment<'tcx>) |
85aaf69f | 507 | { |
a7813a04 XL |
508 | let fn_ty = match raw_fty.sty { |
509 | ty::TyFnDef(_, _, f) => f, | |
54a0048b | 510 | _ => span_bug!(body.span, "check_bare_fn: function type expected") |
a7813a04 XL |
511 | }; |
512 | ||
513 | ccx.inherited(Some(param_env)).enter(|inh| { | |
514 | // Compute the fty from point of view of inside fn. | |
515 | let fn_scope = inh.tcx.region_maps.call_site_extent(fn_id, body.id); | |
516 | let fn_sig = | |
517 | fn_ty.sig.subst(inh.tcx, &inh.parameter_environment.free_substs); | |
518 | let fn_sig = | |
519 | inh.tcx.liberate_late_bound_regions(fn_scope, &fn_sig); | |
520 | let fn_sig = | |
521 | inh.normalize_associated_types_in(body.span, body.id, &fn_sig); | |
522 | ||
523 | let fcx = check_fn(&inh, fn_ty.unsafety, fn_id, &fn_sig, decl, fn_id, body); | |
524 | ||
525 | fcx.select_all_obligations_and_apply_defaults(); | |
526 | fcx.closure_analyze_fn(body); | |
527 | fcx.select_obligations_where_possible(); | |
528 | fcx.check_casts(); | |
529 | fcx.select_all_obligations_or_error(); // Casts can introduce new obligations. | |
530 | ||
531 | fcx.regionck_fn(fn_id, fn_span, decl, body); | |
532 | fcx.resolve_type_vars_in_fn(decl, body); | |
533 | }); | |
1a4d82fc JJ |
534 | } |
535 | ||
a7813a04 XL |
536 | struct GatherLocalsVisitor<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { |
537 | fcx: &'a FnCtxt<'a, 'gcx, 'tcx> | |
1a4d82fc JJ |
538 | } |
539 | ||
a7813a04 | 540 | impl<'a, 'gcx, 'tcx> GatherLocalsVisitor<'a, 'gcx, 'tcx> { |
1a4d82fc JJ |
541 | fn assign(&mut self, _span: Span, nid: ast::NodeId, ty_opt: Option<Ty<'tcx>>) -> Ty<'tcx> { |
542 | match ty_opt { | |
543 | None => { | |
544 | // infer the variable's type | |
a7813a04 XL |
545 | let var_ty = self.fcx.next_ty_var(); |
546 | self.fcx.locals.borrow_mut().insert(nid, var_ty); | |
1a4d82fc JJ |
547 | var_ty |
548 | } | |
549 | Some(typ) => { | |
550 | // take type that the user specified | |
a7813a04 | 551 | self.fcx.locals.borrow_mut().insert(nid, typ); |
1a4d82fc JJ |
552 | typ |
553 | } | |
554 | } | |
555 | } | |
556 | } | |
557 | ||
a7813a04 | 558 | impl<'a, 'gcx, 'tcx> Visitor<'gcx> for GatherLocalsVisitor<'a, 'gcx, 'tcx> { |
1a4d82fc | 559 | // Add explicitly-declared locals. |
a7813a04 | 560 | fn visit_local(&mut self, local: &'gcx hir::Local) { |
1a4d82fc | 561 | let o_ty = match local.ty { |
7453a54e | 562 | Some(ref ty) => Some(self.fcx.to_ty(&ty)), |
1a4d82fc JJ |
563 | None => None |
564 | }; | |
565 | self.assign(local.span, local.id, o_ty); | |
62682a34 SL |
566 | debug!("Local variable {:?} is assigned type {}", |
567 | local.pat, | |
a7813a04 XL |
568 | self.fcx.ty_to_string( |
569 | self.fcx.locals.borrow().get(&local.id).unwrap().clone())); | |
92a42be0 | 570 | intravisit::walk_local(self, local); |
1a4d82fc JJ |
571 | } |
572 | ||
573 | // Add pattern bindings. | |
a7813a04 | 574 | fn visit_pat(&mut self, p: &'gcx hir::Pat) { |
7453a54e | 575 | if let PatKind::Ident(_, ref path1, _) = p.node { |
a7813a04 | 576 | if pat_util::pat_is_binding(&self.fcx.tcx.def_map.borrow(), p) { |
1a4d82fc JJ |
577 | let var_ty = self.assign(p.span, p.id, None); |
578 | ||
579 | self.fcx.require_type_is_sized(var_ty, p.span, | |
580 | traits::VariableType(p.id)); | |
581 | ||
62682a34 | 582 | debug!("Pattern binding {} is assigned to {} with type {:?}", |
c1a9b12d | 583 | path1.node, |
a7813a04 XL |
584 | self.fcx.ty_to_string( |
585 | self.fcx.locals.borrow().get(&p.id).unwrap().clone()), | |
62682a34 | 586 | var_ty); |
1a4d82fc JJ |
587 | } |
588 | } | |
92a42be0 | 589 | intravisit::walk_pat(self, p); |
1a4d82fc JJ |
590 | } |
591 | ||
a7813a04 | 592 | fn visit_block(&mut self, b: &'gcx hir::Block) { |
1a4d82fc JJ |
593 | // non-obvious: the `blk` variable maps to region lb, so |
594 | // we have to keep this up-to-date. This | |
595 | // is... unfortunate. It'd be nice to not need this. | |
92a42be0 | 596 | intravisit::walk_block(self, b); |
1a4d82fc JJ |
597 | } |
598 | ||
599 | // Since an expr occurs as part of the type fixed size arrays we | |
600 | // need to record the type for that node | |
a7813a04 | 601 | fn visit_ty(&mut self, t: &'gcx hir::Ty) { |
1a4d82fc | 602 | match t.node { |
e9174d1e | 603 | hir::TyFixedLengthVec(ref ty, ref count_expr) => { |
7453a54e | 604 | self.visit_ty(&ty); |
a7813a04 | 605 | self.fcx.check_expr_with_hint(&count_expr, self.fcx.tcx.types.usize); |
1a4d82fc | 606 | } |
b039eaaf | 607 | hir::TyBareFn(ref function_declaration) => { |
92a42be0 | 608 | intravisit::walk_fn_decl_nopat(self, &function_declaration.decl); |
b039eaaf SL |
609 | walk_list!(self, visit_lifetime_def, &function_declaration.lifetimes); |
610 | } | |
92a42be0 | 611 | _ => intravisit::walk_ty(self, t) |
1a4d82fc JJ |
612 | } |
613 | } | |
614 | ||
92a42be0 | 615 | // Don't descend into the bodies of nested closures |
a7813a04 XL |
616 | fn visit_fn(&mut self, _: intravisit::FnKind<'gcx>, _: &'gcx hir::FnDecl, |
617 | _: &'gcx hir::Block, _: Span, _: ast::NodeId) { } | |
1a4d82fc JJ |
618 | } |
619 | ||
620 | /// Helper used by check_bare_fn and check_expr_fn. Does the grungy work of checking a function | |
621 | /// body and returns the function context used for that purpose, since in the case of a fn item | |
622 | /// there is still a bit more to do. | |
623 | /// | |
624 | /// * ... | |
625 | /// * inherited: other fields inherited from the enclosing fn (if any) | |
a7813a04 XL |
626 | fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>, |
627 | unsafety: hir::Unsafety, | |
628 | unsafety_id: ast::NodeId, | |
629 | fn_sig: &ty::FnSig<'tcx>, | |
630 | decl: &'gcx hir::FnDecl, | |
631 | fn_id: ast::NodeId, | |
632 | body: &'gcx hir::Block) | |
633 | -> FnCtxt<'a, 'gcx, 'tcx> | |
1a4d82fc | 634 | { |
a7813a04 | 635 | let tcx = inherited.tcx; |
1a4d82fc | 636 | |
c34b1796 | 637 | let arg_tys = &fn_sig.inputs; |
1a4d82fc JJ |
638 | let ret_ty = fn_sig.output; |
639 | ||
62682a34 SL |
640 | debug!("check_fn(arg_tys={:?}, ret_ty={:?}, fn_id={})", |
641 | arg_tys, | |
642 | ret_ty, | |
1a4d82fc JJ |
643 | fn_id); |
644 | ||
645 | // Create the function context. This is either derived from scratch or, | |
646 | // in the case of function expressions, based on the outer context. | |
a7813a04 XL |
647 | let fcx = FnCtxt::new(inherited, ret_ty, body.id); |
648 | *fcx.ps.borrow_mut() = UnsafetyState::function(unsafety, unsafety_id); | |
1a4d82fc | 649 | |
1a4d82fc JJ |
650 | if let ty::FnConverging(ret_ty) = ret_ty { |
651 | fcx.require_type_is_sized(ret_ty, decl.output.span(), traits::ReturnType); | |
1a4d82fc JJ |
652 | } |
653 | ||
92a42be0 | 654 | debug!("fn-sig-map: fn_id={} fn_sig={:?}", fn_id, fn_sig); |
1a4d82fc | 655 | |
92a42be0 | 656 | inherited.tables.borrow_mut().liberated_fn_sigs.insert(fn_id, fn_sig.clone()); |
1a4d82fc JJ |
657 | |
658 | { | |
659 | let mut visit = GatherLocalsVisitor { fcx: &fcx, }; | |
660 | ||
661 | // Add formal parameters. | |
62682a34 | 662 | for (arg_ty, input) in arg_tys.iter().zip(&decl.inputs) { |
e9174d1e SL |
663 | // The type of the argument must be well-formed. |
664 | // | |
665 | // NB -- this is now checked in wfcheck, but that | |
666 | // currently only results in warnings, so we issue an | |
667 | // old-style WF obligation here so that we still get the | |
668 | // errors that we used to get. | |
669 | fcx.register_old_wf_obligation(arg_ty, input.ty.span, traits::MiscObligation); | |
670 | ||
1a4d82fc JJ |
671 | // Create type variables for each argument. |
672 | pat_util::pat_bindings( | |
673 | &tcx.def_map, | |
7453a54e | 674 | &input.pat, |
1a4d82fc JJ |
675 | |_bm, pat_id, sp, _path| { |
676 | let var_ty = visit.assign(sp, pat_id, None); | |
677 | fcx.require_type_is_sized(var_ty, sp, | |
678 | traits::VariableType(pat_id)); | |
679 | }); | |
680 | ||
681 | // Check the pattern. | |
a7813a04 | 682 | let pcx = PatCtxt { |
1a4d82fc | 683 | fcx: &fcx, |
7453a54e | 684 | map: pat_id_map(&tcx.def_map, &input.pat), |
1a4d82fc | 685 | }; |
a7813a04 | 686 | pcx.check_pat(&input.pat, *arg_ty); |
1a4d82fc JJ |
687 | } |
688 | ||
689 | visit.visit_block(body); | |
690 | } | |
691 | ||
a7813a04 | 692 | fcx.check_block_with_expected(body, match ret_ty { |
1a4d82fc JJ |
693 | ty::FnConverging(result_type) => ExpectHasType(result_type), |
694 | ty::FnDiverging => NoExpectation | |
695 | }); | |
696 | ||
62682a34 SL |
697 | for (input, arg) in decl.inputs.iter().zip(arg_tys) { |
698 | fcx.write_ty(input.id, arg); | |
1a4d82fc JJ |
699 | } |
700 | ||
701 | fcx | |
702 | } | |
703 | ||
704 | pub fn check_struct(ccx: &CrateCtxt, id: ast::NodeId, span: Span) { | |
705 | let tcx = ccx.tcx; | |
706 | ||
707 | check_representable(tcx, span, id, "struct"); | |
1a4d82fc | 708 | |
b039eaaf | 709 | if tcx.lookup_simd(ccx.tcx.map.local_def_id(id)) { |
1a4d82fc JJ |
710 | check_simd(tcx, span, id); |
711 | } | |
712 | } | |
713 | ||
e9174d1e | 714 | pub fn check_item_type<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, it: &'tcx hir::Item) { |
b039eaaf | 715 | debug!("check_item_type(it.id={}, it.name={})", |
1a4d82fc | 716 | it.id, |
b039eaaf | 717 | ccx.tcx.item_path_str(ccx.tcx.map.local_def_id(it.id))); |
1a4d82fc | 718 | let _indenter = indenter(); |
1a4d82fc | 719 | match it.node { |
9346a6ac | 720 | // Consts can play a role in type-checking, so they are included here. |
e9174d1e | 721 | hir::ItemStatic(_, _, ref e) | |
7453a54e | 722 | hir::ItemConst(_, ref e) => check_const(ccx, it.span, &e, it.id), |
e9174d1e | 723 | hir::ItemEnum(ref enum_definition, _) => { |
1a4d82fc JJ |
724 | check_enum_variants(ccx, |
725 | it.span, | |
c34b1796 | 726 | &enum_definition.variants, |
1a4d82fc JJ |
727 | it.id); |
728 | } | |
e9174d1e SL |
729 | hir::ItemFn(..) => {} // entirely within check_item_body |
730 | hir::ItemImpl(_, _, _, _, _, ref impl_items) => { | |
b039eaaf | 731 | debug!("ItemImpl {} with id {}", it.name, it.id); |
54a0048b SL |
732 | let impl_def_id = ccx.tcx.map.local_def_id(it.id); |
733 | match ccx.tcx.impl_trait_ref(impl_def_id) { | |
1a4d82fc | 734 | Some(impl_trait_ref) => { |
a7813a04 XL |
735 | let trait_def_id = impl_trait_ref.def_id; |
736 | ||
737 | check_impl_items_against_trait(ccx, | |
738 | it.span, | |
739 | impl_def_id, | |
740 | &impl_trait_ref, | |
741 | impl_items); | |
742 | check_on_unimplemented( | |
743 | ccx, | |
744 | &ccx.tcx.lookup_trait_def(trait_def_id).generics, | |
745 | it, | |
746 | ccx.tcx.item_name(trait_def_id)); | |
1a4d82fc JJ |
747 | } |
748 | None => { } | |
749 | } | |
1a4d82fc | 750 | } |
a7813a04 XL |
751 | hir::ItemTrait(..) => { |
752 | let def_id = ccx.tcx.map.local_def_id(it.id); | |
753 | let generics = &ccx.tcx.lookup_trait_def(def_id).generics; | |
754 | check_on_unimplemented(ccx, generics, it, it.name); | |
1a4d82fc | 755 | } |
e9174d1e | 756 | hir::ItemStruct(..) => { |
1a4d82fc JJ |
757 | check_struct(ccx, it.id, it.span); |
758 | } | |
92a42be0 | 759 | hir::ItemTy(_, ref generics) => { |
c1a9b12d | 760 | let pty_ty = ccx.tcx.node_id_to_type(it.id); |
92a42be0 | 761 | check_bounds_are_used(ccx, &generics.ty_params, pty_ty); |
1a4d82fc | 762 | } |
e9174d1e | 763 | hir::ItemForeignMod(ref m) => { |
7453a54e | 764 | if m.abi == Abi::RustIntrinsic { |
85aaf69f | 765 | for item in &m.items { |
92a42be0 | 766 | intrinsic::check_intrinsic_type(ccx, item); |
e9174d1e | 767 | } |
7453a54e | 768 | } else if m.abi == Abi::PlatformIntrinsic { |
e9174d1e | 769 | for item in &m.items { |
92a42be0 | 770 | intrinsic::check_platform_intrinsic_type(ccx, item); |
1a4d82fc JJ |
771 | } |
772 | } else { | |
85aaf69f | 773 | for item in &m.items { |
b039eaaf | 774 | let pty = ccx.tcx.lookup_item_type(ccx.tcx.map.local_def_id(item.id)); |
1a4d82fc | 775 | if !pty.generics.types.is_empty() { |
9cc50fc6 | 776 | let mut err = struct_span_err!(ccx.tcx.sess, item.span, E0044, |
1a4d82fc | 777 | "foreign items may not have type parameters"); |
9cc50fc6 | 778 | span_help!(&mut err, item.span, |
e9174d1e SL |
779 | "consider using specialization instead of \ |
780 | type parameters"); | |
9cc50fc6 | 781 | err.emit(); |
1a4d82fc JJ |
782 | } |
783 | ||
e9174d1e | 784 | if let hir::ForeignItemFn(ref fn_decl, _) = item.node { |
c1a9b12d | 785 | require_c_abi_if_variadic(ccx.tcx, fn_decl, m.abi, item.span); |
1a4d82fc JJ |
786 | } |
787 | } | |
788 | } | |
789 | } | |
790 | _ => {/* nothing to do */ } | |
791 | } | |
792 | } | |
793 | ||
e9174d1e | 794 | pub fn check_item_body<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, it: &'tcx hir::Item) { |
b039eaaf | 795 | debug!("check_item_body(it.id={}, it.name={})", |
9346a6ac | 796 | it.id, |
b039eaaf | 797 | ccx.tcx.item_path_str(ccx.tcx.map.local_def_id(it.id))); |
9346a6ac AL |
798 | let _indenter = indenter(); |
799 | match it.node { | |
e9174d1e | 800 | hir::ItemFn(ref decl, _, _, _, _, ref body) => { |
b039eaaf | 801 | let fn_pty = ccx.tcx.lookup_item_type(ccx.tcx.map.local_def_id(it.id)); |
9346a6ac | 802 | let param_env = ParameterEnvironment::for_item(ccx.tcx, it.id); |
7453a54e | 803 | check_bare_fn(ccx, &decl, &body, it.id, it.span, fn_pty.ty, param_env); |
9346a6ac | 804 | } |
e9174d1e | 805 | hir::ItemImpl(_, _, _, _, _, ref impl_items) => { |
b039eaaf | 806 | debug!("ItemImpl {} with id {}", it.name, it.id); |
9346a6ac | 807 | |
b039eaaf | 808 | let impl_pty = ccx.tcx.lookup_item_type(ccx.tcx.map.local_def_id(it.id)); |
9346a6ac AL |
809 | |
810 | for impl_item in impl_items { | |
811 | match impl_item.node { | |
92a42be0 | 812 | hir::ImplItemKind::Const(_, ref expr) => { |
7453a54e | 813 | check_const(ccx, impl_item.span, &expr, impl_item.id) |
d9579d0f | 814 | } |
92a42be0 | 815 | hir::ImplItemKind::Method(ref sig, ref body) => { |
9346a6ac AL |
816 | check_method_body(ccx, &impl_pty.generics, sig, body, |
817 | impl_item.id, impl_item.span); | |
818 | } | |
92a42be0 | 819 | hir::ImplItemKind::Type(_) => { |
9346a6ac AL |
820 | // Nothing to do here. |
821 | } | |
822 | } | |
823 | } | |
824 | } | |
e9174d1e | 825 | hir::ItemTrait(_, _, _, ref trait_items) => { |
b039eaaf | 826 | let trait_def = ccx.tcx.lookup_trait_def(ccx.tcx.map.local_def_id(it.id)); |
9346a6ac AL |
827 | for trait_item in trait_items { |
828 | match trait_item.node { | |
e9174d1e | 829 | hir::ConstTraitItem(_, Some(ref expr)) => { |
7453a54e | 830 | check_const(ccx, trait_item.span, &expr, trait_item.id) |
9346a6ac | 831 | } |
e9174d1e | 832 | hir::MethodTraitItem(ref sig, Some(ref body)) => { |
62682a34 SL |
833 | check_trait_fn_not_const(ccx, trait_item.span, sig.constness); |
834 | ||
9346a6ac AL |
835 | check_method_body(ccx, &trait_def.generics, sig, body, |
836 | trait_item.id, trait_item.span); | |
837 | } | |
e9174d1e | 838 | hir::MethodTraitItem(ref sig, None) => { |
62682a34 SL |
839 | check_trait_fn_not_const(ccx, trait_item.span, sig.constness); |
840 | } | |
e9174d1e SL |
841 | hir::ConstTraitItem(_, None) | |
842 | hir::TypeTraitItem(..) => { | |
9346a6ac AL |
843 | // Nothing to do. |
844 | } | |
845 | } | |
846 | } | |
847 | } | |
848 | _ => {/* nothing to do */ } | |
849 | } | |
850 | } | |
851 | ||
62682a34 SL |
852 | fn check_trait_fn_not_const<'a,'tcx>(ccx: &CrateCtxt<'a, 'tcx>, |
853 | span: Span, | |
e9174d1e | 854 | constness: hir::Constness) |
62682a34 SL |
855 | { |
856 | match constness { | |
e9174d1e | 857 | hir::Constness::NotConst => { |
62682a34 SL |
858 | // good |
859 | } | |
e9174d1e | 860 | hir::Constness::Const => { |
62682a34 SL |
861 | span_err!(ccx.tcx.sess, span, E0379, "trait fns cannot be declared const"); |
862 | } | |
863 | } | |
864 | } | |
865 | ||
a7813a04 XL |
866 | fn check_on_unimplemented<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, |
867 | generics: &ty::Generics, | |
868 | item: &hir::Item, | |
869 | name: ast::Name) { | |
85aaf69f SL |
870 | if let Some(ref attr) = item.attrs.iter().find(|a| { |
871 | a.check_name("rustc_on_unimplemented") | |
872 | }) { | |
873 | if let Some(ref istring) = attr.value_str() { | |
874 | let parser = Parser::new(&istring); | |
a7813a04 | 875 | let types = &generics.types; |
85aaf69f SL |
876 | for token in parser { |
877 | match token { | |
878 | Piece::String(_) => (), // Normal string, no need to check it | |
879 | Piece::NextArgument(a) => match a.position { | |
880 | // `{Self}` is allowed | |
881 | Position::ArgumentNamed(s) if s == "Self" => (), | |
882 | // So is `{A}` if A is a type parameter | |
883 | Position::ArgumentNamed(s) => match types.iter().find(|t| { | |
b039eaaf | 884 | t.name.as_str() == s |
85aaf69f SL |
885 | }) { |
886 | Some(_) => (), | |
887 | None => { | |
888 | span_err!(ccx.tcx.sess, attr.span, E0230, | |
889 | "there is no type parameter \ | |
890 | {} on trait {}", | |
a7813a04 | 891 | s, name); |
85aaf69f SL |
892 | } |
893 | }, | |
894 | // `{:1}` and `{}` are not to be used | |
895 | Position::ArgumentIs(_) | Position::ArgumentNext => { | |
896 | span_err!(ccx.tcx.sess, attr.span, E0231, | |
897 | "only named substitution \ | |
898 | parameters are allowed"); | |
899 | } | |
900 | } | |
901 | } | |
902 | } | |
903 | } else { | |
904 | span_err!(ccx.tcx.sess, attr.span, E0232, | |
905 | "this attribute must have a value, \ | |
906 | eg `#[rustc_on_unimplemented = \"foo\"]`") | |
907 | } | |
908 | } | |
909 | } | |
910 | ||
1a4d82fc JJ |
911 | /// Type checks a method body. |
912 | /// | |
913 | /// # Parameters | |
914 | /// | |
915 | /// * `item_generics`: generics defined on the impl/trait that contains | |
916 | /// the method | |
917 | /// * `self_bound`: bound for the `Self` type parameter, if any | |
918 | /// * `method`: the method definition | |
919 | fn check_method_body<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, | |
920 | item_generics: &ty::Generics<'tcx>, | |
e9174d1e SL |
921 | sig: &'tcx hir::MethodSig, |
922 | body: &'tcx hir::Block, | |
c34b1796 | 923 | id: ast::NodeId, span: Span) { |
62682a34 SL |
924 | debug!("check_method_body(item_generics={:?}, id={})", |
925 | item_generics, id); | |
c34b1796 AL |
926 | let param_env = ParameterEnvironment::for_item(ccx.tcx, id); |
927 | ||
c1a9b12d | 928 | let fty = ccx.tcx.node_id_to_type(id); |
62682a34 | 929 | debug!("check_method_body: fty={:?}", fty); |
1a4d82fc | 930 | |
c34b1796 | 931 | check_bare_fn(ccx, &sig.decl, body, id, span, fty, param_env); |
1a4d82fc JJ |
932 | } |
933 | ||
a7813a04 XL |
934 | fn report_forbidden_specialization<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
935 | impl_item: &hir::ImplItem, | |
936 | parent_impl: DefId) | |
54a0048b SL |
937 | { |
938 | let mut err = struct_span_err!( | |
939 | tcx.sess, impl_item.span, E0520, | |
940 | "item `{}` is provided by an `impl` that specializes \ | |
941 | another, but the item in the parent `impl` is not \ | |
942 | marked `default` and so it cannot be specialized.", | |
943 | impl_item.name); | |
944 | ||
945 | match tcx.span_of_impl(parent_impl) { | |
946 | Ok(span) => { | |
947 | err.span_note(span, "parent implementation is here:"); | |
948 | } | |
949 | Err(cname) => { | |
950 | err.note(&format!("parent implementation is in crate `{}`", cname)); | |
951 | } | |
952 | } | |
953 | ||
954 | err.emit(); | |
955 | } | |
956 | ||
a7813a04 XL |
957 | fn check_specialization_validity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
958 | trait_def: &ty::TraitDef<'tcx>, | |
959 | impl_id: DefId, | |
960 | impl_item: &hir::ImplItem) | |
54a0048b SL |
961 | { |
962 | let ancestors = trait_def.ancestors(impl_id); | |
963 | ||
964 | let parent = match impl_item.node { | |
965 | hir::ImplItemKind::Const(..) => { | |
966 | ancestors.const_defs(tcx, impl_item.name).skip(1).next() | |
967 | .map(|node_item| node_item.map(|parent| parent.defaultness)) | |
968 | } | |
969 | hir::ImplItemKind::Method(..) => { | |
970 | ancestors.fn_defs(tcx, impl_item.name).skip(1).next() | |
971 | .map(|node_item| node_item.map(|parent| parent.defaultness)) | |
972 | ||
973 | } | |
974 | hir::ImplItemKind::Type(_) => { | |
975 | ancestors.type_defs(tcx, impl_item.name).skip(1).next() | |
976 | .map(|node_item| node_item.map(|parent| parent.defaultness)) | |
977 | } | |
978 | }; | |
979 | ||
980 | if let Some(parent) = parent { | |
981 | if parent.item.is_final() { | |
982 | report_forbidden_specialization(tcx, impl_item, parent.node.def_id()); | |
983 | } | |
984 | } | |
985 | ||
986 | } | |
987 | ||
1a4d82fc JJ |
988 | fn check_impl_items_against_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, |
989 | impl_span: Span, | |
54a0048b | 990 | impl_id: DefId, |
1a4d82fc | 991 | impl_trait_ref: &ty::TraitRef<'tcx>, |
92a42be0 | 992 | impl_items: &[hir::ImplItem]) { |
54a0048b SL |
993 | // If the trait reference itself is erroneous (so the compilation is going |
994 | // to fail), skip checking the items here -- the `impl_item` table in `tcx` | |
995 | // isn't populated for such impls. | |
996 | if impl_trait_ref.references_error() { return; } | |
997 | ||
998 | // Locate trait definition and items | |
1a4d82fc | 999 | let tcx = ccx.tcx; |
54a0048b | 1000 | let trait_def = tcx.lookup_trait_def(impl_trait_ref.def_id); |
c1a9b12d SL |
1001 | let trait_items = tcx.trait_items(impl_trait_ref.def_id); |
1002 | let mut overridden_associated_type = None; | |
1a4d82fc JJ |
1003 | |
1004 | // Check existing impl methods to see if they are both present in trait | |
1005 | // and compatible with trait signature | |
85aaf69f | 1006 | for impl_item in impl_items { |
b039eaaf | 1007 | let ty_impl_item = ccx.tcx.impl_or_trait_item(ccx.tcx.map.local_def_id(impl_item.id)); |
c1a9b12d | 1008 | let ty_trait_item = trait_items.iter() |
9cc50fc6 | 1009 | .find(|ac| ac.name() == ty_impl_item.name()); |
d9579d0f | 1010 | |
54a0048b | 1011 | // Check that impl definition matches trait definition |
9cc50fc6 SL |
1012 | if let Some(ty_trait_item) = ty_trait_item { |
1013 | match impl_item.node { | |
1014 | hir::ImplItemKind::Const(..) => { | |
1015 | let impl_const = match ty_impl_item { | |
1016 | ty::ConstTraitItem(ref cti) => cti, | |
54a0048b | 1017 | _ => span_bug!(impl_item.span, "non-const impl-item for const") |
9cc50fc6 SL |
1018 | }; |
1019 | ||
1020 | // Find associated const definition. | |
1021 | if let &ty::ConstTraitItem(ref trait_const) = ty_trait_item { | |
a7813a04 | 1022 | compare_const_impl(ccx, |
9cc50fc6 SL |
1023 | &impl_const, |
1024 | impl_item.span, | |
1025 | trait_const, | |
7453a54e | 1026 | &impl_trait_ref); |
9cc50fc6 SL |
1027 | } else { |
1028 | span_err!(tcx.sess, impl_item.span, E0323, | |
1029 | "item `{}` is an associated const, \ | |
1030 | which doesn't match its trait `{:?}`", | |
1031 | impl_const.name, | |
1032 | impl_trait_ref) | |
1033 | } | |
d9579d0f | 1034 | } |
9cc50fc6 SL |
1035 | hir::ImplItemKind::Method(ref sig, ref body) => { |
1036 | check_trait_fn_not_const(ccx, impl_item.span, sig.constness); | |
62682a34 | 1037 | |
9cc50fc6 SL |
1038 | let impl_method = match ty_impl_item { |
1039 | ty::MethodTraitItem(ref mti) => mti, | |
54a0048b | 1040 | _ => span_bug!(impl_item.span, "non-method impl-item for method") |
9cc50fc6 | 1041 | }; |
c1a9b12d | 1042 | |
9cc50fc6 | 1043 | if let &ty::MethodTraitItem(ref trait_method) = ty_trait_item { |
a7813a04 | 1044 | compare_impl_method(ccx, |
9cc50fc6 SL |
1045 | &impl_method, |
1046 | impl_item.span, | |
1047 | body.id, | |
1048 | &trait_method, | |
1049 | &impl_trait_ref); | |
1050 | } else { | |
1051 | span_err!(tcx.sess, impl_item.span, E0324, | |
1052 | "item `{}` is an associated method, \ | |
1053 | which doesn't match its trait `{:?}`", | |
1054 | impl_method.name, | |
1055 | impl_trait_ref) | |
1056 | } | |
1a4d82fc | 1057 | } |
9cc50fc6 SL |
1058 | hir::ImplItemKind::Type(_) => { |
1059 | let impl_type = match ty_impl_item { | |
1060 | ty::TypeTraitItem(ref tti) => tti, | |
54a0048b | 1061 | _ => span_bug!(impl_item.span, "non-type impl-item for type") |
9cc50fc6 | 1062 | }; |
c1a9b12d | 1063 | |
9cc50fc6 SL |
1064 | if let &ty::TypeTraitItem(ref at) = ty_trait_item { |
1065 | if let Some(_) = at.ty { | |
1066 | overridden_associated_type = Some(impl_item); | |
1067 | } | |
1068 | } else { | |
1069 | span_err!(tcx.sess, impl_item.span, E0325, | |
1070 | "item `{}` is an associated type, \ | |
1071 | which doesn't match its trait `{:?}`", | |
1072 | impl_type.name, | |
1073 | impl_trait_ref) | |
1a4d82fc JJ |
1074 | } |
1075 | } | |
1076 | } | |
1077 | } | |
54a0048b SL |
1078 | |
1079 | check_specialization_validity(tcx, trait_def, impl_id, impl_item); | |
1a4d82fc JJ |
1080 | } |
1081 | ||
1082 | // Check for missing items from trait | |
c1a9b12d | 1083 | let provided_methods = tcx.provided_trait_methods(impl_trait_ref.def_id); |
62682a34 | 1084 | let mut missing_items = Vec::new(); |
c1a9b12d SL |
1085 | let mut invalidated_items = Vec::new(); |
1086 | let associated_type_overridden = overridden_associated_type.is_some(); | |
62682a34 | 1087 | for trait_item in trait_items.iter() { |
54a0048b SL |
1088 | let is_implemented; |
1089 | let is_provided; | |
1090 | ||
1a4d82fc | 1091 | match *trait_item { |
d9579d0f | 1092 | ty::ConstTraitItem(ref associated_const) => { |
54a0048b SL |
1093 | is_provided = associated_const.has_value; |
1094 | is_implemented = impl_items.iter().any(|ii| { | |
d9579d0f | 1095 | match ii.node { |
92a42be0 | 1096 | hir::ImplItemKind::Const(..) => { |
b039eaaf | 1097 | ii.name == associated_const.name |
d9579d0f AL |
1098 | } |
1099 | _ => false, | |
1100 | } | |
1101 | }); | |
d9579d0f | 1102 | } |
1a4d82fc | 1103 | ty::MethodTraitItem(ref trait_method) => { |
54a0048b SL |
1104 | is_provided = provided_methods.iter().any(|m| m.name == trait_method.name); |
1105 | is_implemented = trait_def.ancestors(impl_id) | |
1106 | .fn_defs(tcx, trait_method.name) | |
1107 | .next() | |
1108 | .map(|node_item| !node_item.node.is_from_trait()) | |
1109 | .unwrap_or(false); | |
1a4d82fc | 1110 | } |
54a0048b SL |
1111 | ty::TypeTraitItem(ref trait_assoc_ty) => { |
1112 | is_provided = trait_assoc_ty.ty.is_some(); | |
1113 | is_implemented = trait_def.ancestors(impl_id) | |
1114 | .type_defs(tcx, trait_assoc_ty.name) | |
1115 | .next() | |
1116 | .map(|node_item| !node_item.node.is_from_trait()) | |
1117 | .unwrap_or(false); | |
1118 | } | |
1119 | } | |
1120 | ||
1121 | if !is_implemented { | |
1122 | if !is_provided { | |
1123 | missing_items.push(trait_item.name()); | |
1124 | } else if associated_type_overridden { | |
1125 | invalidated_items.push(trait_item.name()); | |
1a4d82fc JJ |
1126 | } |
1127 | } | |
1128 | } | |
1129 | ||
62682a34 | 1130 | if !missing_items.is_empty() { |
1a4d82fc | 1131 | span_err!(tcx.sess, impl_span, E0046, |
c1a9b12d SL |
1132 | "not all trait items implemented, missing: `{}`", |
1133 | missing_items.iter() | |
1134 | .map(|name| name.to_string()) | |
1135 | .collect::<Vec<_>>().join("`, `")) | |
1136 | } | |
1137 | ||
1138 | if !invalidated_items.is_empty() { | |
1139 | let invalidator = overridden_associated_type.unwrap(); | |
1140 | span_err!(tcx.sess, invalidator.span, E0399, | |
1141 | "the following trait items need to be reimplemented \ | |
1142 | as `{}` was overridden: `{}`", | |
b039eaaf | 1143 | invalidator.name, |
c1a9b12d SL |
1144 | invalidated_items.iter() |
1145 | .map(|name| name.to_string()) | |
1146 | .collect::<Vec<_>>().join("`, `")) | |
1a4d82fc JJ |
1147 | } |
1148 | } | |
1149 | ||
a7813a04 XL |
1150 | /// Checks a constant appearing in a type. At the moment this is just the |
1151 | /// length expression in a fixed-length vector, but someday it might be | |
1152 | /// extended to type-level numeric literals. | |
1153 | fn check_const_in_type<'a,'tcx>(ccx: &'a CrateCtxt<'a,'tcx>, | |
1154 | expr: &'tcx hir::Expr, | |
1155 | expected_type: Ty<'tcx>) { | |
1156 | ccx.inherited(None).enter(|inh| { | |
1157 | let fcx = FnCtxt::new(&inh, ty::FnConverging(expected_type), expr.id); | |
1158 | fcx.check_const_with_ty(expr.span, expr, expected_type); | |
1159 | }); | |
1160 | } | |
1161 | ||
1162 | fn check_const<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, | |
1163 | sp: Span, | |
1164 | e: &'tcx hir::Expr, | |
1165 | id: ast::NodeId) { | |
1166 | let param_env = ParameterEnvironment::for_item(ccx.tcx, id); | |
1167 | ccx.inherited(Some(param_env)).enter(|inh| { | |
1168 | let rty = ccx.tcx.node_id_to_type(id); | |
1169 | let fcx = FnCtxt::new(&inh, ty::FnConverging(rty), e.id); | |
1170 | let declty = fcx.tcx.lookup_item_type(ccx.tcx.map.local_def_id(id)).ty; | |
1171 | fcx.check_const_with_ty(sp, e, declty); | |
1172 | }); | |
1173 | } | |
1174 | ||
1175 | /// Checks whether a type can be represented in memory. In particular, it | |
1176 | /// identifies types that contain themselves without indirection through a | |
1177 | /// pointer, which would mean their size is unbounded. | |
1178 | pub fn check_representable<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, | |
1179 | sp: Span, | |
1180 | item_id: ast::NodeId, | |
1181 | _designation: &str) -> bool { | |
1182 | let rty = tcx.node_id_to_type(item_id); | |
1183 | ||
1184 | // Check that it is possible to represent this type. This call identifies | |
1185 | // (1) types that contain themselves and (2) types that contain a different | |
1186 | // recursive type. It is only necessary to throw an error on those that | |
1187 | // contain themselves. For case 2, there must be an inner type that will be | |
1188 | // caught by case 1. | |
1189 | match rty.is_representable(tcx, sp) { | |
1190 | Representability::SelfRecursive => { | |
1191 | let item_def_id = tcx.map.local_def_id(item_id); | |
1192 | tcx.recursive_type_with_infinite_size_error(item_def_id).emit(); | |
1193 | return false | |
1194 | } | |
1195 | Representability::Representable | Representability::ContainsRecursive => (), | |
1196 | } | |
1197 | return true | |
1198 | } | |
1199 | ||
1200 | pub fn check_simd<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, sp: Span, id: ast::NodeId) { | |
1201 | let t = tcx.node_id_to_type(id); | |
1202 | match t.sty { | |
1203 | ty::TyStruct(def, substs) => { | |
1204 | let fields = &def.struct_variant().fields; | |
1205 | if fields.is_empty() { | |
1206 | span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty"); | |
1207 | return; | |
1208 | } | |
1209 | let e = fields[0].ty(tcx, substs); | |
1210 | if !fields.iter().all(|f| f.ty(tcx, substs) == e) { | |
1211 | span_err!(tcx.sess, sp, E0076, "SIMD vector should be homogeneous"); | |
1212 | return; | |
1213 | } | |
1214 | match e.sty { | |
1215 | ty::TyParam(_) => { /* struct<T>(T, T, T, T) is ok */ } | |
1216 | _ if e.is_machine() => { /* struct(u8, u8, u8, u8) is ok */ } | |
1217 | _ => { | |
1218 | span_err!(tcx.sess, sp, E0077, | |
1219 | "SIMD vector element type should be machine type"); | |
1220 | return; | |
d9579d0f | 1221 | } |
1a4d82fc JJ |
1222 | } |
1223 | } | |
a7813a04 XL |
1224 | _ => () |
1225 | } | |
1226 | } | |
1227 | ||
1228 | #[allow(trivial_numeric_casts)] | |
1229 | pub fn check_enum_variants<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, | |
1230 | sp: Span, | |
1231 | vs: &'tcx [hir::Variant], | |
1232 | id: ast::NodeId) { | |
1233 | let def_id = ccx.tcx.map.local_def_id(id); | |
1234 | let hint = *ccx.tcx.lookup_repr_hints(def_id).get(0).unwrap_or(&attr::ReprAny); | |
1235 | ||
1236 | if hint != attr::ReprAny && vs.is_empty() { | |
1237 | span_err!(ccx.tcx.sess, sp, E0084, | |
1238 | "unsupported representation for zero-variant enum"); | |
1239 | } | |
1240 | ||
1241 | ccx.inherited(None).enter(|inh| { | |
1242 | let rty = ccx.tcx.node_id_to_type(id); | |
1243 | let fcx = FnCtxt::new(&inh, ty::FnConverging(rty), id); | |
1244 | ||
1245 | let repr_type_ty = ccx.tcx.enum_repr_type(Some(&hint)).to_ty(ccx.tcx); | |
1246 | for v in vs { | |
1247 | if let Some(ref e) = v.node.disr_expr { | |
1248 | fcx.check_const_with_ty(e.span, e, repr_type_ty); | |
d9579d0f | 1249 | } |
1a4d82fc | 1250 | } |
a7813a04 XL |
1251 | |
1252 | let def_id = ccx.tcx.map.local_def_id(id); | |
1253 | ||
1254 | let variants = &ccx.tcx.lookup_adt_def(def_id).variants; | |
1255 | let mut disr_vals: Vec<ty::Disr> = Vec::new(); | |
1256 | for (v, variant) in vs.iter().zip(variants.iter()) { | |
1257 | let current_disr_val = variant.disr_val; | |
1258 | ||
1259 | // Check for duplicate discriminant values | |
1260 | if let Some(i) = disr_vals.iter().position(|&x| x == current_disr_val) { | |
1261 | let mut err = struct_span_err!(ccx.tcx.sess, v.span, E0081, | |
1262 | "discriminant value `{}` already exists", disr_vals[i]); | |
1263 | let variant_i_node_id = ccx.tcx.map.as_local_node_id(variants[i].did).unwrap(); | |
1264 | span_note!(&mut err, ccx.tcx.map.span(variant_i_node_id), | |
1265 | "conflicting discriminant here"); | |
1266 | err.emit(); | |
1267 | } | |
1268 | disr_vals.push(current_disr_val); | |
1a4d82fc | 1269 | } |
a7813a04 XL |
1270 | }); |
1271 | ||
1272 | check_representable(ccx.tcx, sp, id, "enum"); | |
1a4d82fc JJ |
1273 | } |
1274 | ||
a7813a04 XL |
1275 | impl<'a, 'gcx, 'tcx> AstConv<'gcx, 'tcx> for FnCtxt<'a, 'gcx, 'tcx> { |
1276 | fn tcx<'b>(&'b self) -> TyCtxt<'b, 'gcx, 'tcx> { self.tcx } | |
1a4d82fc | 1277 | |
a7813a04 XL |
1278 | fn ast_ty_to_ty_cache(&self) -> &RefCell<NodeMap<Ty<'tcx>>> { |
1279 | &self.ast_ty_to_ty_cache | |
1280 | } | |
1a4d82fc | 1281 | |
e9174d1e | 1282 | fn get_item_type_scheme(&self, _: Span, id: DefId) |
c34b1796 AL |
1283 | -> Result<ty::TypeScheme<'tcx>, ErrorReported> |
1284 | { | |
c1a9b12d | 1285 | Ok(self.tcx().lookup_item_type(id)) |
1a4d82fc JJ |
1286 | } |
1287 | ||
e9174d1e | 1288 | fn get_trait_def(&self, _: Span, id: DefId) |
d9579d0f | 1289 | -> Result<&'tcx ty::TraitDef<'tcx>, ErrorReported> |
c34b1796 | 1290 | { |
c1a9b12d | 1291 | Ok(self.tcx().lookup_trait_def(id)) |
c34b1796 AL |
1292 | } |
1293 | ||
e9174d1e | 1294 | fn ensure_super_predicates(&self, _: Span, _: DefId) -> Result<(), ErrorReported> { |
c34b1796 AL |
1295 | // all super predicates are ensured during collect pass |
1296 | Ok(()) | |
1a4d82fc JJ |
1297 | } |
1298 | ||
1299 | fn get_free_substs(&self) -> Option<&Substs<'tcx>> { | |
a7813a04 | 1300 | Some(&self.parameter_environment.free_substs) |
1a4d82fc JJ |
1301 | } |
1302 | ||
c34b1796 AL |
1303 | fn get_type_parameter_bounds(&self, |
1304 | _: Span, | |
1305 | node_id: ast::NodeId) | |
1306 | -> Result<Vec<ty::PolyTraitRef<'tcx>>, ErrorReported> | |
1307 | { | |
a7813a04 XL |
1308 | let def = self.tcx.type_parameter_def(node_id); |
1309 | let r = self.parameter_environment | |
c1a9b12d | 1310 | .caller_bounds |
c34b1796 AL |
1311 | .iter() |
1312 | .filter_map(|predicate| { | |
1313 | match *predicate { | |
1314 | ty::Predicate::Trait(ref data) => { | |
1315 | if data.0.self_ty().is_param(def.space, def.index) { | |
1316 | Some(data.to_poly_trait_ref()) | |
1317 | } else { | |
1318 | None | |
1319 | } | |
1320 | } | |
1321 | _ => { | |
1322 | None | |
1323 | } | |
1324 | } | |
1325 | }) | |
1326 | .collect(); | |
1327 | Ok(r) | |
1328 | } | |
1329 | ||
1330 | fn trait_defines_associated_type_named(&self, | |
e9174d1e | 1331 | trait_def_id: DefId, |
c34b1796 AL |
1332 | assoc_name: ast::Name) |
1333 | -> bool | |
1334 | { | |
a7813a04 | 1335 | let trait_def = self.tcx().lookup_trait_def(trait_def_id); |
c34b1796 AL |
1336 | trait_def.associated_type_names.contains(&assoc_name) |
1337 | } | |
1338 | ||
c1a9b12d SL |
1339 | fn ty_infer(&self, |
1340 | ty_param_def: Option<ty::TypeParameterDef<'tcx>>, | |
1341 | substs: Option<&mut subst::Substs<'tcx>>, | |
1342 | space: Option<subst::ParamSpace>, | |
1343 | span: Span) -> Ty<'tcx> { | |
1344 | // Grab the default doing subsitution | |
1345 | let default = ty_param_def.and_then(|def| { | |
1346 | def.default.map(|ty| type_variable::Default { | |
1347 | ty: ty.subst_spanned(self.tcx(), substs.as_ref().unwrap(), Some(span)), | |
1348 | origin_span: span, | |
1349 | def_id: def.default_def_id | |
1350 | }) | |
1351 | }); | |
1352 | ||
a7813a04 | 1353 | let ty_var = self.next_ty_var_with_default(default); |
c1a9b12d SL |
1354 | |
1355 | // Finally we add the type variable to the substs | |
1356 | match substs { | |
1357 | None => ty_var, | |
1358 | Some(substs) => { substs.types.push(space.unwrap(), ty_var); ty_var } | |
1359 | } | |
1a4d82fc JJ |
1360 | } |
1361 | ||
1362 | fn projected_ty_from_poly_trait_ref(&self, | |
1363 | span: Span, | |
1364 | poly_trait_ref: ty::PolyTraitRef<'tcx>, | |
1365 | item_name: ast::Name) | |
1366 | -> Ty<'tcx> | |
1367 | { | |
1368 | let (trait_ref, _) = | |
a7813a04 | 1369 | self.replace_late_bound_regions_with_fresh_var( |
1a4d82fc JJ |
1370 | span, |
1371 | infer::LateBoundRegionConversionTime::AssocTypeProjection(item_name), | |
1372 | &poly_trait_ref); | |
1373 | ||
1374 | self.normalize_associated_type(span, trait_ref, item_name) | |
1375 | } | |
1376 | ||
1377 | fn projected_ty(&self, | |
1378 | span: Span, | |
d9579d0f | 1379 | trait_ref: ty::TraitRef<'tcx>, |
1a4d82fc JJ |
1380 | item_name: ast::Name) |
1381 | -> Ty<'tcx> | |
1382 | { | |
1383 | self.normalize_associated_type(span, trait_ref, item_name) | |
1384 | } | |
a7813a04 XL |
1385 | |
1386 | fn set_tainted_by_errors(&self) { | |
1387 | self.infcx.set_tainted_by_errors() | |
1388 | } | |
1389 | } | |
1390 | ||
1391 | impl<'a, 'gcx, 'tcx> RegionScope for FnCtxt<'a, 'gcx, 'tcx> { | |
1392 | fn object_lifetime_default(&self, span: Span) -> Option<ty::Region> { | |
1393 | Some(self.base_object_lifetime_default(span)) | |
1394 | } | |
1395 | ||
1396 | fn base_object_lifetime_default(&self, span: Span) -> ty::Region { | |
1397 | // RFC #599 specifies that object lifetime defaults take | |
1398 | // precedence over other defaults. But within a fn body we | |
1399 | // don't have a *default* region, rather we use inference to | |
1400 | // find the *correct* region, which is strictly more general | |
1401 | // (and anyway, within a fn body the right region may not even | |
1402 | // be something the user can write explicitly, since it might | |
1403 | // be some expression). | |
1404 | self.next_region_var(infer::MiscVariable(span)) | |
1405 | } | |
1406 | ||
1407 | fn anon_regions(&self, span: Span, count: usize) | |
1408 | -> Result<Vec<ty::Region>, Option<Vec<ElisionFailureInfo>>> { | |
1409 | Ok((0..count).map(|_| { | |
1410 | self.next_region_var(infer::MiscVariable(span)) | |
1411 | }).collect()) | |
1412 | } | |
1413 | } | |
1414 | ||
1415 | /// Whether `autoderef` requires types to resolve. | |
1416 | #[derive(Copy, Clone, Debug, PartialEq, Eq)] | |
1417 | pub enum UnresolvedTypeAction { | |
1418 | /// Produce an error and return `TyError` whenever a type cannot | |
1419 | /// be resolved (i.e. it is `TyInfer`). | |
1420 | Error, | |
1421 | /// Go on without emitting any errors, and return the unresolved | |
1422 | /// type. Useful for probing, e.g. in coercions. | |
1423 | Ignore | |
1a4d82fc JJ |
1424 | } |
1425 | ||
a7813a04 XL |
1426 | /// Controls whether the arguments are tupled. This is used for the call |
1427 | /// operator. | |
1428 | /// | |
1429 | /// Tupling means that all call-side arguments are packed into a tuple and | |
1430 | /// passed as a single parameter. For example, if tupling is enabled, this | |
1431 | /// function: | |
1432 | /// | |
1433 | /// fn f(x: (isize, isize)) | |
1434 | /// | |
1435 | /// Can be called as: | |
1436 | /// | |
1437 | /// f(1, 2); | |
1438 | /// | |
1439 | /// Instead of: | |
1440 | /// | |
1441 | /// f((1, 2)); | |
1442 | #[derive(Clone, Eq, PartialEq)] | |
1443 | enum TupleArgumentsFlag { | |
1444 | DontTupleArguments, | |
1445 | TupleArguments, | |
1446 | } | |
1a4d82fc | 1447 | |
a7813a04 XL |
1448 | impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { |
1449 | pub fn new(inh: &'a Inherited<'a, 'gcx, 'tcx>, | |
1450 | rty: ty::FnOutput<'tcx>, | |
1451 | body_id: ast::NodeId) | |
1452 | -> FnCtxt<'a, 'gcx, 'tcx> { | |
1453 | FnCtxt { | |
1454 | ast_ty_to_ty_cache: RefCell::new(NodeMap()), | |
1455 | body_id: body_id, | |
1456 | writeback_errors: Cell::new(false), | |
1457 | err_count_on_creation: inh.tcx.sess.err_count(), | |
1458 | ret_ty: rty, | |
1459 | ps: RefCell::new(UnsafetyState::function(hir::Unsafety::Normal, 0)), | |
1460 | inh: inh, | |
1461 | } | |
1a4d82fc JJ |
1462 | } |
1463 | ||
a7813a04 XL |
1464 | pub fn param_env(&self) -> &ty::ParameterEnvironment<'tcx> { |
1465 | &self.parameter_environment | |
1a4d82fc JJ |
1466 | } |
1467 | ||
1468 | pub fn sess(&self) -> &Session { | |
a7813a04 | 1469 | &self.tcx.sess |
1a4d82fc JJ |
1470 | } |
1471 | ||
c34b1796 | 1472 | pub fn err_count_since_creation(&self) -> usize { |
a7813a04 | 1473 | self.tcx.sess.err_count() - self.err_count_on_creation |
1a4d82fc JJ |
1474 | } |
1475 | ||
85aaf69f | 1476 | /// Resolves type variables in `ty` if possible. Unlike the infcx |
a7813a04 XL |
1477 | /// version (resolve_type_vars_if_possible), this version will |
1478 | /// also select obligations if it seems useful, in an effort | |
1479 | /// to get more type information. | |
1480 | fn resolve_type_vars_with_obligations(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> { | |
1481 | debug!("resolve_type_vars_with_obligations(ty={:?})", ty); | |
c34b1796 | 1482 | |
c1a9b12d SL |
1483 | // No TyInfer()? Nothing needs doing. |
1484 | if !ty.has_infer_types() { | |
a7813a04 | 1485 | debug!("resolve_type_vars_with_obligations: ty={:?}", ty); |
85aaf69f SL |
1486 | return ty; |
1487 | } | |
1488 | ||
1489 | // If `ty` is a type variable, see whether we already know what it is. | |
a7813a04 | 1490 | ty = self.resolve_type_vars_if_possible(&ty); |
c1a9b12d | 1491 | if !ty.has_infer_types() { |
a7813a04 | 1492 | debug!("resolve_type_vars_with_obligations: ty={:?}", ty); |
85aaf69f SL |
1493 | return ty; |
1494 | } | |
1495 | ||
7453a54e | 1496 | // If not, try resolving pending obligations as much as |
85aaf69f SL |
1497 | // possible. This can help substantially when there are |
1498 | // indirect dependencies that don't seem worth tracking | |
1499 | // precisely. | |
d9579d0f | 1500 | self.select_obligations_where_possible(); |
a7813a04 | 1501 | ty = self.resolve_type_vars_if_possible(&ty); |
c34b1796 | 1502 | |
a7813a04 | 1503 | debug!("resolve_type_vars_with_obligations: ty={:?}", ty); |
c34b1796 | 1504 | ty |
85aaf69f SL |
1505 | } |
1506 | ||
85aaf69f | 1507 | fn record_deferred_call_resolution(&self, |
e9174d1e | 1508 | closure_def_id: DefId, |
a7813a04 XL |
1509 | r: DeferredCallResolutionHandler<'gcx, 'tcx>) { |
1510 | let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut(); | |
c34b1796 | 1511 | deferred_call_resolutions.entry(closure_def_id).or_insert(vec![]).push(r); |
85aaf69f SL |
1512 | } |
1513 | ||
1514 | fn remove_deferred_call_resolutions(&self, | |
e9174d1e | 1515 | closure_def_id: DefId) |
a7813a04 | 1516 | -> Vec<DeferredCallResolutionHandler<'gcx, 'tcx>> |
85aaf69f | 1517 | { |
a7813a04 | 1518 | let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut(); |
85aaf69f SL |
1519 | deferred_call_resolutions.remove(&closure_def_id).unwrap_or(Vec::new()) |
1520 | } | |
1521 | ||
1a4d82fc | 1522 | pub fn tag(&self) -> String { |
c34b1796 AL |
1523 | let self_ptr: *const FnCtxt = self; |
1524 | format!("{:?}", self_ptr) | |
1a4d82fc JJ |
1525 | } |
1526 | ||
1527 | pub fn local_ty(&self, span: Span, nid: ast::NodeId) -> Ty<'tcx> { | |
a7813a04 | 1528 | match self.locals.borrow().get(&nid) { |
1a4d82fc JJ |
1529 | Some(&t) => t, |
1530 | None => { | |
a7813a04 | 1531 | span_err!(self.tcx.sess, span, E0513, |
b039eaaf SL |
1532 | "no type for local variable {}", |
1533 | nid); | |
a7813a04 | 1534 | self.tcx.types.err |
1a4d82fc JJ |
1535 | } |
1536 | } | |
1537 | } | |
1538 | ||
1a4d82fc JJ |
1539 | #[inline] |
1540 | pub fn write_ty(&self, node_id: ast::NodeId, ty: Ty<'tcx>) { | |
62682a34 SL |
1541 | debug!("write_ty({}, {:?}) in fcx {}", |
1542 | node_id, ty, self.tag()); | |
a7813a04 | 1543 | self.tables.borrow_mut().node_types.insert(node_id, ty); |
1a4d82fc JJ |
1544 | } |
1545 | ||
1a4d82fc JJ |
1546 | pub fn write_substs(&self, node_id: ast::NodeId, substs: ty::ItemSubsts<'tcx>) { |
1547 | if !substs.substs.is_noop() { | |
62682a34 | 1548 | debug!("write_substs({}, {:?}) in fcx {}", |
1a4d82fc | 1549 | node_id, |
62682a34 | 1550 | substs, |
1a4d82fc JJ |
1551 | self.tag()); |
1552 | ||
a7813a04 | 1553 | self.tables.borrow_mut().item_substs.insert(node_id, substs); |
1a4d82fc JJ |
1554 | } |
1555 | } | |
1556 | ||
1557 | pub fn write_autoderef_adjustment(&self, | |
1558 | node_id: ast::NodeId, | |
c34b1796 | 1559 | derefs: usize) { |
1a4d82fc JJ |
1560 | self.write_adjustment( |
1561 | node_id, | |
e9174d1e | 1562 | adjustment::AdjustDerefRef(adjustment::AutoDerefRef { |
1a4d82fc | 1563 | autoderefs: derefs, |
9346a6ac AL |
1564 | autoref: None, |
1565 | unsize: None | |
1566 | }) | |
1a4d82fc JJ |
1567 | ); |
1568 | } | |
1569 | ||
1570 | pub fn write_adjustment(&self, | |
1571 | node_id: ast::NodeId, | |
e9174d1e | 1572 | adj: adjustment::AutoAdjustment<'tcx>) { |
62682a34 | 1573 | debug!("write_adjustment(node_id={}, adj={:?})", node_id, adj); |
1a4d82fc JJ |
1574 | |
1575 | if adj.is_identity() { | |
1576 | return; | |
1577 | } | |
1578 | ||
a7813a04 | 1579 | self.tables.borrow_mut().adjustments.insert(node_id, adj); |
1a4d82fc JJ |
1580 | } |
1581 | ||
1582 | /// Basically whenever we are converting from a type scheme into | |
1583 | /// the fn body space, we always want to normalize associated | |
1584 | /// types as well. This function combines the two. | |
1585 | fn instantiate_type_scheme<T>(&self, | |
1586 | span: Span, | |
1587 | substs: &Substs<'tcx>, | |
1588 | value: &T) | |
1589 | -> T | |
9cc50fc6 | 1590 | where T : TypeFoldable<'tcx> |
1a4d82fc | 1591 | { |
a7813a04 | 1592 | let value = value.subst(self.tcx, substs); |
1a4d82fc | 1593 | let result = self.normalize_associated_types_in(span, &value); |
62682a34 SL |
1594 | debug!("instantiate_type_scheme(value={:?}, substs={:?}) = {:?}", |
1595 | value, | |
1596 | substs, | |
1597 | result); | |
1a4d82fc JJ |
1598 | result |
1599 | } | |
1600 | ||
1601 | /// As `instantiate_type_scheme`, but for the bounds found in a | |
1602 | /// generic type scheme. | |
1603 | fn instantiate_bounds(&self, | |
1604 | span: Span, | |
1605 | substs: &Substs<'tcx>, | |
85aaf69f SL |
1606 | bounds: &ty::GenericPredicates<'tcx>) |
1607 | -> ty::InstantiatedPredicates<'tcx> | |
1a4d82fc | 1608 | { |
85aaf69f SL |
1609 | ty::InstantiatedPredicates { |
1610 | predicates: self.instantiate_type_scheme(span, substs, &bounds.predicates) | |
1a4d82fc JJ |
1611 | } |
1612 | } | |
1613 | ||
1614 | ||
1615 | fn normalize_associated_types_in<T>(&self, span: Span, value: &T) -> T | |
9cc50fc6 | 1616 | where T : TypeFoldable<'tcx> |
1a4d82fc | 1617 | { |
c1a9b12d | 1618 | self.inh.normalize_associated_types_in(span, self.body_id, value) |
1a4d82fc JJ |
1619 | } |
1620 | ||
1621 | fn normalize_associated_type(&self, | |
1622 | span: Span, | |
d9579d0f | 1623 | trait_ref: ty::TraitRef<'tcx>, |
1a4d82fc JJ |
1624 | item_name: ast::Name) |
1625 | -> Ty<'tcx> | |
1626 | { | |
1627 | let cause = traits::ObligationCause::new(span, | |
1628 | self.body_id, | |
1629 | traits::ObligationCauseCode::MiscObligation); | |
a7813a04 | 1630 | self.fulfillment_cx |
1a4d82fc | 1631 | .borrow_mut() |
a7813a04 | 1632 | .normalize_projection_type(self, |
1a4d82fc JJ |
1633 | ty::ProjectionTy { |
1634 | trait_ref: trait_ref, | |
1635 | item_name: item_name, | |
1636 | }, | |
1637 | cause) | |
1638 | } | |
1639 | ||
e9174d1e SL |
1640 | /// Instantiates the type in `did` with the generics in `path` and returns |
1641 | /// it (registering the necessary trait obligations along the way). | |
1a4d82fc | 1642 | /// |
e9174d1e SL |
1643 | /// Note that this function is only intended to be used with type-paths, |
1644 | /// not with value-paths. | |
1a4d82fc | 1645 | pub fn instantiate_type(&self, |
e9174d1e SL |
1646 | did: DefId, |
1647 | path: &hir::Path) | |
1648 | -> Ty<'tcx> | |
1a4d82fc | 1649 | { |
e9174d1e | 1650 | debug!("instantiate_type(did={:?}, path={:?})", did, path); |
1a4d82fc | 1651 | let type_scheme = |
a7813a04 | 1652 | self.tcx.lookup_item_type(did); |
85aaf69f | 1653 | let type_predicates = |
a7813a04 XL |
1654 | self.tcx.lookup_predicates(did); |
1655 | let substs = AstConv::ast_path_substs_for_ty(self, self, | |
e9174d1e SL |
1656 | path.span, |
1657 | PathParamMode::Optional, | |
1658 | &type_scheme.generics, | |
1659 | path.segments.last().unwrap()); | |
1660 | debug!("instantiate_type: ty={:?} substs={:?}", &type_scheme.ty, &substs); | |
1a4d82fc | 1661 | let bounds = |
e9174d1e | 1662 | self.instantiate_bounds(path.span, &substs, &type_predicates); |
1a4d82fc JJ |
1663 | self.add_obligations_for_parameters( |
1664 | traits::ObligationCause::new( | |
e9174d1e | 1665 | path.span, |
1a4d82fc | 1666 | self.body_id, |
e9174d1e | 1667 | traits::ItemObligation(did)), |
1a4d82fc | 1668 | &bounds); |
1a4d82fc | 1669 | |
e9174d1e | 1670 | self.instantiate_type_scheme(path.span, &substs, &type_scheme.ty) |
1a4d82fc JJ |
1671 | } |
1672 | ||
e9174d1e SL |
1673 | /// Return the dict-like variant corresponding to a given `Def`. |
1674 | pub fn def_struct_variant(&self, | |
7453a54e SL |
1675 | def: Def, |
1676 | _span: Span) | |
e9174d1e | 1677 | -> Option<(ty::AdtDef<'tcx>, ty::VariantDef<'tcx>)> |
1a4d82fc | 1678 | { |
e9174d1e | 1679 | let (adt, variant) = match def { |
7453a54e | 1680 | Def::Variant(enum_id, variant_id) => { |
a7813a04 | 1681 | let adt = self.tcx.lookup_adt_def(enum_id); |
e9174d1e SL |
1682 | (adt, adt.variant_with_id(variant_id)) |
1683 | } | |
7453a54e | 1684 | Def::Struct(did) | Def::TyAlias(did) => { |
a7813a04 | 1685 | let typ = self.tcx.lookup_item_type(did); |
e9174d1e SL |
1686 | if let ty::TyStruct(adt, _) = typ.ty.sty { |
1687 | (adt, adt.struct_variant()) | |
1688 | } else { | |
1689 | return None; | |
1690 | } | |
1691 | } | |
1692 | _ => return None | |
1693 | }; | |
1a4d82fc | 1694 | |
b039eaaf SL |
1695 | let var_kind = variant.kind(); |
1696 | if var_kind == ty::VariantKind::Struct { | |
e9174d1e | 1697 | Some((adt, variant)) |
b039eaaf | 1698 | } else if var_kind == ty::VariantKind::Unit { |
b039eaaf SL |
1699 | Some((adt, variant)) |
1700 | } else { | |
1701 | None | |
1702 | } | |
1703 | } | |
e9174d1e | 1704 | |
1a4d82fc | 1705 | pub fn write_nil(&self, node_id: ast::NodeId) { |
a7813a04 | 1706 | self.write_ty(node_id, self.tcx.mk_nil()); |
1a4d82fc JJ |
1707 | } |
1708 | pub fn write_error(&self, node_id: ast::NodeId) { | |
a7813a04 | 1709 | self.write_ty(node_id, self.tcx.types.err); |
1a4d82fc JJ |
1710 | } |
1711 | ||
1712 | pub fn require_type_meets(&self, | |
1713 | ty: Ty<'tcx>, | |
1714 | span: Span, | |
1715 | code: traits::ObligationCauseCode<'tcx>, | |
1716 | bound: ty::BuiltinBound) | |
1717 | { | |
1718 | self.register_builtin_bound( | |
1719 | ty, | |
1720 | bound, | |
1721 | traits::ObligationCause::new(span, self.body_id, code)); | |
1722 | } | |
1723 | ||
1724 | pub fn require_type_is_sized(&self, | |
1725 | ty: Ty<'tcx>, | |
1726 | span: Span, | |
1727 | code: traits::ObligationCauseCode<'tcx>) | |
1728 | { | |
1729 | self.require_type_meets(ty, span, code, ty::BoundSized); | |
1730 | } | |
1731 | ||
1732 | pub fn require_expr_have_sized_type(&self, | |
e9174d1e | 1733 | expr: &hir::Expr, |
1a4d82fc JJ |
1734 | code: traits::ObligationCauseCode<'tcx>) |
1735 | { | |
1736 | self.require_type_is_sized(self.expr_ty(expr), expr.span, code); | |
1737 | } | |
1738 | ||
1a4d82fc JJ |
1739 | pub fn register_builtin_bound(&self, |
1740 | ty: Ty<'tcx>, | |
1741 | builtin_bound: ty::BuiltinBound, | |
1742 | cause: traits::ObligationCause<'tcx>) | |
1743 | { | |
a7813a04 XL |
1744 | self.fulfillment_cx.borrow_mut() |
1745 | .register_builtin_bound(self, ty, builtin_bound, cause); | |
1a4d82fc JJ |
1746 | } |
1747 | ||
1748 | pub fn register_predicate(&self, | |
1749 | obligation: traits::PredicateObligation<'tcx>) | |
1750 | { | |
62682a34 SL |
1751 | debug!("register_predicate({:?})", |
1752 | obligation); | |
a7813a04 | 1753 | self.fulfillment_cx |
1a4d82fc | 1754 | .borrow_mut() |
a7813a04 | 1755 | .register_predicate_obligation(self, obligation); |
1a4d82fc JJ |
1756 | } |
1757 | ||
e9174d1e | 1758 | pub fn to_ty(&self, ast_t: &hir::Ty) -> Ty<'tcx> { |
a7813a04 | 1759 | let t = AstConv::ast_ty_to_ty(self, self, ast_t); |
b039eaaf | 1760 | self.register_wf_obligation(t, ast_t.span, traits::MiscObligation); |
1a4d82fc JJ |
1761 | t |
1762 | } | |
1763 | ||
e9174d1e | 1764 | pub fn expr_ty(&self, ex: &hir::Expr) -> Ty<'tcx> { |
a7813a04 | 1765 | match self.tables.borrow().node_types.get(&ex.id) { |
1a4d82fc JJ |
1766 | Some(&t) => t, |
1767 | None => { | |
54a0048b | 1768 | bug!("no type for expr in fcx {}", self.tag()); |
1a4d82fc JJ |
1769 | } |
1770 | } | |
1771 | } | |
1772 | ||
1773 | /// Apply `adjustment` to the type of `expr` | |
1774 | pub fn adjust_expr_ty(&self, | |
e9174d1e SL |
1775 | expr: &hir::Expr, |
1776 | adjustment: Option<&adjustment::AutoAdjustment<'tcx>>) | |
1a4d82fc JJ |
1777 | -> Ty<'tcx> |
1778 | { | |
1779 | let raw_ty = self.expr_ty(expr); | |
a7813a04 XL |
1780 | let raw_ty = self.shallow_resolve(raw_ty); |
1781 | let resolve_ty = |ty: Ty<'tcx>| self.resolve_type_vars_if_possible(&ty); | |
1782 | raw_ty.adjust(self.tcx, expr.span, expr.id, adjustment, |method_call| { | |
1783 | self.tables.borrow().method_map.get(&method_call) | |
c1a9b12d SL |
1784 | .map(|method| resolve_ty(method.ty)) |
1785 | }) | |
1a4d82fc JJ |
1786 | } |
1787 | ||
1788 | pub fn node_ty(&self, id: ast::NodeId) -> Ty<'tcx> { | |
a7813a04 | 1789 | match self.tables.borrow().node_types.get(&id) { |
1a4d82fc | 1790 | Some(&t) => t, |
a7813a04 | 1791 | None if self.err_count_since_creation() != 0 => self.tcx.types.err, |
1a4d82fc | 1792 | None => { |
54a0048b | 1793 | bug!("no type for node {}: {} in fcx {}", |
a7813a04 | 1794 | id, self.tcx.map.node_to_string(id), |
54a0048b | 1795 | self.tag()); |
1a4d82fc JJ |
1796 | } |
1797 | } | |
1798 | } | |
1799 | ||
1800 | pub fn item_substs(&self) -> Ref<NodeMap<ty::ItemSubsts<'tcx>>> { | |
c1a9b12d SL |
1801 | // NOTE: @jroesch this is hack that appears to be fixed on nightly, will monitor if |
1802 | // it changes when we upgrade the snapshot compiler | |
1803 | fn project_item_susbts<'a, 'tcx>(tables: &'a ty::Tables<'tcx>) | |
1804 | -> &'a NodeMap<ty::ItemSubsts<'tcx>> { | |
1805 | &tables.item_substs | |
1806 | } | |
1807 | ||
a7813a04 | 1808 | Ref::map(self.tables.borrow(), project_item_susbts) |
1a4d82fc JJ |
1809 | } |
1810 | ||
1811 | pub fn opt_node_ty_substs<F>(&self, | |
1812 | id: ast::NodeId, | |
1813 | f: F) where | |
1814 | F: FnOnce(&ty::ItemSubsts<'tcx>), | |
1815 | { | |
a7813a04 | 1816 | match self.tables.borrow().item_substs.get(&id) { |
1a4d82fc JJ |
1817 | Some(s) => { f(s) } |
1818 | None => { } | |
1819 | } | |
1820 | } | |
1821 | ||
1a4d82fc JJ |
1822 | /// Registers an obligation for checking later, during regionck, that the type `ty` must |
1823 | /// outlive the region `r`. | |
1824 | pub fn register_region_obligation(&self, | |
1825 | ty: Ty<'tcx>, | |
1826 | region: ty::Region, | |
1827 | cause: traits::ObligationCause<'tcx>) | |
1828 | { | |
a7813a04 | 1829 | let mut fulfillment_cx = self.fulfillment_cx.borrow_mut(); |
62682a34 | 1830 | fulfillment_cx.register_region_obligation(ty, region, cause); |
1a4d82fc JJ |
1831 | } |
1832 | ||
e9174d1e SL |
1833 | /// Registers an obligation for checking later, during regionck, that the type `ty` must |
1834 | /// outlive the region `r`. | |
1835 | pub fn register_wf_obligation(&self, | |
1836 | ty: Ty<'tcx>, | |
1837 | span: Span, | |
1838 | code: traits::ObligationCauseCode<'tcx>) | |
1839 | { | |
1840 | // WF obligations never themselves fail, so no real need to give a detailed cause: | |
1841 | let cause = traits::ObligationCause::new(span, self.body_id, code); | |
1842 | self.register_predicate(traits::Obligation::new(cause, ty::Predicate::WellFormed(ty))); | |
1843 | } | |
1844 | ||
1845 | pub fn register_old_wf_obligation(&self, | |
1846 | ty: Ty<'tcx>, | |
1847 | span: Span, | |
1848 | code: traits::ObligationCauseCode<'tcx>) | |
1849 | { | |
1850 | // Registers an "old-style" WF obligation that uses the | |
1851 | // implicator code. This is basically a buggy version of | |
1852 | // `register_wf_obligation` that is being kept around | |
1853 | // temporarily just to help with phasing in the newer rules. | |
1854 | // | |
1855 | // FIXME(#27579) all uses of this should be migrated to register_wf_obligation eventually | |
1856 | let cause = traits::ObligationCause::new(span, self.body_id, code); | |
1857 | self.register_region_obligation(ty, ty::ReEmpty, cause); | |
1858 | } | |
1859 | ||
1860 | /// Registers obligations that all types appearing in `substs` are well-formed. | |
1861 | pub fn add_wf_bounds(&self, substs: &Substs<'tcx>, expr: &hir::Expr) | |
1a4d82fc | 1862 | { |
62682a34 | 1863 | for &ty in &substs.types { |
e9174d1e | 1864 | self.register_wf_obligation(ty, expr.span, traits::MiscObligation); |
1a4d82fc JJ |
1865 | } |
1866 | } | |
1867 | ||
1868 | /// Given a fully substituted set of bounds (`generic_bounds`), and the values with which each | |
1869 | /// type/region parameter was instantiated (`substs`), creates and registers suitable | |
1870 | /// trait/region obligations. | |
1871 | /// | |
1872 | /// For example, if there is a function: | |
1873 | /// | |
1874 | /// ``` | |
1875 | /// fn foo<'a,T:'a>(...) | |
1876 | /// ``` | |
1877 | /// | |
1878 | /// and a reference: | |
1879 | /// | |
1880 | /// ``` | |
1881 | /// let f = foo; | |
1882 | /// ``` | |
1883 | /// | |
1884 | /// Then we will create a fresh region variable `'$0` and a fresh type variable `$1` for `'a` | |
1885 | /// and `T`. This routine will add a region obligation `$1:'$0` and register it locally. | |
1886 | pub fn add_obligations_for_parameters(&self, | |
1887 | cause: traits::ObligationCause<'tcx>, | |
85aaf69f | 1888 | predicates: &ty::InstantiatedPredicates<'tcx>) |
1a4d82fc | 1889 | { |
85aaf69f | 1890 | assert!(!predicates.has_escaping_regions()); |
1a4d82fc | 1891 | |
62682a34 SL |
1892 | debug!("add_obligations_for_parameters(predicates={:?})", |
1893 | predicates); | |
1a4d82fc | 1894 | |
62682a34 SL |
1895 | for obligation in traits::predicates_for_generics(cause, predicates) { |
1896 | self.register_predicate(obligation); | |
1897 | } | |
1a4d82fc | 1898 | } |
85aaf69f | 1899 | |
e9174d1e | 1900 | // FIXME(arielb1): use this instead of field.ty everywhere |
54a0048b SL |
1901 | // Only for fields! Returns <none> for methods> |
1902 | // Indifferent to privacy flags | |
e9174d1e SL |
1903 | pub fn field_ty(&self, |
1904 | span: Span, | |
1905 | field: ty::FieldDef<'tcx>, | |
1906 | substs: &Substs<'tcx>) | |
1907 | -> Ty<'tcx> | |
85aaf69f | 1908 | { |
e9174d1e | 1909 | self.normalize_associated_types_in(span, |
a7813a04 | 1910 | &field.ty(self.tcx, substs)) |
85aaf69f | 1911 | } |
c34b1796 AL |
1912 | |
1913 | fn check_casts(&self) { | |
a7813a04 | 1914 | let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut(); |
62682a34 SL |
1915 | for cast in deferred_cast_checks.drain(..) { |
1916 | cast.check(self); | |
c34b1796 | 1917 | } |
c34b1796 | 1918 | } |
d9579d0f | 1919 | |
c1a9b12d SL |
1920 | /// Apply "fallbacks" to some types |
1921 | /// ! gets replaced with (), unconstrained ints with i32, and unconstrained floats with f64. | |
1922 | fn default_type_parameters(&self) { | |
54a0048b SL |
1923 | use rustc::ty::error::UnconstrainedNumeric::Neither; |
1924 | use rustc::ty::error::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat}; | |
a7813a04 XL |
1925 | |
1926 | // Defaulting inference variables becomes very dubious if we have | |
1927 | // encountered type-checking errors. Therefore, if we think we saw | |
1928 | // some errors in this function, just resolve all uninstanted type | |
1929 | // varibles to TyError. | |
1930 | if self.is_tainted_by_errors() { | |
1931 | for ty in &self.unsolved_variables() { | |
1932 | if let ty::TyInfer(_) = self.shallow_resolve(ty).sty { | |
1933 | debug!("default_type_parameters: defaulting `{:?}` to error", ty); | |
1934 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx().types.err); | |
1935 | } | |
1936 | } | |
1937 | return; | |
1938 | } | |
1939 | ||
1940 | for ty in &self.unsolved_variables() { | |
1941 | let resolved = self.resolve_type_vars_if_possible(ty); | |
1942 | if self.type_var_diverges(resolved) { | |
1943 | debug!("default_type_parameters: defaulting `{:?}` to `()` because it diverges", | |
1944 | resolved); | |
1945 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.mk_nil()); | |
c1a9b12d | 1946 | } else { |
a7813a04 | 1947 | match self.type_is_unconstrained_numeric(resolved) { |
c1a9b12d | 1948 | UnconstrainedInt => { |
a7813a04 XL |
1949 | debug!("default_type_parameters: defaulting `{:?}` to `i32`", |
1950 | resolved); | |
1951 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.i32) | |
c1a9b12d SL |
1952 | }, |
1953 | UnconstrainedFloat => { | |
a7813a04 XL |
1954 | debug!("default_type_parameters: defaulting `{:?}` to `f32`", |
1955 | resolved); | |
1956 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.f64) | |
c1a9b12d SL |
1957 | } |
1958 | Neither => { } | |
1959 | } | |
1960 | } | |
1961 | } | |
1962 | } | |
1963 | ||
d9579d0f | 1964 | fn select_all_obligations_and_apply_defaults(&self) { |
a7813a04 | 1965 | if self.tcx.sess.features.borrow().default_type_parameter_fallback { |
c1a9b12d SL |
1966 | self.new_select_all_obligations_and_apply_defaults(); |
1967 | } else { | |
1968 | self.old_select_all_obligations_and_apply_defaults(); | |
1969 | } | |
1970 | } | |
d9579d0f | 1971 | |
c1a9b12d SL |
1972 | // Implements old type inference fallback algorithm |
1973 | fn old_select_all_obligations_and_apply_defaults(&self) { | |
d9579d0f AL |
1974 | self.select_obligations_where_possible(); |
1975 | self.default_type_parameters(); | |
1976 | self.select_obligations_where_possible(); | |
1977 | } | |
1978 | ||
c1a9b12d | 1979 | fn new_select_all_obligations_and_apply_defaults(&self) { |
54a0048b SL |
1980 | use rustc::ty::error::UnconstrainedNumeric::Neither; |
1981 | use rustc::ty::error::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat}; | |
c1a9b12d | 1982 | |
e9174d1e | 1983 | // For the time being this errs on the side of being memory wasteful but provides better |
c1a9b12d | 1984 | // error reporting. |
a7813a04 | 1985 | // let type_variables = self.type_variables.clone(); |
c1a9b12d SL |
1986 | |
1987 | // There is a possibility that this algorithm will have to run an arbitrary number of times | |
1988 | // to terminate so we bound it by the compiler's recursion limit. | |
a7813a04 | 1989 | for _ in 0..self.tcx.sess.recursion_limit.get() { |
c1a9b12d SL |
1990 | // First we try to solve all obligations, it is possible that the last iteration |
1991 | // has made it possible to make more progress. | |
1992 | self.select_obligations_where_possible(); | |
1993 | ||
1994 | let mut conflicts = Vec::new(); | |
1995 | ||
1996 | // Collect all unsolved type, integral and floating point variables. | |
a7813a04 | 1997 | let unsolved_variables = self.unsolved_variables(); |
c1a9b12d SL |
1998 | |
1999 | // We must collect the defaults *before* we do any unification. Because we have | |
2000 | // directly attached defaults to the type variables any unification that occurs | |
2001 | // will erase defaults causing conflicting defaults to be completely ignored. | |
2002 | let default_map: FnvHashMap<_, _> = | |
2003 | unsolved_variables | |
2004 | .iter() | |
a7813a04 | 2005 | .filter_map(|t| self.default(t).map(|d| (t, d))) |
c1a9b12d SL |
2006 | .collect(); |
2007 | ||
2008 | let mut unbound_tyvars = HashSet::new(); | |
2009 | ||
2010 | debug!("select_all_obligations_and_apply_defaults: defaults={:?}", default_map); | |
2011 | ||
2012 | // We loop over the unsolved variables, resolving them and if they are | |
7453a54e | 2013 | // and unconstrainted numeric type we add them to the set of unbound |
c1a9b12d SL |
2014 | // variables. We do this so we only apply literal fallback to type |
2015 | // variables without defaults. | |
2016 | for ty in &unsolved_variables { | |
a7813a04 XL |
2017 | let resolved = self.resolve_type_vars_if_possible(ty); |
2018 | if self.type_var_diverges(resolved) { | |
2019 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.mk_nil()); | |
c1a9b12d | 2020 | } else { |
a7813a04 | 2021 | match self.type_is_unconstrained_numeric(resolved) { |
c1a9b12d SL |
2022 | UnconstrainedInt | UnconstrainedFloat => { |
2023 | unbound_tyvars.insert(resolved); | |
2024 | }, | |
2025 | Neither => {} | |
2026 | } | |
2027 | } | |
2028 | } | |
2029 | ||
2030 | // We now remove any numeric types that also have defaults, and instead insert | |
2031 | // the type variable with a defined fallback. | |
2032 | for ty in &unsolved_variables { | |
2033 | if let Some(_default) = default_map.get(ty) { | |
a7813a04 | 2034 | let resolved = self.resolve_type_vars_if_possible(ty); |
c1a9b12d | 2035 | |
a7813a04 XL |
2036 | debug!("select_all_obligations_and_apply_defaults: \ |
2037 | ty: {:?} with default: {:?}", | |
c1a9b12d SL |
2038 | ty, _default); |
2039 | ||
2040 | match resolved.sty { | |
2041 | ty::TyInfer(ty::TyVar(_)) => { | |
2042 | unbound_tyvars.insert(ty); | |
2043 | } | |
2044 | ||
2045 | ty::TyInfer(ty::IntVar(_)) | ty::TyInfer(ty::FloatVar(_)) => { | |
2046 | unbound_tyvars.insert(ty); | |
2047 | if unbound_tyvars.contains(resolved) { | |
2048 | unbound_tyvars.remove(resolved); | |
2049 | } | |
2050 | } | |
2051 | ||
2052 | _ => {} | |
2053 | } | |
2054 | } | |
2055 | } | |
2056 | ||
2057 | // If there are no more fallbacks to apply at this point we have applied all possible | |
b039eaaf | 2058 | // defaults and type inference will proceed as normal. |
c1a9b12d SL |
2059 | if unbound_tyvars.is_empty() { |
2060 | break; | |
2061 | } | |
2062 | ||
2063 | // Finally we go through each of the unbound type variables and unify them with | |
2064 | // the proper fallback, reporting a conflicting default error if any of the | |
2065 | // unifications fail. We know it must be a conflicting default because the | |
2066 | // variable would only be in `unbound_tyvars` and have a concrete value if | |
2067 | // it had been solved by previously applying a default. | |
2068 | ||
2069 | // We wrap this in a transaction for error reporting, if we detect a conflict | |
2070 | // we will rollback the inference context to its prior state so we can probe | |
2071 | // for conflicts and correctly report them. | |
2072 | ||
2073 | ||
a7813a04 | 2074 | let _ = self.commit_if_ok(|_: &infer::CombinedSnapshot| { |
c1a9b12d | 2075 | for ty in &unbound_tyvars { |
a7813a04 XL |
2076 | if self.type_var_diverges(ty) { |
2077 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.mk_nil()); | |
c1a9b12d | 2078 | } else { |
a7813a04 | 2079 | match self.type_is_unconstrained_numeric(ty) { |
c1a9b12d | 2080 | UnconstrainedInt => { |
a7813a04 | 2081 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.i32) |
c1a9b12d SL |
2082 | }, |
2083 | UnconstrainedFloat => { | |
a7813a04 | 2084 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.f64) |
c1a9b12d SL |
2085 | } |
2086 | Neither => { | |
2087 | if let Some(default) = default_map.get(ty) { | |
2088 | let default = default.clone(); | |
a7813a04 XL |
2089 | match self.eq_types(false, |
2090 | TypeOrigin::Misc(default.origin_span), | |
2091 | ty, default.ty) { | |
54a0048b SL |
2092 | Ok(InferOk { obligations, .. }) => { |
2093 | // FIXME(#32730) propagate obligations | |
2094 | assert!(obligations.is_empty()) | |
2095 | }, | |
c1a9b12d SL |
2096 | Err(_) => { |
2097 | conflicts.push((*ty, default)); | |
2098 | } | |
2099 | } | |
2100 | } | |
2101 | } | |
2102 | } | |
2103 | } | |
2104 | } | |
2105 | ||
2106 | // If there are conflicts we rollback, otherwise commit | |
2107 | if conflicts.len() > 0 { | |
2108 | Err(()) | |
2109 | } else { | |
2110 | Ok(()) | |
2111 | } | |
2112 | }); | |
2113 | ||
2114 | if conflicts.len() > 0 { | |
2115 | // Loop through each conflicting default, figuring out the default that caused | |
2116 | // a unification failure and then report an error for each. | |
2117 | for (conflict, default) in conflicts { | |
2118 | let conflicting_default = | |
2119 | self.find_conflicting_default(&unbound_tyvars, &default_map, conflict) | |
2120 | .unwrap_or(type_variable::Default { | |
a7813a04 | 2121 | ty: self.next_ty_var(), |
c1a9b12d | 2122 | origin_span: codemap::DUMMY_SP, |
a7813a04 | 2123 | def_id: self.tcx.map.local_def_id(0) // what do I put here? |
c1a9b12d SL |
2124 | }); |
2125 | ||
2126 | // This is to ensure that we elimnate any non-determinism from the error | |
2127 | // reporting by fixing an order, it doesn't matter what order we choose | |
2128 | // just that it is consistent. | |
2129 | let (first_default, second_default) = | |
2130 | if default.def_id < conflicting_default.def_id { | |
2131 | (default, conflicting_default) | |
2132 | } else { | |
2133 | (conflicting_default, default) | |
2134 | }; | |
2135 | ||
2136 | ||
a7813a04 | 2137 | self.report_conflicting_default_types( |
c1a9b12d SL |
2138 | first_default.origin_span, |
2139 | first_default, | |
2140 | second_default) | |
2141 | } | |
2142 | } | |
2143 | } | |
2144 | ||
2145 | self.select_obligations_where_possible(); | |
2146 | } | |
2147 | ||
2148 | // For use in error handling related to default type parameter fallback. We explicitly | |
2149 | // apply the default that caused conflict first to a local version of the type variable | |
2150 | // table then apply defaults until we find a conflict. That default must be the one | |
2151 | // that caused conflict earlier. | |
2152 | fn find_conflicting_default(&self, | |
2153 | unbound_vars: &HashSet<Ty<'tcx>>, | |
2154 | default_map: &FnvHashMap<&Ty<'tcx>, type_variable::Default<'tcx>>, | |
2155 | conflict: Ty<'tcx>) | |
2156 | -> Option<type_variable::Default<'tcx>> { | |
54a0048b SL |
2157 | use rustc::ty::error::UnconstrainedNumeric::Neither; |
2158 | use rustc::ty::error::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat}; | |
c1a9b12d SL |
2159 | |
2160 | // Ensure that we apply the conflicting default first | |
2161 | let mut unbound_tyvars = Vec::with_capacity(unbound_vars.len() + 1); | |
2162 | unbound_tyvars.push(conflict); | |
2163 | unbound_tyvars.extend(unbound_vars.iter()); | |
2164 | ||
2165 | let mut result = None; | |
2166 | // We run the same code as above applying defaults in order, this time when | |
2167 | // we find the conflict we just return it for error reporting above. | |
2168 | ||
2169 | // We also run this inside snapshot that never commits so we can do error | |
2170 | // reporting for more then one conflict. | |
2171 | for ty in &unbound_tyvars { | |
a7813a04 XL |
2172 | if self.type_var_diverges(ty) { |
2173 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.mk_nil()); | |
c1a9b12d | 2174 | } else { |
a7813a04 | 2175 | match self.type_is_unconstrained_numeric(ty) { |
c1a9b12d | 2176 | UnconstrainedInt => { |
a7813a04 | 2177 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.i32) |
c1a9b12d SL |
2178 | }, |
2179 | UnconstrainedFloat => { | |
a7813a04 | 2180 | self.demand_eqtype(codemap::DUMMY_SP, *ty, self.tcx.types.f64) |
c1a9b12d SL |
2181 | }, |
2182 | Neither => { | |
2183 | if let Some(default) = default_map.get(ty) { | |
2184 | let default = default.clone(); | |
a7813a04 XL |
2185 | match self.eq_types(false, |
2186 | TypeOrigin::Misc(default.origin_span), | |
2187 | ty, default.ty) { | |
54a0048b SL |
2188 | // FIXME(#32730) propagate obligations |
2189 | Ok(InferOk { obligations, .. }) => assert!(obligations.is_empty()), | |
c1a9b12d SL |
2190 | Err(_) => { |
2191 | result = Some(default); | |
2192 | } | |
2193 | } | |
2194 | } | |
2195 | } | |
2196 | } | |
2197 | } | |
2198 | } | |
2199 | ||
2200 | return result; | |
2201 | } | |
2202 | ||
d9579d0f AL |
2203 | fn select_all_obligations_or_error(&self) { |
2204 | debug!("select_all_obligations_or_error"); | |
2205 | ||
2206 | // upvar inference should have ensured that all deferred call | |
2207 | // resolutions are handled by now. | |
a7813a04 | 2208 | assert!(self.deferred_call_resolutions.borrow().is_empty()); |
d9579d0f AL |
2209 | |
2210 | self.select_all_obligations_and_apply_defaults(); | |
c1a9b12d | 2211 | |
a7813a04 XL |
2212 | let mut fulfillment_cx = self.fulfillment_cx.borrow_mut(); |
2213 | match fulfillment_cx.select_all_or_error(self) { | |
d9579d0f | 2214 | Ok(()) => { } |
a7813a04 XL |
2215 | Err(errors) => { self.report_fulfillment_errors(&errors); } |
2216 | } | |
2217 | ||
2218 | if let Err(ref errors) = fulfillment_cx.select_rfc1592_obligations(self) { | |
2219 | self.report_fulfillment_errors_as_warnings(errors, self.body_id); | |
d9579d0f AL |
2220 | } |
2221 | } | |
2222 | ||
2223 | /// Select as many obligations as we can at present. | |
2224 | fn select_obligations_where_possible(&self) { | |
a7813a04 | 2225 | match self.fulfillment_cx.borrow_mut().select_where_possible(self) { |
d9579d0f | 2226 | Ok(()) => { } |
a7813a04 | 2227 | Err(errors) => { self.report_fulfillment_errors(&errors); } |
d9579d0f AL |
2228 | } |
2229 | } | |
62682a34 | 2230 | |
a7813a04 XL |
2231 | /// Executes an autoderef loop for the type `t`. At each step, invokes `should_stop` |
2232 | /// to decide whether to terminate the loop. Returns the final type and number of | |
2233 | /// derefs that it performed. | |
2234 | /// | |
2235 | /// Note: this method does not modify the adjustments table. The caller is responsible for | |
2236 | /// inserting an AutoAdjustment record into the `self` using one of the suitable methods. | |
2237 | pub fn autoderef<'b, E, I, T, F>(&self, | |
2238 | sp: Span, | |
2239 | base_ty: Ty<'tcx>, | |
2240 | maybe_exprs: E, | |
2241 | unresolved_type_action: UnresolvedTypeAction, | |
2242 | mut lvalue_pref: LvaluePreference, | |
2243 | mut should_stop: F) | |
2244 | -> (Ty<'tcx>, usize, Option<T>) | |
2245 | // FIXME(eddyb) use copyable iterators when that becomes ergonomic. | |
2246 | where E: Fn() -> I, | |
2247 | I: IntoIterator<Item=&'b hir::Expr>, | |
2248 | F: FnMut(Ty<'tcx>, usize) -> Option<T>, | |
2249 | { | |
2250 | debug!("autoderef(base_ty={:?}, lvalue_pref={:?})", | |
2251 | base_ty, lvalue_pref); | |
2252 | ||
2253 | let mut t = base_ty; | |
2254 | for autoderefs in 0..self.tcx.sess.recursion_limit.get() { | |
2255 | let resolved_t = match unresolved_type_action { | |
2256 | UnresolvedTypeAction::Error => { | |
2257 | self.structurally_resolved_type(sp, t) | |
2258 | } | |
2259 | UnresolvedTypeAction::Ignore => { | |
2260 | // We can continue even when the type cannot be resolved | |
2261 | // (i.e. it is an inference variable) because `Ty::builtin_deref` | |
2262 | // and `try_overloaded_deref` both simply return `None` | |
2263 | // in such a case without producing spurious errors. | |
2264 | self.resolve_type_vars_if_possible(&t) | |
2265 | } | |
2266 | }; | |
2267 | if resolved_t.references_error() { | |
2268 | return (resolved_t, autoderefs, None); | |
2269 | } | |
1a4d82fc | 2270 | |
a7813a04 XL |
2271 | match should_stop(resolved_t, autoderefs) { |
2272 | Some(x) => return (resolved_t, autoderefs, Some(x)), | |
2273 | None => {} | |
2274 | } | |
1a4d82fc | 2275 | |
a7813a04 XL |
2276 | // Otherwise, deref if type is derefable: |
2277 | ||
2278 | // Super subtle: it might seem as though we should | |
2279 | // pass `opt_expr` to `try_overloaded_deref`, so that | |
2280 | // the (implicit) autoref of using an overloaded deref | |
2281 | // would get added to the adjustment table. However we | |
2282 | // do not do that, because it's kind of a | |
2283 | // "meta-adjustment" -- instead, we just leave it | |
2284 | // unrecorded and know that there "will be" an | |
2285 | // autoref. regionck and other bits of the code base, | |
2286 | // when they encounter an overloaded autoderef, have | |
2287 | // to do some reconstructive surgery. This is a pretty | |
2288 | // complex mess that is begging for a proper MIR. | |
2289 | let mt = if let Some(mt) = resolved_t.builtin_deref(false, lvalue_pref) { | |
2290 | mt | |
2291 | } else if let Some(method) = self.try_overloaded_deref(sp, None, | |
2292 | resolved_t, lvalue_pref) { | |
2293 | for expr in maybe_exprs() { | |
2294 | let method_call = MethodCall::autoderef(expr.id, autoderefs as u32); | |
2295 | self.tables.borrow_mut().method_map.insert(method_call, method); | |
2296 | } | |
2297 | self.make_overloaded_lvalue_return_type(method) | |
2298 | } else { | |
2299 | return (resolved_t, autoderefs, None); | |
2300 | }; | |
85aaf69f | 2301 | |
a7813a04 XL |
2302 | t = mt.ty; |
2303 | if mt.mutbl == hir::MutImmutable { | |
2304 | lvalue_pref = NoPreference; | |
85aaf69f | 2305 | } |
d9579d0f | 2306 | } |
1a4d82fc | 2307 | |
a7813a04 XL |
2308 | // We've reached the recursion limit, error gracefully. |
2309 | span_err!(self.tcx.sess, sp, E0055, | |
2310 | "reached the recursion limit while auto-dereferencing {:?}", | |
2311 | base_ty); | |
2312 | (self.tcx.types.err, 0, None) | |
2313 | } | |
1a4d82fc | 2314 | |
a7813a04 XL |
2315 | fn try_overloaded_deref(&self, |
2316 | span: Span, | |
2317 | base_expr: Option<&hir::Expr>, | |
2318 | base_ty: Ty<'tcx>, | |
2319 | lvalue_pref: LvaluePreference) | |
2320 | -> Option<MethodCallee<'tcx>> | |
2321 | { | |
2322 | // Try DerefMut first, if preferred. | |
2323 | let method = match (lvalue_pref, self.tcx.lang_items.deref_mut_trait()) { | |
2324 | (PreferMutLvalue, Some(trait_did)) => { | |
2325 | self.lookup_method_in_trait(span, base_expr, | |
2326 | token::intern("deref_mut"), trait_did, | |
2327 | base_ty, None) | |
1a4d82fc | 2328 | } |
a7813a04 | 2329 | _ => None |
1a4d82fc | 2330 | }; |
54a0048b | 2331 | |
a7813a04 XL |
2332 | // Otherwise, fall back to Deref. |
2333 | let method = match (method, self.tcx.lang_items.deref_trait()) { | |
2334 | (None, Some(trait_did)) => { | |
2335 | self.lookup_method_in_trait(span, base_expr, | |
2336 | token::intern("deref"), trait_did, | |
2337 | base_ty, None) | |
2338 | } | |
2339 | (method, _) => method | |
2340 | }; | |
2341 | ||
2342 | method | |
1a4d82fc JJ |
2343 | } |
2344 | ||
a7813a04 XL |
2345 | /// For the overloaded lvalue expressions (`*x`, `x[3]`), the trait |
2346 | /// returns a type of `&T`, but the actual type we assign to the | |
2347 | /// *expression* is `T`. So this function just peels off the return | |
2348 | /// type by one layer to yield `T`. | |
2349 | fn make_overloaded_lvalue_return_type(&self, | |
2350 | method: MethodCallee<'tcx>) | |
2351 | -> ty::TypeAndMut<'tcx> | |
2352 | { | |
2353 | // extract method return type, which will be &T; | |
2354 | // all LB regions should have been instantiated during method lookup | |
2355 | let ret_ty = method.ty.fn_ret(); | |
2356 | let ret_ty = self.tcx.no_late_bound_regions(&ret_ty).unwrap().unwrap(); | |
2357 | ||
2358 | // method returns &T, but the type as visible to user is T, so deref | |
2359 | ret_ty.builtin_deref(true, NoPreference).unwrap() | |
2360 | } | |
2361 | ||
2362 | fn lookup_indexing(&self, | |
2363 | expr: &hir::Expr, | |
2364 | base_expr: &'gcx hir::Expr, | |
2365 | base_ty: Ty<'tcx>, | |
2366 | idx_ty: Ty<'tcx>, | |
2367 | lvalue_pref: LvaluePreference) | |
2368 | -> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)> | |
2369 | { | |
2370 | // FIXME(#18741) -- this is almost but not quite the same as the | |
2371 | // autoderef that normal method probing does. They could likely be | |
2372 | // consolidated. | |
2373 | ||
2374 | let (ty, autoderefs, final_mt) = self.autoderef(base_expr.span, | |
2375 | base_ty, | |
2376 | || Some(base_expr), | |
2377 | UnresolvedTypeAction::Error, | |
2378 | lvalue_pref, | |
2379 | |adj_ty, idx| { | |
2380 | self.try_index_step(MethodCall::expr(expr.id), expr, base_expr, | |
2381 | adj_ty, idx, false, lvalue_pref, idx_ty) | |
2382 | }); | |
1a4d82fc | 2383 | |
a7813a04 XL |
2384 | if final_mt.is_some() { |
2385 | return final_mt; | |
1a4d82fc | 2386 | } |
1a4d82fc | 2387 | |
a7813a04 XL |
2388 | // After we have fully autoderef'd, if the resulting type is [T; n], then |
2389 | // do a final unsized coercion to yield [T]. | |
2390 | if let ty::TyArray(element_ty, _) = ty.sty { | |
2391 | let adjusted_ty = self.tcx.mk_slice(element_ty); | |
2392 | self.try_index_step(MethodCall::expr(expr.id), expr, base_expr, | |
2393 | adjusted_ty, autoderefs, true, lvalue_pref, idx_ty) | |
2394 | } else { | |
2395 | None | |
1a4d82fc | 2396 | } |
1a4d82fc | 2397 | } |
1a4d82fc | 2398 | |
a7813a04 XL |
2399 | /// To type-check `base_expr[index_expr]`, we progressively autoderef |
2400 | /// (and otherwise adjust) `base_expr`, looking for a type which either | |
2401 | /// supports builtin indexing or overloaded indexing. | |
2402 | /// This loop implements one step in that search; the autoderef loop | |
2403 | /// is implemented by `lookup_indexing`. | |
2404 | fn try_index_step(&self, | |
2405 | method_call: MethodCall, | |
2406 | expr: &hir::Expr, | |
2407 | base_expr: &'gcx hir::Expr, | |
2408 | adjusted_ty: Ty<'tcx>, | |
2409 | autoderefs: usize, | |
2410 | unsize: bool, | |
2411 | lvalue_pref: LvaluePreference, | |
2412 | index_ty: Ty<'tcx>) | |
2413 | -> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)> | |
2414 | { | |
2415 | let tcx = self.tcx; | |
2416 | debug!("try_index_step(expr={:?}, base_expr.id={:?}, adjusted_ty={:?}, \ | |
2417 | autoderefs={}, unsize={}, index_ty={:?})", | |
2418 | expr, | |
2419 | base_expr, | |
2420 | adjusted_ty, | |
2421 | autoderefs, | |
2422 | unsize, | |
2423 | index_ty); | |
2424 | ||
2425 | let input_ty = self.next_ty_var(); | |
2426 | ||
2427 | // First, try built-in indexing. | |
2428 | match (adjusted_ty.builtin_index(), &index_ty.sty) { | |
2429 | (Some(ty), &ty::TyUint(ast::UintTy::Us)) | (Some(ty), &ty::TyInfer(ty::IntVar(_))) => { | |
2430 | debug!("try_index_step: success, using built-in indexing"); | |
2431 | // If we had `[T; N]`, we should've caught it before unsizing to `[T]`. | |
2432 | assert!(!unsize); | |
2433 | self.write_autoderef_adjustment(base_expr.id, autoderefs); | |
2434 | return Some((tcx.types.usize, ty)); | |
2435 | } | |
2436 | _ => {} | |
1a4d82fc | 2437 | } |
1a4d82fc | 2438 | |
a7813a04 XL |
2439 | // Try `IndexMut` first, if preferred. |
2440 | let method = match (lvalue_pref, tcx.lang_items.index_mut_trait()) { | |
2441 | (PreferMutLvalue, Some(trait_did)) => { | |
2442 | self.lookup_method_in_trait_adjusted(expr.span, | |
2443 | Some(&base_expr), | |
2444 | token::intern("index_mut"), | |
2445 | trait_did, | |
2446 | autoderefs, | |
2447 | unsize, | |
2448 | adjusted_ty, | |
2449 | Some(vec![input_ty])) | |
2450 | } | |
2451 | _ => None, | |
1a4d82fc JJ |
2452 | }; |
2453 | ||
a7813a04 XL |
2454 | // Otherwise, fall back to `Index`. |
2455 | let method = match (method, tcx.lang_items.index_trait()) { | |
2456 | (None, Some(trait_did)) => { | |
2457 | self.lookup_method_in_trait_adjusted(expr.span, | |
2458 | Some(&base_expr), | |
2459 | token::intern("index"), | |
2460 | trait_did, | |
2461 | autoderefs, | |
2462 | unsize, | |
2463 | adjusted_ty, | |
2464 | Some(vec![input_ty])) | |
1a4d82fc | 2465 | } |
a7813a04 XL |
2466 | (method, _) => method, |
2467 | }; | |
2468 | ||
2469 | // If some lookup succeeds, write callee into table and extract index/element | |
2470 | // type from the method signature. | |
2471 | // If some lookup succeeded, install method in table | |
2472 | method.map(|method| { | |
2473 | debug!("try_index_step: success, using overloaded indexing"); | |
2474 | self.tables.borrow_mut().method_map.insert(method_call, method); | |
2475 | (input_ty, self.make_overloaded_lvalue_return_type(method).ty) | |
2476 | }) | |
2477 | } | |
2478 | ||
2479 | fn check_method_argument_types(&self, | |
2480 | sp: Span, | |
2481 | method_fn_ty: Ty<'tcx>, | |
2482 | callee_expr: &'gcx hir::Expr, | |
2483 | args_no_rcvr: &'gcx [P<hir::Expr>], | |
2484 | tuple_arguments: TupleArgumentsFlag, | |
2485 | expected: Expectation<'tcx>) | |
2486 | -> ty::FnOutput<'tcx> { | |
2487 | if method_fn_ty.references_error() { | |
2488 | let err_inputs = self.err_args(args_no_rcvr.len()); | |
2489 | ||
2490 | let err_inputs = match tuple_arguments { | |
2491 | DontTupleArguments => err_inputs, | |
2492 | TupleArguments => vec![self.tcx.mk_tup(err_inputs)], | |
2493 | }; | |
2494 | ||
2495 | self.check_argument_types(sp, &err_inputs[..], &[], args_no_rcvr, | |
2496 | false, tuple_arguments); | |
2497 | ty::FnConverging(self.tcx.types.err) | |
2498 | } else { | |
2499 | match method_fn_ty.sty { | |
2500 | ty::TyFnDef(_, _, ref fty) => { | |
2501 | // HACK(eddyb) ignore self in the definition (see above). | |
2502 | let expected_arg_tys = self.expected_types_for_fn_args(sp, expected, | |
2503 | fty.sig.0.output, | |
2504 | &fty.sig.0.inputs[1..]); | |
2505 | self.check_argument_types(sp, &fty.sig.0.inputs[1..], &expected_arg_tys[..], | |
2506 | args_no_rcvr, fty.sig.0.variadic, tuple_arguments); | |
2507 | fty.sig.0.output | |
2508 | } | |
2509 | _ => { | |
2510 | span_bug!(callee_expr.span, "method without bare fn type"); | |
2511 | } | |
1a4d82fc JJ |
2512 | } |
2513 | } | |
2514 | } | |
1a4d82fc | 2515 | |
a7813a04 XL |
2516 | /// Generic function that factors out common logic from function calls, |
2517 | /// method calls and overloaded operators. | |
2518 | fn check_argument_types(&self, | |
2519 | sp: Span, | |
2520 | fn_inputs: &[Ty<'tcx>], | |
2521 | expected_arg_tys: &[Ty<'tcx>], | |
2522 | args: &'gcx [P<hir::Expr>], | |
2523 | variadic: bool, | |
2524 | tuple_arguments: TupleArgumentsFlag) { | |
2525 | let tcx = self.tcx; | |
2526 | ||
2527 | // Grab the argument types, supplying fresh type variables | |
2528 | // if the wrong number of arguments were supplied | |
2529 | let supplied_arg_count = if tuple_arguments == DontTupleArguments { | |
2530 | args.len() | |
2531 | } else { | |
2532 | 1 | |
2533 | }; | |
1a4d82fc | 2534 | |
a7813a04 XL |
2535 | // All the input types from the fn signature must outlive the call |
2536 | // so as to validate implied bounds. | |
2537 | for &fn_input_ty in fn_inputs { | |
2538 | self.register_wf_obligation(fn_input_ty, sp, traits::MiscObligation); | |
2539 | } | |
2540 | ||
2541 | let mut expected_arg_tys = expected_arg_tys; | |
2542 | let expected_arg_count = fn_inputs.len(); | |
2543 | let formal_tys = if tuple_arguments == TupleArguments { | |
2544 | let tuple_type = self.structurally_resolved_type(sp, fn_inputs[0]); | |
2545 | match tuple_type.sty { | |
2546 | ty::TyTuple(arg_types) => { | |
2547 | if arg_types.len() != args.len() { | |
2548 | span_err!(tcx.sess, sp, E0057, | |
2549 | "this function takes {} parameter{} but {} parameter{} supplied", | |
2550 | arg_types.len(), | |
2551 | if arg_types.len() == 1 {""} else {"s"}, | |
2552 | args.len(), | |
2553 | if args.len() == 1 {" was"} else {"s were"}); | |
2554 | expected_arg_tys = &[]; | |
2555 | self.err_args(args.len()) | |
2556 | } else { | |
2557 | expected_arg_tys = match expected_arg_tys.get(0) { | |
2558 | Some(&ty) => match ty.sty { | |
2559 | ty::TyTuple(ref tys) => &tys, | |
2560 | _ => &[] | |
2561 | }, | |
2562 | None => &[] | |
2563 | }; | |
2564 | arg_types.to_vec() | |
2565 | } | |
2566 | } | |
2567 | _ => { | |
2568 | span_err!(tcx.sess, sp, E0059, | |
2569 | "cannot use call notation; the first type parameter \ | |
2570 | for the function trait is neither a tuple nor unit"); | |
c34b1796 | 2571 | expected_arg_tys = &[]; |
a7813a04 | 2572 | self.err_args(args.len()) |
1a4d82fc JJ |
2573 | } |
2574 | } | |
a7813a04 XL |
2575 | } else if expected_arg_count == supplied_arg_count { |
2576 | fn_inputs.to_vec() | |
2577 | } else if variadic { | |
2578 | if supplied_arg_count >= expected_arg_count { | |
2579 | fn_inputs.to_vec() | |
2580 | } else { | |
2581 | span_err!(tcx.sess, sp, E0060, | |
2582 | "this function takes at least {} parameter{} \ | |
2583 | but {} parameter{} supplied", | |
2584 | expected_arg_count, | |
2585 | if expected_arg_count == 1 {""} else {"s"}, | |
2586 | supplied_arg_count, | |
2587 | if supplied_arg_count == 1 {" was"} else {"s were"}); | |
c34b1796 | 2588 | expected_arg_tys = &[]; |
a7813a04 | 2589 | self.err_args(supplied_arg_count) |
1a4d82fc | 2590 | } |
1a4d82fc | 2591 | } else { |
a7813a04 XL |
2592 | span_err!(tcx.sess, sp, E0061, |
2593 | "this function takes {} parameter{} but {} parameter{} supplied", | |
1a4d82fc JJ |
2594 | expected_arg_count, |
2595 | if expected_arg_count == 1 {""} else {"s"}, | |
2596 | supplied_arg_count, | |
2597 | if supplied_arg_count == 1 {" was"} else {"s were"}); | |
c34b1796 | 2598 | expected_arg_tys = &[]; |
a7813a04 | 2599 | self.err_args(supplied_arg_count) |
1a4d82fc | 2600 | }; |
a7813a04 XL |
2601 | |
2602 | debug!("check_argument_types: formal_tys={:?}", | |
2603 | formal_tys.iter().map(|t| self.ty_to_string(*t)).collect::<Vec<String>>()); | |
2604 | ||
2605 | // Check the arguments. | |
2606 | // We do this in a pretty awful way: first we typecheck any arguments | |
2607 | // that are not anonymous functions, then we typecheck the anonymous | |
2608 | // functions. This is so that we have more information about the types | |
2609 | // of arguments when we typecheck the functions. This isn't really the | |
2610 | // right way to do this. | |
2611 | let xs = [false, true]; | |
2612 | let mut any_diverges = false; // has any of the arguments diverged? | |
2613 | let mut warned = false; // have we already warned about unreachable code? | |
2614 | for check_blocks in &xs { | |
2615 | let check_blocks = *check_blocks; | |
2616 | debug!("check_blocks={}", check_blocks); | |
2617 | ||
2618 | // More awful hacks: before we check argument types, try to do | |
2619 | // an "opportunistic" vtable resolution of any trait bounds on | |
2620 | // the call. This helps coercions. | |
2621 | if check_blocks { | |
2622 | self.select_obligations_where_possible(); | |
92a42be0 | 2623 | } |
a7813a04 XL |
2624 | |
2625 | // For variadic functions, we don't have a declared type for all of | |
2626 | // the arguments hence we only do our usual type checking with | |
2627 | // the arguments who's types we do know. | |
2628 | let t = if variadic { | |
2629 | expected_arg_count | |
2630 | } else if tuple_arguments == TupleArguments { | |
2631 | args.len() | |
2632 | } else { | |
2633 | supplied_arg_count | |
1a4d82fc | 2634 | }; |
a7813a04 XL |
2635 | for (i, arg) in args.iter().take(t).enumerate() { |
2636 | if any_diverges && !warned { | |
2637 | self.tcx | |
2638 | .sess | |
2639 | .add_lint(lint::builtin::UNREACHABLE_CODE, | |
2640 | arg.id, | |
2641 | arg.span, | |
2642 | "unreachable expression".to_string()); | |
2643 | warned = true; | |
2644 | } | |
2645 | let is_block = match arg.node { | |
2646 | hir::ExprClosure(..) => true, | |
2647 | _ => false | |
2648 | }; | |
1a4d82fc | 2649 | |
a7813a04 XL |
2650 | if is_block == check_blocks { |
2651 | debug!("checking the argument"); | |
2652 | let formal_ty = formal_tys[i]; | |
1a4d82fc | 2653 | |
a7813a04 XL |
2654 | // The special-cased logic below has three functions: |
2655 | // 1. Provide as good of an expected type as possible. | |
2656 | let expected = expected_arg_tys.get(i).map(|&ty| { | |
2657 | Expectation::rvalue_hint(self, ty) | |
2658 | }); | |
85aaf69f | 2659 | |
a7813a04 XL |
2660 | self.check_expr_with_expectation(&arg, |
2661 | expected.unwrap_or(ExpectHasType(formal_ty))); | |
2662 | // 2. Coerce to the most detailed type that could be coerced | |
2663 | // to, which is `expected_ty` if `rvalue_hint` returns an | |
2664 | // `ExpectHasType(expected_ty)`, or the `formal_ty` otherwise. | |
2665 | let coerce_ty = expected.and_then(|e| e.only_has_type(self)); | |
2666 | self.demand_coerce(&arg, coerce_ty.unwrap_or(formal_ty)); | |
2667 | ||
2668 | // 3. Relate the expected type and the formal one, | |
2669 | // if the expected type was used for the coercion. | |
2670 | coerce_ty.map(|ty| self.demand_suptype(arg.span, formal_ty, ty)); | |
2671 | } | |
92a42be0 | 2672 | |
a7813a04 XL |
2673 | if let Some(&arg_ty) = self.tables.borrow().node_types.get(&arg.id) { |
2674 | any_diverges = any_diverges || self.type_var_diverges(arg_ty); | |
2675 | } | |
92a42be0 | 2676 | } |
a7813a04 XL |
2677 | if any_diverges && !warned { |
2678 | let parent = self.tcx.map.get_parent_node(args[0].id); | |
2679 | self.tcx | |
2680 | .sess | |
2681 | .add_lint(lint::builtin::UNREACHABLE_CODE, | |
2682 | parent, | |
2683 | sp, | |
2684 | "unreachable call".to_string()); | |
2685 | warned = true; | |
2686 | } | |
2687 | ||
92a42be0 SL |
2688 | } |
2689 | ||
a7813a04 XL |
2690 | // We also need to make sure we at least write the ty of the other |
2691 | // arguments which we skipped above. | |
2692 | if variadic { | |
2693 | for arg in args.iter().skip(expected_arg_count) { | |
2694 | self.check_expr(&arg); | |
1a4d82fc | 2695 | |
a7813a04 XL |
2696 | // There are a few types which get autopromoted when passed via varargs |
2697 | // in C but we just error out instead and require explicit casts. | |
2698 | let arg_ty = self.structurally_resolved_type(arg.span, | |
2699 | self.expr_ty(&arg)); | |
2700 | match arg_ty.sty { | |
2701 | ty::TyFloat(ast::FloatTy::F32) => { | |
2702 | self.type_error_message(arg.span, |t| { | |
2703 | format!("can't pass an `{}` to variadic \ | |
2704 | function, cast to `c_double`", t) | |
2705 | }, arg_ty, None); | |
2706 | } | |
2707 | ty::TyInt(ast::IntTy::I8) | ty::TyInt(ast::IntTy::I16) | ty::TyBool => { | |
2708 | self.type_error_message(arg.span, |t| { | |
2709 | format!("can't pass `{}` to variadic \ | |
2710 | function, cast to `c_int`", | |
2711 | t) | |
2712 | }, arg_ty, None); | |
2713 | } | |
2714 | ty::TyUint(ast::UintTy::U8) | ty::TyUint(ast::UintTy::U16) => { | |
2715 | self.type_error_message(arg.span, |t| { | |
2716 | format!("can't pass `{}` to variadic \ | |
2717 | function, cast to `c_uint`", | |
2718 | t) | |
2719 | }, arg_ty, None); | |
2720 | } | |
2721 | ty::TyFnDef(_, _, f) => { | |
2722 | let ptr_ty = self.tcx.mk_fn_ptr(f); | |
2723 | let ptr_ty = self.resolve_type_vars_if_possible(&ptr_ty); | |
2724 | self.type_error_message(arg.span, | |
2725 | |t| { | |
2726 | format!("can't pass `{}` to variadic \ | |
2727 | function, cast to `{}`", t, ptr_ty) | |
2728 | }, arg_ty, None); | |
2729 | } | |
2730 | _ => {} | |
54a0048b | 2731 | } |
1a4d82fc JJ |
2732 | } |
2733 | } | |
2734 | } | |
1a4d82fc | 2735 | |
a7813a04 XL |
2736 | fn err_args(&self, len: usize) -> Vec<Ty<'tcx>> { |
2737 | (0..len).map(|_| self.tcx.types.err).collect() | |
1a4d82fc | 2738 | } |
1a4d82fc | 2739 | |
a7813a04 XL |
2740 | fn write_call(&self, |
2741 | call_expr: &hir::Expr, | |
2742 | output: ty::FnOutput<'tcx>) { | |
2743 | self.write_ty(call_expr.id, match output { | |
2744 | ty::FnConverging(output_ty) => output_ty, | |
2745 | ty::FnDiverging => self.next_diverging_ty_var() | |
2746 | }); | |
2747 | } | |
1a4d82fc | 2748 | |
a7813a04 XL |
2749 | // AST fragment checking |
2750 | fn check_lit(&self, | |
2751 | lit: &ast::Lit, | |
2752 | expected: Expectation<'tcx>) | |
2753 | -> Ty<'tcx> | |
2754 | { | |
2755 | let tcx = self.tcx; | |
85aaf69f | 2756 | |
a7813a04 XL |
2757 | match lit.node { |
2758 | ast::LitKind::Str(..) => tcx.mk_static_str(), | |
2759 | ast::LitKind::ByteStr(ref v) => { | |
2760 | tcx.mk_imm_ref(tcx.mk_region(ty::ReStatic), | |
2761 | tcx.mk_array(tcx.types.u8, v.len())) | |
2762 | } | |
2763 | ast::LitKind::Byte(_) => tcx.types.u8, | |
2764 | ast::LitKind::Char(_) => tcx.types.char, | |
2765 | ast::LitKind::Int(_, ast::LitIntType::Signed(t)) => tcx.mk_mach_int(t), | |
2766 | ast::LitKind::Int(_, ast::LitIntType::Unsigned(t)) => tcx.mk_mach_uint(t), | |
2767 | ast::LitKind::Int(_, ast::LitIntType::Unsuffixed) => { | |
2768 | let opt_ty = expected.to_option(self).and_then(|ty| { | |
2769 | match ty.sty { | |
2770 | ty::TyInt(_) | ty::TyUint(_) => Some(ty), | |
2771 | ty::TyChar => Some(tcx.types.u8), | |
2772 | ty::TyRawPtr(..) => Some(tcx.types.usize), | |
2773 | ty::TyFnDef(..) | ty::TyFnPtr(_) => Some(tcx.types.usize), | |
2774 | _ => None | |
2775 | } | |
2776 | }); | |
2777 | opt_ty.unwrap_or_else( | |
2778 | || tcx.mk_int_var(self.next_int_var_id())) | |
2779 | } | |
2780 | ast::LitKind::Float(_, t) => tcx.mk_mach_float(t), | |
2781 | ast::LitKind::FloatUnsuffixed(_) => { | |
2782 | let opt_ty = expected.to_option(self).and_then(|ty| { | |
2783 | match ty.sty { | |
2784 | ty::TyFloat(_) => Some(ty), | |
2785 | _ => None | |
2786 | } | |
2787 | }); | |
2788 | opt_ty.unwrap_or_else( | |
2789 | || tcx.mk_float_var(self.next_float_var_id())) | |
2790 | } | |
2791 | ast::LitKind::Bool(_) => tcx.types.bool | |
2792 | } | |
2793 | } | |
2794 | ||
2795 | fn check_expr_eq_type(&self, | |
2796 | expr: &'gcx hir::Expr, | |
2797 | expected: Ty<'tcx>) { | |
2798 | self.check_expr_with_hint(expr, expected); | |
2799 | self.demand_eqtype(expr.span, expected, self.expr_ty(expr)); | |
2800 | } | |
2801 | ||
2802 | pub fn check_expr_has_type(&self, | |
2803 | expr: &'gcx hir::Expr, | |
2804 | expected: Ty<'tcx>) { | |
2805 | self.check_expr_with_hint(expr, expected); | |
2806 | self.demand_suptype(expr.span, expected, self.expr_ty(expr)); | |
2807 | } | |
2808 | ||
2809 | fn check_expr_coercable_to_type(&self, | |
2810 | expr: &'gcx hir::Expr, | |
2811 | expected: Ty<'tcx>) { | |
2812 | self.check_expr_with_hint(expr, expected); | |
2813 | self.demand_coerce(expr, expected); | |
2814 | } | |
2815 | ||
2816 | fn check_expr_with_hint(&self, expr: &'gcx hir::Expr, | |
2817 | expected: Ty<'tcx>) { | |
2818 | self.check_expr_with_expectation(expr, ExpectHasType(expected)) | |
2819 | } | |
2820 | ||
2821 | fn check_expr_with_expectation(&self, | |
2822 | expr: &'gcx hir::Expr, | |
2823 | expected: Expectation<'tcx>) { | |
2824 | self.check_expr_with_expectation_and_lvalue_pref(expr, expected, NoPreference) | |
2825 | } | |
2826 | ||
2827 | fn check_expr(&self, expr: &'gcx hir::Expr) { | |
2828 | self.check_expr_with_expectation(expr, NoExpectation) | |
2829 | } | |
2830 | ||
2831 | fn check_expr_with_lvalue_pref(&self, expr: &'gcx hir::Expr, | |
2832 | lvalue_pref: LvaluePreference) { | |
2833 | self.check_expr_with_expectation_and_lvalue_pref(expr, NoExpectation, lvalue_pref) | |
2834 | } | |
2835 | ||
2836 | // determine the `self` type, using fresh variables for all variables | |
2837 | // declared on the impl declaration e.g., `impl<A,B> for Vec<(A,B)>` | |
2838 | // would return ($0, $1) where $0 and $1 are freshly instantiated type | |
2839 | // variables. | |
2840 | pub fn impl_self_ty(&self, | |
2841 | span: Span, // (potential) receiver for this impl | |
2842 | did: DefId) | |
2843 | -> TypeAndSubsts<'tcx> { | |
2844 | let tcx = self.tcx; | |
2845 | ||
2846 | let ity = tcx.lookup_item_type(did); | |
2847 | let (tps, rps, raw_ty) = | |
2848 | (ity.generics.types.get_slice(subst::TypeSpace), | |
2849 | ity.generics.regions.get_slice(subst::TypeSpace), | |
2850 | ity.ty); | |
2851 | ||
2852 | debug!("impl_self_ty: tps={:?} rps={:?} raw_ty={:?}", tps, rps, raw_ty); | |
2853 | ||
2854 | let rps = self.region_vars_for_defs(span, rps); | |
2855 | let mut substs = subst::Substs::new( | |
2856 | VecPerParamSpace::empty(), | |
2857 | VecPerParamSpace::new(rps, Vec::new(), Vec::new())); | |
2858 | self.type_vars_for_defs(span, ParamSpace::TypeSpace, &mut substs, tps); | |
2859 | let substd_ty = self.instantiate_type_scheme(span, &substs, &raw_ty); | |
2860 | ||
2861 | TypeAndSubsts { substs: substs, ty: substd_ty } | |
2862 | } | |
2863 | ||
2864 | /// Unifies the return type with the expected type early, for more coercions | |
2865 | /// and forward type information on the argument expressions. | |
2866 | fn expected_types_for_fn_args(&self, | |
2867 | call_span: Span, | |
2868 | expected_ret: Expectation<'tcx>, | |
2869 | formal_ret: ty::FnOutput<'tcx>, | |
2870 | formal_args: &[Ty<'tcx>]) | |
2871 | -> Vec<Ty<'tcx>> { | |
2872 | let expected_args = expected_ret.only_has_type(self).and_then(|ret_ty| { | |
2873 | if let ty::FnConverging(formal_ret_ty) = formal_ret { | |
2874 | self.commit_regions_if_ok(|| { | |
2875 | // Attempt to apply a subtyping relationship between the formal | |
2876 | // return type (likely containing type variables if the function | |
2877 | // is polymorphic) and the expected return type. | |
2878 | // No argument expectations are produced if unification fails. | |
2879 | let origin = TypeOrigin::Misc(call_span); | |
2880 | let ures = self.sub_types(false, origin, formal_ret_ty, ret_ty); | |
2881 | // FIXME(#15760) can't use try! here, FromError doesn't default | |
2882 | // to identity so the resulting type is not constrained. | |
2883 | match ures { | |
2884 | // FIXME(#32730) propagate obligations | |
2885 | Ok(InferOk { obligations, .. }) => assert!(obligations.is_empty()), | |
2886 | Err(e) => return Err(e), | |
2887 | } | |
85aaf69f | 2888 | |
a7813a04 XL |
2889 | // Record all the argument types, with the substitutions |
2890 | // produced from the above subtyping unification. | |
2891 | Ok(formal_args.iter().map(|ty| { | |
2892 | self.resolve_type_vars_if_possible(ty) | |
2893 | }).collect()) | |
2894 | }).ok() | |
2895 | } else { | |
2896 | None | |
2897 | } | |
2898 | }).unwrap_or(vec![]); | |
2899 | debug!("expected_types_for_fn_args(formal={:?} -> {:?}, expected={:?} -> {:?})", | |
2900 | formal_args, formal_ret, | |
2901 | expected_args, expected_ret); | |
2902 | expected_args | |
2903 | } | |
1a4d82fc JJ |
2904 | |
2905 | // Checks a method call. | |
a7813a04 XL |
2906 | fn check_method_call(&self, |
2907 | expr: &'gcx hir::Expr, | |
2908 | method_name: Spanned<ast::Name>, | |
2909 | args: &'gcx [P<hir::Expr>], | |
2910 | tps: &[P<hir::Ty>], | |
2911 | expected: Expectation<'tcx>, | |
2912 | lvalue_pref: LvaluePreference) { | |
7453a54e | 2913 | let rcvr = &args[0]; |
a7813a04 | 2914 | self.check_expr_with_lvalue_pref(&rcvr, lvalue_pref); |
1a4d82fc JJ |
2915 | |
2916 | // no need to check for bot/err -- callee does that | |
a7813a04 XL |
2917 | let expr_t = self.structurally_resolved_type(expr.span, self.expr_ty(&rcvr)); |
2918 | ||
2919 | let tps = tps.iter().map(|ast_ty| self.to_ty(&ast_ty)).collect::<Vec<_>>(); | |
2920 | let fn_ty = match self.lookup_method(method_name.span, | |
2921 | method_name.node, | |
2922 | expr_t, | |
2923 | tps, | |
2924 | expr, | |
2925 | rcvr) { | |
1a4d82fc JJ |
2926 | Ok(method) => { |
2927 | let method_ty = method.ty; | |
2928 | let method_call = MethodCall::expr(expr.id); | |
a7813a04 | 2929 | self.tables.borrow_mut().method_map.insert(method_call, method); |
1a4d82fc JJ |
2930 | method_ty |
2931 | } | |
2932 | Err(error) => { | |
a7813a04 XL |
2933 | if method_name.node != keywords::Invalid.name() { |
2934 | self.report_method_error(method_name.span, expr_t, | |
2935 | method_name.node, Some(rcvr), error); | |
7453a54e | 2936 | } |
a7813a04 XL |
2937 | self.write_error(expr.id); |
2938 | self.tcx.types.err | |
1a4d82fc JJ |
2939 | } |
2940 | }; | |
2941 | ||
2942 | // Call the generic checker. | |
a7813a04 XL |
2943 | let ret_ty = self.check_method_argument_types(method_name.span, fn_ty, |
2944 | expr, &args[1..], | |
2945 | DontTupleArguments, | |
2946 | expected); | |
1a4d82fc | 2947 | |
a7813a04 | 2948 | self.write_call(expr, ret_ty); |
1a4d82fc JJ |
2949 | } |
2950 | ||
2951 | // A generic function for checking the then and else in an if | |
2952 | // or if-else. | |
a7813a04 XL |
2953 | fn check_then_else(&self, |
2954 | cond_expr: &'gcx hir::Expr, | |
2955 | then_blk: &'gcx hir::Block, | |
2956 | opt_else_expr: Option<&'gcx hir::Expr>, | |
2957 | id: ast::NodeId, | |
2958 | sp: Span, | |
2959 | expected: Expectation<'tcx>) { | |
2960 | self.check_expr_has_type(cond_expr, self.tcx.types.bool); | |
2961 | ||
2962 | let expected = expected.adjust_for_branches(self); | |
2963 | self.check_block_with_expected(then_blk, expected); | |
2964 | let then_ty = self.node_ty(then_blk.id); | |
2965 | ||
2966 | let unit = self.tcx.mk_nil(); | |
54a0048b SL |
2967 | let (origin, expected, found, result) = |
2968 | if let Some(else_expr) = opt_else_expr { | |
a7813a04 XL |
2969 | self.check_expr_with_expectation(else_expr, expected); |
2970 | let else_ty = self.expr_ty(else_expr); | |
54a0048b SL |
2971 | let origin = TypeOrigin::IfExpression(sp); |
2972 | ||
2973 | // Only try to coerce-unify if we have a then expression | |
2974 | // to assign coercions to, otherwise it's () or diverging. | |
2975 | let result = if let Some(ref then) = then_blk.expr { | |
a7813a04 XL |
2976 | let res = self.try_find_coercion_lub(origin, || Some(&**then), |
2977 | then_ty, else_expr); | |
54a0048b SL |
2978 | |
2979 | // In case we did perform an adjustment, we have to update | |
2980 | // the type of the block, because old trans still uses it. | |
a7813a04 | 2981 | let adj = self.tables.borrow().adjustments.get(&then.id).cloned(); |
54a0048b | 2982 | if res.is_ok() && adj.is_some() { |
a7813a04 | 2983 | self.write_ty(then_blk.id, self.adjust_expr_ty(then, adj.as_ref())); |
54a0048b | 2984 | } |
1a4d82fc | 2985 | |
54a0048b SL |
2986 | res |
2987 | } else { | |
a7813a04 | 2988 | self.commit_if_ok(|_| { |
54a0048b | 2989 | let trace = TypeTrace::types(origin, true, then_ty, else_ty); |
a7813a04 | 2990 | self.lub(true, trace, &then_ty, &else_ty) |
54a0048b SL |
2991 | .map(|InferOk { value, obligations }| { |
2992 | // FIXME(#32730) propagate obligations | |
2993 | assert!(obligations.is_empty()); | |
2994 | value | |
2995 | }) | |
2996 | }) | |
2997 | }; | |
2998 | (origin, then_ty, else_ty, result) | |
1a4d82fc | 2999 | } else { |
54a0048b SL |
3000 | let origin = TypeOrigin::IfExpressionWithNoElse(sp); |
3001 | (origin, unit, then_ty, | |
a7813a04 | 3002 | self.eq_types(true, origin, unit, then_ty) |
54a0048b SL |
3003 | .map(|InferOk { obligations, .. }| { |
3004 | // FIXME(#32730) propagate obligations | |
3005 | assert!(obligations.is_empty()); | |
3006 | unit | |
3007 | })) | |
3008 | }; | |
3009 | ||
3010 | let if_ty = match result { | |
3011 | Ok(ty) => { | |
a7813a04 XL |
3012 | if self.expr_ty(cond_expr).references_error() { |
3013 | self.tcx.types.err | |
54a0048b SL |
3014 | } else { |
3015 | ty | |
3016 | } | |
3017 | } | |
3018 | Err(e) => { | |
a7813a04 XL |
3019 | self.report_mismatched_types(origin, expected, found, e); |
3020 | self.tcx.types.err | |
54a0048b | 3021 | } |
1a4d82fc JJ |
3022 | }; |
3023 | ||
a7813a04 | 3024 | self.write_ty(id, if_ty); |
1a4d82fc JJ |
3025 | } |
3026 | ||
1a4d82fc | 3027 | // Check field access expressions |
a7813a04 XL |
3028 | fn check_field(&self, |
3029 | expr: &'gcx hir::Expr, | |
3030 | lvalue_pref: LvaluePreference, | |
3031 | base: &'gcx hir::Expr, | |
3032 | field: &Spanned<ast::Name>) { | |
3033 | self.check_expr_with_lvalue_pref(base, lvalue_pref); | |
3034 | let expr_t = self.structurally_resolved_type(expr.span, | |
3035 | self.expr_ty(base)); | |
54a0048b | 3036 | let mut private_candidate = None; |
a7813a04 XL |
3037 | let (_, autoderefs, field_ty) = self.autoderef(expr.span, |
3038 | expr_t, | |
3039 | || Some(base), | |
3040 | UnresolvedTypeAction::Error, | |
3041 | lvalue_pref, | |
3042 | |base_t, _| { | |
54a0048b SL |
3043 | if let ty::TyStruct(base_def, substs) = base_t.sty { |
3044 | debug!("struct named {:?}", base_t); | |
3045 | if let Some(field) = base_def.struct_variant().find_field_named(field.node) { | |
a7813a04 XL |
3046 | let field_ty = self.field_ty(expr.span, field, substs); |
3047 | if field.vis.is_accessible_from(self.body_id, &self.tcx().map) { | |
54a0048b SL |
3048 | return Some(field_ty); |
3049 | } | |
3050 | private_candidate = Some((base_def.did, field_ty)); | |
1a4d82fc | 3051 | } |
1a4d82fc | 3052 | } |
54a0048b | 3053 | None |
1a4d82fc JJ |
3054 | }); |
3055 | match field_ty { | |
3056 | Some(field_ty) => { | |
a7813a04 XL |
3057 | self.write_ty(expr.id, field_ty); |
3058 | self.write_autoderef_adjustment(base.id, autoderefs); | |
1a4d82fc JJ |
3059 | return; |
3060 | } | |
3061 | None => {} | |
3062 | } | |
3063 | ||
54a0048b | 3064 | if let Some((did, field_ty)) = private_candidate { |
a7813a04 XL |
3065 | let struct_path = self.tcx().item_path_str(did); |
3066 | self.write_ty(expr.id, field_ty); | |
54a0048b | 3067 | let msg = format!("field `{}` of struct `{}` is private", field.node, struct_path); |
a7813a04 XL |
3068 | let mut err = self.tcx().sess.struct_span_err(expr.span, &msg); |
3069 | // Also check if an accessible method exists, which is often what is meant. | |
3070 | if self.method_exists(field.span, field.node, expr_t, expr.id, false) { | |
3071 | err.note(&format!("a method `{}` also exists, perhaps you wish to call it", | |
3072 | field.node)); | |
3073 | } | |
3074 | err.emit(); | |
3075 | } else if field.node == keywords::Invalid.name() { | |
3076 | self.write_error(expr.id); | |
3077 | } else if self.method_exists(field.span, field.node, expr_t, expr.id, true) { | |
3078 | self.type_error_struct(field.span, |actual| { | |
3079 | format!("attempted to take value of method `{}` on type \ | |
3080 | `{}`", field.node, actual) | |
3081 | }, expr_t, None) | |
3082 | .help( | |
3083 | "maybe a `()` to call it is missing? \ | |
3084 | If not, try an anonymous function") | |
9cc50fc6 | 3085 | .emit(); |
a7813a04 | 3086 | self.write_error(expr.id); |
1a4d82fc | 3087 | } else { |
a7813a04 XL |
3088 | let mut err = self.type_error_struct(expr.span, |actual| { |
3089 | format!("attempted access of field `{}` on type `{}`, \ | |
3090 | but no field with that name was found", | |
3091 | field.node, actual) | |
3092 | }, expr_t, None); | |
e9174d1e | 3093 | if let ty::TyStruct(def, _) = expr_t.sty { |
a7813a04 | 3094 | Self::suggest_field_names(&mut err, def.struct_variant(), field, vec![]); |
85aaf69f | 3095 | } |
9cc50fc6 | 3096 | err.emit(); |
a7813a04 | 3097 | self.write_error(expr.id); |
1a4d82fc | 3098 | } |
1a4d82fc JJ |
3099 | } |
3100 | ||
85aaf69f | 3101 | // displays hints about the closest matches in field names |
a7813a04 XL |
3102 | fn suggest_field_names(err: &mut DiagnosticBuilder, |
3103 | variant: ty::VariantDef<'tcx>, | |
3104 | field: &Spanned<ast::Name>, | |
3105 | skip : Vec<InternedString>) { | |
b039eaaf | 3106 | let name = field.node.as_str(); |
a7813a04 XL |
3107 | let names = variant.fields.iter().filter_map(|field| { |
3108 | // ignore already set fields and private fields from non-local crates | |
3109 | if skip.iter().any(|x| *x == field.name.as_str()) || | |
3110 | (variant.did.krate != LOCAL_CRATE && field.vis != Visibility::Public) { | |
3111 | None | |
3112 | } else { | |
3113 | Some(&field.name) | |
3114 | } | |
3115 | }); | |
9cc50fc6 | 3116 | |
85aaf69f | 3117 | // only find fits with at least one matching letter |
9cc50fc6 SL |
3118 | if let Some(name) = find_best_match_for_name(names, &name, Some(name.len())) { |
3119 | err.span_help(field.span, | |
3120 | &format!("did you mean `{}`?", name)); | |
85aaf69f SL |
3121 | } |
3122 | } | |
3123 | ||
1a4d82fc | 3124 | // Check tuple index expressions |
a7813a04 XL |
3125 | fn check_tup_field(&self, |
3126 | expr: &'gcx hir::Expr, | |
3127 | lvalue_pref: LvaluePreference, | |
3128 | base: &'gcx hir::Expr, | |
3129 | idx: codemap::Spanned<usize>) { | |
3130 | self.check_expr_with_lvalue_pref(base, lvalue_pref); | |
3131 | let expr_t = self.structurally_resolved_type(expr.span, | |
3132 | self.expr_ty(base)); | |
54a0048b | 3133 | let mut private_candidate = None; |
1a4d82fc | 3134 | let mut tuple_like = false; |
a7813a04 XL |
3135 | let (_, autoderefs, field_ty) = self.autoderef(expr.span, |
3136 | expr_t, | |
3137 | || Some(base), | |
3138 | UnresolvedTypeAction::Error, | |
3139 | lvalue_pref, | |
3140 | |base_t, _| { | |
54a0048b SL |
3141 | let (base_def, substs) = match base_t.sty { |
3142 | ty::TyStruct(base_def, substs) => (base_def, substs), | |
62682a34 | 3143 | ty::TyTuple(ref v) => { |
1a4d82fc | 3144 | tuple_like = true; |
54a0048b | 3145 | return if idx.node < v.len() { Some(v[idx.node]) } else { None } |
1a4d82fc | 3146 | } |
54a0048b SL |
3147 | _ => return None, |
3148 | }; | |
3149 | ||
3150 | tuple_like = base_def.struct_variant().is_tuple_struct(); | |
3151 | if !tuple_like { return None } | |
3152 | ||
3153 | debug!("tuple struct named {:?}", base_t); | |
3154 | if let Some(field) = base_def.struct_variant().fields.get(idx.node) { | |
a7813a04 XL |
3155 | let field_ty = self.field_ty(expr.span, field, substs); |
3156 | if field.vis.is_accessible_from(self.body_id, &self.tcx().map) { | |
54a0048b SL |
3157 | return Some(field_ty); |
3158 | } | |
3159 | private_candidate = Some((base_def.did, field_ty)); | |
1a4d82fc | 3160 | } |
54a0048b | 3161 | None |
1a4d82fc JJ |
3162 | }); |
3163 | match field_ty { | |
3164 | Some(field_ty) => { | |
a7813a04 XL |
3165 | self.write_ty(expr.id, field_ty); |
3166 | self.write_autoderef_adjustment(base.id, autoderefs); | |
1a4d82fc JJ |
3167 | return; |
3168 | } | |
3169 | None => {} | |
3170 | } | |
54a0048b SL |
3171 | |
3172 | if let Some((did, field_ty)) = private_candidate { | |
a7813a04 | 3173 | let struct_path = self.tcx().item_path_str(did); |
54a0048b | 3174 | let msg = format!("field `{}` of struct `{}` is private", idx.node, struct_path); |
a7813a04 XL |
3175 | self.tcx().sess.span_err(expr.span, &msg); |
3176 | self.write_ty(expr.id, field_ty); | |
54a0048b SL |
3177 | return; |
3178 | } | |
3179 | ||
a7813a04 | 3180 | self.type_error_message( |
1a4d82fc JJ |
3181 | expr.span, |
3182 | |actual| { | |
3183 | if tuple_like { | |
3184 | format!("attempted out-of-bounds tuple index `{}` on \ | |
3185 | type `{}`", | |
3186 | idx.node, | |
3187 | actual) | |
3188 | } else { | |
3189 | format!("attempted tuple index `{}` on type `{}`, but the \ | |
3190 | type was not a tuple or tuple struct", | |
3191 | idx.node, | |
3192 | actual) | |
3193 | } | |
3194 | }, | |
3195 | expr_t, None); | |
3196 | ||
a7813a04 | 3197 | self.write_error(expr.id); |
1a4d82fc JJ |
3198 | } |
3199 | ||
a7813a04 XL |
3200 | fn report_unknown_field(&self, |
3201 | ty: Ty<'tcx>, | |
3202 | variant: ty::VariantDef<'tcx>, | |
3203 | field: &hir::Field, | |
3204 | skip_fields: &[hir::Field]) { | |
3205 | let mut err = self.type_error_struct( | |
b039eaaf | 3206 | field.name.span, |
e9174d1e SL |
3207 | |actual| if let ty::TyEnum(..) = ty.sty { |
3208 | format!("struct variant `{}::{}` has no field named `{}`", | |
b039eaaf | 3209 | actual, variant.name.as_str(), field.name.node) |
e9174d1e SL |
3210 | } else { |
3211 | format!("structure `{}` has no field named `{}`", | |
b039eaaf | 3212 | actual, field.name.node) |
e9174d1e SL |
3213 | }, |
3214 | ty, | |
3215 | None); | |
3216 | // prevent all specified fields from being suggested | |
b039eaaf | 3217 | let skip_fields = skip_fields.iter().map(|ref x| x.name.node.as_str()); |
a7813a04 | 3218 | Self::suggest_field_names(&mut err, variant, &field.name, skip_fields.collect()); |
9cc50fc6 | 3219 | err.emit(); |
e9174d1e SL |
3220 | } |
3221 | ||
a7813a04 XL |
3222 | fn check_expr_struct_fields(&self, |
3223 | adt_ty: Ty<'tcx>, | |
3224 | span: Span, | |
3225 | variant: ty::VariantDef<'tcx>, | |
3226 | ast_fields: &'gcx [hir::Field], | |
3227 | check_completeness: bool) { | |
3228 | let tcx = self.tcx; | |
e9174d1e SL |
3229 | let substs = match adt_ty.sty { |
3230 | ty::TyStruct(_, substs) | ty::TyEnum(_, substs) => substs, | |
54a0048b | 3231 | _ => span_bug!(span, "non-ADT passed to check_expr_struct_fields") |
e9174d1e | 3232 | }; |
1a4d82fc | 3233 | |
e9174d1e SL |
3234 | let mut remaining_fields = FnvHashMap(); |
3235 | for field in &variant.fields { | |
3236 | remaining_fields.insert(field.name, field); | |
1a4d82fc JJ |
3237 | } |
3238 | ||
3239 | let mut error_happened = false; | |
3240 | ||
3241 | // Typecheck each field. | |
85aaf69f | 3242 | for field in ast_fields { |
e9174d1e SL |
3243 | let expected_field_type; |
3244 | ||
b039eaaf | 3245 | if let Some(v_field) = remaining_fields.remove(&field.name.node) { |
a7813a04 | 3246 | expected_field_type = self.field_ty(field.span, v_field, substs); |
e9174d1e SL |
3247 | } else { |
3248 | error_happened = true; | |
3249 | expected_field_type = tcx.types.err; | |
b039eaaf | 3250 | if let Some(_) = variant.find_field_named(field.name.node) { |
a7813a04 | 3251 | span_err!(self.tcx.sess, field.name.span, E0062, |
1a4d82fc | 3252 | "field `{}` specified more than once", |
b039eaaf | 3253 | field.name.node); |
e9174d1e | 3254 | } else { |
a7813a04 | 3255 | self.report_unknown_field(adt_ty, variant, field, ast_fields); |
1a4d82fc JJ |
3256 | } |
3257 | } | |
3258 | ||
3259 | // Make sure to give a type to the field even if there's | |
3260 | // an error, so we can continue typechecking | |
a7813a04 | 3261 | self.check_expr_coercable_to_type(&field.expr, expected_field_type); |
1a4d82fc JJ |
3262 | } |
3263 | ||
1a4d82fc | 3264 | // Make sure the programmer specified all the fields. |
e9174d1e SL |
3265 | if check_completeness && |
3266 | !error_happened && | |
3267 | !remaining_fields.is_empty() | |
3268 | { | |
3269 | span_err!(tcx.sess, span, E0063, | |
9cc50fc6 | 3270 | "missing field{} {} in initializer of `{}`", |
e9174d1e SL |
3271 | if remaining_fields.len() == 1 {""} else {"s"}, |
3272 | remaining_fields.keys() | |
3273 | .map(|n| format!("`{}`", n)) | |
3274 | .collect::<Vec<_>>() | |
9cc50fc6 SL |
3275 | .join(", "), |
3276 | adt_ty); | |
1a4d82fc JJ |
3277 | } |
3278 | ||
1a4d82fc JJ |
3279 | } |
3280 | ||
a7813a04 XL |
3281 | fn check_struct_fields_on_error(&self, |
3282 | id: ast::NodeId, | |
3283 | fields: &'gcx [hir::Field], | |
3284 | base_expr: &'gcx Option<P<hir::Expr>>) { | |
1a4d82fc JJ |
3285 | // Make sure to still write the types |
3286 | // otherwise we might ICE | |
a7813a04 | 3287 | self.write_error(id); |
85aaf69f | 3288 | for field in fields { |
a7813a04 | 3289 | self.check_expr(&field.expr); |
1a4d82fc JJ |
3290 | } |
3291 | match *base_expr { | |
a7813a04 | 3292 | Some(ref base) => self.check_expr(&base), |
1a4d82fc JJ |
3293 | None => {} |
3294 | } | |
3295 | } | |
3296 | ||
a7813a04 XL |
3297 | fn check_expr_struct(&self, |
3298 | expr: &hir::Expr, | |
3299 | path: &hir::Path, | |
3300 | fields: &'gcx [hir::Field], | |
3301 | base_expr: &'gcx Option<P<hir::Expr>>) | |
e9174d1e | 3302 | { |
a7813a04 | 3303 | let tcx = self.tcx; |
e9174d1e SL |
3304 | |
3305 | // Find the relevant variant | |
3306 | let def = lookup_full_def(tcx, path.span, expr.id); | |
7453a54e | 3307 | if def == Def::Err { |
a7813a04 XL |
3308 | self.set_tainted_by_errors(); |
3309 | self.check_struct_fields_on_error(expr.id, fields, base_expr); | |
9cc50fc6 SL |
3310 | return; |
3311 | } | |
a7813a04 | 3312 | let variant = match self.def_struct_variant(def, path.span) { |
7453a54e | 3313 | Some((_, variant)) => variant, |
e9174d1e | 3314 | None => { |
a7813a04 | 3315 | span_err!(self.tcx.sess, path.span, E0071, |
e9174d1e SL |
3316 | "`{}` does not name a structure", |
3317 | pprust::path_to_string(path)); | |
a7813a04 | 3318 | self.check_struct_fields_on_error(expr.id, fields, base_expr); |
e9174d1e SL |
3319 | return; |
3320 | } | |
3321 | }; | |
3322 | ||
a7813a04 XL |
3323 | let expr_ty = self.instantiate_type(def.def_id(), path); |
3324 | self.write_ty(expr.id, expr_ty); | |
e9174d1e | 3325 | |
a7813a04 XL |
3326 | self.check_expr_struct_fields(expr_ty, path.span, variant, fields, |
3327 | base_expr.is_none()); | |
e9174d1e | 3328 | if let &Some(ref base_expr) = base_expr { |
a7813a04 | 3329 | self.check_expr_has_type(base_expr, expr_ty); |
7453a54e SL |
3330 | match expr_ty.sty { |
3331 | ty::TyStruct(adt, substs) => { | |
a7813a04 | 3332 | self.tables.borrow_mut().fru_field_types.insert( |
7453a54e SL |
3333 | expr.id, |
3334 | adt.struct_variant().fields.iter().map(|f| { | |
a7813a04 | 3335 | self.normalize_associated_types_in( |
7453a54e SL |
3336 | expr.span, &f.ty(tcx, substs) |
3337 | ) | |
3338 | }).collect() | |
3339 | ); | |
3340 | } | |
3341 | _ => { | |
3342 | span_err!(tcx.sess, base_expr.span, E0436, | |
3343 | "functional record update syntax requires a struct"); | |
3344 | } | |
e9174d1e SL |
3345 | } |
3346 | } | |
3347 | } | |
3348 | ||
1a4d82fc | 3349 | |
a7813a04 XL |
3350 | /// Invariant: |
3351 | /// If an expression has any sub-expressions that result in a type error, | |
3352 | /// inspecting that expression's type with `ty.references_error()` will return | |
3353 | /// true. Likewise, if an expression is known to diverge, inspecting its | |
3354 | /// type with `ty::type_is_bot` will return true (n.b.: since Rust is | |
3355 | /// strict, _|_ can appear in the type of an expression that does not, | |
3356 | /// itself, diverge: for example, fn() -> _|_.) | |
3357 | /// Note that inspecting a type's structure *directly* may expose the fact | |
3358 | /// that there are actually multiple representations for `TyError`, so avoid | |
3359 | /// that when err needs to be handled differently. | |
3360 | fn check_expr_with_expectation_and_lvalue_pref(&self, | |
3361 | expr: &'gcx hir::Expr, | |
3362 | expected: Expectation<'tcx>, | |
3363 | lvalue_pref: LvaluePreference) { | |
3364 | debug!(">> typechecking: expr={:?} expected={:?}", | |
3365 | expr, expected); | |
3366 | ||
3367 | let tcx = self.tcx; | |
3368 | let id = expr.id; | |
3369 | match expr.node { | |
3370 | hir::ExprBox(ref subexpr) => { | |
3371 | let expected_inner = expected.to_option(self).map_or(NoExpectation, |ty| { | |
3372 | match ty.sty { | |
3373 | ty::TyBox(ty) => Expectation::rvalue_hint(self, ty), | |
3374 | _ => NoExpectation | |
3375 | } | |
3376 | }); | |
3377 | self.check_expr_with_expectation(subexpr, expected_inner); | |
3378 | let referent_ty = self.expr_ty(&subexpr); | |
3379 | self.write_ty(id, tcx.mk_box(referent_ty)); | |
3380 | } | |
1a4d82fc | 3381 | |
a7813a04 XL |
3382 | hir::ExprLit(ref lit) => { |
3383 | let typ = self.check_lit(&lit, expected); | |
3384 | self.write_ty(id, typ); | |
3385 | } | |
3386 | hir::ExprBinary(op, ref lhs, ref rhs) => { | |
3387 | self.check_binop(expr, op, lhs, rhs); | |
3388 | } | |
3389 | hir::ExprAssignOp(op, ref lhs, ref rhs) => { | |
3390 | self.check_binop_assign(expr, op, lhs, rhs); | |
3391 | } | |
3392 | hir::ExprUnary(unop, ref oprnd) => { | |
3393 | let expected_inner = match unop { | |
3394 | hir::UnNot | hir::UnNeg => { | |
3395 | expected | |
3396 | } | |
e9174d1e | 3397 | hir::UnDeref => { |
a7813a04 | 3398 | NoExpectation |
1a4d82fc | 3399 | } |
a7813a04 XL |
3400 | }; |
3401 | let lvalue_pref = match unop { | |
3402 | hir::UnDeref => lvalue_pref, | |
3403 | _ => NoPreference | |
3404 | }; | |
3405 | self.check_expr_with_expectation_and_lvalue_pref(&oprnd, | |
3406 | expected_inner, | |
3407 | lvalue_pref); | |
3408 | let mut oprnd_t = self.expr_ty(&oprnd); | |
3409 | ||
3410 | if !oprnd_t.references_error() { | |
3411 | match unop { | |
3412 | hir::UnDeref => { | |
3413 | oprnd_t = self.structurally_resolved_type(expr.span, oprnd_t); | |
3414 | ||
3415 | if let Some(mt) = oprnd_t.builtin_deref(true, NoPreference) { | |
3416 | oprnd_t = mt.ty; | |
3417 | } else if let Some(method) = self.try_overloaded_deref( | |
3418 | expr.span, Some(&oprnd), oprnd_t, lvalue_pref) { | |
3419 | oprnd_t = self.make_overloaded_lvalue_return_type(method).ty; | |
3420 | self.tables.borrow_mut().method_map.insert(MethodCall::expr(expr.id), | |
3421 | method); | |
3422 | } else { | |
3423 | self.type_error_message(expr.span, |actual| { | |
3424 | format!("type `{}` cannot be \ | |
3425 | dereferenced", actual) | |
3426 | }, oprnd_t, None); | |
3427 | oprnd_t = tcx.types.err; | |
3428 | } | |
1a4d82fc | 3429 | } |
a7813a04 XL |
3430 | hir::UnNot => { |
3431 | oprnd_t = self.structurally_resolved_type(oprnd.span, | |
3432 | oprnd_t); | |
3433 | if !(oprnd_t.is_integral() || oprnd_t.sty == ty::TyBool) { | |
3434 | oprnd_t = self.check_user_unop("!", "not", | |
3435 | tcx.lang_items.not_trait(), | |
3436 | expr, &oprnd, oprnd_t, unop); | |
3437 | } | |
c34b1796 | 3438 | } |
a7813a04 XL |
3439 | hir::UnNeg => { |
3440 | oprnd_t = self.structurally_resolved_type(oprnd.span, | |
3441 | oprnd_t); | |
3442 | if !(oprnd_t.is_integral() || oprnd_t.is_fp()) { | |
3443 | oprnd_t = self.check_user_unop("-", "neg", | |
3444 | tcx.lang_items.neg_trait(), | |
3445 | expr, &oprnd, oprnd_t, unop); | |
3446 | } | |
1a4d82fc JJ |
3447 | } |
3448 | } | |
1a4d82fc | 3449 | } |
a7813a04 XL |
3450 | self.write_ty(id, oprnd_t); |
3451 | } | |
3452 | hir::ExprAddrOf(mutbl, ref oprnd) => { | |
3453 | let hint = expected.only_has_type(self).map_or(NoExpectation, |ty| { | |
3454 | match ty.sty { | |
3455 | ty::TyRef(_, ref mt) | ty::TyRawPtr(ref mt) => { | |
3456 | if self.tcx.expr_is_lval(&oprnd) { | |
3457 | // Lvalues may legitimately have unsized types. | |
3458 | // For example, dereferences of a fat pointer and | |
3459 | // the last field of a struct can be unsized. | |
3460 | ExpectHasType(mt.ty) | |
3461 | } else { | |
3462 | Expectation::rvalue_hint(self, mt.ty) | |
3463 | } | |
3464 | } | |
3465 | _ => NoExpectation | |
c34b1796 | 3466 | } |
a7813a04 XL |
3467 | }); |
3468 | let lvalue_pref = LvaluePreference::from_mutbl(mutbl); | |
3469 | self.check_expr_with_expectation_and_lvalue_pref(&oprnd, hint, lvalue_pref); | |
3470 | ||
3471 | let tm = ty::TypeAndMut { ty: self.expr_ty(&oprnd), mutbl: mutbl }; | |
3472 | let oprnd_t = if tm.ty.references_error() { | |
3473 | tcx.types.err | |
c34b1796 | 3474 | } else { |
a7813a04 XL |
3475 | // Note: at this point, we cannot say what the best lifetime |
3476 | // is to use for resulting pointer. We want to use the | |
3477 | // shortest lifetime possible so as to avoid spurious borrowck | |
3478 | // errors. Moreover, the longest lifetime will depend on the | |
3479 | // precise details of the value whose address is being taken | |
3480 | // (and how long it is valid), which we don't know yet until type | |
3481 | // inference is complete. | |
3482 | // | |
3483 | // Therefore, here we simply generate a region variable. The | |
3484 | // region inferencer will then select the ultimate value. | |
3485 | // Finally, borrowck is charged with guaranteeing that the | |
3486 | // value whose address was taken can actually be made to live | |
3487 | // as long as it needs to live. | |
3488 | let region = self.next_region_var(infer::AddrOfRegion(expr.span)); | |
3489 | tcx.mk_ref(tcx.mk_region(region), tm) | |
3490 | }; | |
3491 | self.write_ty(id, oprnd_t); | |
c34b1796 | 3492 | } |
a7813a04 XL |
3493 | hir::ExprPath(ref maybe_qself, ref path) => { |
3494 | let opt_self_ty = maybe_qself.as_ref().map(|qself| { | |
3495 | self.to_ty(&qself.ty) | |
3496 | }); | |
3497 | ||
3498 | let path_res = if let Some(&d) = tcx.def_map.borrow().get(&id) { | |
3499 | d | |
3500 | } else if let Some(hir::QSelf { position: 0, .. }) = *maybe_qself { | |
3501 | // Create some fake resolution that can't possibly be a type. | |
3502 | def::PathResolution { | |
3503 | base_def: Def::Mod(tcx.map.local_def_id(ast::CRATE_NODE_ID)), | |
3504 | depth: path.segments.len() | |
3505 | } | |
3506 | } else { | |
3507 | span_bug!(expr.span, "unbound path {:?}", expr) | |
3508 | }; | |
3509 | ||
3510 | if let Some((opt_ty, segments, def)) = | |
3511 | self.resolve_ty_and_def_ufcs(path_res, opt_self_ty, path, | |
3512 | expr.span, expr.id) { | |
3513 | if def != Def::Err { | |
3514 | let (scheme, predicates) = self.type_scheme_and_predicates_for_def(expr.span, | |
3515 | def); | |
3516 | self.instantiate_path(segments, scheme, &predicates, | |
3517 | opt_ty, def, expr.span, id); | |
3518 | } else { | |
3519 | self.set_tainted_by_errors(); | |
3520 | self.write_ty(id, self.tcx.types.err); | |
3521 | } | |
3522 | } | |
1a4d82fc | 3523 | |
a7813a04 XL |
3524 | // We always require that the type provided as the value for |
3525 | // a type parameter outlives the moment of instantiation. | |
3526 | self.opt_node_ty_substs(expr.id, |item_substs| { | |
3527 | self.add_wf_bounds(&item_substs.substs, expr); | |
3528 | }); | |
1a4d82fc | 3529 | } |
a7813a04 XL |
3530 | hir::ExprInlineAsm(_, ref outputs, ref inputs) => { |
3531 | for output in outputs { | |
3532 | self.check_expr(output); | |
3533 | } | |
3534 | for input in inputs { | |
3535 | self.check_expr(input); | |
3536 | } | |
3537 | self.write_nil(id); | |
1a4d82fc | 3538 | } |
a7813a04 XL |
3539 | hir::ExprBreak(_) => { self.write_ty(id, self.next_diverging_ty_var()); } |
3540 | hir::ExprAgain(_) => { self.write_ty(id, self.next_diverging_ty_var()); } | |
3541 | hir::ExprRet(ref expr_opt) => { | |
3542 | match self.ret_ty { | |
3543 | ty::FnConverging(result_type) => { | |
3544 | if let Some(ref e) = *expr_opt { | |
3545 | self.check_expr_coercable_to_type(&e, result_type); | |
3546 | } else { | |
3547 | let eq_result = self.eq_types(false, | |
3548 | TypeOrigin::Misc(expr.span), | |
3549 | result_type, | |
3550 | tcx.mk_nil()) | |
3551 | // FIXME(#32730) propagate obligations | |
3552 | .map(|InferOk { obligations, .. }| assert!(obligations.is_empty())); | |
3553 | if eq_result.is_err() { | |
1a4d82fc | 3554 | span_err!(tcx.sess, expr.span, E0069, |
a7813a04 XL |
3555 | "`return;` in a function whose return type is not `()`"); |
3556 | } | |
1a4d82fc JJ |
3557 | } |
3558 | } | |
a7813a04 XL |
3559 | ty::FnDiverging => { |
3560 | if let Some(ref e) = *expr_opt { | |
3561 | self.check_expr(&e); | |
3562 | } | |
3563 | span_err!(tcx.sess, expr.span, E0166, | |
3564 | "`return` in a function declared as diverging"); | |
1a4d82fc | 3565 | } |
1a4d82fc | 3566 | } |
a7813a04 XL |
3567 | self.write_ty(id, self.next_diverging_ty_var()); |
3568 | } | |
3569 | hir::ExprAssign(ref lhs, ref rhs) => { | |
3570 | self.check_expr_with_lvalue_pref(&lhs, PreferMutLvalue); | |
1a4d82fc | 3571 | |
a7813a04 XL |
3572 | let tcx = self.tcx; |
3573 | if !tcx.expr_is_lval(&lhs) { | |
3574 | span_err!(tcx.sess, expr.span, E0070, | |
3575 | "invalid left-hand side expression"); | |
3576 | } | |
1a4d82fc | 3577 | |
a7813a04 XL |
3578 | let lhs_ty = self.expr_ty(&lhs); |
3579 | self.check_expr_coercable_to_type(&rhs, lhs_ty); | |
3580 | let rhs_ty = self.expr_ty(&rhs); | |
1a4d82fc | 3581 | |
a7813a04 | 3582 | self.require_expr_have_sized_type(&lhs, traits::AssignmentLhsSized); |
e9174d1e | 3583 | |
a7813a04 XL |
3584 | if lhs_ty.references_error() || rhs_ty.references_error() { |
3585 | self.write_error(id); | |
3586 | } else { | |
3587 | self.write_nil(id); | |
3588 | } | |
e9174d1e | 3589 | } |
a7813a04 XL |
3590 | hir::ExprIf(ref cond, ref then_blk, ref opt_else_expr) => { |
3591 | self.check_then_else(&cond, &then_blk, opt_else_expr.as_ref().map(|e| &**e), | |
3592 | id, expr.span, expected); | |
3593 | } | |
3594 | hir::ExprWhile(ref cond, ref body, _) => { | |
3595 | self.check_expr_has_type(&cond, tcx.types.bool); | |
3596 | self.check_block_no_value(&body); | |
3597 | let cond_ty = self.expr_ty(&cond); | |
3598 | let body_ty = self.node_ty(body.id); | |
3599 | if cond_ty.references_error() || body_ty.references_error() { | |
3600 | self.write_error(id); | |
1a4d82fc | 3601 | } |
a7813a04 XL |
3602 | else { |
3603 | self.write_nil(id); | |
3604 | } | |
3605 | } | |
3606 | hir::ExprLoop(ref body, _) => { | |
3607 | self.check_block_no_value(&body); | |
3608 | if !may_break(tcx, expr.id, &body) { | |
3609 | self.write_ty(id, self.next_diverging_ty_var()); | |
3610 | } else { | |
3611 | self.write_nil(id); | |
3612 | } | |
3613 | } | |
3614 | hir::ExprMatch(ref discrim, ref arms, match_src) => { | |
3615 | self.check_match(expr, &discrim, arms, expected, match_src); | |
3616 | } | |
3617 | hir::ExprClosure(capture, ref decl, ref body, _) => { | |
3618 | self.check_expr_closure(expr, capture, &decl, &body, expected); | |
3619 | } | |
3620 | hir::ExprBlock(ref b) => { | |
3621 | self.check_block_with_expected(&b, expected); | |
3622 | self.write_ty(id, self.node_ty(b.id)); | |
3623 | } | |
3624 | hir::ExprCall(ref callee, ref args) => { | |
3625 | self.check_call(expr, &callee, &args[..], expected); | |
54a0048b | 3626 | |
a7813a04 XL |
3627 | // we must check that return type of called functions is WF: |
3628 | let ret_ty = self.expr_ty(expr); | |
3629 | self.register_wf_obligation(ret_ty, expr.span, traits::MiscObligation); | |
3630 | } | |
3631 | hir::ExprMethodCall(name, ref tps, ref args) => { | |
3632 | self.check_method_call(expr, name, &args[..], &tps[..], expected, lvalue_pref); | |
3633 | let arg_tys = args.iter().map(|a| self.expr_ty(&a)); | |
3634 | let args_err = arg_tys.fold(false, |rest_err, a| rest_err || a.references_error()); | |
3635 | if args_err { | |
3636 | self.write_error(id); | |
3637 | } | |
3638 | } | |
3639 | hir::ExprCast(ref e, ref t) => { | |
3640 | if let hir::TyFixedLengthVec(_, ref count_expr) = t.node { | |
3641 | self.check_expr_with_hint(&count_expr, tcx.types.usize); | |
3642 | } | |
54a0048b | 3643 | |
a7813a04 XL |
3644 | // Find the type of `e`. Supply hints based on the type we are casting to, |
3645 | // if appropriate. | |
3646 | let t_cast = self.to_ty(t); | |
3647 | let t_cast = self.resolve_type_vars_if_possible(&t_cast); | |
3648 | self.check_expr_with_expectation(e, ExpectCastableToType(t_cast)); | |
3649 | let t_expr = self.expr_ty(e); | |
3650 | let t_cast = self.resolve_type_vars_if_possible(&t_cast); | |
3651 | ||
3652 | // Eagerly check for some obvious errors. | |
3653 | if t_expr.references_error() || t_cast.references_error() { | |
3654 | self.write_error(id); | |
54a0048b | 3655 | } else { |
a7813a04 XL |
3656 | // Write a type for the whole expression, assuming everything is going |
3657 | // to work out Ok. | |
3658 | self.write_ty(id, t_cast); | |
3659 | ||
3660 | // Defer other checks until we're done type checking. | |
3661 | let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut(); | |
3662 | match cast::CastCheck::new(self, e, t_expr, t_cast, t.span, expr.span) { | |
3663 | Ok(cast_check) => { | |
3664 | deferred_cast_checks.push(cast_check); | |
3665 | } | |
3666 | Err(ErrorReported) => { | |
3667 | self.write_error(id); | |
3668 | } | |
1a4d82fc | 3669 | } |
1a4d82fc | 3670 | } |
a7813a04 XL |
3671 | } |
3672 | hir::ExprType(ref e, ref t) => { | |
3673 | let typ = self.to_ty(&t); | |
3674 | self.check_expr_eq_type(&e, typ); | |
3675 | self.write_ty(id, typ); | |
3676 | } | |
3677 | hir::ExprVec(ref args) => { | |
3678 | let uty = expected.to_option(self).and_then(|uty| { | |
1a4d82fc | 3679 | match uty.sty { |
62682a34 | 3680 | ty::TyArray(ty, _) | ty::TySlice(ty) => Some(ty), |
1a4d82fc JJ |
3681 | _ => None |
3682 | } | |
a7813a04 | 3683 | }); |
1a4d82fc | 3684 | |
a7813a04 XL |
3685 | let mut unified = self.next_ty_var(); |
3686 | let coerce_to = uty.unwrap_or(unified); | |
1a4d82fc | 3687 | |
a7813a04 XL |
3688 | for (i, e) in args.iter().enumerate() { |
3689 | self.check_expr_with_hint(e, coerce_to); | |
3690 | let e_ty = self.expr_ty(e); | |
3691 | let origin = TypeOrigin::Misc(e.span); | |
1a4d82fc | 3692 | |
a7813a04 XL |
3693 | // Special-case the first element, as it has no "previous expressions". |
3694 | let result = if i == 0 { | |
3695 | self.try_coerce(e, coerce_to) | |
3696 | } else { | |
3697 | let prev_elems = || args[..i].iter().map(|e| &**e); | |
3698 | self.try_find_coercion_lub(origin, prev_elems, unified, e) | |
3699 | }; | |
3700 | ||
3701 | match result { | |
3702 | Ok(ty) => unified = ty, | |
3703 | Err(e) => { | |
3704 | self.report_mismatched_types(origin, unified, e_ty, e); | |
3705 | } | |
1a4d82fc | 3706 | } |
a7813a04 XL |
3707 | } |
3708 | self.write_ty(id, tcx.mk_array(unified, args.len())); | |
3709 | } | |
3710 | hir::ExprRepeat(ref element, ref count_expr) => { | |
3711 | self.check_expr_has_type(&count_expr, tcx.types.usize); | |
3712 | let count = eval_repeat_count(self.tcx.global_tcx(), &count_expr); | |
3713 | ||
3714 | let uty = match expected { | |
3715 | ExpectHasType(uty) => { | |
3716 | match uty.sty { | |
3717 | ty::TyArray(ty, _) | ty::TySlice(ty) => Some(ty), | |
3718 | _ => None | |
3719 | } | |
1a4d82fc | 3720 | } |
a7813a04 | 3721 | _ => None |
1a4d82fc | 3722 | }; |
1a4d82fc | 3723 | |
a7813a04 XL |
3724 | let (element_ty, t) = match uty { |
3725 | Some(uty) => { | |
3726 | self.check_expr_coercable_to_type(&element, uty); | |
3727 | (uty, uty) | |
3728 | } | |
3729 | None => { | |
3730 | let t: Ty = self.next_ty_var(); | |
3731 | self.check_expr_has_type(&element, t); | |
3732 | (self.expr_ty(&element), t) | |
3733 | } | |
3734 | }; | |
1a4d82fc | 3735 | |
a7813a04 XL |
3736 | if count > 1 { |
3737 | // For [foo, ..n] where n > 1, `foo` must have | |
3738 | // Copy type: | |
3739 | self.require_type_meets(t, expr.span, traits::RepeatVec, ty::BoundCopy); | |
3740 | } | |
62682a34 | 3741 | |
a7813a04 XL |
3742 | if element_ty.references_error() { |
3743 | self.write_error(id); | |
3744 | } else { | |
3745 | let t = tcx.mk_array(t, count); | |
3746 | self.write_ty(id, t); | |
3747 | } | |
3748 | } | |
3749 | hir::ExprTup(ref elts) => { | |
3750 | let flds = expected.only_has_type(self).and_then(|ty| { | |
3751 | match ty.sty { | |
3752 | ty::TyTuple(ref flds) => Some(&flds[..]), | |
3753 | _ => None | |
7453a54e | 3754 | } |
a7813a04 XL |
3755 | }); |
3756 | let mut err_field = false; | |
3757 | ||
3758 | let elt_ts = elts.iter().enumerate().map(|(i, e)| { | |
3759 | let t = match flds { | |
3760 | Some(ref fs) if i < fs.len() => { | |
3761 | let ety = fs[i]; | |
3762 | self.check_expr_coercable_to_type(&e, ety); | |
3763 | ety | |
3764 | } | |
3765 | _ => { | |
3766 | self.check_expr_with_expectation(&e, NoExpectation); | |
3767 | self.expr_ty(&e) | |
3768 | } | |
3769 | }; | |
3770 | err_field = err_field || t.references_error(); | |
3771 | t | |
3772 | }).collect(); | |
3773 | if err_field { | |
3774 | self.write_error(id); | |
3775 | } else { | |
3776 | let typ = tcx.mk_tup(elt_ts); | |
3777 | self.write_ty(id, typ); | |
d9579d0f | 3778 | } |
a7813a04 XL |
3779 | } |
3780 | hir::ExprStruct(ref path, ref fields, ref base_expr) => { | |
3781 | self.check_expr_struct(expr, path, fields, base_expr); | |
54a0048b | 3782 | |
a7813a04 XL |
3783 | self.require_expr_have_sized_type(expr, traits::StructInitializerSized); |
3784 | } | |
3785 | hir::ExprField(ref base, ref field) => { | |
3786 | self.check_field(expr, lvalue_pref, &base, field); | |
3787 | } | |
3788 | hir::ExprTupField(ref base, idx) => { | |
3789 | self.check_tup_field(expr, lvalue_pref, &base, idx); | |
3790 | } | |
3791 | hir::ExprIndex(ref base, ref idx) => { | |
3792 | self.check_expr_with_lvalue_pref(&base, lvalue_pref); | |
3793 | self.check_expr(&idx); | |
d9579d0f | 3794 | |
a7813a04 XL |
3795 | let base_t = self.expr_ty(&base); |
3796 | let idx_t = self.expr_ty(&idx); | |
1a4d82fc | 3797 | |
a7813a04 XL |
3798 | if base_t.references_error() { |
3799 | self.write_ty(id, base_t); | |
3800 | } else if idx_t.references_error() { | |
3801 | self.write_ty(id, idx_t); | |
3802 | } else { | |
3803 | let base_t = self.structurally_resolved_type(expr.span, base_t); | |
3804 | match self.lookup_indexing(expr, base, base_t, idx_t, lvalue_pref) { | |
3805 | Some((index_ty, element_ty)) => { | |
3806 | let idx_expr_ty = self.expr_ty(idx); | |
3807 | self.demand_eqtype(expr.span, index_ty, idx_expr_ty); | |
3808 | self.write_ty(id, element_ty); | |
3809 | } | |
3810 | None => { | |
3811 | self.check_expr_has_type(&idx, self.tcx.types.err); | |
3812 | let mut err = self.type_error_struct( | |
3813 | expr.span, | |
3814 | |actual| { | |
3815 | format!("cannot index a value of type `{}`", | |
3816 | actual) | |
3817 | }, | |
3818 | base_t, | |
3819 | None); | |
3820 | // Try to give some advice about indexing tuples. | |
3821 | if let ty::TyTuple(_) = base_t.sty { | |
3822 | let mut needs_note = true; | |
3823 | // If the index is an integer, we can show the actual | |
3824 | // fixed expression: | |
3825 | if let hir::ExprLit(ref lit) = idx.node { | |
3826 | if let ast::LitKind::Int(i, | |
3827 | ast::LitIntType::Unsuffixed) = lit.node { | |
3828 | let snip = tcx.sess.codemap().span_to_snippet(base.span); | |
3829 | if let Ok(snip) = snip { | |
3830 | err.span_suggestion(expr.span, | |
3831 | "to access tuple elements, \ | |
3832 | use tuple indexing syntax \ | |
3833 | as shown", | |
3834 | format!("{}.{}", snip, i)); | |
3835 | needs_note = false; | |
3836 | } | |
3837 | } | |
3838 | } | |
3839 | if needs_note { | |
3840 | err.help("to access tuple elements, use tuple indexing \ | |
3841 | syntax (e.g. `tuple.0`)"); | |
3842 | } | |
3843 | } | |
3844 | err.emit(); | |
3845 | self.write_ty(id, self.tcx().types.err); | |
3846 | } | |
3847 | } | |
3848 | } | |
3849 | } | |
1a4d82fc | 3850 | } |
1a4d82fc | 3851 | |
a7813a04 XL |
3852 | debug!("type of expr({}) {} is...", expr.id, |
3853 | pprust::expr_to_string(expr)); | |
3854 | debug!("... {:?}, expected is {:?}", | |
3855 | self.expr_ty(expr), | |
3856 | expected); | |
1a4d82fc JJ |
3857 | } |
3858 | ||
a7813a04 XL |
3859 | pub fn resolve_ty_and_def_ufcs<'b>(&self, |
3860 | path_res: def::PathResolution, | |
3861 | opt_self_ty: Option<Ty<'tcx>>, | |
3862 | path: &'b hir::Path, | |
3863 | span: Span, | |
3864 | node_id: ast::NodeId) | |
3865 | -> Option<(Option<Ty<'tcx>>, &'b [hir::PathSegment], Def)> | |
3866 | { | |
3867 | ||
3868 | // If fully resolved already, we don't have to do anything. | |
3869 | if path_res.depth == 0 { | |
3870 | Some((opt_self_ty, &path.segments, path_res.base_def)) | |
3871 | } else { | |
3872 | let def = path_res.base_def; | |
3873 | let ty_segments = path.segments.split_last().unwrap().1; | |
3874 | let base_ty_end = path.segments.len() - path_res.depth; | |
3875 | let (ty, _def) = AstConv::finish_resolving_def_to_ty(self, self, span, | |
3876 | PathParamMode::Optional, | |
3877 | def, | |
3878 | opt_self_ty, | |
3879 | node_id, | |
3880 | &ty_segments[..base_ty_end], | |
3881 | &ty_segments[base_ty_end..]); | |
3882 | let item_segment = path.segments.last().unwrap(); | |
3883 | let item_name = item_segment.name; | |
3884 | let def = match self.resolve_ufcs(span, item_name, ty, node_id) { | |
3885 | Ok(def) => Some(def), | |
3886 | Err(error) => { | |
3887 | let def = match error { | |
3888 | method::MethodError::PrivateMatch(def) => Some(def), | |
3889 | _ => None, | |
3890 | }; | |
3891 | if item_name != keywords::Invalid.name() { | |
3892 | self.report_method_error(span, ty, item_name, None, error); | |
3893 | } | |
3894 | def | |
3895 | } | |
3896 | }; | |
3897 | ||
3898 | if let Some(def) = def { | |
3899 | // Write back the new resolution. | |
3900 | self.tcx().def_map.borrow_mut().insert(node_id, def::PathResolution { | |
3901 | base_def: def, | |
3902 | depth: 0, | |
3903 | }); | |
3904 | Some((Some(ty), slice::ref_slice(item_segment), def)) | |
3905 | } else { | |
3906 | self.write_error(node_id); | |
3907 | None | |
3908 | } | |
1a4d82fc JJ |
3909 | } |
3910 | } | |
1a4d82fc | 3911 | |
a7813a04 XL |
3912 | pub fn check_decl_initializer(&self, |
3913 | local: &'gcx hir::Local, | |
3914 | init: &'gcx hir::Expr) | |
3915 | { | |
3916 | let ref_bindings = self.tcx.pat_contains_ref_binding(&local.pat); | |
3917 | ||
3918 | let local_ty = self.local_ty(init.span, local.id); | |
3919 | if let Some(m) = ref_bindings { | |
3920 | // Somewhat subtle: if we have a `ref` binding in the pattern, | |
3921 | // we want to avoid introducing coercions for the RHS. This is | |
3922 | // both because it helps preserve sanity and, in the case of | |
3923 | // ref mut, for soundness (issue #23116). In particular, in | |
3924 | // the latter case, we need to be clear that the type of the | |
3925 | // referent for the reference that results is *equal to* the | |
3926 | // type of the lvalue it is referencing, and not some | |
3927 | // supertype thereof. | |
3928 | self.check_expr_with_lvalue_pref(init, LvaluePreference::from_mutbl(m)); | |
3929 | let init_ty = self.expr_ty(init); | |
3930 | self.demand_eqtype(init.span, init_ty, local_ty); | |
3931 | } else { | |
3932 | self.check_expr_coercable_to_type(init, local_ty) | |
3933 | }; | |
3934 | } | |
1a4d82fc | 3935 | |
a7813a04 XL |
3936 | pub fn check_decl_local(&self, local: &'gcx hir::Local) { |
3937 | let tcx = self.tcx; | |
1a4d82fc | 3938 | |
a7813a04 XL |
3939 | let t = self.local_ty(local.span, local.id); |
3940 | self.write_ty(local.id, t); | |
1a4d82fc | 3941 | |
a7813a04 XL |
3942 | if let Some(ref init) = local.init { |
3943 | self.check_decl_initializer(local, &init); | |
3944 | let init_ty = self.expr_ty(&init); | |
3945 | if init_ty.references_error() { | |
3946 | self.write_ty(local.id, init_ty); | |
3947 | } | |
1a4d82fc | 3948 | } |
1a4d82fc | 3949 | |
a7813a04 XL |
3950 | let pcx = PatCtxt { |
3951 | fcx: self, | |
3952 | map: pat_id_map(&tcx.def_map, &local.pat), | |
3953 | }; | |
3954 | pcx.check_pat(&local.pat, t); | |
3955 | let pat_ty = self.node_ty(local.pat.id); | |
3956 | if pat_ty.references_error() { | |
3957 | self.write_ty(local.id, pat_ty); | |
3958 | } | |
3959 | } | |
3960 | ||
3961 | pub fn check_stmt(&self, stmt: &'gcx hir::Stmt) { | |
3962 | let node_id; | |
3963 | let mut saw_bot = false; | |
3964 | let mut saw_err = false; | |
3965 | match stmt.node { | |
3966 | hir::StmtDecl(ref decl, id) => { | |
3967 | node_id = id; | |
3968 | match decl.node { | |
3969 | hir::DeclLocal(ref l) => { | |
3970 | self.check_decl_local(&l); | |
3971 | let l_t = self.node_ty(l.id); | |
3972 | saw_bot = saw_bot || self.type_var_diverges(l_t); | |
3973 | saw_err = saw_err || l_t.references_error(); | |
3974 | } | |
3975 | hir::DeclItem(_) => {/* ignore for now */ } | |
3976 | } | |
3977 | } | |
3978 | hir::StmtExpr(ref expr, id) => { | |
3979 | node_id = id; | |
3980 | // Check with expected type of () | |
3981 | self.check_expr_has_type(&expr, self.tcx.mk_nil()); | |
3982 | let expr_ty = self.expr_ty(&expr); | |
3983 | saw_bot = saw_bot || self.type_var_diverges(expr_ty); | |
3984 | saw_err = saw_err || expr_ty.references_error(); | |
3985 | } | |
3986 | hir::StmtSemi(ref expr, id) => { | |
3987 | node_id = id; | |
3988 | self.check_expr(&expr); | |
3989 | let expr_ty = self.expr_ty(&expr); | |
3990 | saw_bot |= self.type_var_diverges(expr_ty); | |
3991 | saw_err |= expr_ty.references_error(); | |
1a4d82fc | 3992 | } |
1a4d82fc | 3993 | } |
a7813a04 XL |
3994 | if saw_bot { |
3995 | self.write_ty(node_id, self.next_diverging_ty_var()); | |
3996 | } | |
3997 | else if saw_err { | |
3998 | self.write_error(node_id); | |
3999 | } | |
4000 | else { | |
4001 | self.write_nil(node_id) | |
4002 | } | |
1a4d82fc | 4003 | } |
1a4d82fc | 4004 | |
a7813a04 XL |
4005 | pub fn check_block_no_value(&self, blk: &'gcx hir::Block) { |
4006 | self.check_block_with_expected(blk, ExpectHasType(self.tcx.mk_nil())); | |
4007 | let blkty = self.node_ty(blk.id); | |
4008 | if blkty.references_error() { | |
4009 | self.write_error(blk.id); | |
4010 | } else { | |
4011 | let nilty = self.tcx.mk_nil(); | |
4012 | self.demand_suptype(blk.span, nilty, blkty); | |
4013 | } | |
1a4d82fc | 4014 | } |
1a4d82fc | 4015 | |
a7813a04 XL |
4016 | fn check_block_with_expected(&self, |
4017 | blk: &'gcx hir::Block, | |
4018 | expected: Expectation<'tcx>) { | |
4019 | let prev = { | |
4020 | let mut fcx_ps = self.ps.borrow_mut(); | |
4021 | let unsafety_state = fcx_ps.recurse(blk); | |
4022 | replace(&mut *fcx_ps, unsafety_state) | |
4023 | }; | |
1a4d82fc | 4024 | |
a7813a04 XL |
4025 | let mut warned = false; |
4026 | let mut any_diverges = false; | |
4027 | let mut any_err = false; | |
4028 | for s in &blk.stmts { | |
4029 | self.check_stmt(s); | |
4030 | let s_id = s.node.id(); | |
4031 | let s_ty = self.node_ty(s_id); | |
4032 | if any_diverges && !warned && match s.node { | |
4033 | hir::StmtDecl(ref decl, _) => { | |
4034 | match decl.node { | |
4035 | hir::DeclLocal(_) => true, | |
4036 | _ => false, | |
4037 | } | |
1a4d82fc | 4038 | } |
a7813a04 XL |
4039 | hir::StmtExpr(_, _) | hir::StmtSemi(_, _) => true, |
4040 | } { | |
4041 | self.tcx | |
1a4d82fc JJ |
4042 | .sess |
4043 | .add_lint(lint::builtin::UNREACHABLE_CODE, | |
a7813a04 XL |
4044 | s_id, |
4045 | s.span, | |
4046 | "unreachable statement".to_string()); | |
4047 | warned = true; | |
1a4d82fc | 4048 | } |
a7813a04 XL |
4049 | any_diverges = any_diverges || self.type_var_diverges(s_ty); |
4050 | any_err = any_err || s_ty.references_error(); | |
4051 | } | |
4052 | match blk.expr { | |
4053 | None => if any_err { | |
4054 | self.write_error(blk.id); | |
1a4d82fc | 4055 | } else if any_diverges { |
a7813a04 | 4056 | self.write_ty(blk.id, self.next_diverging_ty_var()); |
1a4d82fc | 4057 | } else { |
a7813a04 XL |
4058 | self.write_nil(blk.id); |
4059 | }, | |
4060 | Some(ref e) => { | |
4061 | if any_diverges && !warned { | |
4062 | self.tcx | |
4063 | .sess | |
4064 | .add_lint(lint::builtin::UNREACHABLE_CODE, | |
4065 | e.id, | |
4066 | e.span, | |
4067 | "unreachable expression".to_string()); | |
4068 | } | |
4069 | let ety = match expected { | |
4070 | ExpectHasType(ety) => { | |
4071 | self.check_expr_coercable_to_type(&e, ety); | |
4072 | ety | |
4073 | } | |
4074 | _ => { | |
4075 | self.check_expr_with_expectation(&e, expected); | |
4076 | self.expr_ty(&e) | |
4077 | } | |
4078 | }; | |
1a4d82fc | 4079 | |
a7813a04 XL |
4080 | if any_err { |
4081 | self.write_error(blk.id); | |
4082 | } else if any_diverges { | |
4083 | self.write_ty(blk.id, self.next_diverging_ty_var()); | |
4084 | } else { | |
4085 | self.write_ty(blk.id, ety); | |
4086 | } | |
4087 | } | |
4088 | }; | |
1a4d82fc | 4089 | |
a7813a04 XL |
4090 | *self.ps.borrow_mut() = prev; |
4091 | } | |
1a4d82fc | 4092 | |
1a4d82fc | 4093 | |
a7813a04 XL |
4094 | fn check_const_with_ty(&self, |
4095 | _: Span, | |
4096 | e: &'gcx hir::Expr, | |
4097 | declty: Ty<'tcx>) { | |
4098 | // Gather locals in statics (because of block expressions). | |
4099 | // This is technically unnecessary because locals in static items are forbidden, | |
4100 | // but prevents type checking from blowing up before const checking can properly | |
4101 | // emit an error. | |
4102 | GatherLocalsVisitor { fcx: self }.visit_expr(e); | |
1a4d82fc | 4103 | |
a7813a04 | 4104 | self.check_expr_coercable_to_type(e, declty); |
1a4d82fc | 4105 | |
a7813a04 XL |
4106 | self.select_all_obligations_and_apply_defaults(); |
4107 | self.closure_analyze_const(e); | |
4108 | self.select_obligations_where_possible(); | |
4109 | self.check_casts(); | |
4110 | self.select_all_obligations_or_error(); | |
4111 | ||
4112 | self.regionck_expr(e); | |
4113 | self.resolve_type_vars_in_expr(e); | |
4114 | } | |
4115 | ||
4116 | // Returns the type parameter count and the type for the given definition. | |
4117 | fn type_scheme_and_predicates_for_def(&self, | |
4118 | sp: Span, | |
4119 | defn: Def) | |
4120 | -> (TypeScheme<'tcx>, GenericPredicates<'tcx>) { | |
4121 | match defn { | |
4122 | Def::Local(_, nid) | Def::Upvar(_, nid, _, _) => { | |
4123 | let typ = self.local_ty(sp, nid); | |
4124 | (ty::TypeScheme { generics: ty::Generics::empty(), ty: typ }, | |
4125 | ty::GenericPredicates::empty()) | |
1a4d82fc | 4126 | } |
a7813a04 XL |
4127 | Def::Fn(id) | Def::Method(id) | |
4128 | Def::Static(id, _) | Def::Variant(_, id) | | |
4129 | Def::Struct(id) | Def::Const(id) | Def::AssociatedConst(id) => { | |
4130 | (self.tcx.lookup_item_type(id), self.tcx.lookup_predicates(id)) | |
1a4d82fc | 4131 | } |
a7813a04 XL |
4132 | Def::Trait(_) | |
4133 | Def::Enum(..) | | |
4134 | Def::TyAlias(..) | | |
4135 | Def::AssociatedTy(..) | | |
4136 | Def::PrimTy(_) | | |
4137 | Def::TyParam(..) | | |
4138 | Def::Mod(..) | | |
4139 | Def::ForeignMod(..) | | |
4140 | Def::Label(..) | | |
4141 | Def::SelfTy(..) | | |
4142 | Def::Err => { | |
4143 | span_bug!(sp, "expected value, found {:?}", defn); | |
1a4d82fc JJ |
4144 | } |
4145 | } | |
1a4d82fc | 4146 | } |
1a4d82fc | 4147 | |
a7813a04 XL |
4148 | // Instantiates the given path, which must refer to an item with the given |
4149 | // number of type parameters and type. | |
4150 | pub fn instantiate_path(&self, | |
4151 | segments: &[hir::PathSegment], | |
4152 | type_scheme: TypeScheme<'tcx>, | |
4153 | type_predicates: &ty::GenericPredicates<'tcx>, | |
4154 | opt_self_ty: Option<Ty<'tcx>>, | |
4155 | def: Def, | |
4156 | span: Span, | |
4157 | node_id: ast::NodeId) { | |
4158 | debug!("instantiate_path(path={:?}, def={:?}, node_id={}, type_scheme={:?})", | |
4159 | segments, | |
4160 | def, | |
4161 | node_id, | |
4162 | type_scheme); | |
4163 | ||
4164 | // We need to extract the type parameters supplied by the user in | |
4165 | // the path `path`. Due to the current setup, this is a bit of a | |
4166 | // tricky-process; the problem is that resolve only tells us the | |
4167 | // end-point of the path resolution, and not the intermediate steps. | |
4168 | // Luckily, we can (at least for now) deduce the intermediate steps | |
4169 | // just from the end-point. | |
4170 | // | |
4171 | // There are basically four cases to consider: | |
4172 | // | |
4173 | // 1. Reference to a *type*, such as a struct or enum: | |
4174 | // | |
4175 | // mod a { struct Foo<T> { ... } } | |
4176 | // | |
4177 | // Because we don't allow types to be declared within one | |
4178 | // another, a path that leads to a type will always look like | |
4179 | // `a::b::Foo<T>` where `a` and `b` are modules. This implies | |
4180 | // that only the final segment can have type parameters, and | |
4181 | // they are located in the TypeSpace. | |
4182 | // | |
4183 | // *Note:* Generally speaking, references to types don't | |
4184 | // actually pass through this function, but rather the | |
4185 | // `ast_ty_to_ty` function in `astconv`. However, in the case | |
4186 | // of struct patterns (and maybe literals) we do invoke | |
4187 | // `instantiate_path` to get the general type of an instance of | |
4188 | // a struct. (In these cases, there are actually no type | |
4189 | // parameters permitted at present, but perhaps we will allow | |
4190 | // them in the future.) | |
4191 | // | |
4192 | // 1b. Reference to an enum variant or tuple-like struct: | |
4193 | // | |
4194 | // struct foo<T>(...) | |
4195 | // enum E<T> { foo(...) } | |
4196 | // | |
4197 | // In these cases, the parameters are declared in the type | |
4198 | // space. | |
4199 | // | |
4200 | // 2. Reference to a *fn item*: | |
4201 | // | |
4202 | // fn foo<T>() { } | |
4203 | // | |
4204 | // In this case, the path will again always have the form | |
4205 | // `a::b::foo::<T>` where only the final segment should have | |
4206 | // type parameters. However, in this case, those parameters are | |
4207 | // declared on a value, and hence are in the `FnSpace`. | |
4208 | // | |
4209 | // 3. Reference to a *method*: | |
4210 | // | |
4211 | // impl<A> SomeStruct<A> { | |
4212 | // fn foo<B>(...) | |
4213 | // } | |
4214 | // | |
4215 | // Here we can have a path like | |
4216 | // `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters | |
4217 | // may appear in two places. The penultimate segment, | |
4218 | // `SomeStruct::<A>`, contains parameters in TypeSpace, and the | |
4219 | // final segment, `foo::<B>` contains parameters in fn space. | |
4220 | // | |
4221 | // 4. Reference to an *associated const*: | |
4222 | // | |
4223 | // impl<A> AnotherStruct<A> { | |
4224 | // const FOO: B = BAR; | |
4225 | // } | |
4226 | // | |
4227 | // The path in this case will look like | |
4228 | // `a::b::AnotherStruct::<A>::FOO`, so the penultimate segment | |
4229 | // only will have parameters in TypeSpace. | |
4230 | // | |
4231 | // The first step then is to categorize the segments appropriately. | |
4232 | ||
4233 | assert!(!segments.is_empty()); | |
4234 | ||
4235 | let mut ufcs_associated = None; | |
4236 | let mut segment_spaces: Vec<_>; | |
4237 | match def { | |
4238 | // Case 1 and 1b. Reference to a *type* or *enum variant*. | |
4239 | Def::SelfTy(..) | | |
4240 | Def::Struct(..) | | |
4241 | Def::Variant(..) | | |
4242 | Def::Enum(..) | | |
4243 | Def::TyAlias(..) | | |
4244 | Def::AssociatedTy(..) | | |
4245 | Def::Trait(..) | | |
4246 | Def::PrimTy(..) | | |
4247 | Def::TyParam(..) => { | |
4248 | // Everything but the final segment should have no | |
4249 | // parameters at all. | |
4250 | segment_spaces = vec![None; segments.len() - 1]; | |
4251 | segment_spaces.push(Some(subst::TypeSpace)); | |
c34b1796 | 4252 | } |
1a4d82fc | 4253 | |
a7813a04 XL |
4254 | // Case 2. Reference to a top-level value. |
4255 | Def::Fn(..) | | |
4256 | Def::Const(..) | | |
4257 | Def::Static(..) => { | |
4258 | segment_spaces = vec![None; segments.len() - 1]; | |
4259 | segment_spaces.push(Some(subst::FnSpace)); | |
4260 | } | |
1a4d82fc | 4261 | |
a7813a04 XL |
4262 | // Case 3. Reference to a method. |
4263 | Def::Method(def_id) => { | |
4264 | let container = self.tcx.impl_or_trait_item(def_id).container(); | |
4265 | match container { | |
4266 | ty::TraitContainer(trait_did) => { | |
4267 | callee::check_legal_trait_for_method_call(self.ccx, span, trait_did) | |
4268 | } | |
4269 | ty::ImplContainer(_) => {} | |
4270 | } | |
1a4d82fc | 4271 | |
a7813a04 XL |
4272 | if segments.len() >= 2 { |
4273 | segment_spaces = vec![None; segments.len() - 2]; | |
4274 | segment_spaces.push(Some(subst::TypeSpace)); | |
4275 | segment_spaces.push(Some(subst::FnSpace)); | |
4276 | } else { | |
4277 | // `<T>::method` will end up here, and so can `T::method`. | |
4278 | let self_ty = opt_self_ty.expect("UFCS sugared method missing Self"); | |
4279 | segment_spaces = vec![Some(subst::FnSpace)]; | |
4280 | ufcs_associated = Some((container, self_ty)); | |
1a4d82fc | 4281 | } |
1a4d82fc | 4282 | } |
1a4d82fc | 4283 | |
a7813a04 XL |
4284 | Def::AssociatedConst(def_id) => { |
4285 | let container = self.tcx.impl_or_trait_item(def_id).container(); | |
4286 | match container { | |
4287 | ty::TraitContainer(trait_did) => { | |
4288 | callee::check_legal_trait_for_method_call(self.ccx, span, trait_did) | |
4289 | } | |
4290 | ty::ImplContainer(_) => {} | |
4291 | } | |
1a4d82fc | 4292 | |
a7813a04 XL |
4293 | if segments.len() >= 2 { |
4294 | segment_spaces = vec![None; segments.len() - 2]; | |
4295 | segment_spaces.push(Some(subst::TypeSpace)); | |
4296 | segment_spaces.push(None); | |
4297 | } else { | |
4298 | // `<T>::CONST` will end up here, and so can `T::CONST`. | |
4299 | let self_ty = opt_self_ty.expect("UFCS sugared const missing Self"); | |
4300 | segment_spaces = vec![None]; | |
4301 | ufcs_associated = Some((container, self_ty)); | |
1a4d82fc | 4302 | } |
1a4d82fc JJ |
4303 | } |
4304 | ||
a7813a04 XL |
4305 | // Other cases. Various nonsense that really shouldn't show up |
4306 | // here. If they do, an error will have been reported | |
4307 | // elsewhere. (I hope) | |
4308 | Def::Mod(..) | | |
4309 | Def::ForeignMod(..) | | |
4310 | Def::Local(..) | | |
4311 | Def::Label(..) | | |
4312 | Def::Upvar(..) => { | |
4313 | segment_spaces = vec![None; segments.len()]; | |
c34b1796 | 4314 | } |
1a4d82fc | 4315 | |
a7813a04 XL |
4316 | Def::Err => { |
4317 | self.set_tainted_by_errors(); | |
4318 | segment_spaces = vec![None; segments.len()]; | |
d9579d0f | 4319 | } |
a7813a04 XL |
4320 | } |
4321 | assert_eq!(segment_spaces.len(), segments.len()); | |
4322 | ||
4323 | // In `<T as Trait<A, B>>::method`, `A` and `B` are mandatory, but | |
4324 | // `opt_self_ty` can also be Some for `Foo::method`, where Foo's | |
4325 | // type parameters are not mandatory. | |
4326 | let require_type_space = opt_self_ty.is_some() && ufcs_associated.is_none(); | |
4327 | ||
4328 | debug!("segment_spaces={:?}", segment_spaces); | |
4329 | ||
4330 | // Next, examine the definition, and determine how many type | |
4331 | // parameters we expect from each space. | |
4332 | let type_defs = &type_scheme.generics.types; | |
4333 | let region_defs = &type_scheme.generics.regions; | |
4334 | ||
4335 | // Now that we have categorized what space the parameters for each | |
4336 | // segment belong to, let's sort out the parameters that the user | |
4337 | // provided (if any) into their appropriate spaces. We'll also report | |
4338 | // errors if type parameters are provided in an inappropriate place. | |
4339 | let mut substs = Substs::empty(); | |
4340 | for (&opt_space, segment) in segment_spaces.iter().zip(segments) { | |
4341 | if let Some(space) = opt_space { | |
4342 | self.push_explicit_parameters_from_segment_to_substs(space, | |
4343 | span, | |
4344 | type_defs, | |
4345 | region_defs, | |
4346 | segment, | |
4347 | &mut substs); | |
d9579d0f | 4348 | } else { |
a7813a04 | 4349 | self.tcx.prohibit_type_params(slice::ref_slice(segment)); |
d9579d0f AL |
4350 | } |
4351 | } | |
a7813a04 XL |
4352 | if let Some(self_ty) = opt_self_ty { |
4353 | if type_defs.len(subst::SelfSpace) == 1 { | |
4354 | substs.types.push(subst::SelfSpace, self_ty); | |
4355 | } | |
1a4d82fc | 4356 | } |
c34b1796 | 4357 | |
a7813a04 XL |
4358 | // Now we have to compare the types that the user *actually* |
4359 | // provided against the types that were *expected*. If the user | |
4360 | // did not provide any types, then we want to substitute inference | |
4361 | // variables. If the user provided some types, we may still need | |
4362 | // to add defaults. If the user provided *too many* types, that's | |
4363 | // a problem. | |
4364 | for &space in &[subst::SelfSpace, subst::TypeSpace, subst::FnSpace] { | |
4365 | self.adjust_type_parameters(span, space, type_defs, | |
4366 | require_type_space, &mut substs); | |
4367 | assert_eq!(substs.types.len(space), type_defs.len(space)); | |
1a4d82fc | 4368 | |
a7813a04 XL |
4369 | self.adjust_region_parameters(span, space, region_defs, &mut substs); |
4370 | assert_eq!(substs.regions.len(space), region_defs.len(space)); | |
4371 | } | |
1a4d82fc | 4372 | |
a7813a04 XL |
4373 | // The things we are substituting into the type should not contain |
4374 | // escaping late-bound regions, and nor should the base type scheme. | |
4375 | let substs = self.tcx.mk_substs(substs); | |
4376 | assert!(!substs.has_regions_escaping_depth(0)); | |
4377 | assert!(!type_scheme.has_escaping_regions()); | |
1a4d82fc | 4378 | |
a7813a04 XL |
4379 | // Add all the obligations that are required, substituting and |
4380 | // normalized appropriately. | |
4381 | let bounds = self.instantiate_bounds(span, &substs, &type_predicates); | |
4382 | self.add_obligations_for_parameters( | |
4383 | traits::ObligationCause::new(span, self.body_id, traits::ItemObligation(def.def_id())), | |
4384 | &bounds); | |
1a4d82fc | 4385 | |
a7813a04 XL |
4386 | // Substitute the values for the type parameters into the type of |
4387 | // the referenced item. | |
4388 | let ty_substituted = self.instantiate_type_scheme(span, &substs, &type_scheme.ty); | |
4389 | ||
4390 | ||
4391 | if let Some((ty::ImplContainer(impl_def_id), self_ty)) = ufcs_associated { | |
4392 | // In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method` | |
4393 | // is inherent, there is no `Self` parameter, instead, the impl needs | |
4394 | // type parameters, which we can infer by unifying the provided `Self` | |
4395 | // with the substituted impl type. | |
4396 | let impl_scheme = self.tcx.lookup_item_type(impl_def_id); | |
4397 | assert_eq!(substs.types.len(subst::TypeSpace), | |
4398 | impl_scheme.generics.types.len(subst::TypeSpace)); | |
4399 | assert_eq!(substs.regions.len(subst::TypeSpace), | |
4400 | impl_scheme.generics.regions.len(subst::TypeSpace)); | |
4401 | ||
4402 | let impl_ty = self.instantiate_type_scheme(span, &substs, &impl_scheme.ty); | |
4403 | match self.sub_types(false, TypeOrigin::Misc(span), self_ty, impl_ty) { | |
4404 | Ok(InferOk { obligations, .. }) => { | |
4405 | // FIXME(#32730) propagate obligations | |
4406 | assert!(obligations.is_empty()); | |
4407 | } | |
4408 | Err(_) => { | |
4409 | span_bug!(span, | |
4410 | "instantiate_path: (UFCS) {:?} was a subtype of {:?} but now is not?", | |
4411 | self_ty, | |
4412 | impl_ty); | |
4413 | } | |
1a4d82fc JJ |
4414 | } |
4415 | } | |
1a4d82fc | 4416 | |
a7813a04 XL |
4417 | debug!("instantiate_path: type of {:?} is {:?}", |
4418 | node_id, | |
4419 | ty_substituted); | |
4420 | self.write_ty(node_id, ty_substituted); | |
4421 | self.write_substs(node_id, ty::ItemSubsts { | |
4422 | substs: substs | |
4423 | }); | |
1a4d82fc JJ |
4424 | } |
4425 | ||
4426 | /// Finds the parameters that the user provided and adds them to `substs`. If too many | |
4427 | /// parameters are provided, then reports an error and clears the output vector. | |
4428 | /// | |
4429 | /// We clear the output vector because that will cause the `adjust_XXX_parameters()` later to | |
4430 | /// use inference variables. This seems less likely to lead to derived errors. | |
4431 | /// | |
4432 | /// Note that we *do not* check for *too few* parameters here. Due to the presence of defaults | |
4433 | /// etc that is more complicated. I wanted however to do the reporting of *too many* parameters | |
4434 | /// here because we can easily use the precise span of the N+1'th parameter. | |
a7813a04 | 4435 | fn push_explicit_parameters_from_segment_to_substs(&self, |
1a4d82fc JJ |
4436 | space: subst::ParamSpace, |
4437 | span: Span, | |
4438 | type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>, | |
4439 | region_defs: &VecPerParamSpace<ty::RegionParameterDef>, | |
e9174d1e | 4440 | segment: &hir::PathSegment, |
1a4d82fc JJ |
4441 | substs: &mut Substs<'tcx>) |
4442 | { | |
4443 | match segment.parameters { | |
e9174d1e | 4444 | hir::AngleBracketedParameters(ref data) => { |
a7813a04 XL |
4445 | self.push_explicit_angle_bracketed_parameters_from_segment_to_substs( |
4446 | space, type_defs, region_defs, data, substs); | |
1a4d82fc JJ |
4447 | } |
4448 | ||
e9174d1e | 4449 | hir::ParenthesizedParameters(ref data) => { |
a7813a04 | 4450 | span_err!(self.tcx.sess, span, E0238, |
1a4d82fc | 4451 | "parenthesized parameters may only be used with a trait"); |
a7813a04 XL |
4452 | self.push_explicit_parenthesized_parameters_from_segment_to_substs( |
4453 | space, span, type_defs, data, substs); | |
1a4d82fc JJ |
4454 | } |
4455 | } | |
4456 | } | |
4457 | ||
a7813a04 | 4458 | fn push_explicit_angle_bracketed_parameters_from_segment_to_substs(&self, |
1a4d82fc JJ |
4459 | space: subst::ParamSpace, |
4460 | type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>, | |
4461 | region_defs: &VecPerParamSpace<ty::RegionParameterDef>, | |
e9174d1e | 4462 | data: &hir::AngleBracketedParameterData, |
1a4d82fc JJ |
4463 | substs: &mut Substs<'tcx>) |
4464 | { | |
4465 | { | |
4466 | let type_count = type_defs.len(space); | |
4467 | assert_eq!(substs.types.len(space), 0); | |
4468 | for (i, typ) in data.types.iter().enumerate() { | |
a7813a04 | 4469 | let t = self.to_ty(&typ); |
1a4d82fc JJ |
4470 | if i < type_count { |
4471 | substs.types.push(space, t); | |
4472 | } else if i == type_count { | |
a7813a04 | 4473 | span_err!(self.tcx.sess, typ.span, E0087, |
1a4d82fc | 4474 | "too many type parameters provided: \ |
62682a34 SL |
4475 | expected at most {} parameter{}, \ |
4476 | found {} parameter{}", | |
4477 | type_count, | |
4478 | if type_count == 1 {""} else {"s"}, | |
4479 | data.types.len(), | |
4480 | if data.types.len() == 1 {""} else {"s"}); | |
1a4d82fc JJ |
4481 | substs.types.truncate(space, 0); |
4482 | break; | |
4483 | } | |
4484 | } | |
4485 | } | |
4486 | ||
9346a6ac | 4487 | if !data.bindings.is_empty() { |
a7813a04 | 4488 | span_err!(self.tcx.sess, data.bindings[0].span, E0182, |
1a4d82fc JJ |
4489 | "unexpected binding of associated item in expression path \ |
4490 | (only allowed in type paths)"); | |
4491 | } | |
4492 | ||
4493 | { | |
4494 | let region_count = region_defs.len(space); | |
54a0048b | 4495 | assert_eq!(substs.regions.len(space), 0); |
1a4d82fc | 4496 | for (i, lifetime) in data.lifetimes.iter().enumerate() { |
a7813a04 | 4497 | let r = ast_region_to_region(self.tcx, lifetime); |
1a4d82fc | 4498 | if i < region_count { |
54a0048b | 4499 | substs.regions.push(space, r); |
1a4d82fc | 4500 | } else if i == region_count { |
a7813a04 | 4501 | span_err!(self.tcx.sess, lifetime.span, E0088, |
1a4d82fc | 4502 | "too many lifetime parameters provided: \ |
62682a34 | 4503 | expected {} parameter{}, found {} parameter{}", |
1a4d82fc | 4504 | region_count, |
62682a34 SL |
4505 | if region_count == 1 {""} else {"s"}, |
4506 | data.lifetimes.len(), | |
4507 | if data.lifetimes.len() == 1 {""} else {"s"}); | |
54a0048b | 4508 | substs.regions.truncate(space, 0); |
1a4d82fc JJ |
4509 | break; |
4510 | } | |
4511 | } | |
4512 | } | |
4513 | } | |
4514 | ||
4515 | /// As with | |
4516 | /// `push_explicit_angle_bracketed_parameters_from_segment_to_substs`, | |
4517 | /// but intended for `Foo(A,B) -> C` form. This expands to | |
4518 | /// roughly the same thing as `Foo<(A,B),C>`. One important | |
4519 | /// difference has to do with the treatment of anonymous | |
4520 | /// regions, which are translated into bound regions (NYI). | |
a7813a04 | 4521 | fn push_explicit_parenthesized_parameters_from_segment_to_substs(&self, |
1a4d82fc JJ |
4522 | space: subst::ParamSpace, |
4523 | span: Span, | |
4524 | type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>, | |
e9174d1e | 4525 | data: &hir::ParenthesizedParameterData, |
1a4d82fc JJ |
4526 | substs: &mut Substs<'tcx>) |
4527 | { | |
4528 | let type_count = type_defs.len(space); | |
4529 | if type_count < 2 { | |
a7813a04 | 4530 | span_err!(self.tcx.sess, span, E0167, |
1a4d82fc JJ |
4531 | "parenthesized form always supplies 2 type parameters, \ |
4532 | but only {} parameter(s) were expected", | |
4533 | type_count); | |
4534 | } | |
4535 | ||
4536 | let input_tys: Vec<Ty> = | |
a7813a04 | 4537 | data.inputs.iter().map(|ty| self.to_ty(&ty)).collect(); |
1a4d82fc | 4538 | |
a7813a04 | 4539 | let tuple_ty = self.tcx.mk_tup(input_tys); |
1a4d82fc JJ |
4540 | |
4541 | if type_count >= 1 { | |
4542 | substs.types.push(space, tuple_ty); | |
4543 | } | |
4544 | ||
4545 | let output_ty: Option<Ty> = | |
a7813a04 | 4546 | data.output.as_ref().map(|ty| self.to_ty(&ty)); |
1a4d82fc JJ |
4547 | |
4548 | let output_ty = | |
a7813a04 | 4549 | output_ty.unwrap_or(self.tcx.mk_nil()); |
1a4d82fc JJ |
4550 | |
4551 | if type_count >= 2 { | |
4552 | substs.types.push(space, output_ty); | |
4553 | } | |
4554 | } | |
4555 | ||
a7813a04 | 4556 | fn adjust_type_parameters(&self, |
1a4d82fc JJ |
4557 | span: Span, |
4558 | space: ParamSpace, | |
4559 | defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>, | |
c34b1796 | 4560 | require_type_space: bool, |
1a4d82fc JJ |
4561 | substs: &mut Substs<'tcx>) |
4562 | { | |
4563 | let provided_len = substs.types.len(space); | |
4564 | let desired = defs.get_slice(space); | |
4565 | let required_len = desired.iter() | |
4566 | .take_while(|d| d.default.is_none()) | |
4567 | .count(); | |
4568 | ||
4569 | debug!("adjust_type_parameters(space={:?}, \ | |
4570 | provided_len={}, \ | |
4571 | desired_len={}, \ | |
4572 | required_len={})", | |
4573 | space, | |
4574 | provided_len, | |
4575 | desired.len(), | |
4576 | required_len); | |
4577 | ||
4578 | // Enforced by `push_explicit_parameters_from_segment_to_substs()`. | |
4579 | assert!(provided_len <= desired.len()); | |
4580 | ||
4581 | // Nothing specified at all: supply inference variables for | |
4582 | // everything. | |
c34b1796 | 4583 | if provided_len == 0 && !(require_type_space && space == subst::TypeSpace) { |
c1a9b12d | 4584 | substs.types.replace(space, Vec::new()); |
a7813a04 | 4585 | self.type_vars_for_defs(span, space, substs, &desired[..]); |
1a4d82fc JJ |
4586 | return; |
4587 | } | |
4588 | ||
4589 | // Too few parameters specified: report an error and use Err | |
4590 | // for everything. | |
4591 | if provided_len < required_len { | |
4592 | let qualifier = | |
4593 | if desired.len() != required_len { "at least " } else { "" }; | |
a7813a04 | 4594 | span_err!(self.tcx.sess, span, E0089, |
62682a34 SL |
4595 | "too few type parameters provided: expected {}{} parameter{}, \ |
4596 | found {} parameter{}", | |
4597 | qualifier, required_len, | |
4598 | if required_len == 1 {""} else {"s"}, | |
4599 | provided_len, | |
4600 | if provided_len == 1 {""} else {"s"}); | |
a7813a04 | 4601 | substs.types.replace(space, vec![self.tcx.types.err; desired.len()]); |
1a4d82fc JJ |
4602 | return; |
4603 | } | |
4604 | ||
4605 | // Otherwise, add in any optional parameters that the user | |
4606 | // omitted. The case of *too many* parameters is handled | |
4607 | // already by | |
4608 | // push_explicit_parameters_from_segment_to_substs(). Note | |
4609 | // that the *default* type are expressed in terms of all prior | |
4610 | // parameters, so we have to substitute as we go with the | |
4611 | // partial substitution that we have built up. | |
85aaf69f | 4612 | for i in provided_len..desired.len() { |
1a4d82fc | 4613 | let default = desired[i].default.unwrap(); |
a7813a04 | 4614 | let default = default.subst_spanned(self.tcx, substs, Some(span)); |
1a4d82fc JJ |
4615 | substs.types.push(space, default); |
4616 | } | |
4617 | assert_eq!(substs.types.len(space), desired.len()); | |
4618 | ||
62682a34 | 4619 | debug!("Final substs: {:?}", substs); |
1a4d82fc JJ |
4620 | } |
4621 | ||
a7813a04 | 4622 | fn adjust_region_parameters(&self, |
1a4d82fc JJ |
4623 | span: Span, |
4624 | space: ParamSpace, | |
4625 | defs: &VecPerParamSpace<ty::RegionParameterDef>, | |
4626 | substs: &mut Substs) | |
4627 | { | |
54a0048b | 4628 | let provided_len = substs.regions.len(space); |
1a4d82fc JJ |
4629 | let desired = defs.get_slice(space); |
4630 | ||
4631 | // Enforced by `push_explicit_parameters_from_segment_to_substs()`. | |
4632 | assert!(provided_len <= desired.len()); | |
4633 | ||
4634 | // If nothing was provided, just use inference variables. | |
4635 | if provided_len == 0 { | |
54a0048b | 4636 | substs.regions.replace( |
1a4d82fc | 4637 | space, |
a7813a04 | 4638 | self.region_vars_for_defs(span, desired)); |
1a4d82fc JJ |
4639 | return; |
4640 | } | |
4641 | ||
4642 | // If just the right number were provided, everybody is happy. | |
4643 | if provided_len == desired.len() { | |
4644 | return; | |
4645 | } | |
4646 | ||
4647 | // Otherwise, too few were provided. Report an error and then | |
4648 | // use inference variables. | |
a7813a04 | 4649 | span_err!(self.tcx.sess, span, E0090, |
62682a34 SL |
4650 | "too few lifetime parameters provided: expected {} parameter{}, \ |
4651 | found {} parameter{}", | |
4652 | desired.len(), | |
4653 | if desired.len() == 1 {""} else {"s"}, | |
4654 | provided_len, | |
4655 | if provided_len == 1 {""} else {"s"}); | |
1a4d82fc | 4656 | |
54a0048b | 4657 | substs.regions.replace( |
1a4d82fc | 4658 | space, |
a7813a04 | 4659 | self.region_vars_for_defs(span, desired)); |
1a4d82fc | 4660 | } |
1a4d82fc | 4661 | |
a7813a04 XL |
4662 | fn structurally_resolve_type_or_else<F>(&self, sp: Span, ty: Ty<'tcx>, f: F) |
4663 | -> Ty<'tcx> | |
4664 | where F: Fn() -> Ty<'tcx> | |
4665 | { | |
4666 | let mut ty = self.resolve_type_vars_with_obligations(ty); | |
4667 | ||
4668 | if ty.is_ty_var() { | |
4669 | let alternative = f(); | |
4670 | ||
4671 | // If not, error. | |
4672 | if alternative.is_ty_var() || alternative.references_error() { | |
4673 | if !self.is_tainted_by_errors() { | |
4674 | self.type_error_message(sp, |_actual| { | |
4675 | "the type of this value must be known in this context".to_string() | |
4676 | }, ty, None); | |
4677 | } | |
4678 | self.demand_suptype(sp, self.tcx.types.err, ty); | |
4679 | ty = self.tcx.types.err; | |
4680 | } else { | |
4681 | self.demand_suptype(sp, alternative, ty); | |
4682 | ty = alternative; | |
4683 | } | |
85aaf69f | 4684 | } |
1a4d82fc | 4685 | |
a7813a04 XL |
4686 | ty |
4687 | } | |
1a4d82fc | 4688 | |
a7813a04 XL |
4689 | // Resolves `typ` by a single level if `typ` is a type variable. If no |
4690 | // resolution is possible, then an error is reported. | |
4691 | pub fn structurally_resolved_type(&self, sp: Span, ty: Ty<'tcx>) -> Ty<'tcx> { | |
4692 | self.structurally_resolve_type_or_else(sp, ty, || { | |
4693 | self.tcx.types.err | |
4694 | }) | |
4695 | } | |
85aaf69f SL |
4696 | } |
4697 | ||
1a4d82fc | 4698 | // Returns true if b contains a break that can exit from b |
a7813a04 | 4699 | pub fn may_break(tcx: TyCtxt, id: ast::NodeId, b: &hir::Block) -> bool { |
1a4d82fc JJ |
4700 | // First: is there an unlabeled break immediately |
4701 | // inside the loop? | |
7453a54e | 4702 | (loop_query(&b, |e| { |
1a4d82fc | 4703 | match *e { |
e9174d1e | 4704 | hir::ExprBreak(None) => true, |
1a4d82fc JJ |
4705 | _ => false |
4706 | } | |
4707 | })) || | |
c34b1796 AL |
4708 | // Second: is there a labeled break with label |
4709 | // <id> nested anywhere inside the loop? | |
1a4d82fc | 4710 | (block_query(b, |e| { |
e9174d1e | 4711 | if let hir::ExprBreak(Some(_)) = e.node { |
a7813a04 | 4712 | lookup_full_def(tcx, e.span, e.id) == Def::Label(id) |
c34b1796 AL |
4713 | } else { |
4714 | false | |
4715 | } | |
4716 | })) | |
1a4d82fc JJ |
4717 | } |
4718 | ||
4719 | pub fn check_bounds_are_used<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, | |
9cc50fc6 | 4720 | tps: &[hir::TyParam], |
1a4d82fc | 4721 | ty: Ty<'tcx>) { |
62682a34 SL |
4722 | debug!("check_bounds_are_used(n_tps={}, ty={:?})", |
4723 | tps.len(), ty); | |
1a4d82fc JJ |
4724 | |
4725 | // make a vector of booleans initially false, set to true when used | |
9346a6ac | 4726 | if tps.is_empty() { return; } |
c1a9b12d | 4727 | let mut tps_used = vec![false; tps.len()]; |
1a4d82fc | 4728 | |
c1a9b12d SL |
4729 | for leaf_ty in ty.walk() { |
4730 | if let ty::TyParam(ParamTy {idx, ..}) = leaf_ty.sty { | |
4731 | debug!("Found use of ty param num {}", idx); | |
4732 | tps_used[idx as usize] = true; | |
4733 | } | |
4734 | } | |
1a4d82fc JJ |
4735 | |
4736 | for (i, b) in tps_used.iter().enumerate() { | |
4737 | if !*b { | |
92a42be0 | 4738 | span_err!(ccx.tcx.sess, tps[i].span, E0091, |
1a4d82fc | 4739 | "type parameter `{}` is unused", |
b039eaaf | 4740 | tps[i].name); |
1a4d82fc JJ |
4741 | } |
4742 | } | |
4743 | } |