1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669
use super::{probe, MethodCallee};
use crate::{callee, FnCtxt};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_hir::GenericArg;
use rustc_hir_analysis::astconv::generics::{
check_generic_arg_count_for_call, create_args_for_parent_generic_args,
};
use rustc_hir_analysis::astconv::{AstConv, CreateSubstsForGenericArgsCtxt, IsMethodCall};
use rustc_infer::infer::{self, DefineOpaqueTypes, InferOk};
use rustc_middle::traits::{ObligationCauseCode, UnifyReceiverContext};
use rustc_middle::ty::adjustment::{Adjust, Adjustment, PointerCoercion};
use rustc_middle::ty::adjustment::{AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
use rustc_middle::ty::fold::TypeFoldable;
use rustc_middle::ty::{
self, GenericArgs, GenericArgsRef, GenericParamDefKind, Ty, TyCtxt, UserArgs, UserType,
};
use rustc_span::{Span, DUMMY_SP};
use rustc_trait_selection::traits;
use std::ops::Deref;
struct ConfirmContext<'a, 'tcx> {
fcx: &'a FnCtxt<'a, 'tcx>,
span: Span,
self_expr: &'tcx hir::Expr<'tcx>,
call_expr: &'tcx hir::Expr<'tcx>,
skip_record_for_diagnostics: bool,
}
impl<'a, 'tcx> Deref for ConfirmContext<'a, 'tcx> {
type Target = FnCtxt<'a, 'tcx>;
fn deref(&self) -> &Self::Target {
self.fcx
}
}
#[derive(Debug)]
pub struct ConfirmResult<'tcx> {
pub callee: MethodCallee<'tcx>,
pub illegal_sized_bound: Option<Span>,
}
impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub fn confirm_method(
&self,
span: Span,
self_expr: &'tcx hir::Expr<'tcx>,
call_expr: &'tcx hir::Expr<'tcx>,
unadjusted_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
segment: &hir::PathSegment<'_>,
) -> ConfirmResult<'tcx> {
debug!(
"confirm(unadjusted_self_ty={:?}, pick={:?}, generic_args={:?})",
unadjusted_self_ty, pick, segment.args,
);
let mut confirm_cx = ConfirmContext::new(self, span, self_expr, call_expr);
confirm_cx.confirm(unadjusted_self_ty, pick, segment)
}
pub fn confirm_method_for_diagnostic(
&self,
span: Span,
self_expr: &'tcx hir::Expr<'tcx>,
call_expr: &'tcx hir::Expr<'tcx>,
unadjusted_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
segment: &hir::PathSegment<'_>,
) -> ConfirmResult<'tcx> {
let mut confirm_cx = ConfirmContext::new(self, span, self_expr, call_expr);
confirm_cx.skip_record_for_diagnostics = true;
confirm_cx.confirm(unadjusted_self_ty, pick, segment)
}
}
impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
fn new(
fcx: &'a FnCtxt<'a, 'tcx>,
span: Span,
self_expr: &'tcx hir::Expr<'tcx>,
call_expr: &'tcx hir::Expr<'tcx>,
) -> ConfirmContext<'a, 'tcx> {
ConfirmContext { fcx, span, self_expr, call_expr, skip_record_for_diagnostics: false }
}
fn confirm(
&mut self,
unadjusted_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
segment: &hir::PathSegment<'_>,
) -> ConfirmResult<'tcx> {
// Adjust the self expression the user provided and obtain the adjusted type.
let self_ty = self.adjust_self_ty(unadjusted_self_ty, &pick);
// Create substitutions for the method's type parameters.
let rcvr_args = self.fresh_receiver_args(self_ty, &pick);
let all_args = self.instantiate_method_args(&pick, segment, rcvr_args);
debug!("rcvr_args={rcvr_args:?}, all_args={all_args:?}");
// Create the final signature for the method, replacing late-bound regions.
let (method_sig, method_predicates) = self.instantiate_method_sig(&pick, all_args);
// If there is a `Self: Sized` bound and `Self` is a trait object, it is possible that
// something which derefs to `Self` actually implements the trait and the caller
// wanted to make a static dispatch on it but forgot to import the trait.
// See test `tests/ui/issue-35976.rs`.
//
// In that case, we'll error anyway, but we'll also re-run the search with all traits
// in scope, and if we find another method which can be used, we'll output an
// appropriate hint suggesting to import the trait.
let filler_args = rcvr_args
.extend_to(self.tcx, pick.item.def_id, |def, _| self.tcx.mk_param_from_def(def));
let illegal_sized_bound = self.predicates_require_illegal_sized_bound(
self.tcx.predicates_of(pick.item.def_id).instantiate(self.tcx, filler_args),
);
// Unify the (adjusted) self type with what the method expects.
//
// SUBTLE: if we want good error messages, because of "guessing" while matching
// traits, no trait system method can be called before this point because they
// could alter our Self-type, except for normalizing the receiver from the
// signature (which is also done during probing).
let method_sig_rcvr = self.normalize(self.span, method_sig.inputs()[0]);
debug!(
"confirm: self_ty={:?} method_sig_rcvr={:?} method_sig={:?} method_predicates={:?}",
self_ty, method_sig_rcvr, method_sig, method_predicates
);
self.unify_receivers(self_ty, method_sig_rcvr, &pick, all_args);
let (method_sig, method_predicates) =
self.normalize(self.span, (method_sig, method_predicates));
let method_sig = ty::Binder::dummy(method_sig);
// Make sure nobody calls `drop()` explicitly.
self.enforce_illegal_method_limitations(&pick);
// Add any trait/regions obligations specified on the method's type parameters.
// We won't add these if we encountered an illegal sized bound, so that we can use
// a custom error in that case.
if illegal_sized_bound.is_none() {
self.add_obligations(
Ty::new_fn_ptr(self.tcx, method_sig),
all_args,
method_predicates,
pick.item.def_id,
);
}
// Create the final `MethodCallee`.
let callee = MethodCallee {
def_id: pick.item.def_id,
args: all_args,
sig: method_sig.skip_binder(),
};
ConfirmResult { callee, illegal_sized_bound }
}
///////////////////////////////////////////////////////////////////////////
// ADJUSTMENTS
fn adjust_self_ty(
&mut self,
unadjusted_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
) -> Ty<'tcx> {
// Commit the autoderefs by calling `autoderef` again, but this
// time writing the results into the various typeck results.
let mut autoderef = self.autoderef(self.call_expr.span, unadjusted_self_ty);
let Some((ty, n)) = autoderef.nth(pick.autoderefs) else {
return Ty::new_error_with_message(
self.tcx,
rustc_span::DUMMY_SP,
format!("failed autoderef {}", pick.autoderefs),
);
};
assert_eq!(n, pick.autoderefs);
let mut adjustments = self.adjust_steps(&autoderef);
let mut target = self.structurally_resolve_type(autoderef.span(), ty);
match pick.autoref_or_ptr_adjustment {
Some(probe::AutorefOrPtrAdjustment::Autoref { mutbl, unsize }) => {
let region = self.next_region_var(infer::Autoref(self.span));
// Type we're wrapping in a reference, used later for unsizing
let base_ty = target;
target = Ty::new_ref(self.tcx, region, ty::TypeAndMut { mutbl, ty: target });
// Method call receivers are the primary use case
// for two-phase borrows.
let mutbl = AutoBorrowMutability::new(mutbl, AllowTwoPhase::Yes);
adjustments.push(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)),
target,
});
if unsize {
let unsized_ty = if let ty::Array(elem_ty, _) = base_ty.kind() {
Ty::new_slice(self.tcx, *elem_ty)
} else {
bug!(
"AutorefOrPtrAdjustment's unsize flag should only be set for array ty, found {}",
base_ty
)
};
target = Ty::new_ref(
self.tcx,
region,
ty::TypeAndMut { mutbl: mutbl.into(), ty: unsized_ty },
);
adjustments.push(Adjustment {
kind: Adjust::Pointer(PointerCoercion::Unsize),
target,
});
}
}
Some(probe::AutorefOrPtrAdjustment::ToConstPtr) => {
target = match target.kind() {
&ty::RawPtr(ty::TypeAndMut { ty, mutbl }) => {
assert!(mutbl.is_mut());
Ty::new_ptr(self.tcx, ty::TypeAndMut { mutbl: hir::Mutability::Not, ty })
}
other => panic!("Cannot adjust receiver type {other:?} to const ptr"),
};
adjustments.push(Adjustment {
kind: Adjust::Pointer(PointerCoercion::MutToConstPointer),
target,
});
}
None => {}
}
self.register_predicates(autoderef.into_obligations());
// Write out the final adjustments.
if !self.skip_record_for_diagnostics {
self.apply_adjustments(self.self_expr, adjustments);
}
target
}
/// Returns a set of substitutions for the method *receiver* where all type and region
/// parameters are instantiated with fresh variables. This substitution does not include any
/// parameters declared on the method itself.
///
/// Note that this substitution may include late-bound regions from the impl level. If so,
/// these are instantiated later in the `instantiate_method_sig` routine.
fn fresh_receiver_args(
&mut self,
self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
) -> GenericArgsRef<'tcx> {
match pick.kind {
probe::InherentImplPick => {
let impl_def_id = pick.item.container_id(self.tcx);
assert!(
self.tcx.impl_trait_ref(impl_def_id).is_none(),
"impl {impl_def_id:?} is not an inherent impl"
);
self.fresh_args_for_item(self.span, impl_def_id)
}
probe::ObjectPick => {
let trait_def_id = pick.item.container_id(self.tcx);
self.extract_existential_trait_ref(self_ty, |this, object_ty, principal| {
// The object data has no entry for the Self
// Type. For the purposes of this method call, we
// substitute the object type itself. This
// wouldn't be a sound substitution in all cases,
// since each instance of the object type is a
// different existential and hence could match
// distinct types (e.g., if `Self` appeared as an
// argument type), but those cases have already
// been ruled out when we deemed the trait to be
// "object safe".
let original_poly_trait_ref = principal.with_self_ty(this.tcx, object_ty);
let upcast_poly_trait_ref = this.upcast(original_poly_trait_ref, trait_def_id);
let upcast_trait_ref =
this.instantiate_binder_with_fresh_vars(upcast_poly_trait_ref);
debug!(
"original_poly_trait_ref={:?} upcast_trait_ref={:?} target_trait={:?}",
original_poly_trait_ref, upcast_trait_ref, trait_def_id
);
upcast_trait_ref.args
})
}
probe::TraitPick => {
let trait_def_id = pick.item.container_id(self.tcx);
// Make a trait reference `$0 : Trait<$1...$n>`
// consisting entirely of type variables. Later on in
// the process we will unify the transformed-self-type
// of the method with the actual type in order to
// unify some of these variables.
self.fresh_args_for_item(self.span, trait_def_id)
}
probe::WhereClausePick(poly_trait_ref) => {
// Where clauses can have bound regions in them. We need to instantiate
// those to convert from a poly-trait-ref to a trait-ref.
self.instantiate_binder_with_fresh_vars(poly_trait_ref).args
}
}
}
fn extract_existential_trait_ref<R, F>(&mut self, self_ty: Ty<'tcx>, mut closure: F) -> R
where
F: FnMut(&mut ConfirmContext<'a, 'tcx>, Ty<'tcx>, ty::PolyExistentialTraitRef<'tcx>) -> R,
{
// If we specified that this is an object method, then the
// self-type ought to be something that can be dereferenced to
// yield an object-type (e.g., `&Object` or `Box<Object>`
// etc).
// FIXME: this feels, like, super dubious
self.fcx
.autoderef(self.span, self_ty)
.include_raw_pointers()
.find_map(|(ty, _)| match ty.kind() {
ty::Dynamic(data, ..) => Some(closure(
self,
ty,
data.principal().unwrap_or_else(|| {
span_bug!(self.span, "calling trait method on empty object?")
}),
)),
_ => None,
})
.unwrap_or_else(|| {
span_bug!(
self.span,
"self-type `{}` for ObjectPick never dereferenced to an object",
self_ty
)
})
}
fn instantiate_method_args(
&mut self,
pick: &probe::Pick<'tcx>,
seg: &hir::PathSegment<'_>,
parent_args: GenericArgsRef<'tcx>,
) -> GenericArgsRef<'tcx> {
// Determine the values for the generic parameters of the method.
// If they were not explicitly supplied, just construct fresh
// variables.
let generics = self.tcx.generics_of(pick.item.def_id);
let arg_count_correct = check_generic_arg_count_for_call(
self.tcx,
self.span,
pick.item.def_id,
generics,
seg,
IsMethodCall::Yes,
);
// Create subst for early-bound lifetime parameters, combining
// parameters from the type and those from the method.
assert_eq!(generics.parent_count, parent_args.len());
struct MethodSubstsCtxt<'a, 'tcx> {
cfcx: &'a ConfirmContext<'a, 'tcx>,
pick: &'a probe::Pick<'tcx>,
seg: &'a hir::PathSegment<'a>,
}
impl<'a, 'tcx> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for MethodSubstsCtxt<'a, 'tcx> {
fn args_for_def_id(
&mut self,
def_id: DefId,
) -> (Option<&'a hir::GenericArgs<'a>>, bool) {
if def_id == self.pick.item.def_id {
if let Some(data) = self.seg.args {
return (Some(data), false);
}
}
(None, false)
}
fn provided_kind(
&mut self,
param: &ty::GenericParamDef,
arg: &GenericArg<'_>,
) -> ty::GenericArg<'tcx> {
match (¶m.kind, arg) {
(GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => {
self.cfcx.fcx.astconv().ast_region_to_region(lt, Some(param)).into()
}
(GenericParamDefKind::Type { .. }, GenericArg::Type(ty)) => {
self.cfcx.to_ty(ty).raw.into()
}
(GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => {
self.cfcx.const_arg_to_const(&ct.value, param.def_id).into()
}
(GenericParamDefKind::Type { .. }, GenericArg::Infer(inf)) => {
self.cfcx.ty_infer(Some(param), inf.span).into()
}
(GenericParamDefKind::Const { .. }, GenericArg::Infer(inf)) => {
let tcx = self.cfcx.tcx();
self.cfcx
.ct_infer(
tcx.type_of(param.def_id)
.no_bound_vars()
.expect("const parameter types cannot be generic"),
Some(param),
inf.span,
)
.into()
}
_ => unreachable!(),
}
}
fn inferred_kind(
&mut self,
_args: Option<&[ty::GenericArg<'tcx>]>,
param: &ty::GenericParamDef,
_infer_args: bool,
) -> ty::GenericArg<'tcx> {
self.cfcx.var_for_def(self.cfcx.span, param)
}
}
let args = create_args_for_parent_generic_args(
self.tcx,
pick.item.def_id,
parent_args,
false,
None,
&arg_count_correct,
&mut MethodSubstsCtxt { cfcx: self, pick, seg },
);
// When the method is confirmed, the `args` includes
// parameters from not just the method, but also the impl of
// the method -- in particular, the `Self` type will be fully
// resolved. However, those are not something that the "user
// specified" -- i.e., those types come from the inferred type
// of the receiver, not something the user wrote. So when we
// create the user-args, we want to replace those earlier
// types with just the types that the user actually wrote --
// that is, those that appear on the *method itself*.
//
// As an example, if the user wrote something like
// `foo.bar::<u32>(...)` -- the `Self` type here will be the
// type of `foo` (possibly adjusted), but we don't want to
// include that. We want just the `[_, u32]` part.
if !args.is_empty() && !generics.params.is_empty() {
let user_type_annotation = self.probe(|_| {
let user_args = UserArgs {
args: GenericArgs::for_item(self.tcx, pick.item.def_id, |param, _| {
let i = param.index as usize;
if i < generics.parent_count {
self.fcx.var_for_def(DUMMY_SP, param)
} else {
args[i]
}
}),
user_self_ty: None, // not relevant here
};
self.fcx.canonicalize_user_type_annotation(UserType::TypeOf(
pick.item.def_id,
user_args,
))
});
debug!("instantiate_method_args: user_type_annotation={:?}", user_type_annotation);
if !self.skip_record_for_diagnostics {
self.fcx.write_user_type_annotation(self.call_expr.hir_id, user_type_annotation);
}
}
self.normalize(self.span, args)
}
fn unify_receivers(
&mut self,
self_ty: Ty<'tcx>,
method_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>,
args: GenericArgsRef<'tcx>,
) {
debug!(
"unify_receivers: self_ty={:?} method_self_ty={:?} span={:?} pick={:?}",
self_ty, method_self_ty, self.span, pick
);
let cause = self.cause(
self.self_expr.span,
ObligationCauseCode::UnifyReceiver(Box::new(UnifyReceiverContext {
assoc_item: pick.item,
param_env: self.param_env,
args,
})),
);
match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::No, method_self_ty, self_ty) {
Ok(InferOk { obligations, value: () }) => {
self.register_predicates(obligations);
}
Err(terr) => {
// FIXME(arbitrary_self_types): We probably should limit the
// situations where this can occur by adding additional restrictions
// to the feature, like the self type can't reference method args.
if self.tcx.features().arbitrary_self_types {
self.err_ctxt()
.report_mismatched_types(&cause, method_self_ty, self_ty, terr)
.emit();
} else {
span_bug!(
self.span,
"{} was a subtype of {} but now is not?",
self_ty,
method_self_ty
);
}
}
}
}
// NOTE: this returns the *unnormalized* predicates and method sig. Because of
// inference guessing, the predicates and method signature can't be normalized
// until we unify the `Self` type.
fn instantiate_method_sig(
&mut self,
pick: &probe::Pick<'tcx>,
all_args: GenericArgsRef<'tcx>,
) -> (ty::FnSig<'tcx>, ty::InstantiatedPredicates<'tcx>) {
debug!("instantiate_method_sig(pick={:?}, all_args={:?})", pick, all_args);
// Instantiate the bounds on the method with the
// type/early-bound-regions substitutions performed. There can
// be no late-bound regions appearing here.
let def_id = pick.item.def_id;
let method_predicates = self.tcx.predicates_of(def_id).instantiate(self.tcx, all_args);
debug!("method_predicates after subst = {:?}", method_predicates);
let sig = self.tcx.fn_sig(def_id).instantiate(self.tcx, all_args);
debug!("type scheme substituted, sig={:?}", sig);
let sig = self.instantiate_binder_with_fresh_vars(sig);
debug!("late-bound lifetimes from method instantiated, sig={:?}", sig);
(sig, method_predicates)
}
fn add_obligations(
&mut self,
fty: Ty<'tcx>,
all_args: GenericArgsRef<'tcx>,
method_predicates: ty::InstantiatedPredicates<'tcx>,
def_id: DefId,
) {
debug!(
"add_obligations: fty={:?} all_args={:?} method_predicates={:?} def_id={:?}",
fty, all_args, method_predicates, def_id
);
// FIXME: could replace with the following, but we already calculated `method_predicates`,
// so we just call `predicates_for_generics` directly to avoid redoing work.
// `self.add_required_obligations(self.span, def_id, &all_args);`
for obligation in traits::predicates_for_generics(
|idx, span| {
let code = if span.is_dummy() {
ObligationCauseCode::ExprItemObligation(def_id, self.call_expr.hir_id, idx)
} else {
ObligationCauseCode::ExprBindingObligation(
def_id,
span,
self.call_expr.hir_id,
idx,
)
};
traits::ObligationCause::new(self.span, self.body_id, code)
},
self.param_env,
method_predicates,
) {
self.register_predicate(obligation);
}
// this is a projection from a trait reference, so we have to
// make sure that the trait reference inputs are well-formed.
self.add_wf_bounds(all_args, self.call_expr);
// the function type must also be well-formed (this is not
// implied by the args being well-formed because of inherent
// impls and late-bound regions - see issue #28609).
self.register_wf_obligation(fty.into(), self.span, traits::WellFormed(None));
}
///////////////////////////////////////////////////////////////////////////
// MISCELLANY
fn predicates_require_illegal_sized_bound(
&self,
predicates: ty::InstantiatedPredicates<'tcx>,
) -> Option<Span> {
let sized_def_id = self.tcx.lang_items().sized_trait()?;
traits::elaborate(self.tcx, predicates.predicates.iter().copied())
// We don't care about regions here.
.filter_map(|pred| match pred.kind().skip_binder() {
ty::ClauseKind::Trait(trait_pred) if trait_pred.def_id() == sized_def_id => {
let span = predicates
.iter()
.find_map(|(p, span)| if p == pred { Some(span) } else { None })
.unwrap_or(rustc_span::DUMMY_SP);
Some((trait_pred, span))
}
_ => None,
})
.find_map(|(trait_pred, span)| match trait_pred.self_ty().kind() {
ty::Dynamic(..) => Some(span),
_ => None,
})
}
fn enforce_illegal_method_limitations(&self, pick: &probe::Pick<'_>) {
// Disallow calls to the method `drop` defined in the `Drop` trait.
if let Some(trait_def_id) = pick.item.trait_container(self.tcx) {
callee::check_legal_trait_for_method_call(
self.tcx,
self.span,
Some(self.self_expr.span),
self.call_expr.span,
trait_def_id,
)
}
}
fn upcast(
&mut self,
source_trait_ref: ty::PolyTraitRef<'tcx>,
target_trait_def_id: DefId,
) -> ty::PolyTraitRef<'tcx> {
let upcast_trait_refs =
traits::upcast_choices(self.tcx, source_trait_ref, target_trait_def_id);
// must be exactly one trait ref or we'd get an ambig error etc
if upcast_trait_refs.len() != 1 {
span_bug!(
self.span,
"cannot uniquely upcast `{:?}` to `{:?}`: `{:?}`",
source_trait_ref,
target_trait_def_id,
upcast_trait_refs
);
}
upcast_trait_refs.into_iter().next().unwrap()
}
fn instantiate_binder_with_fresh_vars<T>(&self, value: ty::Binder<'tcx, T>) -> T
where
T: TypeFoldable<TyCtxt<'tcx>> + Copy,
{
self.fcx.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, value)
}
}