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iat selection: erase regions in self type

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This commit is contained in:
León Orell Valerian Liehr 2023-03-21 01:09:00 +01:00
parent 44f5180584
commit 293f21c876
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GPG Key ID: D17A07215F68E713
5 changed files with 101 additions and 31 deletions
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82
compiler/rustc_hir_analysis/src/astconv/mod.rs
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@ -31,6 +31,7 @@
use rustc_infer::traits::ObligationCause;
use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
use rustc_middle::middle::stability::AllowUnstable;
use rustc_middle::ty::fold::FnMutDelegate;
use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
use rustc_middle::ty::DynKind;
use rustc_middle::ty::GenericParamDefKind;
@ -2226,47 +2227,66 @@ fn lookup_inherent_assoc_ty(
let param_env = tcx.param_env(block.owner.to_def_id());
let cause = ObligationCause::misc(span, block.owner.def_id);
let mut fulfillment_errors = Vec::new();
let mut applicable_candidates: Vec<_> = candidates
.iter()
.filter_map(|&(impl_, (assoc_item, def_scope))| {
infcx.probe(|_| {
let ocx = ObligationCtxt::new_in_snapshot(&infcx);
let mut applicable_candidates: Vec<_> = infcx.probe(|_| {
let universe = infcx.create_next_universe();
let impl_ty = tcx.type_of(impl_);
let impl_substs = infcx.fresh_item_substs(impl_);
let impl_ty = impl_ty.subst(tcx, impl_substs);
let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
// Regions are not considered during selection.
let self_ty = tcx.replace_escaping_bound_vars_uncached(
self_ty,
FnMutDelegate {
regions: &mut |_| tcx.lifetimes.re_erased,
types: &mut |bv| {
tcx.mk_placeholder(ty::PlaceholderType { universe, name: bv.kind })
},
consts: &mut |bv, ty| {
tcx.mk_const(ty::PlaceholderConst { universe, name: bv }, ty)
},
},
);
// Check that the Self-types can be related.
// FIXME(fmease): Should we use `eq` here?
ocx.sup(&ObligationCause::dummy(), param_env, impl_ty, self_ty).ok()?;
candidates
.iter()
.filter_map(|&(impl_, (assoc_item, def_scope))| {
infcx.probe(|_| {
let ocx = ObligationCtxt::new_in_snapshot(&infcx);
// Check whether the impl imposes obligations we have to worry about.
let impl_bounds = tcx.predicates_of(impl_);
let impl_bounds = impl_bounds.instantiate(tcx, impl_substs);
let impl_ty = tcx.type_of(impl_);
let impl_substs = infcx.fresh_item_substs(impl_);
let impl_ty = impl_ty.subst(tcx, impl_substs);
let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
let impl_bounds = ocx.normalize(&cause, param_env, impl_bounds);
// Check that the Self-types can be related.
// FIXME(fmease): Should we use `eq` here?
ocx.sup(&ObligationCause::dummy(), param_env, impl_ty, self_ty).ok()?;
let impl_obligations = traits::predicates_for_generics(
|_, _| cause.clone(),
param_env,
impl_bounds,
);
// Check whether the impl imposes obligations we have to worry about.
let impl_bounds = tcx.predicates_of(impl_);
let impl_bounds = impl_bounds.instantiate(tcx, impl_substs);
ocx.register_obligations(impl_obligations);
let impl_bounds = ocx.normalize(&cause, param_env, impl_bounds);
let mut errors = ocx.select_where_possible();
if !errors.is_empty() {
fulfillment_errors.append(&mut errors);
return None;
}
let impl_obligations = traits::predicates_for_generics(
|_, _| cause.clone(),
param_env,
impl_bounds,
);
// FIXME(fmease): Unsolved vars can escape this InferCtxt snapshot.
Some((assoc_item, def_scope, infcx.resolve_vars_if_possible(impl_substs)))
ocx.register_obligations(impl_obligations);
let mut errors = ocx.select_where_possible();
if !errors.is_empty() {
fulfillment_errors.append(&mut errors);
return None;
}
// FIXME(fmease): Unsolved vars can escape this InferCtxt snapshot.
Some((assoc_item, def_scope, infcx.resolve_vars_if_possible(impl_substs)))
})
})
})
.collect();
.collect()
});
if applicable_candidates.len() > 1 {
return Err(self.complain_about_ambiguous_inherent_assoc_type(

12
tests/ui/associated-inherent-types/issue-109299-1.rs Normal file
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@ -0,0 +1,12 @@
#![feature(inherent_associated_types, non_lifetime_binders, type_alias_impl_trait)]
#![allow(incomplete_features)]
struct Lexer<T>(T);
impl Lexer<i32> {
type Cursor = ();
}
type X = impl for<T> Fn() -> Lexer<T>::Cursor; //~ ERROR associated type `Cursor` not found for `Lexer<T>` in the current scope
fn main() {}

15
tests/ui/associated-inherent-types/issue-109299-1.stderr Normal file
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@ -0,0 +1,15 @@
error[E0220]: associated type `Cursor` not found for `Lexer<T>` in the current scope
--> $DIR/issue-109299-1.rs:10:40
|
LL | struct Lexer<T>(T);
| --------------- associated item `Cursor` not found for this struct
...
LL | type X = impl for<T> Fn() -> Lexer<T>::Cursor;
| ^^^^^^ associated item not found in `Lexer<T>`
|
= note: the associated type was found for
- `Lexer<i32>`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0220`.

12
tests/ui/associated-inherent-types/issue-109299.rs Normal file
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@ -0,0 +1,12 @@
#![feature(inherent_associated_types)]
#![allow(incomplete_features)]
struct Lexer<'d>(&'d ());
impl Lexer<'d> { //~ ERROR use of undeclared lifetime name `'d`
type Cursor = ();
}
fn test(_: Lexer::Cursor) {}
fn main() {}

11
tests/ui/associated-inherent-types/issue-109299.stderr Normal file
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@ -0,0 +1,11 @@
error[E0261]: use of undeclared lifetime name `'d`
--> $DIR/issue-109299.rs:6:12
|
LL | impl Lexer<'d> {
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'d` here: `<'d>`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0261`.