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Method resolution constrains hidden types instead of rejecting method…
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… candidates
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oli-obk committed Jun 13, 2024
1 parent c75f728 commit 9cf60ee
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Showing 17 changed files with 58 additions and 213 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1418,7 +1418,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let impl_ty = self.normalize(span, tcx.type_of(impl_def_id).instantiate(tcx, args));
let self_ty = self.normalize(span, self_ty);
match self.at(&self.misc(span), self.param_env).eq(
DefineOpaqueTypes::No,
DefineOpaqueTypes::Yes,
impl_ty,
self_ty,
) {
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_hir_typeck/src/method/confirm.rs
Original file line number Diff line number Diff line change
Expand Up @@ -497,7 +497,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
args,
})),
);
match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::No, method_self_ty, self_ty) {
match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::Yes, method_self_ty, self_ty) {
Ok(InferOk { obligations, value: () }) => {
self.register_predicates(obligations);
}
Expand Down
65 changes: 29 additions & 36 deletions compiler/rustc_hir_typeck/src/method/probe.rs
Original file line number Diff line number Diff line change
Expand Up @@ -634,8 +634,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_probe(&mut self, self_ty: &Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>) {
debug!("assemble_probe: self_ty={:?}", self_ty);
let raw_self_ty = self_ty.value.value;
match *raw_self_ty.kind() {
ty::Dynamic(data, ..) if let Some(p) = data.principal() => {
Expand Down Expand Up @@ -713,13 +713,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_inherent_impl_probe(&mut self, impl_def_id: DefId) {
if !self.impl_dups.insert(impl_def_id) {
return; // already visited
}

debug!("assemble_inherent_impl_probe {:?}", impl_def_id);

for item in self.impl_or_trait_item(impl_def_id) {
if !self.has_applicable_self(&item) {
// No receiver declared. Not a candidate.
Expand All @@ -737,9 +736,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_inherent_candidates_from_object(&mut self, self_ty: Ty<'tcx>) {
debug!("assemble_inherent_candidates_from_object(self_ty={:?})", self_ty);

let principal = match self_ty.kind() {
ty::Dynamic(ref data, ..) => Some(data),
_ => None,
Expand Down Expand Up @@ -768,9 +766,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
});
}

#[instrument(level = "debug", skip(self))]
fn assemble_inherent_candidates_from_param(&mut self, param_ty: ty::ParamTy) {
// FIXME: do we want to commit to this behavior for param bounds?
debug!("assemble_inherent_candidates_from_param(param_ty={:?})", param_ty);

let bounds = self.param_env.caller_bounds().iter().filter_map(|predicate| {
let bound_predicate = predicate.kind();
Expand Down Expand Up @@ -826,6 +824,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_extension_candidates_for_traits_in_scope(&mut self) {
let mut duplicates = FxHashSet::default();
let opt_applicable_traits = self.tcx.in_scope_traits(self.scope_expr_id);
Expand All @@ -842,6 +841,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_extension_candidates_for_all_traits(&mut self) {
let mut duplicates = FxHashSet::default();
for trait_info in suggest::all_traits(self.tcx) {
Expand All @@ -863,12 +863,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "debug", skip(self))]
fn assemble_extension_candidates_for_trait(
&mut self,
import_ids: &SmallVec<[LocalDefId; 1]>,
trait_def_id: DefId,
) {
debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);
let trait_args = self.fresh_args_for_item(self.span, trait_def_id);
let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, trait_args);

Expand Down Expand Up @@ -958,6 +958,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
///////////////////////////////////////////////////////////////////////////
// THE ACTUAL SEARCH

#[instrument(level = "debug", skip(self))]
fn pick(mut self) -> PickResult<'tcx> {
assert!(self.method_name.is_some());

Expand Down Expand Up @@ -1386,6 +1387,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}

#[instrument(level = "trace", skip(self, possibly_unsatisfied_predicates), ret)]
fn consider_probe(
&self,
self_ty: Ty<'tcx>,
Expand Down Expand Up @@ -1415,15 +1417,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
(xform_self_ty, xform_ret_ty) =
self.xform_self_ty(probe.item, impl_ty, impl_args);
xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
// FIXME: Make this `ocx.sup` once we define opaques more eagerly.
match self.at(cause, self.param_env).sup(
DefineOpaqueTypes::No,
xform_self_ty,
self_ty,
) {
Ok(infer_ok) => {
ocx.register_infer_ok_obligations(infer_ok);
}
match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
Ok(()) => {}
Err(err) => {
debug!("--> cannot relate self-types {:?}", err);
return ProbeResult::NoMatch;
Expand Down Expand Up @@ -1484,19 +1479,23 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
(xform_self_ty, xform_ret_ty) =
self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
// FIXME: Make this `ocx.sup` once we define opaques more eagerly.
match self.at(cause, self.param_env).sup(
DefineOpaqueTypes::No,
xform_self_ty,
self_ty,
) {
Ok(infer_ok) => {
ocx.register_infer_ok_obligations(infer_ok);
}
Err(err) => {
debug!("--> cannot relate self-types {:?}", err);
match self_ty.kind() {
// HACK: opaque types will match anything for which their bounds hold.
// Thus we need to prevent them from trying to match the `&_` autoref
// candidates that get created for `&self` trait methods.
ty::Alias(ty::Opaque, alias_ty)
if self.infcx.can_define_opaque_ty(alias_ty.def_id)
&& !xform_self_ty.is_ty_var() =>
{
return ProbeResult::NoMatch;
}
_ => match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
Ok(()) => {}
Err(err) => {
debug!("--> cannot relate self-types {:?}", err);
return ProbeResult::NoMatch;
}
},
}
let obligation = traits::Obligation::new(
self.tcx,
Expand Down Expand Up @@ -1536,15 +1535,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
(xform_self_ty, xform_ret_ty) =
self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
// FIXME: Make this `ocx.sup` once we define opaques more eagerly.
match self.at(cause, self.param_env).sup(
DefineOpaqueTypes::No,
xform_self_ty,
self_ty,
) {
Ok(infer_ok) => {
ocx.register_infer_ok_obligations(infer_ok);
}
match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
Ok(()) => {}
Err(err) => {
debug!("--> cannot relate self-types {:?}", err);
return ProbeResult::NoMatch;
Expand Down Expand Up @@ -1665,6 +1657,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
/// Similarly to `probe_for_return_type`, this method attempts to find the best matching
/// candidate method where the method name may have been misspelled. Similarly to other
/// edit distance based suggestions, we provide at most one such suggestion.
#[instrument(level = "debug", skip(self))]
pub(crate) fn probe_for_similar_candidate(
&mut self,
) -> Result<Option<ty::AssocItem>, MethodError<'tcx>> {
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/traits/query.rs
Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,7 @@ pub struct CandidateStep<'tcx> {

#[derive(Copy, Clone, Debug, HashStable)]
pub struct MethodAutoderefStepsResult<'tcx> {
/// The valid autoderef steps that could be find.
/// The valid autoderef steps that could be found.
pub steps: &'tcx [CandidateStep<'tcx>],
/// If Some(T), a type autoderef reported an error on.
pub opt_bad_ty: Option<&'tcx MethodAutoderefBadTy<'tcx>>,
Expand Down
36 changes: 0 additions & 36 deletions tests/ui/impl-trait/method-resolution.current.stderr

This file was deleted.

9 changes: 3 additions & 6 deletions tests/ui/impl-trait/method-resolution.rs
Original file line number Diff line number Diff line change
@@ -1,10 +1,9 @@
//! Check that we do not constrain hidden types during method resolution.
//! Otherwise we'd pick up that calling `bar` can be satisfied iff `u32`
//! is the hidden type of the RPIT.
//! Since there is only one possible `bar` method, we invoke it and subsequently
//! constrain `foo`'s RPIT to `u32`.

//@ revisions: current next
//@[next] compile-flags: -Znext-solver
//@[next] check-pass
//@ check-pass

trait Trait {}

Expand All @@ -17,11 +16,9 @@ impl Bar<u32> {
}

fn foo(x: bool) -> Bar<impl Sized> {
//[current]~^ ERROR: cycle detected
if x {
let x = foo(false);
x.bar();
//[current]~^ ERROR: no method named `bar` found
}
todo!()
}
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/impl-trait/method-resolution2.rs
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
//! Check that the method call does not constrain the RPIT to `i32`, even though
//! `i32` is the only trait that satisfies the RPIT's trait bounds.
//! `i32` is the only type that satisfies the RPIT's trait bounds.

//@ revisions: current next
//@[next] compile-flags: -Znext-solver
Expand Down
43 changes: 13 additions & 30 deletions tests/ui/impl-trait/method-resolution3.current.stderr
Original file line number Diff line number Diff line change
@@ -1,37 +1,20 @@
error[E0599]: no method named `bar` found for struct `Bar<impl Sized>` in the current scope
--> $DIR/method-resolution3.rs:22:11
error[E0034]: multiple applicable items in scope
--> $DIR/method-resolution3.rs:21:11
|
LL | struct Bar<T>(T);
| ------------- method `bar` not found for this struct
...
LL | x.bar();
| ^^^ method not found in `Bar<impl Sized>`
| ^^^ multiple `bar` found
|
= note: the method was found for
- `Bar<i32>`
- `Bar<u32>`

error[E0391]: cycle detected when computing type of opaque `foo::{opaque#0}`
--> $DIR/method-resolution3.rs:18:24
|
LL | fn foo(x: bool) -> Bar<impl Sized> {
| ^^^^^^^^^^
note: candidate #1 is defined in an impl for the type `Bar<i32>`
--> $DIR/method-resolution3.rs:15:5
|
note: ...which requires type-checking `foo`...
--> $DIR/method-resolution3.rs:22:9
|
LL | x.bar();
| ^
= note: ...which requires evaluating trait selection obligation `Bar<foo::{opaque#0}>: core::marker::Unpin`...
= note: ...which again requires computing type of opaque `foo::{opaque#0}`, completing the cycle
note: cycle used when computing type of `foo::{opaque#0}`
--> $DIR/method-resolution3.rs:18:24
LL | fn bar(self) {}
| ^^^^^^^^^^^^
note: candidate #2 is defined in an impl for the type `Bar<u32>`
--> $DIR/method-resolution3.rs:11:5
|
LL | fn foo(x: bool) -> Bar<impl Sized> {
| ^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
LL | fn bar(self) {}
| ^^^^^^^^^^^^

error: aborting due to 2 previous errors
error: aborting due to 1 previous error

Some errors have detailed explanations: E0391, E0599.
For more information about an error, try `rustc --explain E0391`.
For more information about this error, try `rustc --explain E0034`.
2 changes: 1 addition & 1 deletion tests/ui/impl-trait/method-resolution3.next.stderr
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error[E0034]: multiple applicable items in scope
--> $DIR/method-resolution3.rs:22:11
--> $DIR/method-resolution3.rs:21:11
|
LL | x.bar();
| ^^^ multiple `bar` found
Expand Down
4 changes: 1 addition & 3 deletions tests/ui/impl-trait/method-resolution3.rs
Original file line number Diff line number Diff line change
Expand Up @@ -16,12 +16,10 @@ impl Bar<i32> {
}

fn foo(x: bool) -> Bar<impl Sized> {
//[current]~^ ERROR: cycle
if x {
let x = foo(false);
x.bar();
//[current]~^ ERROR: no method named `bar`
//[next]~^^ ERROR: multiple applicable items in scope
//~^ ERROR: multiple applicable items in scope
}
todo!()
}
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/impl-trait/method-resolution4.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,9 +4,9 @@
//! variable, but get a type mismatch when comparing `&mut _` with
//! `std::iter::Empty`.

//@[current] check-pass
//@ revisions: current next
//@[next] compile-flags: -Znext-solver
//@[current] check-pass

fn foo(b: bool) -> impl Iterator<Item = ()> {
if b {
Expand Down
6 changes: 3 additions & 3 deletions tests/ui/methods/opaque_param_in_ufc.rs
Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
#![feature(type_alias_impl_trait)]

//@ check-pass

struct Foo<T>(T);

impl Foo<u32> {
Expand All @@ -15,14 +18,11 @@ fn bar() -> Bar {
impl Foo<Bar> {
fn foo() -> Bar {
Self::method();
//~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
Foo::<Bar>::method();
//~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
let x = Foo(bar());
Foo::method2(x);
let x = Self(bar());
Self::method2(x);
//~^ ERROR: no function or associated item named `method2` found for struct `Foo<Bar>`
todo!()
}
}
Expand Down
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