mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Implement a dummy drop-in-favor-of for the new solver

Browse Source
This commit is contained in:
Michael Goulet 2023-02-08 03:03:15 +00:00
parent 8c67ecd124
commit 8987e68247
5 changed files with 65 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
compiler/rustc_trait_selection/src/solve/project_goals.rs
View File

@ -3,7 +3,7 @@
use super::assembly::{self, Candidate, CandidateSource};
use super::infcx_ext::InferCtxtExt;
use super::trait_goals::structural_traits;
use super::{Certainty, EvalCtxt, Goal, QueryResult};
use super::{Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
@ -182,11 +182,17 @@ fn merge_project_candidates(
// If there are *STILL* multiple candidates, give up
// and report ambiguity.
i += 1;
if i > 1 {
debug!("multiple matches, ambig");
// FIXME: return overflow if all candidates overflow, otherwise return ambiguity.
unimplemented!();
}
if candidates.len() > 1 {
let certainty = if candidates.iter().all(|x| {
matches!(x.result.value.certainty, Certainty::Maybe(MaybeCause::Overflow))
}) {
Certainty::Maybe(MaybeCause::Overflow)
} else {
Certainty::AMBIGUOUS
};
return self.make_canonical_response(certainty);
}
}
@ -203,7 +209,7 @@ fn project_candidate_should_be_dropped_in_favor_of(
(CandidateSource::Impl(_), _)
| (CandidateSource::ParamEnv(_), _)
| (CandidateSource::BuiltinImpl, _)
| (CandidateSource::AliasBound, _) => unimplemented!(),
| (CandidateSource::AliasBound, _) => false,
}
}
}
@ -452,7 +458,8 @@ fn consider_builtin_pointee_candidate(
[ty::GenericArg::from(goal.predicate.self_ty())],
));
let is_sized_certainty = ecx.evaluate_goal(goal.with(tcx, sized_predicate))?.1;
let (_, is_sized_certainty) =
ecx.evaluate_goal(goal.with(tcx, sized_predicate))?;
return ecx.eq_term_and_make_canonical_response(
goal,
is_sized_certainty,

27
compiler/rustc_trait_selection/src/solve/trait_goals.rs
View File

@ -4,7 +4,7 @@
use super::assembly::{self, Candidate, CandidateSource};
use super::infcx_ext::InferCtxtExt;
use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, QueryResult};
use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use rustc_hir::def_id::DefId;
use rustc_infer::infer::InferCtxt;
use rustc_infer::traits::query::NoSolution;
@ -511,11 +511,17 @@ pub(super) fn merge_trait_candidates_discard_reservation_impls(
// If there are *STILL* multiple candidates, give up
// and report ambiguity.
i += 1;
if i > 1 {
debug!("multiple matches, ambig");
// FIXME: return overflow if all candidates overflow, otherwise return ambiguity.
unimplemented!();
}
if candidates.len() > 1 {
let certainty = if candidates.iter().all(|x| {
matches!(x.result.value.certainty, Certainty::Maybe(MaybeCause::Overflow))
}) {
Certainty::Maybe(MaybeCause::Overflow)
} else {
Certainty::AMBIGUOUS
};
return self.make_canonical_response(certainty);
}
}
@ -532,17 +538,18 @@ fn trait_candidate_should_be_dropped_in_favor_of(
(CandidateSource::Impl(_), _)
| (CandidateSource::ParamEnv(_), _)
| (CandidateSource::AliasBound, _)
| (CandidateSource::BuiltinImpl, _) => unimplemented!(),
| (CandidateSource::BuiltinImpl, _) => false,
}
}
fn discard_reservation_impl(&self, candidate: Candidate<'tcx>) -> Candidate<'tcx> {
fn discard_reservation_impl(&self, mut candidate: Candidate<'tcx>) -> Candidate<'tcx> {
if let CandidateSource::Impl(def_id) = candidate.source {
if let ty::ImplPolarity::Reservation = self.tcx().impl_polarity(def_id) {
debug!("Selected reservation impl");
// FIXME: reduce candidate to ambiguous
// FIXME: replace `var_values` with identity, yeet external constraints.
unimplemented!()
// We assemble all candidates inside of a probe so by
// making a new canonical response here our result will
// have no constraints.
candidate.result = self.make_canonical_response(Certainty::AMBIGUOUS).unwrap();
}
}

4
tests/ui/traits/new-solver/provisional-result-done.rs
View File

@ -1,9 +1,5 @@
// known-bug: unknown
// compile-flags: -Ztrait-solver=next
// failure-status: 101
// normalize-stderr-test "note: .*\n\n" -> ""
// normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
// rustc-env:RUST_BACKTRACE=0
// This tests checks that we update results in the provisional cache when
// we pop a goal from the stack.

15
tests/ui/traits/new-solver/provisional-result-done.stderr
View File

@ -1,6 +1,11 @@
error: the compiler unexpectedly panicked. this is a bug.
error[E0283]: type annotations needed: cannot satisfy `Bar<T>: Coinductive`
--> $DIR/provisional-result-done.rs:16:25
|
LL | impl<T> Coinductive for Bar<T>
| ^^^^^^
|
= note: cannot satisfy `Bar<T>: Coinductive`
query stack during panic:
#0 [check_well_formed] checking that `<impl at $DIR/provisional-result-done.rs:20:1: 20:31>` is well-formed
#1 [check_mod_type_wf] checking that types are well-formed in top-level module
end of query stack
error: aborting due to previous error
For more information about this error, try `rustc --explain E0283`.

22
tests/ui/traits/new-solver/temporary-ambiguity.rs Normal file
View File

@ -0,0 +1,22 @@
// compile-flags: -Ztrait-solver=next
// check-pass
// Checks that we don't explode when we assemble >1 candidate for a goal.
struct Wrapper<T>(T);
trait Foo {}
impl Foo for Wrapper<i32> {}
impl Foo for Wrapper<()> {}
fn needs_foo(_: impl Foo) {}
fn main() {
let mut x = Default::default();
let w = Wrapper(x);
needs_foo(w);
x = 1;
drop(x);
}