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Rollup merge of #124418 - compiler-errors:better-cause, r=lcnr

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Use a proof tree visitor to refine the `Obligation` for error reporting in new solver

With the magic of `ProofTreeVisitor`, we can close the gap that we have on `ObligationCause`s being not as descriptive in the new trait solver.

r? lcnr

Needs some work and obviously documentation.
This commit is contained in:
Michael Goulet 2024-05-03 23:34:21 -04:00 committed by GitHub
commit e3bf0a13cf
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GPG Key ID: B5690EEEBB952194
39 changed files with 474 additions and 102 deletions
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2
compiler/rustc_middle/src/traits/solve.rs
View File

@ -273,6 +273,8 @@ pub enum GoalSource {
/// they are from an impl where-clause. This is necessary due to
/// backwards compatability, cc trait-system-refactor-initiatitive#70.
ImplWhereBound,
/// Instantiating a higher-ranked goal and re-proving it.
InstantiateHigherRanked,
}
/// Possible ways the given goal can be proven.

1
compiler/rustc_middle/src/traits/solve/inspect/format.rs
View File

@ -127,6 +127,7 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> {
let source = match source {
GoalSource::Misc => "misc",
GoalSource::ImplWhereBound => "impl where-bound",
GoalSource::InstantiateHigherRanked => "higher-ranked goal",
};
writeln!(this.f, "ADDED GOAL ({source}): {goal:?}")?
}

15
compiler/rustc_trait_selection/src/solve/assembly/mod.rs
View File

@ -58,15 +58,15 @@ pub(super) trait GoalKind<'tcx>:
/// goal by equating it with the assumption.
fn probe_and_consider_implied_clause(
ecx: &mut EvalCtxt<'_, 'tcx>,
source: CandidateSource,
parent_source: CandidateSource,
goal: Goal<'tcx, Self>,
assumption: ty::Clause<'tcx>,
requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>,
requirements: impl IntoIterator<Item = (GoalSource, Goal<'tcx, ty::Predicate<'tcx>>)>,
) -> Result<Candidate<'tcx>, NoSolution> {
Self::probe_and_match_goal_against_assumption(ecx, source, goal, assumption, |ecx| {
// FIXME(-Znext-solver=coinductive): check whether this should be
// `GoalSource::ImplWhereBound` for any caller.
ecx.add_goals(GoalSource::Misc, requirements);
Self::probe_and_match_goal_against_assumption(ecx, parent_source, goal, assumption, |ecx| {
for (nested_source, goal) in requirements {
ecx.add_goal(nested_source, goal);
}
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})
}
@ -85,9 +85,8 @@ pub(super) trait GoalKind<'tcx>:
let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else {
bug!("expected object type in `probe_and_consider_object_bound_candidate`");
};
// FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`?
ecx.add_goals(
GoalSource::Misc,
GoalSource::ImplWhereBound,
structural_traits::predicates_for_object_candidate(
ecx,
goal.param_env,

4
compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
View File

@ -90,6 +90,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
&mut self,
certainty: Certainty,
) -> QueryResult<'tcx> {
self.inspect.make_canonical_response(certainty);
let goals_certainty = self.try_evaluate_added_goals()?;
assert_eq!(
self.tainted,
@ -98,8 +100,6 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
previous call to `try_evaluate_added_goals!`"
);
self.inspect.make_canonical_response(certainty);
// When normalizing, we've replaced the expected term with an unconstrained
// inference variable. This means that we dropped information which could
// have been important. We handle this by instead returning the nested goals

2
compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
View File

@ -454,7 +454,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
} else {
self.infcx.enter_forall(kind, |kind| {
let goal = goal.with(self.tcx(), ty::Binder::dummy(kind));
self.add_goal(GoalSource::Misc, goal);
self.add_goal(GoalSource::InstantiateHigherRanked, goal);
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})
}

156
compiler/rustc_trait_selection/src/solve/fulfill.rs
View File

@ -1,15 +1,19 @@
use std::mem;
use std::ops::ControlFlow;
use rustc_infer::infer::InferCtxt;
use rustc_infer::traits::solve::MaybeCause;
use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::solve::inspect::ProbeKind;
use rustc_infer::traits::solve::{CandidateSource, GoalSource, MaybeCause};
use rustc_infer::traits::{
query::NoSolution, FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes,
PredicateObligation, SelectionError, TraitEngine,
self, FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes, Obligation,
ObligationCause, PredicateObligation, SelectionError, TraitEngine,
};
use rustc_middle::ty;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use rustc_middle::ty::{self, TyCtxt};
use super::eval_ctxt::GenerateProofTree;
use super::inspect::{ProofTreeInferCtxtExt, ProofTreeVisitor};
use super::{Certainty, InferCtxtEvalExt};
/// A trait engine using the new trait solver.
@ -133,9 +137,9 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
.collect();
errors.extend(self.obligations.overflowed.drain(..).map(|obligation| FulfillmentError {
root_obligation: obligation.clone(),
obligation: find_best_leaf_obligation(infcx, &obligation),
code: FulfillmentErrorCode::Ambiguity { overflow: Some(true) },
obligation,
root_obligation: obligation,
}));
errors
@ -192,8 +196,10 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
fn fulfillment_error_for_no_solution<'tcx>(
infcx: &InferCtxt<'tcx>,
obligation: PredicateObligation<'tcx>,
root_obligation: PredicateObligation<'tcx>,
) -> FulfillmentError<'tcx> {
let obligation = find_best_leaf_obligation(infcx, &root_obligation);
let code = match obligation.predicate.kind().skip_binder() {
ty::PredicateKind::Clause(ty::ClauseKind::Projection(_)) => {
FulfillmentErrorCode::ProjectionError(
@ -234,7 +240,8 @@ fn fulfillment_error_for_no_solution<'tcx>(
bug!("unexpected goal: {obligation:?}")
}
};
FulfillmentError { root_obligation: obligation.clone(), code, obligation }
FulfillmentError { obligation, code, root_obligation }
}
fn fulfillment_error_for_stalled<'tcx>(
@ -258,5 +265,136 @@ fn fulfillment_error_for_stalled<'tcx>(
}
});
FulfillmentError { obligation: obligation.clone(), code, root_obligation: obligation }
FulfillmentError {
obligation: find_best_leaf_obligation(infcx, &obligation),
code,
root_obligation: obligation,
}
}
fn find_best_leaf_obligation<'tcx>(
infcx: &InferCtxt<'tcx>,
obligation: &PredicateObligation<'tcx>,
) -> PredicateObligation<'tcx> {
let obligation = infcx.resolve_vars_if_possible(obligation.clone());
infcx
.visit_proof_tree(
obligation.clone().into(),
&mut BestObligation { obligation: obligation.clone() },
)
.break_value()
.unwrap_or(obligation)
}
struct BestObligation<'tcx> {
obligation: PredicateObligation<'tcx>,
}
impl<'tcx> BestObligation<'tcx> {
fn with_derived_obligation(
&mut self,
derived_obligation: PredicateObligation<'tcx>,
and_then: impl FnOnce(&mut Self) -> <Self as ProofTreeVisitor<'tcx>>::Result,
) -> <Self as ProofTreeVisitor<'tcx>>::Result {
let old_obligation = std::mem::replace(&mut self.obligation, derived_obligation);
let res = and_then(self);
self.obligation = old_obligation;
res
}
}
impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> {
type Result = ControlFlow<PredicateObligation<'tcx>>;
fn span(&self) -> rustc_span::Span {
self.obligation.cause.span
}
fn visit_goal(&mut self, goal: &super::inspect::InspectGoal<'_, 'tcx>) -> Self::Result {
// FIXME: Throw out candidates that have no failing WC and >0 failing misc goal.
// This most likely means that the goal just didn't unify at all, e.g. a param
// candidate with an alias in it.
let candidates = goal.candidates();
let [candidate] = candidates.as_slice() else {
return ControlFlow::Break(self.obligation.clone());
};
// FIXME: Could we extract a trait ref from a projection here too?
// FIXME: Also, what about considering >1 layer up the stack? May be necessary
// for normalizes-to.
let Some(parent_trait_pred) = goal.goal().predicate.to_opt_poly_trait_pred() else {
return ControlFlow::Break(self.obligation.clone());
};
let tcx = goal.infcx().tcx;
let mut impl_where_bound_count = 0;
for nested_goal in candidate.instantiate_nested_goals(self.span()) {
let obligation;
match nested_goal.source() {
GoalSource::Misc => {
continue;
}
GoalSource::ImplWhereBound => {
obligation = Obligation {
cause: derive_cause(
tcx,
candidate.kind(),
self.obligation.cause.clone(),
impl_where_bound_count,
parent_trait_pred,
),
param_env: nested_goal.goal().param_env,
predicate: nested_goal.goal().predicate,
recursion_depth: self.obligation.recursion_depth + 1,
};
impl_where_bound_count += 1;
}
GoalSource::InstantiateHigherRanked => {
obligation = self.obligation.clone();
}
}
// Skip nested goals that hold.
//FIXME: We should change the max allowed certainty based on if we're
// visiting an ambiguity or error obligation.
if matches!(nested_goal.result(), Ok(Certainty::Yes)) {
continue;
}
self.with_derived_obligation(obligation, |this| nested_goal.visit_with(this))?;
}
ControlFlow::Break(self.obligation.clone())
}
}
fn derive_cause<'tcx>(
tcx: TyCtxt<'tcx>,
candidate_kind: ProbeKind<'tcx>,
mut cause: ObligationCause<'tcx>,
idx: usize,
parent_trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> ObligationCause<'tcx> {
match candidate_kind {
ProbeKind::TraitCandidate { source: CandidateSource::Impl(impl_def_id), result: _ } => {
if let Some((_, span)) =
tcx.predicates_of(impl_def_id).instantiate_identity(tcx).iter().nth(idx)
{
cause = cause.derived_cause(parent_trait_pred, |derived| {
traits::ImplDerivedObligation(Box::new(traits::ImplDerivedObligationCause {
derived,
impl_or_alias_def_id: impl_def_id,
impl_def_predicate_index: Some(idx),
span,
}))
})
}
}
ProbeKind::TraitCandidate { source: CandidateSource::BuiltinImpl(..), result: _ } => {
cause = cause.derived_cause(parent_trait_pred, traits::BuiltinDerivedObligation);
}
_ => {}
};
cause
}

53
compiler/rustc_trait_selection/src/solve/inspect/analyse.rs
View File

@ -41,6 +41,7 @@ pub struct InspectGoal<'a, 'tcx> {
result: Result<Certainty, NoSolution>,
evaluation_kind: inspect::CanonicalGoalEvaluationKind<'tcx>,
normalizes_to_term_hack: Option<NormalizesToTermHack<'tcx>>,
source: GoalSource,
}
/// The expected term of a `NormalizesTo` goal gets replaced
@ -90,7 +91,7 @@ impl<'tcx> NormalizesToTermHack<'tcx> {
pub struct InspectCandidate<'a, 'tcx> {
goal: &'a InspectGoal<'a, 'tcx>,
kind: inspect::ProbeKind<'tcx>,
nested_goals: Vec<inspect::CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>>,
nested_goals: Vec<(GoalSource, inspect::CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>)>,
final_state: inspect::CanonicalState<'tcx, ()>,
result: QueryResult<'tcx>,
shallow_certainty: Certainty,
@ -125,10 +126,8 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
/// back their inference constraints. This function modifies
/// the state of the `infcx`.
pub fn visit_nested_no_probe<V: ProofTreeVisitor<'tcx>>(&self, visitor: &mut V) -> V::Result {
if self.goal.depth < visitor.config().max_depth {
for goal in self.instantiate_nested_goals(visitor.span()) {
try_visit!(visitor.visit_goal(&goal));
}
for goal in self.instantiate_nested_goals(visitor.span()) {
try_visit!(goal.visit_with(visitor));
}
V::Result::output()
@ -143,13 +142,16 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
let instantiated_goals: Vec<_> = self
.nested_goals
.iter()
.map(|goal| {
canonical::instantiate_canonical_state(
infcx,
span,
param_env,
&mut orig_values,
*goal,
.map(|(source, goal)| {
(
*source,
canonical::instantiate_canonical_state(
infcx,
span,
param_env,
&mut orig_values,
*goal,
),
)
})
.collect();
@ -171,7 +173,7 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
instantiated_goals
.into_iter()
.map(|goal| match goal.predicate.kind().no_bound_vars() {
.map(|(source, goal)| match goal.predicate.kind().no_bound_vars() {
Some(ty::PredicateKind::NormalizesTo(ty::NormalizesTo { alias, term })) => {
let unconstrained_term = match term.unpack() {
ty::TermKind::Ty(_) => infcx
@ -195,6 +197,7 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
self.goal.depth + 1,
proof_tree.unwrap(),
Some(NormalizesToTermHack { term, unconstrained_term }),
source,
)
}
_ => InspectGoal::new(
@ -202,6 +205,7 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
self.goal.depth + 1,
infcx.evaluate_root_goal(goal, GenerateProofTree::Yes).1.unwrap(),
None,
source,
),
})
.collect()
@ -227,16 +231,23 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> {
self.result
}
pub fn source(&self) -> GoalSource {
self.source
}
fn candidates_recur(
&'a self,
candidates: &mut Vec<InspectCandidate<'a, 'tcx>>,
nested_goals: &mut Vec<inspect::CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>>,
nested_goals: &mut Vec<(
GoalSource,
inspect::CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>,
)>,
probe: &inspect::Probe<'tcx>,
) {
let mut shallow_certainty = None;
for step in &probe.steps {
match step {
&inspect::ProbeStep::AddGoal(_source, goal) => nested_goals.push(goal),
&inspect::ProbeStep::AddGoal(source, goal) => nested_goals.push((source, goal)),
inspect::ProbeStep::NestedProbe(ref probe) => {
// Nested probes have to prove goals added in their parent
// but do not leak them, so we truncate the added goals
@ -319,6 +330,7 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> {
depth: usize,
root: inspect::GoalEvaluation<'tcx>,
normalizes_to_term_hack: Option<NormalizesToTermHack<'tcx>>,
source: GoalSource,
) -> Self {
let inspect::GoalEvaluation { uncanonicalized_goal, kind, evaluation } = root;
let inspect::GoalEvaluationKind::Root { orig_values } = kind else { unreachable!() };
@ -341,8 +353,17 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> {
result,
evaluation_kind: evaluation.kind,
normalizes_to_term_hack,
source,
}
}
pub(crate) fn visit_with<V: ProofTreeVisitor<'tcx>>(&self, visitor: &mut V) -> V::Result {
if self.depth < visitor.config().max_depth {
try_visit!(visitor.visit_goal(self));
}
V::Result::output()
}
}
/// The public API to interact with proof trees.
@ -367,6 +388,6 @@ impl<'tcx> InferCtxt<'tcx> {
) -> V::Result {
let (_, proof_tree) = self.evaluate_root_goal(goal, GenerateProofTree::Yes);
let proof_tree = proof_tree.unwrap();
visitor.visit_goal(&InspectGoal::new(self, 0, proof_tree, None))
visitor.visit_goal(&InspectGoal::new(self, 0, proof_tree, None, GoalSource::Misc))
}
}

5
compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
View File

@ -389,7 +389,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
goal,
pred,
[goal.with(tcx, output_is_sized_pred)],
[(GoalSource::ImplWhereBound, goal.with(tcx, output_is_sized_pred))],
)
}
@ -473,7 +473,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
pred,
[goal.with(tcx, output_is_sized_pred)]
.into_iter()
.chain(nested_preds.into_iter().map(|pred| goal.with(tcx, pred))),
.chain(nested_preds.into_iter().map(|pred| goal.with(tcx, pred)))
.map(|goal| (GoalSource::ImplWhereBound, goal)),
)
}

5
compiler/rustc_trait_selection/src/solve/trait_goals.rs
View File

@ -321,7 +321,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
goal,
pred,
[goal.with(tcx, output_is_sized_pred)],
[(GoalSource::ImplWhereBound, goal.with(tcx, output_is_sized_pred))],
)
}
@ -367,7 +367,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
pred,
[goal.with(tcx, output_is_sized_pred)]
.into_iter()
.chain(nested_preds.into_iter().map(|pred| goal.with(tcx, pred))),
.chain(nested_preds.into_iter().map(|pred| goal.with(tcx, pred)))
.map(|goal| (GoalSource::ImplWhereBound, goal)),
)
}

2
tests/ui/coherence/occurs-check/opaques.next.stderr
View File

@ -11,7 +11,7 @@ error[E0282]: type annotations needed
--> $DIR/opaques.rs:13:20
|
LL | pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
| ^ cannot infer type for struct `Container<T, T>`
| ^ cannot infer type for associated type `<T as Trait<T>>::Assoc`
error: aborting due to 2 previous errors

9
tests/ui/for/issue-20605.next.stderr
View File

@ -2,9 +2,14 @@ error[E0277]: `dyn Iterator<Item = &'a mut u8>` is not an iterator
--> $DIR/issue-20605.rs:6:17
|
LL | for item in *things { *item = 0 }
| ^^^^^^^ `dyn Iterator<Item = &'a mut u8>` is not an iterator
| ^^^^^^^ the trait `IntoIterator` is not implemented for `dyn Iterator<Item = &'a mut u8>`
|
= help: the trait `IntoIterator` is not implemented for `dyn Iterator<Item = &'a mut u8>`
= note: the trait bound `dyn Iterator<Item = &'a mut u8>: IntoIterator` is not satisfied
= note: required for `dyn Iterator<Item = &'a mut u8>` to implement `IntoIterator`
help: consider mutably borrowing here
|
LL | for item in &mut *things { *item = 0 }
| ++++
error: the type `<dyn Iterator<Item = &'a mut u8> as IntoIterator>::IntoIter` is not well-formed
--> $DIR/issue-20605.rs:6:17

15
tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.next.stderr
View File

@ -23,7 +23,20 @@ error[E0283]: type annotations needed
LL | impls_indirect_leak::<Box<_>>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_indirect_leak`
|
= note: cannot satisfy `for<'a> Box<_>: IndirectLeak<'a>`
note: multiple `impl`s satisfying `for<'a> Box<_>: Leak<'a>` found
--> $DIR/leak-check-in-selection-3.rs:9:1
|
LL | impl Leak<'_> for Box<u32> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | impl Leak<'static> for Box<u16> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: required for `Box<_>` to implement `for<'a> IndirectLeak<'a>`
--> $DIR/leak-check-in-selection-3.rs:23:23
|
LL | impl<'a, T: Leak<'a>> IndirectLeak<'a> for T {}
| -------- ^^^^^^^^^^^^^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `impls_indirect_leak`
--> $DIR/leak-check-in-selection-3.rs:25:27
|

20
tests/ui/traits/next-solver/auto-with-drop_tracking_mir.fail.stderr
View File

@ -1,18 +1,26 @@
error[E0277]: `impl Future<Output = ()>` cannot be sent between threads safely
error: future cannot be sent between threads safely
--> $DIR/auto-with-drop_tracking_mir.rs:25:13
|
LL | is_send(foo());
| ------- ^^^^^ `impl Future<Output = ()>` cannot be sent between threads safely
| |
| required by a bound introduced by this call
| ^^^^^ future returned by `foo` is not `Send`
|
= help: the trait `Send` is not implemented for `impl Future<Output = ()>`
= help: the trait `Sync` is not implemented for `impl Future<Output = ()>`, which is required by `impl Future<Output = ()>: Send`
note: future is not `Send` as this value is used across an await
--> $DIR/auto-with-drop_tracking_mir.rs:16:11
|
LL | let x = &NotSync;
| - has type `&NotSync` which is not `Send`
LL | bar().await;
| ^^^^^ await occurs here, with `x` maybe used later
note: required by a bound in `is_send`
--> $DIR/auto-with-drop_tracking_mir.rs:24:24
|
LL | fn is_send(_: impl Send) {}
| ^^^^ required by this bound in `is_send`
help: consider dereferencing here
|
LL | is_send(*foo());
| +
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0277`.

2
tests/ui/traits/next-solver/auto-with-drop_tracking_mir.rs
View File

@ -23,5 +23,5 @@ async fn bar() {}
fn main() {
fn is_send(_: impl Send) {}
is_send(foo());
//[fail]~^ ERROR `impl Future<Output = ()>` cannot be sent between threads safely
//[fail]~^ ERROR future cannot be sent between threads safely
}

2
tests/ui/traits/next-solver/builtin-fn-must-return-sized.rs
View File

@ -13,5 +13,5 @@ fn foo<F: Fn<T>, T: Tuple>(f: Option<F>, t: T) {
fn main() {
foo::<fn() -> str, _>(None, ());
//~^ expected a `Fn<_>` closure, found `fn() -> str`
//~^ the size for values of type `str` cannot be known at compilation time
}

7
tests/ui/traits/next-solver/builtin-fn-must-return-sized.stderr
View File

@ -1,10 +1,11 @@
error[E0277]: expected a `Fn<_>` closure, found `fn() -> str`
error[E0277]: the size for values of type `str` cannot be known at compilation time
--> $DIR/builtin-fn-must-return-sized.rs:15:11
|
LL | foo::<fn() -> str, _>(None, ());
| ^^^^^^^^^^^ expected an `Fn<_>` closure, found `fn() -> str`
| ^^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Fn<_>` is not implemented for `fn() -> str`
= help: within `fn() -> str`, the trait `Sized` is not implemented for `str`, which is required by `fn() -> str: Fn<_>`
= note: required because it appears within the type `fn() -> str`
note: required by a bound in `foo`
--> $DIR/builtin-fn-must-return-sized.rs:10:11
|

6
tests/ui/traits/next-solver/coherence/coherence-fulfill-overflow.stderr
View File

@ -1,12 +1,12 @@
error[E0119]: conflicting implementations of trait `Trait` for type `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>>>>>>>>>>>`
error[E0119]: conflicting implementations of trait `Trait` for type `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>>>>>>>>>>>>`
--> $DIR/coherence-fulfill-overflow.rs:12:1
|
LL | impl<T: ?Sized + TwoW> Trait for W<T> {}
| ------------------------------------- first implementation here
LL | impl<T: ?Sized + TwoW> Trait for T {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>>>>>>>>>>>`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>>>>>>>>>>>>`
|
= note: overflow evaluating the requirement `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>>>>>>>>>>>: TwoW`
= note: overflow evaluating the requirement `W<W<W<W<_>>>>: TwoW`
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "20"]` attribute to your crate (`coherence_fulfill_overflow`)
error: aborting due to 1 previous error

9
tests/ui/traits/next-solver/cycles/coinduction/fixpoint-exponential-growth.stderr
View File

@ -1,9 +1,16 @@
error[E0275]: overflow evaluating the requirement `W<_>: Trait`
error[E0275]: overflow evaluating the requirement `_: Sized`
--> $DIR/fixpoint-exponential-growth.rs:33:13
|
LL | impls::<W<_>>();
| ^^^^
|
note: required for `W<(W<_>, W<_>)>` to implement `Trait`
--> $DIR/fixpoint-exponential-growth.rs:23:12
|
LL | impl<T, U> Trait for W<(W<T>, W<U>)>
| - ^^^^^ ^^^^^^^^^^^^^^^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `impls`
--> $DIR/fixpoint-exponential-growth.rs:30:13
|

2
tests/ui/traits/next-solver/cycles/coinduction/incompleteness-unstable-result.rs
View File

@ -61,7 +61,7 @@ where
// entering the cycle from `A` fails, but would work if we were to use the cache
// result of `B<X>`.
impls_trait::<A<X>, _, _, _>();
//~^ ERROR the trait bound `A<X>: Trait<_, _, _>` is not satisfied
//~^ ERROR the trait bound `X: IncompleteGuidance<_, _>` is not satisfied
}
fn main() {

17
tests/ui/traits/next-solver/cycles/coinduction/incompleteness-unstable-result.stderr
View File

@ -1,10 +1,21 @@
error[E0277]: the trait bound `A<X>: Trait<_, _, _>` is not satisfied
error[E0277]: the trait bound `X: IncompleteGuidance<_, _>` is not satisfied
--> $DIR/incompleteness-unstable-result.rs:63:19
|
LL | impls_trait::<A<X>, _, _, _>();
| ^^^^ the trait `Trait<_, _, _>` is not implemented for `A<X>`
| ^^^^ the trait `IncompleteGuidance<_, _>` is not implemented for `X`, which is required by `A<X>: Trait<_, _, _>`
|
= help: the trait `Trait<U, V, D>` is implemented for `A<T>`
= help: the following other types implement trait `IncompleteGuidance<T, V>`:
<T as IncompleteGuidance<U, i16>>
<T as IncompleteGuidance<U, i8>>
<T as IncompleteGuidance<U, u8>>
note: required for `A<X>` to implement `Trait<_, _, u8>`
--> $DIR/incompleteness-unstable-result.rs:32:50
|
LL | impl<T: ?Sized, U: ?Sized, V: ?Sized, D: ?Sized> Trait<U, V, D> for A<T>
| ^^^^^^^^^^^^^^ ^^^^
LL | where
LL | T: IncompleteGuidance<U, V>,
| ------------------------ unsatisfied trait bound introduced here
note: required by a bound in `impls_trait`
--> $DIR/incompleteness-unstable-result.rs:51:28
|

36
tests/ui/traits/next-solver/cycles/double-cycle-inductive-coinductive.stderr
View File

@ -1,21 +1,53 @@
error[E0275]: overflow evaluating the requirement `(): Trait`
error[E0275]: overflow evaluating the requirement `(): Inductive`
--> $DIR/double-cycle-inductive-coinductive.rs:32:19
|
LL | impls_trait::<()>();
| ^^
|
note: required for `()` to implement `Trait`
--> $DIR/double-cycle-inductive-coinductive.rs:9:34
|
LL | impl<T: Inductive + Coinductive> Trait for T {}
| --------- ^^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `Inductive`
--> $DIR/double-cycle-inductive-coinductive.rs:12:16
|
LL | impl<T: Trait> Inductive for T {}
| ----- ^^^^^^^^^ ^
| |
| unsatisfied trait bound introduced here
= note: 7 redundant requirements hidden
= note: required for `()` to implement `Trait`
note: required by a bound in `impls_trait`
--> $DIR/double-cycle-inductive-coinductive.rs:17:19
|
LL | fn impls_trait<T: Trait>() {}
| ^^^^^ required by this bound in `impls_trait`
error[E0275]: overflow evaluating the requirement `(): TraitRev`
error[E0275]: overflow evaluating the requirement `(): CoinductiveRev`
--> $DIR/double-cycle-inductive-coinductive.rs:35:23
|
LL | impls_trait_rev::<()>();
| ^^
|
note: required for `()` to implement `TraitRev`
--> $DIR/double-cycle-inductive-coinductive.rs:21:40
|
LL | impl<T: CoinductiveRev + InductiveRev> TraitRev for T {}
| -------------- ^^^^^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `CoinductiveRev`
--> $DIR/double-cycle-inductive-coinductive.rs:27:19
|
LL | impl<T: TraitRev> CoinductiveRev for T {}
| -------- ^^^^^^^^^^^^^^ ^
| |
| unsatisfied trait bound introduced here
= note: 7 redundant requirements hidden
= note: required for `()` to implement `TraitRev`
note: required by a bound in `impls_trait_rev`
--> $DIR/double-cycle-inductive-coinductive.rs:29:23
|

12
tests/ui/traits/next-solver/cycles/inductive-fixpoint-hang.stderr
View File

@ -1,9 +1,19 @@
error[E0275]: overflow evaluating the requirement `W<_>: Trait`
error[E0275]: overflow evaluating the requirement `W<W<_>>: Trait`
--> $DIR/inductive-fixpoint-hang.rs:31:19
|
LL | impls_trait::<W<_>>();
| ^^^^
|
note: required for `W<W<W<_>>>` to implement `Trait`
--> $DIR/inductive-fixpoint-hang.rs:22:17
|
LL | impl<T: ?Sized> Trait for W<W<T>>
| ^^^^^ ^^^^^^^
LL | where
LL | W<T>: Trait,
| ----- unsatisfied trait bound introduced here
= note: 8 redundant requirements hidden
= note: required for `W<W<W<W<W<W<W<W<W<W<W<_>>>>>>>>>>>` to implement `Trait`
note: required by a bound in `impls_trait`
--> $DIR/inductive-fixpoint-hang.rs:28:19
|

2
tests/ui/traits/next-solver/cycles/inductive-not-on-stack.rs
View File

@ -39,7 +39,7 @@ fn impls_ar<T: AR>() {}
fn main() {
impls_a::<()>();
//~^ ERROR overflow evaluating the requirement `(): A`
//~^ ERROR overflow evaluating the requirement `(): B`
impls_ar::<()>();
//~^ ERROR overflow evaluating the requirement `(): AR`

41
tests/ui/traits/next-solver/cycles/inductive-not-on-stack.stderr
View File

@ -1,9 +1,25 @@
error[E0275]: overflow evaluating the requirement `(): A`
error[E0275]: overflow evaluating the requirement `(): B`
--> $DIR/inductive-not-on-stack.rs:41:15
|
LL | impls_a::<()>();
| ^^
|
note: required for `()` to implement `A`
--> $DIR/inductive-not-on-stack.rs:21:16
|
LL | impl<T: B + C> A for T {}
| - ^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `B`
--> $DIR/inductive-not-on-stack.rs:22:12
|
LL | impl<T: A> B for T {}
| - ^ ^
| |
| unsatisfied trait bound introduced here
= note: 7 redundant requirements hidden
= note: required for `()` to implement `A`
note: required by a bound in `impls_a`
--> $DIR/inductive-not-on-stack.rs:25:15
|
@ -16,6 +32,29 @@ error[E0275]: overflow evaluating the requirement `(): AR`
LL | impls_ar::<()>();
| ^^
|
note: required for `()` to implement `BR`
--> $DIR/inductive-not-on-stack.rs:35:13
|
LL | impl<T: AR> BR for T {}
| -- ^^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `CR`
--> $DIR/inductive-not-on-stack.rs:36:13
|
LL | impl<T: BR> CR for T {}
| -- ^^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `AR`
--> $DIR/inductive-not-on-stack.rs:34:18
|
LL | impl<T: CR + BR> AR for T {}
| -- ^^ ^
| |
| unsatisfied trait bound introduced here
= note: 6 redundant requirements hidden
= note: required for `()` to implement `AR`
note: required by a bound in `impls_ar`
--> $DIR/inductive-not-on-stack.rs:38:16
|

2
tests/ui/traits/next-solver/cycles/mixed-cycles-1.rs
View File

@ -35,5 +35,5 @@ fn impls_a<T: A>() {}
fn main() {
impls_a::<()>();
//~^ ERROR overflow evaluating the requirement `(): A`
//~^ ERROR overflow evaluating the requirement `(): CInd`
}

39
tests/ui/traits/next-solver/cycles/mixed-cycles-1.stderr
View File

@ -1,9 +1,46 @@
error[E0275]: overflow evaluating the requirement `(): A`
error[E0275]: overflow evaluating the requirement `(): CInd`
--> $DIR/mixed-cycles-1.rs:37:15
|
LL | impls_a::<()>();
| ^^
|
note: required for `()` to implement `B`
--> $DIR/mixed-cycles-1.rs:31:28
|
LL | impl<T: ?Sized + CInd + C> B for T {}
| ---- ^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `C`
--> $DIR/mixed-cycles-1.rs:32:25
|
LL | impl<T: ?Sized + B + A> C for T {}
| - ^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `CInd`
--> $DIR/mixed-cycles-1.rs:28:21
|
LL | impl<T: ?Sized + C> CInd for T {}
| - ^^^^ ^
| |
| unsatisfied trait bound introduced here
= note: 4 redundant requirements hidden
= note: required for `()` to implement `B`
note: required for `()` to implement `BInd`
--> $DIR/mixed-cycles-1.rs:23:21
|
LL | impl<T: ?Sized + B> BInd for T {}
| - ^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `A`
--> $DIR/mixed-cycles-1.rs:30:28
|
LL | impl<T: ?Sized + BInd + C> A for T {}
| ---- ^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `impls_a`
--> $DIR/mixed-cycles-1.rs:34:15
|

2
tests/ui/traits/next-solver/cycles/mixed-cycles-2.rs
View File

@ -28,5 +28,5 @@ fn impls_a<T: A>() {}
fn main() {
impls_a::<()>();
//~^ ERROR overflow evaluating the requirement `(): A`
//~^ ERROR overflow evaluating the requirement `(): BInd`
}

25
tests/ui/traits/next-solver/cycles/mixed-cycles-2.stderr
View File

@ -1,9 +1,32 @@
error[E0275]: overflow evaluating the requirement `(): A`
error[E0275]: overflow evaluating the requirement `(): BInd`
--> $DIR/mixed-cycles-2.rs:30:15
|
LL | impls_a::<()>();
| ^^
|
note: required for `()` to implement `B`
--> $DIR/mixed-cycles-2.rs:25:24
|
LL | impl<T: ?Sized + BInd> B for T {}
| ---- ^ ^
| |
| unsatisfied trait bound introduced here
note: required for `()` to implement `BInd`
--> $DIR/mixed-cycles-2.rs:22:21
|
LL | impl<T: ?Sized + B> BInd for T {}
| - ^^^^ ^
| |
| unsatisfied trait bound introduced here
= note: 6 redundant requirements hidden
= note: required for `()` to implement `BInd`
note: required for `()` to implement `A`
--> $DIR/mixed-cycles-2.rs:24:28
|
LL | impl<T: ?Sized + BInd + B> A for T {}
| ---- ^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `impls_a`
--> $DIR/mixed-cycles-2.rs:27:15
|

2
tests/ui/traits/next-solver/env-shadows-impls/param-candidate-shadows-project.rs
View File

@ -25,7 +25,7 @@ fn foo<T: Foo>() {
//
// https://github.com/rust-lang/trait-system-refactor-initiative/issues/76
require_bar::<T>();
//~^ ERROR the trait bound `T: Bar` is not satisfied
//~^ ERROR type mismatch resolving `<T as Foo>::Assoc == i32`
}
fn main() {}

20
tests/ui/traits/next-solver/env-shadows-impls/param-candidate-shadows-project.stderr
View File

@ -1,19 +1,25 @@
error[E0277]: the trait bound `T: Bar` is not satisfied
error[E0271]: type mismatch resolving `<T as Foo>::Assoc == i32`
--> $DIR/param-candidate-shadows-project.rs:27:19
|
LL | require_bar::<T>();
| ^ the trait `Bar` is not implemented for `T`
| ^ type mismatch resolving `<T as Foo>::Assoc == i32`
|
note: types differ
--> $DIR/param-candidate-shadows-project.rs:10:18
|
LL | type Assoc = i32;
| ^^^
note: required for `T` to implement `Bar`
--> $DIR/param-candidate-shadows-project.rs:13:9
|
LL | impl<T> Bar for T where T: Foo<Assoc = i32> {}
| ^^^ ^ ----------- unsatisfied trait bound introduced here
note: required by a bound in `require_bar`
--> $DIR/param-candidate-shadows-project.rs:15:19
|
LL | fn require_bar<T: Bar>() {}
| ^^^ required by this bound in `require_bar`
help: consider further restricting this bound
|
LL | fn foo<T: Foo + Bar>() {
| +++++
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0277`.
For more information about this error, try `rustc --explain E0271`.

2
tests/ui/traits/next-solver/more-object-bound.rs
View File

@ -10,7 +10,7 @@ trait Trait: SuperTrait<A = <Self as SuperTrait>::B> {}
fn transmute<A, B>(x: A) -> B {
foo::<A, B, dyn Trait<A = A, B = B>>(x)
//~^ ERROR the trait bound `dyn Trait<A = A, B = B>: Trait` is not satisfied
//~^ ERROR type mismatch resolving `<dyn Trait<A = A, B = B> as SuperTrait>::A == B`
}
fn foo<A, B, T: ?Sized>(x: T::A) -> B

11
tests/ui/traits/next-solver/more-object-bound.stderr
View File

@ -1,9 +1,10 @@
error[E0277]: the trait bound `dyn Trait<A = A, B = B>: Trait` is not satisfied
error[E0271]: type mismatch resolving `<dyn Trait<A = A, B = B> as SuperTrait>::A == B`
--> $DIR/more-object-bound.rs:12:5
|
LL | foo::<A, B, dyn Trait<A = A, B = B>>(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `dyn Trait<A = A, B = B>`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ
|
= note: required because it appears within the type `dyn Trait<A = A, B = B>`
note: required by a bound in `foo`
--> $DIR/more-object-bound.rs:18:8
|
@ -12,11 +13,7 @@ LL | fn foo<A, B, T: ?Sized>(x: T::A) -> B
LL | where
LL | T: Trait<B = B>,
| ^^^^^^^^^^^^ required by this bound in `foo`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
|
LL | fn transmute<A, B>(x: A) -> B where dyn Trait<A = A, B = B>: Trait {
| ++++++++++++++++++++++++++++++++++++
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0277`.
For more information about this error, try `rustc --explain E0271`.

2
tests/ui/traits/next-solver/normalize/two-projection-param-candidates-are-ambiguous.rs
View File

@ -24,7 +24,7 @@ fn needs_bar<T: Bar>() {}
fn foo<T: Foo<Assoc = i32> + Foo<Assoc = u32>>() {
needs_bar::<T>();
//~^ ERROR type annotations needed: cannot satisfy `T: Bar`
//~^ ERROR type annotations needed: cannot satisfy `<T as Foo>::Assoc == i32`
}
fn main() {}

13
tests/ui/traits/next-solver/normalize/two-projection-param-candidates-are-ambiguous.stderr
View File

@ -1,11 +1,14 @@
error[E0283]: type annotations needed: cannot satisfy `T: Bar`
error[E0284]: type annotations needed: cannot satisfy `<T as Foo>::Assoc == i32`
--> $DIR/two-projection-param-candidates-are-ambiguous.rs:26:17
|
LL | needs_bar::<T>();
| ^
| ^ cannot satisfy `<T as Foo>::Assoc == i32`
|
= note: cannot satisfy `T: Bar`
= help: the trait `Bar` is implemented for `T`
note: required for `T` to implement `Bar`
--> $DIR/two-projection-param-candidates-are-ambiguous.rs:21:9
|
LL | impl<T> Bar for T where T: Foo<Assoc = i32> {}
| ^^^ ^ ----------- unsatisfied trait bound introduced here
note: required by a bound in `needs_bar`
--> $DIR/two-projection-param-candidates-are-ambiguous.rs:23:17
|
@ -14,4 +17,4 @@ LL | fn needs_bar<T: Bar>() {}
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0283`.
For more information about this error, try `rustc --explain E0284`.

2
tests/ui/traits/next-solver/object-unsafety.rs
View File

@ -11,9 +11,9 @@ fn copy<U: Setup + ?Sized>(from: &U::From) -> U::From {
pub fn copy_any<T>(t: &T) -> T {
copy::<dyn Setup<From=T>>(t)
//~^ ERROR the type `&<dyn Setup<From = T> as Setup>::From` is not well-formed
//~| ERROR the trait bound `dyn Setup<From = T>: Setup` is not satisfied
//~| ERROR mismatched types
//~| ERROR the type `<dyn Setup<From = T> as Setup>::From` is not well-formed
//~| ERROR the trait bound `T: Copy` is not satisfied
// FIXME(-Znext-solver): These error messages are horrible and some of them
// are even simple fallout from previous error.

11
tests/ui/traits/next-solver/object-unsafety.stderr
View File

@ -1,18 +1,19 @@
error[E0277]: the trait bound `dyn Setup<From = T>: Setup` is not satisfied
error[E0277]: the trait bound `T: Copy` is not satisfied in `dyn Setup<From = T>`
--> $DIR/object-unsafety.rs:12:12
|
LL | copy::<dyn Setup<From=T>>(t)
| ^^^^^^^^^^^^^^^^^ the trait `Setup` is not implemented for `dyn Setup<From = T>`
| ^^^^^^^^^^^^^^^^^ within `dyn Setup<From = T>`, the trait `Copy` is not implemented for `T`, which is required by `dyn Setup<From = T>: Setup`
|
= note: required because it appears within the type `dyn Setup<From = T>`
note: required by a bound in `copy`
--> $DIR/object-unsafety.rs:7:12
|
LL | fn copy<U: Setup + ?Sized>(from: &U::From) -> U::From {
| ^^^^^ required by this bound in `copy`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
help: consider restricting type parameter `T`
|
LL | pub fn copy_any<T>(t: &T) -> T where dyn Setup<From = T>: Setup {
| ++++++++++++++++++++++++++++++++
LL | pub fn copy_any<T: std::marker::Copy>(t: &T) -> T {
| +++++++++++++++++++
error: the type `&<dyn Setup<From = T> as Setup>::From` is not well-formed
--> $DIR/object-unsafety.rs:12:31

2
tests/ui/traits/next-solver/overflow/exponential-trait-goals.rs
View File

@ -15,5 +15,5 @@ fn impls<T: Trait>() {}
fn main() {
impls::<W<_>>();
//~^ ERROR overflow evaluating the requirement `W<_>: Trait`
//~^ ERROR overflow evaluating the requirement `_: Sized`
}

9
tests/ui/traits/next-solver/overflow/exponential-trait-goals.stderr
View File

@ -1,9 +1,16 @@
error[E0275]: overflow evaluating the requirement `W<_>: Trait`
error[E0275]: overflow evaluating the requirement `_: Sized`
--> $DIR/exponential-trait-goals.rs:17:13
|
LL | impls::<W<_>>();
| ^^^^
|
note: required for `W<(W<_>, W<_>)>` to implement `Trait`
--> $DIR/exponential-trait-goals.rs:7:12
|
LL | impl<T, U> Trait for W<(W<T>, W<U>)>
| - ^^^^^ ^^^^^^^^^^^^^^^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `impls`
--> $DIR/exponential-trait-goals.rs:14:13
|

9
tests/ui/traits/next-solver/overflow/global-cache.stderr
View File

@ -5,6 +5,15 @@ LL | impls_trait::<Four<Four<Four<Four<()>>>>>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "18"]` attribute to your crate (`global_cache`)
note: required for `Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<()>>>>>>>>>>>` to implement `Trait`
--> $DIR/global-cache.rs:12:16
|
LL | impl<T: Trait> Trait for Inc<T> {}
| ----- ^^^^^ ^^^^^^
| |
| unsatisfied trait bound introduced here
= note: 5 redundant requirements hidden
= note: required for `Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<Inc<()>>>>>>>>>>>>>>>>` to implement `Trait`
note: required by a bound in `impls_trait`
--> $DIR/global-cache.rs:15:19
|