diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 3fbe8e39d1e3f..926044bd6a803 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -60,6 +60,20 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
mod candidate_assembly;
mod confirmation;
+/// Whether to consider the binder of higher ranked goals for the `leak_check` when
+/// evaluating higher-ranked goals. See #119820 for more info.
+///
+/// While this is a bit hacky, it is necessary to match the behavior of the new solver:
+/// We eagerly instantiate binders in the new solver, outside of candidate selection, so
+/// the leak check inside of candidates does not consider any bound vars from the higher
+/// ranked goal. However, we do exit the binder once we're completely finished with a goal,
+/// so the leak-check can be used in evaluate by causing nested higher-ranked goals to fail.
+#[derive(Debug, Copy, Clone)]
+enum LeakCheckHigherRankedGoal {
+ No,
+ Yes,
+}
+
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub enum IntercrateAmbiguityCause<'tcx> {
DownstreamCrate { trait_ref: ty::TraitRef<'tcx>, self_ty: Option<Ty<'tcx>> },
@@ -384,7 +398,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let mut no_candidates_apply = true;
for c in candidate_set.vec.iter() {
- if self.evaluate_candidate(stack, c)?.may_apply() {
+ if self
+ .evaluate_candidate(stack, c, LeakCheckHigherRankedGoal::No)?
+ .may_apply()
+ {
no_candidates_apply = false;
break;
}
@@ -455,7 +472,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// is needed for specialization. Propagate overflow if it occurs.
let mut candidates = candidates
.into_iter()
- .map(|c| match self.evaluate_candidate(stack, &c) {
+ .map(|c| match self.evaluate_candidate(stack, &c, LeakCheckHigherRankedGoal::No) {
Ok(eval) if eval.may_apply() => {
Ok(Some(EvaluatedCandidate { candidate: c, evaluation: eval }))
}
@@ -545,7 +562,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligation: &PredicateObligation<'tcx>,
) -> Result<EvaluationResult, OverflowError> {
debug_assert!(!self.infcx.next_trait_solver());
- self.evaluation_probe(|this| {
+ self.evaluation_probe(|this, _outer_universe| {
let goal =
this.infcx.resolve_vars_if_possible((obligation.predicate, obligation.param_env));
let mut result = this.evaluate_predicate_recursively(
@@ -561,13 +578,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
})
}
+ /// Computes the evaluation result of `op`, discarding any constraints.
+ ///
+ /// This also runs for leak check to allow higher ranked region errors to impact
+ /// selection. By default it checks for leaks from all universes created inside of
+ /// `op`, but this can be overwritten if necessary.
fn evaluation_probe(
&mut self,
- op: impl FnOnce(&mut Self) -> Result<EvaluationResult, OverflowError>,
+ op: impl FnOnce(&mut Self, &mut ty::UniverseIndex) -> Result<EvaluationResult, OverflowError>,
) -> Result<EvaluationResult, OverflowError> {
self.infcx.probe(|snapshot| -> Result<EvaluationResult, OverflowError> {
- let outer_universe = self.infcx.universe();
- let result = op(self)?;
+ let mut outer_universe = self.infcx.universe();
+ let result = op(self, &mut outer_universe)?;
match self.infcx.leak_check(outer_universe, Some(snapshot)) {
Ok(()) => {}
@@ -586,9 +608,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
})
}
- /// Evaluates the predicates in `predicates` recursively. Note that
- /// this applies projections in the predicates, and therefore
+ /// Evaluates the predicates in `predicates` recursively. This may
+ /// guide inference. If this is not desired, run it inside of a
/// is run within an inference probe.
+ /// `probe`.
#[instrument(skip(self, stack), level = "debug")]
fn evaluate_predicates_recursively<'o, I>(
&mut self,
@@ -1194,7 +1217,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
match self.candidate_from_obligation(stack) {
- Ok(Some(c)) => self.evaluate_candidate(stack, &c),
+ Ok(Some(c)) => self.evaluate_candidate(stack, &c, LeakCheckHigherRankedGoal::Yes),
Ok(None) => Ok(EvaluatedToAmbig),
Err(Overflow(OverflowError::Canonical)) => Err(OverflowError::Canonical),
Err(..) => Ok(EvaluatedToErr),
@@ -1219,6 +1242,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
/// Further evaluates `candidate` to decide whether all type parameters match and whether nested
/// obligations are met. Returns whether `candidate` remains viable after this further
/// scrutiny.
+ ///
+ /// Depending on the value of [LeakCheckHigherRankedGoal], we may ignore the binder of the goal
+ /// when eagerly detecting higher ranked region errors via the `leak_check`. See that enum for
+ /// more info.
#[instrument(
level = "debug",
skip(self, stack),
@@ -1229,10 +1256,25 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
&mut self,
stack: &TraitObligationStack<'o, 'tcx>,
candidate: &SelectionCandidate<'tcx>,
+ leak_check_higher_ranked_goal: LeakCheckHigherRankedGoal,
) -> Result<EvaluationResult, OverflowError> {
- let mut result = self.evaluation_probe(|this| {
- let candidate = (*candidate).clone();
- match this.confirm_candidate(stack.obligation, candidate) {
+ let mut result = self.evaluation_probe(|this, outer_universe| {
+ // We eagerly instantiate higher ranked goals to prevent universe errors
+ // from impacting candidate selection. This matches the behavior of the new
+ // solver. This slightly weakens type inference.
+ //
+ // In case there are no unresolved type or const variables this
+ // should still not be necessary to select a unique impl as any overlap
+ // relying on a universe error from higher ranked goals should have resulted
+ // in an overlap error in coherence.
+ let p = self.infcx.enter_forall_and_leak_universe(stack.obligation.predicate);
+ let obligation = stack.obligation.with(this.tcx(), ty::Binder::dummy(p));
+ match leak_check_higher_ranked_goal {
+ LeakCheckHigherRankedGoal::No => *outer_universe = self.infcx.universe(),
+ LeakCheckHigherRankedGoal::Yes => {}
+ }
+
+ match this.confirm_candidate(&obligation, candidate.clone()) {
Ok(selection) => {
debug!(?selection);
this.evaluate_predicates_recursively(
@@ -1657,8 +1699,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
stack: &TraitObligationStack<'o, 'tcx>,
where_clause_trait_ref: ty::PolyTraitRef<'tcx>,
) -> Result<EvaluationResult, OverflowError> {
- self.evaluation_probe(|this| {
- match this.match_where_clause_trait_ref(stack.obligation, where_clause_trait_ref) {
+ self.evaluation_probe(|this, outer_universe| {
+ // Eagerly instantiate higher ranked goals.
+ //
+ // See the comment in `evaluate_candidate` to see why.
+ let p = self.infcx.enter_forall_and_leak_universe(stack.obligation.predicate);
+ let obligation = stack.obligation.with(this.tcx(), ty::Binder::dummy(p));
+ *outer_universe = self.infcx.universe();
+ match this.match_where_clause_trait_ref(&obligation, where_clause_trait_ref) {
Ok(obligations) => this.evaluate_predicates_recursively(stack.list(), obligations),
Err(()) => Ok(EvaluatedToErr),
}
diff --git a/src/tools/tidy/src/issues.txt b/src/tools/tidy/src/issues.txt
index f6b1d45ee94ef..6b0573f5a3ff2 100644
--- a/src/tools/tidy/src/issues.txt
+++ b/src/tools/tidy/src/issues.txt
@@ -1129,7 +1129,6 @@
"ui/generics/issue-98432.rs",
"ui/higher-ranked/trait-bounds/issue-100689.rs",
"ui/higher-ranked/trait-bounds/issue-102899.rs",
-"ui/higher-ranked/trait-bounds/issue-30786.rs",
"ui/higher-ranked/trait-bounds/issue-36139-normalize-closure-sig.rs",
"ui/higher-ranked/trait-bounds/issue-39292.rs",
"ui/higher-ranked/trait-bounds/issue-42114.rs",
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.rs b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.rs
new file mode 100644
index 0000000000000..b448f0bdc7778
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.rs
@@ -0,0 +1,28 @@
+// cc #119820
+
+trait Trait {}
+
+impl<T: Trait> Trait for &T {}
+impl Trait for u32 {}
+
+fn hr_bound<T>()
+where
+ for<'a> &'a T: Trait,
+{
+}
+
+fn foo<T>()
+where
+ T: Trait,
+ for<'a> &'a &'a T: Trait,
+{
+ // We get a universe error when using the `param_env` candidate
+ // but are able to successfully use the impl candidate. Without
+ // the leak check both candidates may apply and we prefer the
+ // `param_env` candidate in winnowing.
+ hr_bound::<&T>();
+ //~^ ERROR the parameter type `T` may not live long enough
+ //~| ERROR implementation of `Trait` is not general enough
+}
+
+fn main() {}
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.stderr
new file mode 100644
index 0000000000000..febe252d7d1d5
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.stderr
@@ -0,0 +1,26 @@
+error[E0310]: the parameter type `T` may not live long enough
+ --> $DIR/candidate-from-env-universe-err-1.rs:23:5
+ |
+LL | hr_bound::<&T>();
+ | ^^^^^^^^^^^^^^
+ | |
+ | the parameter type `T` must be valid for the static lifetime...
+ | ...so that the type `T` will meet its required lifetime bounds
+ |
+help: consider adding an explicit lifetime bound
+ |
+LL | T: Trait + 'static,
+ | +++++++++
+
+error: implementation of `Trait` is not general enough
+ --> $DIR/candidate-from-env-universe-err-1.rs:23:5
+ |
+LL | hr_bound::<&T>();
+ | ^^^^^^^^^^^^^^ implementation of `Trait` is not general enough
+ |
+ = note: `Trait` would have to be implemented for the type `&'0 &T`, for any lifetime `'0`...
+ = note: ...but `Trait` is actually implemented for the type `&'1 &'1 T`, for some specific lifetime `'1`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0310`.
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.current.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.current.stderr
new file mode 100644
index 0000000000000..22ce87c024861
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.current.stderr
@@ -0,0 +1,25 @@
+error: lifetime may not live long enough
+ --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ |
+LL | fn not_hr<'a, T: for<'b> Trait<'a, 'b> + OtherTrait<'static>>() {
+ | -- lifetime `'a` defined here
+LL | impl_hr::<T>();
+ | ^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+ |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+ --> $DIR/candidate-from-env-universe-err-2.rs:11:19
+ |
+LL | fn impl_hr<'b, T: for<'a> Trait<'a, 'b>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^
+
+error: implementation of `Trait` is not general enough
+ --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ |
+LL | impl_hr::<T>();
+ | ^^^^^^^^^^^^ implementation of `Trait` is not general enough
+ |
+ = note: `T` must implement `Trait<'0, '_>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Trait<'1, '_>`, for some specific lifetime `'1`
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.next.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.next.stderr
new file mode 100644
index 0000000000000..a61bc748bea2d
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.next.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `for<'a> T: Trait<'a, '_>` is not satisfied
+ --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ |
+LL | impl_hr::<T>();
+ | ^^^^^^^^^^^^^^ the trait `for<'a> Trait<'a, '_>` is not implemented for `T`
+ |
+note: required by a bound in `impl_hr`
+ --> $DIR/candidate-from-env-universe-err-2.rs:11:19
+ |
+LL | fn impl_hr<'b, T: for<'a> Trait<'a, 'b>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impl_hr`
+help: consider further restricting this bound
+ |
+LL | fn not_hr<'a, T: for<'b> Trait<'a, 'b> + OtherTrait<'static> + for<'a> Trait<'a, '_>>() {
+ | +++++++++++++++++++++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.old.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.old.stderr
new file mode 100644
index 0000000000000..29a72b1c1b641
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.old.stderr
@@ -0,0 +1,26 @@
+error: lifetime may not live long enough
+ --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ |
+LL | fn not_hr<'a, T: for<'b> Trait<'a, 'b> + OtherTrait<'static>>() {
+ | -- lifetime `'a` defined here
+LL | impl_hr::<T>();
+ | ^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+ |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+ --> $DIR/candidate-from-env-universe-err-2.rs:11:19
+ |
+LL | fn impl_hr<'b, T: for<'a> Trait<'a, 'b>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^
+
+error[E0308]: mismatched types
+ --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ |
+LL | impl_hr::<T>();
+ | ^^^^^^^^^^^^ one type is more general than the other
+ |
+ = note: expected trait `for<'a> Trait<'a, '_>`
+ found trait `for<'b> Trait<'_, 'b>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.rs b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.rs
new file mode 100644
index 0000000000000..56fa70469ccf8
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.rs
@@ -0,0 +1,20 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+// cc #119820
+
+trait Trait<'a, 'b> {}
+
+trait OtherTrait<'b> {}
+impl<'a, 'b, T: OtherTrait<'b>> Trait<'a, 'b> for T {}
+
+fn impl_hr<'b, T: for<'a> Trait<'a, 'b>>() {}
+
+fn not_hr<'a, T: for<'b> Trait<'a, 'b> + OtherTrait<'static>>() {
+ impl_hr::<T>();
+ //[next]~^ ERROR the trait bound `for<'a> T: Trait<'a, '_>` is not satisfied
+ //[current]~^^ERROR lifetime may not live long enough
+ //[current]~| ERROR implementation of `Trait` is not general enough
+}
+
+fn main() {}
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.current.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.current.stderr
new file mode 100644
index 0000000000000..bb0b2de788e83
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.current.stderr
@@ -0,0 +1,54 @@
+error: implementation of `Trait` is not general enough
+ --> $DIR/candidate-from-env-universe-err-project.rs:28:5
+ |
+LL | trait_bound::<T>();
+ | ^^^^^^^^^^^^^^^^^^ implementation of `Trait` is not general enough
+ |
+ = note: `T` must implement `Trait<'0>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Trait<'static>`
+
+error: implementation of `Trait` is not general enough
+ --> $DIR/candidate-from-env-universe-err-project.rs:39:5
+ |
+LL | projection_bound::<T>();
+ | ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Trait` is not general enough
+ |
+ = note: `T` must implement `Trait<'0>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Trait<'static>`
+
+error[E0308]: mismatched types
+ --> $DIR/candidate-from-env-universe-err-project.rs:39:5
+ |
+LL | projection_bound::<T>();
+ | ^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+ |
+ = note: expected associated type `<T as Trait<'static>>::Assoc`
+ found associated type `<T as Trait<'a>>::Assoc`
+note: the lifetime requirement is introduced here
+ --> $DIR/candidate-from-env-universe-err-project.rs:18:42
+ |
+LL | fn projection_bound<T: for<'a> Trait<'a, Assoc = usize>>() {}
+ | ^^^^^^^^^^^^^
+
+error[E0308]: mismatched types
+ --> $DIR/candidate-from-env-universe-err-project.rs:55:30
+ |
+LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+ |
+ = note: expected associated type `<T as Trait<'static>>::Assoc`
+ found associated type `<T as Trait<'a>>::Assoc`
+
+error[E0308]: mismatched types
+ --> $DIR/candidate-from-env-universe-err-project.rs:55:30
+ |
+LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+ |
+ = note: expected associated type `<T as Trait<'static>>::Assoc`
+ found associated type `<T as Trait<'a>>::Assoc`
+ = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.next.stderr b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.next.stderr
new file mode 100644
index 0000000000000..2804d5bbe9408
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.next.stderr
@@ -0,0 +1,67 @@
+error[E0277]: the trait bound `for<'a> T: Trait<'a>` is not satisfied
+ --> $DIR/candidate-from-env-universe-err-project.rs:28:19
+ |
+LL | trait_bound::<T>();
+ | ^ the trait `for<'a> Trait<'a>` is not implemented for `T`
+ |
+note: required by a bound in `trait_bound`
+ --> $DIR/candidate-from-env-universe-err-project.rs:17:19
+ |
+LL | fn trait_bound<T: for<'a> Trait<'a>>() {}
+ | ^^^^^^^^^^^^^^^^^ required by this bound in `trait_bound`
+help: consider further restricting this bound
+ |
+LL | fn function1<T: Trait<'static> + for<'a> Trait<'a>>() {
+ | +++++++++++++++++++
+
+error[E0277]: the trait bound `for<'a> T: Trait<'a>` is not satisfied
+ --> $DIR/candidate-from-env-universe-err-project.rs:39:24
+ |
+LL | projection_bound::<T>();
+ | ^ the trait `for<'a> Trait<'a>` is not implemented for `T`
+ |
+note: required by a bound in `projection_bound`
+ --> $DIR/candidate-from-env-universe-err-project.rs:18:24
+ |
+LL | fn projection_bound<T: for<'a> Trait<'a, Assoc = usize>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `projection_bound`
+help: consider further restricting this bound
+ |
+LL | fn function2<T: Trait<'static, Assoc = usize> + for<'a> Trait<'a>>() {
+ | +++++++++++++++++++
+
+error[E0271]: type mismatch resolving `<T as Trait<'a>>::Assoc == usize`
+ --> $DIR/candidate-from-env-universe-err-project.rs:39:24
+ |
+LL | projection_bound::<T>();
+ | ^ type mismatch resolving `<T as Trait<'a>>::Assoc == usize`
+ |
+note: types differ
+ --> $DIR/candidate-from-env-universe-err-project.rs:14:18
+ |
+LL | type Assoc = usize;
+ | ^^^^^
+note: required by a bound in `projection_bound`
+ --> $DIR/candidate-from-env-universe-err-project.rs:18:42
+ |
+LL | fn projection_bound<T: for<'a> Trait<'a, Assoc = usize>>() {}
+ | ^^^^^^^^^^^^^ required by this bound in `projection_bound`
+
+error: higher-ranked subtype error
+ --> $DIR/candidate-from-env-universe-err-project.rs:55:30
+ |
+LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: higher-ranked subtype error
+ --> $DIR/candidate-from-env-universe-err-project.rs:55:30
+ |
+LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0271, E0277.
+For more information about an error, try `rustc --explain E0271`.
diff --git a/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.rs b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.rs
new file mode 100644
index 0000000000000..2f53bd019b78c
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.rs
@@ -0,0 +1,62 @@
+//@ revisions: next current
+//@[next] compile-flags: -Znext-solver
+
+// cc #119820 the previous behavior here was inconsistent as we discarded
+// the where-bound candidate for trait goals due to the leak check, but did
+// not do so for projection candidates and during normalization.
+//
+// This results in an inconsistency between `Trait` and `Projection` goals as
+// normalizing always constraints the normalized-to term.
+trait Trait<'a> {
+ type Assoc;
+}
+impl<'a, T> Trait<'a> for T {
+ type Assoc = usize;
+}
+
+fn trait_bound<T: for<'a> Trait<'a>>() {}
+fn projection_bound<T: for<'a> Trait<'a, Assoc = usize>>() {}
+
+// We use a function with a trivial where-bound which is more
+// restrictive than the impl.
+fn function1<T: Trait<'static>>() {
+ // err
+ //
+ // Proving `for<'a> T: Trait<'a>` using the where-bound does not
+ // result in a leak check failure even though it does not apply.
+ // We prefer env candidates over impl candidatescausing this to succeed.
+ trait_bound::<T>();
+ //[next]~^ ERROR the trait bound `for<'a> T: Trait<'a>` is not satisfied
+ //[current]~^^ ERROR implementation of `Trait` is not general enough
+}
+
+fn function2<T: Trait<'static, Assoc = usize>>() {
+ // err
+ //
+ // Proving the `Projection` goal `for<'a> T: Trait<'a, Assoc = usize>`
+ // does not use the leak check when trying the where-bound, causing us
+ // to prefer it over the impl, resulting in a placeholder error.
+ projection_bound::<T>();
+ //[next]~^ ERROR type mismatch resolving `<T as Trait<'a>>::Assoc == usize`
+ //[next]~| ERROR the trait bound `for<'a> T: Trait<'a>` is not satisfied
+ //[current]~^^^ ERROR implementation of `Trait` is not general enough
+ //[current]~| ERROR mismatched types
+}
+
+fn function3<T: Trait<'static, Assoc = usize>>() {
+ // err
+ //
+ // Trying to normalize the type `for<'a> fn(<T as Trait<'a>>::Assoc)`
+ // only gets to `<T as Trait<'a>>::Assoc` once `'a` has been already
+ // instantiated, causing us to prefer the where-bound over the impl
+ // resulting in a placeholder error. Even if were were to also use the
+ // leak check during candidate selection for normalization, this
+ // case would still not compile.
+ let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
+ //[next]~^ ERROR higher-ranked subtype error
+ //[next]~| ERROR higher-ranked subtype error
+ //[current]~^^^ ERROR mismatched types
+ //[current]~| ERROR mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/higher-ranked/leak-check-in-selection.rs b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-1.rs
similarity index 100%
rename from tests/ui/higher-ranked/leak-check-in-selection.rs
rename to tests/ui/higher-ranked/leak-check/leak-check-in-selection-1.rs
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.next.stderr b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.next.stderr
new file mode 100644
index 0000000000000..a840304e49c1f
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.next.stderr
@@ -0,0 +1,23 @@
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-2.rs:16:5
+ |
+LL | impls_trait::<(), _>();
+ | ^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the function `impls_trait`
+ |
+note: multiple `impl`s satisfying `for<'a> (): Trait<&'a str, _>` found
+ --> $DIR/leak-check-in-selection-2.rs:9:1
+ |
+LL | impl<'a> Trait<&'a str, &'a str> for () {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | impl<'a> Trait<&'a str, String> for () {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `impls_trait`
+ --> $DIR/leak-check-in-selection-2.rs:13:19
+ |
+LL | fn impls_trait<T: for<'a> Trait<&'a str, U>, U>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impls_trait`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.old.stderr b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.old.stderr
new file mode 100644
index 0000000000000..a840304e49c1f
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.old.stderr
@@ -0,0 +1,23 @@
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-2.rs:16:5
+ |
+LL | impls_trait::<(), _>();
+ | ^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the function `impls_trait`
+ |
+note: multiple `impl`s satisfying `for<'a> (): Trait<&'a str, _>` found
+ --> $DIR/leak-check-in-selection-2.rs:9:1
+ |
+LL | impl<'a> Trait<&'a str, &'a str> for () {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | impl<'a> Trait<&'a str, String> for () {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `impls_trait`
+ --> $DIR/leak-check-in-selection-2.rs:13:19
+ |
+LL | fn impls_trait<T: for<'a> Trait<&'a str, U>, U>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impls_trait`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.rs b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.rs
new file mode 100644
index 0000000000000..48dd569f201b9
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.rs
@@ -0,0 +1,18 @@
+//@ revisions: old next
+//@[next] compile-flags: -Znext-solver
+
+// cc #119820
+
+trait Trait<T, U> {}
+
+// using this impl results in a higher-ranked region error.
+impl<'a> Trait<&'a str, &'a str> for () {}
+
+impl<'a> Trait<&'a str, String> for () {}
+
+fn impls_trait<T: for<'a> Trait<&'a str, U>, U>() {}
+
+fn main() {
+ impls_trait::<(), _>();
+ //~^ ERROR type annotations needed
+}
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.next.stderr b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.next.stderr
new file mode 100644
index 0000000000000..8a8118dea859b
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.next.stderr
@@ -0,0 +1,35 @@
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-3.rs:18:5
+ |
+LL | impls_leak::<Box<_>>();
+ | ^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_leak`
+ |
+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 by a bound in `impls_leak`
+ --> $DIR/leak-check-in-selection-3.rs:12:18
+ |
+LL | fn impls_leak<T: for<'a> Leak<'a>>() {}
+ | ^^^^^^^^^^^^^^^^ required by this bound in `impls_leak`
+
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-3.rs:35:5
+ |
+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: required by a bound in `impls_indirect_leak`
+ --> $DIR/leak-check-in-selection-3.rs:25:27
+ |
+LL | fn impls_indirect_leak<T: for<'a> IndirectLeak<'a>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impls_indirect_leak`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0283`.
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.old.stderr b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.old.stderr
new file mode 100644
index 0000000000000..662a06537401a
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.old.stderr
@@ -0,0 +1,48 @@
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-3.rs:18:5
+ |
+LL | impls_leak::<Box<_>>();
+ | ^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_leak`
+ |
+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 by a bound in `impls_leak`
+ --> $DIR/leak-check-in-selection-3.rs:12:18
+ |
+LL | fn impls_leak<T: for<'a> Leak<'a>>() {}
+ | ^^^^^^^^^^^^^^^^ required by this bound in `impls_leak`
+
+error[E0283]: type annotations needed
+ --> $DIR/leak-check-in-selection-3.rs:35:5
+ |
+LL | impls_indirect_leak::<Box<_>>();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `impls_indirect_leak`
+ |
+note: multiple `impl`s satisfying `Box<_>: Leak<'_>` 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
+ |
+LL | fn impls_indirect_leak<T: for<'a> IndirectLeak<'a>>() {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impls_indirect_leak`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0283`.
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.rs b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.rs
new file mode 100644
index 0000000000000..9e99b6c527d9d
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.rs
@@ -0,0 +1,39 @@
+//@ revisions: old next
+//@[next] compile-flags: -Znext-solver
+
+// cc #119820, the previous behavior here was inconsistent,
+// using the leak check to guide inference for `for<'a> Box<_>: Leak<'a>`
+// but not for `for<'a> Box<_>: IndirectLeak<'a>`
+
+trait Leak<'a> {}
+impl Leak<'_> for Box<u32> {}
+impl Leak<'static> for Box<u16> {}
+
+fn impls_leak<T: for<'a> Leak<'a>>() {}
+fn direct() {
+ // ok
+ //
+ // The `Box<u16>` impls fails the leak check,
+ // meaning that we apply the `Box<u32>` impl.
+ impls_leak::<Box<_>>();
+ //~^ ERROR type annotations needed
+}
+
+trait IndirectLeak<'a> {}
+impl<'a, T: Leak<'a>> IndirectLeak<'a> for T {}
+
+fn impls_indirect_leak<T: for<'a> IndirectLeak<'a>>() {}
+fn indirect() {
+ // error: type annotations needed
+ //
+ // While the `Box<u16>` impl would fail the leak check
+ // we have already instantiated the binder while applying
+ // the generic `IndirectLeak` impl, so during candidate
+ // selection of `Leak` we do not detect the placeholder error.
+ // Evaluation of `Box<_>: Leak<'!a>` is therefore ambiguous,
+ // resulting in `for<'a> Box<_>: Leak<'a>` also being ambiguous.
+ impls_indirect_leak::<Box<_>>();
+ //~^ ERROR type annotations needed
+}
+
+fn main() {}
diff --git a/tests/ui/higher-ranked/leak-check/leak-check-in-selection-4-hr-nested.rs b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-4-hr-nested.rs
new file mode 100644
index 0000000000000..8d87bdd064a06
--- /dev/null
+++ b/tests/ui/higher-ranked/leak-check/leak-check-in-selection-4-hr-nested.rs
@@ -0,0 +1,29 @@
+//@ revisions: old next
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+// cc #119820. While the leak check does not consider the binder
+// of the current goal, leaks from higher-ranked nested goals are
+// considered.
+//
+// We enter and exit the binder of the nested goal while evaluating
+// the candidate.
+
+trait LeakCheckFailure<'a> {}
+impl LeakCheckFailure<'static> for () {}
+
+trait Trait<T> {}
+impl Trait<u32> for () where for<'a> (): LeakCheckFailure<'a> {}
+impl Trait<u16> for () {}
+fn impls_trait<T: Trait<U>, U>() {}
+fn main() {
+ // ok
+ //
+ // It does not matter whether candidate assembly
+ // considers the placeholders from higher-ranked goal.
+ //
+ // Either `for<'a> (): LeakCheckFailure<'a>` has no applicable
+ // candidate or it has a single applicable candidate which then later
+ // results in an error. This allows us to infer `U` to `u16`.
+ impls_trait::<(), _>()
+}
diff --git a/tests/ui/higher-ranked/trait-bounds/issue-30786.rs b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.rs
similarity index 86%
rename from tests/ui/higher-ranked/trait-bounds/issue-30786.rs
rename to tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.rs
index ffb2b306ae76a..799df8cae9fd7 100644
--- a/tests/ui/higher-ranked/trait-bounds/issue-30786.rs
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.rs
@@ -1,6 +1,6 @@
//@ normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
-// rust-lang/rust#30786: the use of `for<'b> &'b mut A: Stream<Item=T`
+// rust-lang/rust#30786: the use of `for<'b> &'b mut A: Stream<Item=T>`
// should act as assertion that item does not borrow from its stream;
// but an earlier buggy rustc allowed `.map(|x: &_| x)` which does
// have such an item.
@@ -97,10 +97,6 @@ where
impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
-fn identity<T>(x: &T) -> &T {
- x
-}
-
fn variant1() {
let source = Repeat(10);
@@ -118,19 +114,7 @@ fn variant1() {
// guess.
let map = source.mapx(|x: &_| x);
let filter = map.filterx(|x: &_| true);
- //~^ ERROR the method
-}
-
-fn variant2() {
- let source = Repeat(10);
-
- // Here, we use a function, which is not subject to the vagaries
- // of closure signature inference. In this case, we get the error
- // on `countx` as, I think, the test originally expected.
- let map = source.mapx(identity);
- let filter = map.filterx(|x: &_| true);
- let count = filter.countx();
- //~^ ERROR the method
+ //~^ ERROR the method `filterx` exists for struct
}
fn main() {}
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.stderr b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.stderr
new file mode 100644
index 0000000000000..ae364de8cc061
--- /dev/null
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-1.stderr
@@ -0,0 +1,27 @@
+error[E0599]: the method `filterx` exists for struct `Map<Repeat, {closure@hrtb-doesnt-borrow-self-1.rs:115:27}>`, but its trait bounds were not satisfied
+ --> $DIR/hrtb-doesnt-borrow-self-1.rs:116:22
+ |
+LL | pub struct Map<S, F> {
+ | -------------------- method `filterx` not found for this struct because it doesn't satisfy `_: StreamExt`
+...
+LL | let filter = map.filterx(|x: &_| true);
+ | ^^^^^^^ method cannot be called due to unsatisfied trait bounds
+ |
+note: the following trait bounds were not satisfied:
+ `&'a mut &Map<Repeat, {closure@$DIR/hrtb-doesnt-borrow-self-1.rs:115:27: 115:34}>: Stream`
+ `&'a mut &mut Map<Repeat, {closure@$DIR/hrtb-doesnt-borrow-self-1.rs:115:27: 115:34}>: Stream`
+ `&'a mut Map<Repeat, {closure@$DIR/hrtb-doesnt-borrow-self-1.rs:115:27: 115:34}>: Stream`
+ --> $DIR/hrtb-doesnt-borrow-self-1.rs:98:50
+ |
+LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
+ | --------- - ^^^^^^ unsatisfied trait bound introduced here
+ = help: items from traits can only be used if the trait is implemented and in scope
+note: `StreamExt` defines an item `filterx`, perhaps you need to implement it
+ --> $DIR/hrtb-doesnt-borrow-self-1.rs:66:1
+ |
+LL | pub trait StreamExt
+ | ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.rs b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.rs
new file mode 100644
index 0000000000000..92e2e7f796eaa
--- /dev/null
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.rs
@@ -0,0 +1,116 @@
+//@ normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
+
+// rust-lang/rust#30786: the use of `for<'b> &'b mut A: Stream<Item=T`
+// should act as assertion that item does not borrow from its stream;
+// but an earlier buggy rustc allowed `.map(|x: &_| x)` which does
+// have such an item.
+//
+// This tests double-checks that we do not allow such behavior to leak
+// through again.
+
+pub trait Stream {
+ type Item;
+ fn next(self) -> Option<Self::Item>;
+}
+
+// Example stream
+pub struct Repeat(u64);
+
+impl<'a> Stream for &'a mut Repeat {
+ type Item = &'a u64;
+ fn next(self) -> Option<Self::Item> {
+ Some(&self.0)
+ }
+}
+
+pub struct Map<S, F> {
+ stream: S,
+ func: F,
+}
+
+impl<'a, A, F, T> Stream for &'a mut Map<A, F>
+where
+ &'a mut A: Stream,
+ F: FnMut(<&'a mut A as Stream>::Item) -> T,
+{
+ type Item = T;
+ fn next(self) -> Option<T> {
+ match self.stream.next() {
+ Some(item) => Some((self.func)(item)),
+ None => None,
+ }
+ }
+}
+
+pub struct Filter<S, F> {
+ stream: S,
+ func: F,
+}
+
+impl<'a, A, F, T> Stream for &'a mut Filter<A, F>
+where
+ for<'b> &'b mut A: Stream<Item = T>, // <---- BAD
+ F: FnMut(&T) -> bool,
+{
+ type Item = <&'a mut A as Stream>::Item;
+ fn next(self) -> Option<Self::Item> {
+ while let Some(item) = self.stream.next() {
+ if (self.func)(&item) {
+ return Some(item);
+ }
+ }
+ None
+ }
+}
+
+pub trait StreamExt
+where
+ for<'b> &'b mut Self: Stream,
+{
+ fn mapx<F>(self, func: F) -> Map<Self, F>
+ where
+ Self: Sized,
+ for<'a> &'a mut Map<Self, F>: Stream,
+ {
+ Map { func: func, stream: self }
+ }
+
+ fn filterx<F>(self, func: F) -> Filter<Self, F>
+ where
+ Self: Sized,
+ for<'a> &'a mut Filter<Self, F>: Stream,
+ {
+ Filter { func: func, stream: self }
+ }
+
+ fn countx(mut self) -> usize
+ where
+ Self: Sized,
+ {
+ let mut count = 0;
+ while let Some(_) = self.next() {
+ count += 1;
+ }
+ count
+ }
+}
+
+impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
+
+fn identity<T>(x: &T) -> &T {
+ x
+}
+
+fn variant2() {
+ let source = Repeat(10);
+
+ // Here, we use a function, which is not subject to the vagaries
+ // of closure signature inference. In this case, we get the error
+ // on `countx` as, I think, the test originally expected.
+ let map = source.mapx(identity);
+ let filter = map.filterx(|x: &_| true);
+ let count = filter.countx();
+ //~^ ERROR the method
+}
+
+fn main() {}
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.stderr b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.stderr
new file mode 100644
index 0000000000000..eeb4e12fa8b31
--- /dev/null
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-doesnt-borrow-self-2.stderr
@@ -0,0 +1,27 @@
+error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, fn(&u64) -> &u64 {identity::<u64>}>, {closure@hrtb-doesnt-borrow-self-2.rs:111:30}>`, but its trait bounds were not satisfied
+ --> $DIR/hrtb-doesnt-borrow-self-2.rs:112:24
+ |
+LL | pub struct Filter<S, F> {
+ | ----------------------- method `countx` not found for this struct because it doesn't satisfy `_: StreamExt`
+...
+LL | let count = filter.countx();
+ | ^^^^^^ method cannot be called due to unsatisfied trait bounds
+ |
+note: the following trait bounds were not satisfied:
+ `&'a mut &Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/hrtb-doesnt-borrow-self-2.rs:111:30: 111:37}>: Stream`
+ `&'a mut &mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/hrtb-doesnt-borrow-self-2.rs:111:30: 111:37}>: Stream`
+ `&'a mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/hrtb-doesnt-borrow-self-2.rs:111:30: 111:37}>: Stream`
+ --> $DIR/hrtb-doesnt-borrow-self-2.rs:98:50
+ |
+LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
+ | --------- - ^^^^^^ unsatisfied trait bound introduced here
+ = help: items from traits can only be used if the trait is implemented and in scope
+note: `StreamExt` defines an item `countx`, perhaps you need to implement it
+ --> $DIR/hrtb-doesnt-borrow-self-2.rs:66:1
+ |
+LL | pub trait StreamExt
+ | ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits-transitive.stderr b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits-transitive.stderr
index e10da26665ebb..be19bf85bd2f3 100644
--- a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits-transitive.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits-transitive.stderr
@@ -1,23 +1,11 @@
-error[E0277]: the trait bound `for<'ccx> B: Bar<'ccx>` is not satisfied
- --> $DIR/hrtb-higher-ranker-supertraits-transitive.rs:47:26
+error: implementation of `Bar` is not general enough
+ --> $DIR/hrtb-higher-ranker-supertraits-transitive.rs:47:5
|
LL | want_bar_for_any_ccx(b);
- | -------------------- ^ the trait `for<'ccx> Bar<'ccx>` is not implemented for `B`
- | |
- | required by a bound introduced by this call
+ | ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Bar` is not general enough
|
-note: required by a bound in `want_bar_for_any_ccx`
- --> $DIR/hrtb-higher-ranker-supertraits-transitive.rs:32:15
- |
-LL | fn want_bar_for_any_ccx<B>(b: &B)
- | -------------------- required by a bound in this function
-LL | where B : for<'ccx> Bar<'ccx>
- | ^^^^^^^^^^^^^^^^^^^ required by this bound in `want_bar_for_any_ccx`
-help: consider further restricting this bound
- |
-LL | where B : Qux + for<'ccx> Bar<'ccx>
- | +++++++++++++++++++++
+ = note: `B` must implement `Bar<'0>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Bar<'static>`
error: aborting due to 1 previous error
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.rs b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.rs
index 33e0ec4635b66..70ce580258d43 100644
--- a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.rs
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.rs
@@ -1,43 +1,37 @@
// Test a trait (`Bar`) with a higher-ranked supertrait.
+#![allow(unconditional_recursion)]
-trait Foo<'tcx>
-{
+trait Foo<'tcx> {
fn foo(&'tcx self) -> &'tcx isize;
}
-trait Bar<'ccx>
- : for<'tcx> Foo<'tcx>
-{
+trait Bar<'ccx>: for<'tcx> Foo<'tcx> {
fn bar(&'ccx self) -> &'ccx isize;
}
-fn want_foo_for_some_tcx<'x,F>(f: &'x F)
- where F : Foo<'x>
-{
+fn want_foo_for_some_tcx<'x, F: Foo<'x>>(f: &'x F) {
want_foo_for_some_tcx(f);
- want_foo_for_any_tcx(f); //~ ERROR not satisfied
+ want_foo_for_any_tcx(f);
+ //~^ ERROR lifetime may not live long enough
+ //~| ERROR implementation of `Foo` is not general enough
}
-fn want_foo_for_any_tcx<F>(f: &F) //~ WARN cannot return without recursing
- where F : for<'tcx> Foo<'tcx>
-{
+fn want_foo_for_any_tcx<F: for<'tcx> Foo<'tcx>>(f: &F) {
want_foo_for_some_tcx(f);
want_foo_for_any_tcx(f);
}
-fn want_bar_for_some_ccx<'x,B>(b: &B)
- where B : Bar<'x>
-{
+fn want_bar_for_some_ccx<'x, B: Bar<'x>>(b: &B) {
want_foo_for_some_tcx(b);
want_foo_for_any_tcx(b);
want_bar_for_some_ccx(b);
- want_bar_for_any_ccx(b); //~ ERROR not satisfied
+ want_bar_for_any_ccx(b);
+ //~^ ERROR lifetime may not live long enough
+ //~| ERROR implementation of `Bar` is not general enough
}
-fn want_bar_for_any_ccx<B>(b: &B) //~ WARN cannot return without recursing
- where B : for<'ccx> Bar<'ccx>
-{
+fn want_bar_for_any_ccx<B: for<'ccx> Bar<'ccx>>(b: &B) {
want_foo_for_some_tcx(b);
want_foo_for_any_tcx(b);
diff --git a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.stderr b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.stderr
index f220ba6f33893..dd760926ea117 100644
--- a/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.stderr
@@ -1,68 +1,50 @@
-error[E0277]: the trait bound `for<'tcx> F: Foo<'tcx>` is not satisfied
- --> $DIR/hrtb-higher-ranker-supertraits.rs:18:26
+error: lifetime may not live long enough
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:14:5
|
+LL | fn want_foo_for_some_tcx<'x, F: Foo<'x>>(f: &'x F) {
+ | -- lifetime `'x` defined here
+LL | want_foo_for_some_tcx(f);
LL | want_foo_for_any_tcx(f);
- | -------------------- ^ the trait `for<'tcx> Foo<'tcx>` is not implemented for `F`
- | |
- | required by a bound introduced by this call
+ | ^^^^^^^^^^^^^^^^^^^^^^^ requires that `'x` must outlive `'static`
|
-note: required by a bound in `want_foo_for_any_tcx`
- --> $DIR/hrtb-higher-ranker-supertraits.rs:22:15
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:19:28
|
-LL | fn want_foo_for_any_tcx<F>(f: &F)
- | -------------------- required by a bound in this function
-LL | where F : for<'tcx> Foo<'tcx>
- | ^^^^^^^^^^^^^^^^^^^ required by this bound in `want_foo_for_any_tcx`
-help: consider further restricting this bound
- |
-LL | where F : Foo<'x> + for<'tcx> Foo<'tcx>
- | +++++++++++++++++++++
+LL | fn want_foo_for_any_tcx<F: for<'tcx> Foo<'tcx>>(f: &F) {
+ | ^^^^^^^^^^^^^^^^^^^
-error[E0277]: the trait bound `for<'ccx> B: Bar<'ccx>` is not satisfied
- --> $DIR/hrtb-higher-ranker-supertraits.rs:35:26
- |
-LL | want_bar_for_any_ccx(b);
- | -------------------- ^ the trait `for<'ccx> Bar<'ccx>` is not implemented for `B`
- | |
- | required by a bound introduced by this call
+error: implementation of `Foo` is not general enough
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:14:5
|
-note: required by a bound in `want_bar_for_any_ccx`
- --> $DIR/hrtb-higher-ranker-supertraits.rs:39:15
- |
-LL | fn want_bar_for_any_ccx<B>(b: &B)
- | -------------------- required by a bound in this function
-LL | where B : for<'ccx> Bar<'ccx>
- | ^^^^^^^^^^^^^^^^^^^ required by this bound in `want_bar_for_any_ccx`
-help: consider further restricting this bound
+LL | want_foo_for_any_tcx(f);
+ | ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Foo` is not general enough
|
-LL | where B : Bar<'x> + for<'ccx> Bar<'ccx>
- | +++++++++++++++++++++
+ = note: `F` must implement `Foo<'0>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Foo<'1>`, for some specific lifetime `'1`
-warning: function cannot return without recursing
- --> $DIR/hrtb-higher-ranker-supertraits.rs:21:1
+error: lifetime may not live long enough
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:29:5
|
-LL | / fn want_foo_for_any_tcx<F>(f: &F)
-LL | | where F : for<'tcx> Foo<'tcx>
- | |_________________________________^ cannot return without recursing
+LL | fn want_bar_for_some_ccx<'x, B: Bar<'x>>(b: &B) {
+ | -- lifetime `'x` defined here
...
-LL | want_foo_for_any_tcx(f);
- | ----------------------- recursive call site
+LL | want_bar_for_any_ccx(b);
+ | ^^^^^^^^^^^^^^^^^^^^^^^ requires that `'x` must outlive `'static`
+ |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:34:28
|
- = help: a `loop` may express intention better if this is on purpose
- = note: `#[warn(unconditional_recursion)]` on by default
+LL | fn want_bar_for_any_ccx<B: for<'ccx> Bar<'ccx>>(b: &B) {
+ | ^^^^^^^^^^^^^^^^^^^
-warning: function cannot return without recursing
- --> $DIR/hrtb-higher-ranker-supertraits.rs:38:1
+error: implementation of `Bar` is not general enough
+ --> $DIR/hrtb-higher-ranker-supertraits.rs:29:5
|
-LL | / fn want_bar_for_any_ccx<B>(b: &B)
-LL | | where B : for<'ccx> Bar<'ccx>
- | |_________________________________^ cannot return without recursing
-...
-LL | want_bar_for_any_ccx(b);
- | ----------------------- recursive call site
+LL | want_bar_for_any_ccx(b);
+ | ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Bar` is not general enough
|
- = help: a `loop` may express intention better if this is on purpose
+ = note: `B` must implement `Bar<'0>`, for any lifetime `'0`...
+ = note: ...but it actually implements `Bar<'1>`, for some specific lifetime `'1`
-error: aborting due to 2 previous errors; 2 warnings emitted
+error: aborting due to 4 previous errors
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr b/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr
deleted file mode 100644
index 699a4ecc42bb9..0000000000000
--- a/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr
+++ /dev/null
@@ -1,51 +0,0 @@
-error[E0599]: the method `filterx` exists for struct `Map<Repeat, {closure@issue-30786.rs:119:27}>`, but its trait bounds were not satisfied
- --> $DIR/issue-30786.rs:120:22
- |
-LL | pub struct Map<S, F> {
- | -------------------- method `filterx` not found for this struct because it doesn't satisfy `_: StreamExt`
-...
-LL | let filter = map.filterx(|x: &_| true);
- | ^^^^^^^ method cannot be called on `Map<Repeat, {closure@issue-30786.rs:119:27}>` due to unsatisfied trait bounds
- |
-note: the following trait bounds were not satisfied:
- `&'a mut &Map<Repeat, {closure@$DIR/issue-30786.rs:119:27: 119:34}>: Stream`
- `&'a mut &mut Map<Repeat, {closure@$DIR/issue-30786.rs:119:27: 119:34}>: Stream`
- `&'a mut Map<Repeat, {closure@$DIR/issue-30786.rs:119:27: 119:34}>: Stream`
- --> $DIR/issue-30786.rs:98:50
- |
-LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
- | --------- - ^^^^^^ unsatisfied trait bound introduced here
- = help: items from traits can only be used if the trait is implemented and in scope
-note: `StreamExt` defines an item `filterx`, perhaps you need to implement it
- --> $DIR/issue-30786.rs:66:1
- |
-LL | pub trait StreamExt
- | ^^^^^^^^^^^^^^^^^^^
-
-error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, fn(&u64) -> &u64 {identity::<u64>}>, {closure@issue-30786.rs:131:30}>`, but its trait bounds were not satisfied
- --> $DIR/issue-30786.rs:132:24
- |
-LL | pub struct Filter<S, F> {
- | ----------------------- method `countx` not found for this struct because it doesn't satisfy `_: StreamExt`
-...
-LL | let count = filter.countx();
- | ^^^^^^ method cannot be called due to unsatisfied trait bounds
- |
-note: the following trait bounds were not satisfied:
- `&'a mut &Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/issue-30786.rs:131:30: 131:37}>: Stream`
- `&'a mut &mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/issue-30786.rs:131:30: 131:37}>: Stream`
- `&'a mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, {closure@$DIR/issue-30786.rs:131:30: 131:37}>: Stream`
- --> $DIR/issue-30786.rs:98:50
- |
-LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
- | --------- - ^^^^^^ unsatisfied trait bound introduced here
- = help: items from traits can only be used if the trait is implemented and in scope
-note: `StreamExt` defines an item `countx`, perhaps you need to implement it
- --> $DIR/issue-30786.rs:66:1
- |
-LL | pub trait StreamExt
- | ^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/implied-bounds/issue-100690.rs b/tests/ui/implied-bounds/issue-100690.rs
index ea33c9f423b77..041c687ec9430 100644
--- a/tests/ui/implied-bounds/issue-100690.rs
+++ b/tests/ui/implied-bounds/issue-100690.rs
@@ -4,11 +4,8 @@
use std::io;
fn real_dispatch<T, F>(f: F) -> Result<(), io::Error>
-//~^ NOTE required by a bound in this
where
F: FnOnce(&mut UIView<T>) -> Result<(), io::Error> + Send + 'static,
- //~^ NOTE required by this bound in `real_dispatch`
- //~| NOTE required by a bound in `real_dispatch`
{
todo!()
}
@@ -35,10 +32,10 @@ impl<'a, T: 'a> Handle<'a, T, UIView<'a, T>, Result<(), io::Error>> for TUIHandl
F: FnOnce(&mut UIView<'a, T>) -> Result<(), io::Error> + Send + 'static,
{
real_dispatch(f)
- //~^ ERROR expected a `FnOnce(&mut UIView<'_, T>)` closure, found `F`
- //~| NOTE expected an `FnOnce(&mut UIView<'_, T>)` closure, found `F`
- //~| NOTE expected a closure with arguments
- //~| NOTE required by a bound introduced by this call
+ //~^ ERROR lifetime may not live long enough
+ //~| ERROR implementation of `FnOnce` is not general enough
+ //~| ERROR mismatched types
+ //
}
}
diff --git a/tests/ui/implied-bounds/issue-100690.stderr b/tests/ui/implied-bounds/issue-100690.stderr
index df069d875cebc..2cfd028f2559b 100644
--- a/tests/ui/implied-bounds/issue-100690.stderr
+++ b/tests/ui/implied-bounds/issue-100690.stderr
@@ -1,22 +1,41 @@
-error[E0277]: expected a `FnOnce(&mut UIView<'_, T>)` closure, found `F`
- --> $DIR/issue-100690.rs:37:23
+error: lifetime may not live long enough
+ --> $DIR/issue-100690.rs:34:9
|
+LL | impl<'a, T: 'a> Handle<'a, T, UIView<'a, T>, Result<(), io::Error>> for TUIHandle<T> {
+ | -- lifetime `'a` defined here
+...
LL | real_dispatch(f)
- | ------------- ^ expected an `FnOnce(&mut UIView<'_, T>)` closure, found `F`
- | |
- | required by a bound introduced by this call
+ | ^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
|
- = note: expected a closure with arguments `(&mut UIView<'a, _>,)`
- found a closure with arguments `(&mut UIView<'_, _>,)`
-note: required by a bound in `real_dispatch`
- --> $DIR/issue-100690.rs:9:8
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+ --> $DIR/issue-100690.rs:8:8
+ |
+LL | F: FnOnce(&mut UIView<T>) -> Result<(), io::Error> + Send + 'static,
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: implementation of `FnOnce` is not general enough
+ --> $DIR/issue-100690.rs:34:9
+ |
+LL | real_dispatch(f)
+ | ^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+ |
+ = note: `F` must implement `FnOnce<(&mut UIView<'0, T>,)>`, for any lifetime `'0`...
+ = note: ...but it actually implements `FnOnce<(&mut UIView<'1, T>,)>`, for some specific lifetime `'1`
+
+error[E0308]: mismatched types
+ --> $DIR/issue-100690.rs:34:9
+ |
+LL | real_dispatch(f)
+ | ^^^^^^^^^^^^^^^^ one type is more general than the other
+ |
+ = note: expected associated type `<F as FnOnce<(&mut UIView<'_, T>,)>>::Output`
+ found associated type `<F as FnOnce<(&mut UIView<'_, T>,)>>::Output`
+note: the lifetime requirement is introduced here
+ --> $DIR/issue-100690.rs:8:34
|
-LL | fn real_dispatch<T, F>(f: F) -> Result<(), io::Error>
- | ------------- required by a bound in this function
-...
LL | F: FnOnce(&mut UIView<T>) -> Result<(), io::Error> + Send + 'static,
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `real_dispatch`
+ | ^^^^^^^^^^^^^^^^^^^^^
-error: aborting due to 1 previous error
+error: aborting due to 3 previous errors
-For more information about this error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0308`.