Auto merge of #125629 - lcnr:undo-leak-check-changes, r=compiler-errors

[BETA] revert leak check changes

reverts the behavior changes from #119820 to give `sqlx` and other affected projects another 6 weeks. fixes #125194

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -562,7 +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, _outer_universe| {
+ self.evaluation_probe(|this| {
  let goal =
  this.infcx.resolve_vars_if_possible((obligation.predicate, obligation.param_env));
  let mut result = this.evaluate_predicate_recursively(
@@ -585,11 +585,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
  /// `op`, but this can be overwritten if necessary.
  fn evaluation_probe(
  &mut self,
- op: impl FnOnce(&mut Self, &mut ty::UniverseIndex) -> Result<EvaluationResult, OverflowError>,
+ op: impl FnOnce(&mut Self) -> Result<EvaluationResult, OverflowError>,
  ) -> Result<EvaluationResult, OverflowError> {
  self.infcx.probe(|snapshot| -> Result<EvaluationResult, OverflowError> {
- let mut outer_universe = self.infcx.universe();
- let result = op(self, &mut outer_universe)?;
+ let outer_universe = self.infcx.universe();
+ let result = op(self)?;
 
  match self.infcx.leak_check(outer_universe, Some(snapshot)) {
  Ok(()) => {}
@@ -1267,9 +1267,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
  &mut self,
  stack: &TraitObligationStack<'o, 'tcx>,
  candidate: &SelectionCandidate<'tcx>,
- leak_check_higher_ranked_goal: LeakCheckHigherRankedGoal,
+ _leak_check_higher_ranked_goal: LeakCheckHigherRankedGoal,
  ) -> Result<EvaluationResult, OverflowError> {
- let mut result = self.evaluation_probe(|this, outer_universe| {
+ let mut result = self.evaluation_probe(|this| {
  // 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.
@@ -1280,10 +1280,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
  // 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) => {
@@ -1710,13 +1706,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
  stack: &TraitObligationStack<'o, 'tcx>,
  where_clause_trait_ref: ty::PolyTraitRef<'tcx>,
  ) -> Result<EvaluationResult, OverflowError> {
- self.evaluation_probe(|this, outer_universe| {
+ self.evaluation_probe(|this| {
  // 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),

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.rs

@@ -1,3 +1,4 @@
+//@ check-pass
 // cc #119820
 
 trait Trait {}
@@ -21,8 +22,6 @@ where
  // 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() {}

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.next.stderr

@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `for<'a> T: Trait<'a, '_>` is not satisfied
- --> $DIR/candidate-from-env-universe-err-2.rs:14:5
+ --> $DIR/candidate-from-env-universe-err-2.rs:15:5
  |
 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
+ --> $DIR/candidate-from-env-universe-err-2.rs:12:19
  |
 LL | fn impl_hr<'b, T: for<'a> Trait<'a, 'b>>() {}
  | ^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impl_hr`

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.rs

@@ -1,5 +1,6 @@
 //@ revisions: current next
 //@[next] compile-flags: -Znext-solver
+//@[current] check-pass
 
 // cc #119820
 
@@ -13,8 +14,6 @@ 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() {}

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.current.stderr

@@ -1,23 +1,5 @@
-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
+ --> $DIR/candidate-from-env-universe-err-project.rs:38:5
  |
 LL | projection_bound::<T>();
  | ^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
@@ -31,7 +13,7 @@ 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
+ --> $DIR/candidate-from-env-universe-err-project.rs:53:30
  |
 LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
@@ -40,7 +22,7 @@ LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
  found associated type `<T as Trait<'a>>::Assoc`
 
 error[E0308]: mismatched types
- --> $DIR/candidate-from-env-universe-err-project.rs:55:30
+ --> $DIR/candidate-from-env-universe-err-project.rs:53:30
  |
 LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
@@ -49,6 +31,6 @@ LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::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
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0308`.

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.next.stderr

@@ -15,7 +15,7 @@ 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
+ --> $DIR/candidate-from-env-universe-err-project.rs:38:24
  |
 LL | projection_bound::<T>();
  | ^ the trait `for<'a> Trait<'a>` is not implemented for `T`
@@ -31,7 +31,7 @@ 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
+ --> $DIR/candidate-from-env-universe-err-project.rs:38:24
  |
 LL | projection_bound::<T>();
  | ^ type mismatch resolving `<T as Trait<'a>>::Assoc == usize`
@@ -48,13 +48,13 @@ 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
+ --> $DIR/candidate-from-env-universe-err-project.rs:53:30
  |
 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
+ --> $DIR/candidate-from-env-universe-err-project.rs:53:30
  |
 LL | let _higher_ranked_norm: for<'a> fn(<T as Trait<'a>>::Assoc) = |_| ();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.rs

@@ -27,7 +27,6 @@ fn function1<T: Trait<'static>>() {
  // 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>>() {
@@ -39,8 +38,7 @@ fn function2<T: Trait<'static, Assoc = usize>>() {
  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
+ //[current]~^^^ ERROR mismatched types
 }
 
 fn function3<T: Trait<'static, Assoc = usize>>() {

tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.next.stderr

@@ -1,19 +1,19 @@
 error[E0283]: type annotations needed
- --> $DIR/leak-check-in-selection-2.rs:16:5
+ --> $DIR/leak-check-in-selection-2.rs:17:5
  |
 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
+ --> $DIR/leak-check-in-selection-2.rs:10:1
  |
 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
+ --> $DIR/leak-check-in-selection-2.rs:14:19
  |
 LL | fn impls_trait<T: for<'a> Trait<&'a str, U>, U>() {}
  | ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `impls_trait`

tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.rs

@@ -1,5 +1,6 @@
 //@ revisions: old next
 //@[next] compile-flags: -Znext-solver
+//@[old] check-pass
 
 // cc #119820
 
@@ -14,5 +15,5 @@ fn impls_trait<T: for<'a> Trait<&'a str, U>, U>() {}
 
 fn main() {
  impls_trait::<(), _>();
- //~^ ERROR type annotations needed
+ //[next]~^ ERROR type annotations needed
 }

tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.old.stderr

@@ -1,22 +1,3 @@
-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
  |
@@ -43,6 +24,6 @@ note: required by a bound in `impls_indirect_leak`
 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
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0283`.

tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.rs

@@ -16,7 +16,7 @@ fn direct() {
  // The `Box<u16>` impls fails the leak check,
  // meaning that we apply the `Box<u32>` impl.
  impls_leak::<Box<_>>();
- //~^ ERROR type annotations needed
+ //[next]~^ ERROR type annotations needed
 }
 
 trait IndirectLeak<'a> {}