register opaques that reference errors

compiler/rustc_infer/src/infer/opaque_types/mod.rs

@@ -94,9 +94,6 @@ impl<'tcx> InferCtxt<'tcx> {
  cause: &ObligationCause<'tcx>,
  param_env: ty::ParamEnv<'tcx>,
  ) -> InferResult<'tcx, ()> {
- if a.references_error() || b.references_error() {
- return Ok(InferOk { value: (), obligations: vec![] });
- }
  let process = |a: Ty<'tcx>, b: Ty<'tcx>| match *a.kind() {
  ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) if def_id.is_local() => {
  let def_id = def_id.expect_local();

tests/ui/const-generics/generic_const_exprs/issue-109141.rs

@@ -4,6 +4,7 @@
 impl EntriesBuffer {
  fn a(&self) -> impl Iterator {
  self.0.iter_mut() //~ ERROR: cannot borrow `*self.0` as mutable, as it is behind a `&` reference
+ //~| ERROR captures lifetime that does not appear in bounds
  }
 }
 

tests/ui/const-generics/generic_const_exprs/issue-109141.stderr

@@ -1,5 +1,5 @@
 error[E0425]: cannot find value `HashesEntryLEN` in this scope
- --> $DIR/issue-109141.rs:10:32
+ --> $DIR/issue-109141.rs:11:32
  |
 LL | struct EntriesBuffer(Box<[[u8; HashesEntryLEN]; 5]>);
  | ^^^^^^^^^^^^^^ not found in this scope
@@ -20,7 +20,22 @@ help: consider changing this to be a mutable reference
 LL | fn a(&mut self) -> impl Iterator {
  | ~~~~~~~~~
 
-error: aborting due to 2 previous errors
+error[E0700]: hidden type for `impl Iterator` captures lifetime that does not appear in bounds
+ --> $DIR/issue-109141.rs:6:9
+ |
+LL | fn a(&self) -> impl Iterator {
+ | ----- ------------- opaque type defined here
+ | |
+ | hidden type `std::slice::IterMut<'_, [u8; {const error}]>` captures the anonymous lifetime defined here
+LL | self.0.iter_mut()
+ | ^^^^^^^^^^^^^^^^^
+ |
+help: to declare that `impl Iterator` captures `'_`, you can add an explicit `'_` lifetime bound
+ |
+LL | fn a(&self) -> impl Iterator + '_ {
+ | ++++
+
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0425, E0596.
+Some errors have detailed explanations: E0425, E0596, E0700.
 For more information about an error, try `rustc --explain E0425`.

tests/ui/impl-trait/nested-rpit-hrtb.rs

@@ -31,6 +31,7 @@ fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {}
 
 fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
 //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
+//~| ERROR implementation of `Bar` is not general enough
 
 fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
 //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
@@ -43,7 +44,7 @@ fn one_hrtb_mention_fn_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl Sized
 
 // This should resolve.
 fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {}
-//~^ ERROR: the trait bound `for<'a> &'a (): Qux<'b>` is not satisfied
+//~^ ERROR type annotations needed: cannot satisfy `for<'a> &'a (): Qux<'b>`
 
 // This should resolve.
 fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {}

tests/ui/impl-trait/nested-rpit-hrtb.stderr

@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'b`
- --> $DIR/nested-rpit-hrtb.rs:56:77
+ --> $DIR/nested-rpit-hrtb.rs:57:77
  |
 LL | fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {}
  | ^^ undeclared lifetime
@@ -15,7 +15,7 @@ LL | fn two_htrb_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Siz
  | ++++
 
 error[E0261]: use of undeclared lifetime name `'b`
- --> $DIR/nested-rpit-hrtb.rs:64:82
+ --> $DIR/nested-rpit-hrtb.rs:65:82
  |
 LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
  | ^^ undeclared lifetime
@@ -65,29 +65,39 @@ note: lifetime declared here
 LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
  | ^^
 
+error: implementation of `Bar` is not general enough
+ --> $DIR/nested-rpit-hrtb.rs:32:78
+ |
+LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
+ | ^^ implementation of `Bar` is not general enough
+ |
+ = note: `()` must implement `Bar<'a>`
+ = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
+
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
- --> $DIR/nested-rpit-hrtb.rs:35:73
+ --> $DIR/nested-rpit-hrtb.rs:36:73
  |
 LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
  | ^^
  |
 note: lifetime declared here
- --> $DIR/nested-rpit-hrtb.rs:35:44
+ --> $DIR/nested-rpit-hrtb.rs:36:44
  |
 LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
  | ^^
 
-error[E0277]: the trait bound `for<'a> &'a (): Qux<'b>` is not satisfied
- --> $DIR/nested-rpit-hrtb.rs:45:79
+error[E0283]: type annotations needed: cannot satisfy `for<'a> &'a (): Qux<'b>`
+ --> $DIR/nested-rpit-hrtb.rs:46:79
  |
 LL | fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {}
- | ^^^^^^^^^^^^ the trait `for<'a> Qux<'b>` is not implemented for `&'a ()`
+ | ^^^^^^^^^^^^
  |
+ = note: cannot satisfy `for<'a> &'a (): Qux<'b>`
  = help: the trait `Qux<'_>` is implemented for `()`
  = help: for that trait implementation, expected `()`, found `&'a ()`
 
 error: implementation of `Bar` is not general enough
- --> $DIR/nested-rpit-hrtb.rs:49:93
+ --> $DIR/nested-rpit-hrtb.rs:50:93
  |
 LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {}
  | ^^ implementation of `Bar` is not general enough
@@ -96,7 +106,7 @@ LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc =
  = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
 
 error[E0277]: the trait bound `for<'a, 'b> &'a (): Qux<'b>` is not satisfied
- --> $DIR/nested-rpit-hrtb.rs:60:64
+ --> $DIR/nested-rpit-hrtb.rs:61:64
  |
 LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Qux<'b>> {}
  | ^^^^^^^^^^^^^^^^^^^^ the trait `for<'a, 'b> Qux<'b>` is not implemented for `&'a ()`
@@ -105,15 +115,15 @@ LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b>
  = help: for that trait implementation, expected `()`, found `&'a ()`
 
 error: implementation of `Bar` is not general enough
- --> $DIR/nested-rpit-hrtb.rs:64:86
+ --> $DIR/nested-rpit-hrtb.rs:65:86
  |
 LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
  | ^^ implementation of `Bar` is not general enough
  |
  = note: `()` must implement `Bar<'a>`
  = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
 
-error: aborting due to 10 previous errors
+error: aborting due to 11 previous errors
 
-Some errors have detailed explanations: E0261, E0277, E0657.
+Some errors have detailed explanations: E0261, E0277, E0283, E0657.
 For more information about an error, try `rustc --explain E0261`.

tests/ui/type-alias-impl-trait/escaping-bound-var.rs

@@ -8,7 +8,6 @@ trait Test<'a> {}
 
 pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
 //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-//~| ERROR unconstrained opaque type
 
 impl Trait<'_> for () {
  type Assoc = ();

tests/ui/type-alias-impl-trait/escaping-bound-var.stderr

@@ -10,14 +10,6 @@ note: lifetime declared here
 LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
  | ^^
 
-error: unconstrained opaque type
- --> $DIR/escaping-bound-var.rs:9:47
- |
-LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
- | ^^^^^^^^^^^^^
- |
- = note: `Foo` must be used in combination with a concrete type within the same module
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0657`.