Rollup merge of #122749 - aliemjay:region-err, r=compiler-errors

make `type_flags(ReError) & HAS_ERROR`

Self-explanatory. `TypeVisitableExt::references_error(ReError)` incorrectly returned `false`.

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -434,10 +434,6 @@ fn check_opaque_type_parameter_valid(
     // Only check the parent generics, which will ignore any of the
     // duplicated lifetime args that come from reifying late-bounds.
     for (i, arg) in opaque_type_key.args.iter().take(parent_generics.count()).enumerate() {
-        if let Err(guar) = arg.error_reported() {
-            return Err(guar);
-        }
-
         let arg_is_param = match arg.unpack() {
             GenericArgKind::Type(ty) => matches!(ty.kind(), ty::Param(_)),
             GenericArgKind::Lifetime(lt) if is_ty_alias => {

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();

compiler/rustc_middle/src/ty/region.rs

@@ -251,6 +251,7 @@ impl<'tcx> Region<'tcx> {
             }
             ty::ReError(_) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_ERROR;
             }
         }
 

compiler/rustc_type_ir/src/flags.rs

@@ -85,7 +85,7 @@ bitflags! {
                                           | TypeFlags::HAS_TY_INHERENT.bits()
                                           | TypeFlags::HAS_CT_PROJECTION.bits();
 
-        /// Is an error type/const reachable?
+        /// Is an error type/lifetime/const reachable?
         const HAS_ERROR                   = 1 << 15;
 
         /// Does this have any region that "appears free" in the type?

tests/ui/async-await/in-trait/return-not-existing-pair.rs

@@ -9,8 +9,7 @@ trait MyTrait<'a, 'b, T> {
 impl<'a, 'b, T, U> MyTrait<T> for U {
     //~^ ERROR: implicit elided lifetime not allowed here [E0726]
     async fn foo(_: T) -> (&'a U, &'b T) {}
-    //~^ ERROR: method `foo` has a `&self` declaration in the trait, but not in the impl [E0186]
-    //~| ERROR: mismatched types [E0308]
+    //~^ ERROR: mismatched types [E0308]
 }
 
 fn main() {}

tests/ui/async-await/in-trait/return-not-existing-pair.stderr

@@ -15,15 +15,6 @@ error[E0412]: cannot find type `ConnImpl` in this scope
 LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
    |                                                ^^^^^^^^ not found in this scope
 
-error[E0186]: method `foo` has a `&self` declaration in the trait, but not in the impl
-  --> $DIR/return-not-existing-pair.rs:11:5
-   |
-LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
-   |     ------------------------------------------------------------ `&self` used in trait
-...
-LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl
-
 error[E0308]: mismatched types
   --> $DIR/return-not-existing-pair.rs:11:42
    |
@@ -33,7 +24,7 @@ LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
    = note:  expected tuple `(&'a U, &'b T)`
            found unit type `()`
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0186, E0308, E0412, E0726.
-For more information about an error, try `rustc --explain E0186`.
+Some errors have detailed explanations: E0308, E0412, E0726.
+For more information about an error, try `rustc --explain E0308`.

tests/ui/async-await/in-trait/unconstrained-impl-region.rs

@@ -14,6 +14,7 @@ impl<'a> Actor for () {
 //~^ ERROR the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
     type Message = &'a ();
     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+    //~^ ERROR the trait bound `impl Inbox<&'a ()>: Inbox<&'a ()>` is not satisfied
 }
 
 fn main() {}

tests/ui/async-await/in-trait/unconstrained-impl-region.stderr

@@ -1,9 +1,26 @@
+error[E0277]: the trait bound `impl Inbox<&'a ()>: Inbox<&'a ()>` is not satisfied
+  --> $DIR/unconstrained-impl-region.rs:16:5
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Inbox<&'a ()>` is not implemented for `impl Inbox<&'a ()>`
+   |
+note: required by a bound in `<() as Actor>::on_mount`
+  --> $DIR/unconstrained-impl-region.rs:16:37
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+   |                                     ^^^^^^^^^^^^^ required by this bound in `<() as Actor>::on_mount`
+help: consider further restricting this bound
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()> + Inbox<&'a ()>) {}
+   |                                                   +++++++++++++++
+
 error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
   --> $DIR/unconstrained-impl-region.rs:13:6
    |
 LL | impl<'a> Actor for () {
    |      ^^ unconstrained lifetime parameter
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0207`.
+Some errors have detailed explanations: E0207, E0277.
+For more information about an error, try `rustc --explain E0207`.

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/const-generics/late-bound-vars/late-bound-in-return-issue-77357.stderr

@@ -4,46 +4,5 @@ error: cannot capture late-bound lifetime in constant
 LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
    |        -- lifetime defined here                     ^^
 
-error: overly complex generic constant
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constants
-   |
-   = help: consider moving this anonymous constant into a `const` function
-   = note: this operation may be supported in the future
-
-error[E0391]: cycle detected when evaluating type-level constant
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: ...which requires const-evaluating + checking `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires caching mir of `bug::{constant#0}` for CTFE...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires elaborating drops for `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires borrow-checking `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which requires normalizing `Binder { value: ConstEvaluatable(UnevaluatedConst { def: DefId(0:8 ~ late_bound_in_return_issue_77357[9394]::bug::{constant#0}), args: [T/#0] }: usize), bound_vars: [] }`...
-   = note: ...which again requires evaluating type-level constant, completing the cycle
-   = note: cycle used when normalizing `&dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]>`
-   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0391`.

tests/ui/error-codes/E0637.rs

@@ -2,9 +2,9 @@ fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
     //~^ ERROR: `'_` cannot be used here [E0637]
     //~| ERROR: missing lifetime specifier
     if str1.len() > str2.len() {
-        str1 //~ ERROR: lifetime may not live long enough
+        str1
     } else {
-        str2 //~ ERROR: lifetime may not live long enough
+        str2
     }
 }
 

tests/ui/error-codes/E0637.stderr

@@ -27,25 +27,7 @@ help: consider introducing a higher-ranked lifetime here
 LL |     T: for<'a> Into<&'a u32>,
    |        +++++++       ++
 
-error: lifetime may not live long enough
-  --> $DIR/E0637.rs:5:9
-   |
-LL | fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
-   |                                  - let's call the lifetime of this reference `'1`
-...
-LL |         str1
-   |         ^^^^ returning this value requires that `'1` must outlive `'static`
-
-error: lifetime may not live long enough
-  --> $DIR/E0637.rs:7:9
-   |
-LL | fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
-   |                                                 - let's call the lifetime of this reference `'2`
-...
-LL |         str2
-   |         ^^^^ returning this value requires that `'2` must outlive `'static`
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0106, E0637.
 For more information about an error, try `rustc --explain E0106`.

tests/ui/generic-associated-types/issue-80433.rs

@@ -29,5 +29,5 @@ fn test_simpler<'a>(dst: &'a mut impl TestMut<Output = &'a mut f32>)
 
 fn main() {
     let mut t1: E<f32> = Default::default();
-    test_simpler(&mut t1); //~ ERROR does not live long enough
+    test_simpler(&mut t1);
 }

tests/ui/generic-associated-types/issue-80433.stderr

@@ -48,20 +48,7 @@ LL |         *dst.test_mut() = n.into();
    |          `dst` escapes the function body here
    |          argument requires that `'a` must outlive `'static`
 
-error[E0597]: `t1` does not live long enough
-  --> $DIR/issue-80433.rs:32:18
-   |
-LL |     let mut t1: E<f32> = Default::default();
-   |         ------ binding `t1` declared here
-LL |     test_simpler(&mut t1);
-   |     -------------^^^^^^^-
-   |     |            |
-   |     |            borrowed value does not live long enough
-   |     argument requires that `t1` is borrowed for `'static`
-LL | }
-   | - `t1` dropped here while still borrowed
-
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0107, E0499, E0521, E0597.
+Some errors have detailed explanations: E0107, E0499, E0521.
 For more information about an error, try `rustc --explain E0107`.

tests/ui/impl-trait/impl-fn-hrtb-bounds.rs

@@ -4,19 +4,16 @@ use std::fmt::Debug;
 fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn d() -> impl Fn() -> (impl Debug + '_) {

tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr

@@ -1,5 +1,5 @@
 error[E0106]: missing lifetime specifier
-  --> $DIR/impl-fn-hrtb-bounds.rs:22:38
+  --> $DIR/impl-fn-hrtb-bounds.rs:19:38
    |
 LL | fn d() -> impl Fn() -> (impl Debug + '_) {
    |                                      ^^ expected named lifetime parameter
@@ -22,58 +22,31 @@ note: lifetime declared here
 LL | fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
    |                   ^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:6:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-  --> $DIR/impl-fn-hrtb-bounds.rs:10:52
+  --> $DIR/impl-fn-hrtb-bounds.rs:9:52
    |
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
    |                                                    ^^
    |
 note: lifetime declared here
-  --> $DIR/impl-fn-hrtb-bounds.rs:10:20
+  --> $DIR/impl-fn-hrtb-bounds.rs:9:20
    |
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
    |                    ^^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:12:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-  --> $DIR/impl-fn-hrtb-bounds.rs:16:52
+  --> $DIR/impl-fn-hrtb-bounds.rs:14:52
    |
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
    |                                                    ^^
    |
 note: lifetime declared here
-  --> $DIR/impl-fn-hrtb-bounds.rs:16:20
+  --> $DIR/impl-fn-hrtb-bounds.rs:14:20
    |
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
    |                    ^^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:18:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
-error: aborting due to 7 previous errors
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0106, E0657.
 For more information about an error, try `rustc --explain E0106`.

tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs

@@ -5,7 +5,6 @@ fn a() -> impl Fn(&u8) -> impl Debug + '_ {
     //~^ ERROR ambiguous `+` in a type
     //~| ERROR cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn b() -> impl Fn() -> impl Debug + Send {

tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr

@@ -5,7 +5,7 @@ LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
    |                           ^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + '_)`
 
 error: ambiguous `+` in a type
-  --> $DIR/impl-fn-parsing-ambiguities.rs:11:24
+  --> $DIR/impl-fn-parsing-ambiguities.rs:10:24
    |
 LL | fn b() -> impl Fn() -> impl Debug + Send {
    |                        ^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + Send)`
@@ -22,15 +22,6 @@ note: lifetime declared here
 LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
    |                   ^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-parsing-ambiguities.rs:7:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0657`.