Unrolled build for rust-lang#133394

Rollup merge of rust-lang#133394 - compiler-errors:dyn-more-errors, r=lcnr Bail on more errors in dyn ty lowering If we have more than one principal trait, or if we have a principal trait with errors in it, then bail with `TyKind::Error` rather than attempting lowering. Lowering a dyn trait with more than one principal just arbitrarily chooses the first one and drops the subsequent ones, and lowering a dyn trait path with errors in it is just kinda useless. This suppresses unnecessary errors which I think is net-good, but also is important to make sure that we don't end up leaking `{type error}` in rust-lang#133388 error messaging :) r? types
rust-lang-ci · Nov 27, 2024 · 681e3c5 · 681e3c5
2 parents dff3e7c + cfa8fcb
commit 681e3c5
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diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs
@@ -8,7 +8,8 @@ use rustc_lint_defs::builtin::UNUSED_ASSOCIATED_TYPE_BOUNDS;
 use rustc_middle::span_bug;
 use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::{
-    self, DynKind, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable, Upcast,
+    self, DynKind, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable,
+    TypeVisitableExt, Upcast,
 };
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::error_reporting::traits::report_dyn_incompatibility;
@@ -92,11 +93,20 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) =
             expanded_traits.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id()));
+
+        // We don't support >1 principal
         if regular_traits.len() > 1 {
-            let _ = self.report_trait_object_addition_traits_error(&regular_traits);
-        } else if regular_traits.is_empty() && auto_traits.is_empty() {
-            let reported = self.report_trait_object_with_no_traits_error(span, &trait_bounds);
-            return Ty::new_error(tcx, reported);
+            let guar = self.report_trait_object_addition_traits_error(&regular_traits);
+            return Ty::new_error(tcx, guar);
+        }
+        // We  don't support empty trait objects.
+        if regular_traits.is_empty() && auto_traits.is_empty() {
+            let guar = self.report_trait_object_with_no_traits_error(span, &trait_bounds);
+            return Ty::new_error(tcx, guar);
+        }
+        // Don't create a dyn trait if we have errors in the principal.
+        if let Err(guar) = trait_bounds.error_reported() {
+            return Ty::new_error(tcx, guar);
         }
 
         // Check that there are no gross dyn-compatibility violations;

diff --git a/tests/crashes/130521.rs b/tests/crashes/130521.rs
@@ -1,7 +1,7 @@
 //@ known-bug: #130521
 
 #![feature(dyn_compatible_for_dispatch)]
-struct Vtable(dyn Cap);
+struct Vtable(dyn Cap<'static>);
 
 trait Cap<'a> {}
 

diff --git a/tests/rustdoc-ui/unable-fulfill-trait.rs b/tests/rustdoc-ui/unable-fulfill-trait.rs
@@ -3,7 +3,6 @@
 pub struct Foo<'a, 'b, T> {
     field1: dyn Bar<'a, 'b>,
     //~^ ERROR
-    //~| ERROR
 }
 
 pub trait Bar<'x, 's, U>

diff --git a/tests/rustdoc-ui/unable-fulfill-trait.stderr b/tests/rustdoc-ui/unable-fulfill-trait.stderr
@@ -5,7 +5,7 @@ LL |     field1: dyn Bar<'a, 'b>,
    |                 ^^^ expected 1 generic argument
    |
 note: trait defined here, with 1 generic parameter: `U`
-  --> $DIR/unable-fulfill-trait.rs:9:11
+  --> $DIR/unable-fulfill-trait.rs:8:11
    |
 LL | pub trait Bar<'x, 's, U>
    |           ^^^         -
@@ -14,13 +14,6 @@ help: add missing generic argument
 LL |     field1: dyn Bar<'a, 'b, U>,
    |                           +++
 
-error[E0227]: ambiguous lifetime bound, explicit lifetime bound required
-  --> $DIR/unable-fulfill-trait.rs:4:13
-   |
-LL |     field1: dyn Bar<'a, 'b>,
-   |             ^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0107, E0227.
-For more information about an error, try `rustc --explain E0107`.
+For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/associated-types/issue-22560.rs b/tests/ui/associated-types/issue-22560.rs
@@ -7,9 +7,6 @@ trait Sub<Rhs=Self> {
 }
 
 type Test = dyn Add + Sub;
-//~^ ERROR E0393
-//~| ERROR E0191
-//~| ERROR E0393
-//~| ERROR E0225
+//~^ ERROR E0225
 
 fn main() { }
diff --git a/tests/ui/associated-types/issue-22560.stderr b/tests/ui/associated-types/issue-22560.stderr
@@ -9,56 +9,6 @@ LL | type Test = dyn Add + Sub;
    = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add + Sub {}`
    = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
 
-error[E0191]: the value of the associated types `Output` in `Add`, `Output` in `Sub` must be specified
-  --> $DIR/issue-22560.rs:9:17
-   |
-LL |     type Output;
-   |     ----------- `Output` defined here
-...
-LL |     type Output;
-   |     ----------- `Output` defined here
-...
-LL | type Test = dyn Add + Sub;
-   |                 ^^^   ^^^ associated type `Output` must be specified
-   |                 |
-   |                 associated type `Output` must be specified
-   |
-help: specify the associated types
-   |
-LL | type Test = dyn Add<Output = Type> + Sub<Output = Type>;
-   |                 ~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~
-
-error[E0393]: the type parameter `Rhs` must be explicitly specified
-  --> $DIR/issue-22560.rs:9:17
-   |
-LL | trait Add<Rhs=Self> {
-   | ------------------- type parameter `Rhs` must be specified for this
-...
-LL | type Test = dyn Add + Sub;
-   |                 ^^^
-   |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
-help: set the type parameter to the desired type
-   |
-LL | type Test = dyn Add<Rhs> + Sub;
-   |                    +++++
-
-error[E0393]: the type parameter `Rhs` must be explicitly specified
-  --> $DIR/issue-22560.rs:9:23
-   |
-LL | trait Sub<Rhs=Self> {
-   | ------------------- type parameter `Rhs` must be specified for this
-...
-LL | type Test = dyn Add + Sub;
-   |                       ^^^
-   |
-   = note: because of the default `Self` reference, type parameters must be specified on object types
-help: set the type parameter to the desired type
-   |
-LL | type Test = dyn Add + Sub<Rhs>;
-   |                          +++++
-
-error: aborting due to 4 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0191, E0225, E0393.
-For more information about an error, try `rustc --explain E0191`.
+For more information about this error, try `rustc --explain E0225`.
diff --git a/tests/ui/associated-types/missing-associated-types.rs b/tests/ui/associated-types/missing-associated-types.rs
@@ -11,16 +11,12 @@ trait Fine<Rhs>: Div<Rhs, Output = Rhs> {}
 
 type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
 //~^ ERROR only auto traits can be used as additional traits in a trait object
-//~| ERROR the value of the associated types
 type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
 //~^ ERROR only auto traits can be used as additional traits in a trait object
-//~| ERROR the value of the associated types
 type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
 //~^ ERROR only auto traits can be used as additional traits in a trait object
-//~| ERROR the value of the associated types
 type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
 //~^ ERROR only auto traits can be used as additional traits in a trait object
-//~| ERROR the value of the associated types
 type Bal<Rhs> = dyn X<Rhs>;
 //~^ ERROR the value of the associated types
 

diff --git a/tests/ui/associated-types/missing-associated-types.stderr b/tests/ui/associated-types/missing-associated-types.stderr
@@ -9,26 +9,8 @@ LL | type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
    = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs> {}`
    = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
 
-error[E0191]: the value of the associated types `A` in `Y`, `Output` in `Add`, `Output` in `Mul`, `Output` in `Sub` must be specified
-  --> $DIR/missing-associated-types.rs:12:21
-   |
-LL |     type A;
-   |     ------ `A` defined here
-...
-LL | type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
-   |                     ^^^^^^^^   ^^^^^^^^   ^^^^^^   ^^^^^^ associated type `A` must be specified
-   |                     |          |          |
-   |                     |          |          associated type `Output` must be specified
-   |                     |          associated type `Output` must be specified
-   |                     associated type `Output` must be specified
-   |
-help: specify the associated types
-   |
-LL | type Foo<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + X<Rhs, Output = Type> + Y<Rhs, A = Type>;
-   |                     ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~
-
 error[E0225]: only auto traits can be used as additional traits in a trait object
-  --> $DIR/missing-associated-types.rs:15:32
+  --> $DIR/missing-associated-types.rs:14:32
    |
 LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
    |                     --------   ^^^^^^^^ additional non-auto trait
@@ -38,33 +20,8 @@ LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
    = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs> {}`
    = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
 
-error[E0191]: the value of the associated types `A` and `B` in `Z`, `Output` and `Output` in `Div`, `Output` in `Add`, `Output` in `Mul`, `Output` in `Sub` must be specified
-  --> $DIR/missing-associated-types.rs:15:21
-   |
-LL |     type A;
-   |     ------ `A` defined here
-LL |     type B;
-   |     ------ `B` defined here
-...
-LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
-   |                     ^^^^^^^^   ^^^^^^^^   ^^^^^^   ^^^^^^ associated types `A`, `B`, `Output` must be specified
-   |                     |          |          |
-   |                     |          |          associated types `Output` (from trait `Div`), `Output` (from trait `Mul`) must be specified
-   |                     |          associated type `Output` must be specified
-   |                     associated type `Output` must be specified
-   |
-help: consider introducing a new type parameter, adding `where` constraints using the fully-qualified path to the associated types
-  --> $DIR/missing-associated-types.rs:15:43
-   |
-LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
-   |                                           ^^^^^^
-help: specify the associated types
-   |
-LL | type Bar<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + X<Rhs> + Z<Rhs, A = Type, B = Type, Output = Type>;
-   |                     ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
 error[E0225]: only auto traits can be used as additional traits in a trait object
-  --> $DIR/missing-associated-types.rs:18:32
+  --> $DIR/missing-associated-types.rs:16:32
    |
 LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
    |                     --------   ^^^^^^^^ additional non-auto trait
@@ -74,25 +31,8 @@ LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
    = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Y<Rhs> {}`
    = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
 
-error[E0191]: the value of the associated types `A` in `Y`, `Output` in `Add`, `Output` in `Sub` must be specified
-  --> $DIR/missing-associated-types.rs:18:21
-   |
-LL |     type A;
-   |     ------ `A` defined here
-...
-LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
-   |                     ^^^^^^^^   ^^^^^^^^   ^^^^^^ associated type `A` must be specified
-   |                     |          |
-   |                     |          associated type `Output` must be specified
-   |                     associated type `Output` must be specified
-   |
-help: specify the associated types
-   |
-LL | type Baz<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + Y<Rhs, A = Type>;
-   |                     ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~
-
 error[E0225]: only auto traits can be used as additional traits in a trait object
-  --> $DIR/missing-associated-types.rs:21:32
+  --> $DIR/missing-associated-types.rs:18:32
    |
 LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
    |                     --------   ^^^^^^^^ additional non-auto trait
@@ -102,28 +42,15 @@ LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
    = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Fine<Rhs> {}`
    = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
 
-error[E0191]: the value of the associated types `Output` in `Add`, `Output` in `Sub` must be specified
-  --> $DIR/missing-associated-types.rs:21:21
-   |
-LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
-   |                     ^^^^^^^^   ^^^^^^^^ associated type `Output` must be specified
-   |                     |
-   |                     associated type `Output` must be specified
-   |
-help: specify the associated types
-   |
-LL | type Bat<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + Fine<Rhs>;
-   |                     ~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~
-
 error[E0191]: the value of the associated types `Output` in `Div`, `Output` in `Mul` must be specified
-  --> $DIR/missing-associated-types.rs:24:21
+  --> $DIR/missing-associated-types.rs:20:21
    |
 LL | type Bal<Rhs> = dyn X<Rhs>;
    |                     ^^^^^^ associated types `Output` (from trait `Div`), `Output` (from trait `Mul`) must be specified
    |
    = help: consider introducing a new type parameter, adding `where` constraints using the fully-qualified path to the associated types
 
-error: aborting due to 9 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0191, E0225.
 For more information about an error, try `rustc --explain E0191`.
diff --git a/tests/ui/const-generics/not_wf_param_in_rpitit.rs b/tests/ui/const-generics/not_wf_param_in_rpitit.rs
@@ -3,9 +3,6 @@
 trait Trait<const N: dyn Trait = bar> {
     //~^ ERROR: cannot find value `bar` in this scope
     //~| ERROR: cycle detected when computing type of `Trait::N`
-    //~| ERROR: the trait `Trait` cannot be made into an object
-    //~| ERROR: the trait `Trait` cannot be made into an object
-    //~| ERROR: the trait `Trait` cannot be made into an object
     async fn a() {}
 }
 

diff --git a/tests/ui/const-generics/not_wf_param_in_rpitit.stderr b/tests/ui/const-generics/not_wf_param_in_rpitit.stderr
@@ -18,77 +18,7 @@ LL | trait Trait<const N: dyn Trait = bar> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = 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[E0038]: the trait `Trait` cannot be made into an object
-  --> $DIR/not_wf_param_in_rpitit.rs:3:22
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |                      ^^^^^^^^^ `Trait` cannot be made into an object
-   |
-note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/not_wf_param_in_rpitit.rs:9:14
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |       ----- this trait cannot be made into an object...
-...
-LL |     async fn a() {}
-   |              ^ ...because associated function `a` has no `self` parameter
-help: consider turning `a` into a method by giving it a `&self` argument
-   |
-LL |     async fn a(&self) {}
-   |                +++++
-help: alternatively, consider constraining `a` so it does not apply to trait objects
-   |
-LL |     async fn a() where Self: Sized {}
-   |                  +++++++++++++++++
-
-error[E0038]: the trait `Trait` cannot be made into an object
-  --> $DIR/not_wf_param_in_rpitit.rs:3:13
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
-   |
-note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/not_wf_param_in_rpitit.rs:9:14
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |       ----- this trait cannot be made into an object...
-...
-LL |     async fn a() {}
-   |              ^ ...because associated function `a` has no `self` parameter
-help: consider turning `a` into a method by giving it a `&self` argument
-   |
-LL |     async fn a(&self) {}
-   |                +++++
-help: alternatively, consider constraining `a` so it does not apply to trait objects
-   |
-LL |     async fn a() where Self: Sized {}
-   |                  +++++++++++++++++
-
-error[E0038]: the trait `Trait` cannot be made into an object
-  --> $DIR/not_wf_param_in_rpitit.rs:3:13
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
-   |
-note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/not_wf_param_in_rpitit.rs:9:14
-   |
-LL | trait Trait<const N: dyn Trait = bar> {
-   |       ----- this trait cannot be made into an object...
-...
-LL |     async fn a() {}
-   |              ^ ...because associated function `a` has no `self` parameter
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-help: consider turning `a` into a method by giving it a `&self` argument
-   |
-LL |     async fn a(&self) {}
-   |                +++++
-help: alternatively, consider constraining `a` so it does not apply to trait objects
-   |
-LL |     async fn a() where Self: Sized {}
-   |                  +++++++++++++++++
-
-error: aborting due to 5 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0038, E0391, E0425.
-For more information about an error, try `rustc --explain E0038`.
+Some errors have detailed explanations: E0391, E0425.
+For more information about an error, try `rustc --explain E0391`.
diff --git a/tests/ui/issues/issue-23024.rs b/tests/ui/issues/issue-23024.rs
@@ -8,5 +8,4 @@ fn main()
     println!("{:?}",(vfnfer[0] as dyn Fn)(3));
     //~^ ERROR the precise format of `Fn`-family traits'
     //~| ERROR missing generics for trait `Fn`
-    //~| ERROR the value of the associated type `Output` in `FnOnce`
 }
diff --git a/tests/ui/issues/issue-23024.stderr b/tests/ui/issues/issue-23024.stderr
@@ -19,13 +19,7 @@ help: add missing generic argument
 LL |     println!("{:?}",(vfnfer[0] as dyn Fn<Args>)(3));
    |                                         ++++++
 
-error[E0191]: the value of the associated type `Output` in `FnOnce` must be specified
-  --> $DIR/issue-23024.rs:8:39
-   |
-LL |     println!("{:?}",(vfnfer[0] as dyn Fn)(3));
-   |                                       ^^ help: specify the associated type: `Fn::<Output = Type>`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0107, E0191, E0658.
+Some errors have detailed explanations: E0107, E0658.
 For more information about an error, try `rustc --explain E0107`.