update tests

tests/ui/coherence/occurs-check/associated-type.next.stderr

@@ -1,11 +1,7 @@
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), 'a) })], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit) }
 error[E0119]: conflicting implementations of trait `Overlap<for<'a> fn(&'a (), ())>` for type `for<'a> fn(&'a (), ())`
   --> $DIR/associated-type.rs:31:1
    |

tests/ui/coherence/occurs-check/opaques.next.stderr

@@ -1,17 +1,17 @@
-error[E0119]: conflicting implementations of trait `Trait<Alias<_>>` for type `Alias<_>`
+error[E0119]: conflicting implementations of trait `Trait<_>`
   --> $DIR/opaques.rs:30:1
    |
 LL | impl<T> Trait<T> for T {
    | ---------------------- first implementation here
 ...
 LL | impl<T> Trait<T> for defining_scope::Alias<T> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Alias<_>`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
 
 error[E0282]: type annotations needed
   --> $DIR/opaques.rs:13:20
    |
 LL |     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
-   |                    ^ cannot infer type for struct `Container<Alias<T>, T>`
+   |                    ^ cannot infer type for struct `Container<T, T>`
 
 error: aborting due to 2 previous errors
 

tests/ui/impl-trait/auto-trait-coherence.next.stderr

@@ -1,11 +1,11 @@
-error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<_>`
   --> $DIR/auto-trait-coherence.rs:24:1
    |
 LL | impl<T: Send> AnotherTrait for T {}
    | -------------------------------- first implementation here
 ...
 LL | impl AnotherTrait for D<OpaqueType> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<_>`
 
 error: aborting due to 1 previous error
 

tests/ui/impl-trait/auto-trait-coherence.rs

@@ -22,7 +22,8 @@ impl<T: Send> AnotherTrait for T {}
 // (We treat opaque types as "foreign types" that could grow more impls
 // in the future.)
 impl AnotherTrait for D<OpaqueType> {
-    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
+    //[old]~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
+    //[next]~^^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<_>`
 }
 
 fn main() {}

tests/ui/impl-trait/two_tait_defining_each_other2.current.stderr

@@ -7,7 +7,7 @@ LL | type A = impl Foo;
    = note: `A` must be used in combination with a concrete type within the same module
 
 error: opaque type's hidden type cannot be another opaque type from the same scope
-  --> $DIR/two_tait_defining_each_other2.rs:11:5
+  --> $DIR/two_tait_defining_each_other2.rs:12:5
    |
 LL |     x // B's hidden type is A (opaquely)
    |     ^ one of the two opaque types used here has to be outside its defining scope

tests/ui/impl-trait/two_tait_defining_each_other2.next.stderr

@@ -1,8 +1,8 @@
-error[E0284]: type annotations needed: cannot satisfy `A == B`
+error[E0284]: type annotations needed: cannot satisfy `_ == A`
-  --> $DIR/two_tait_defining_each_other2.rs:11:5
+  --> $DIR/two_tait_defining_each_other2.rs:10:8
    |
-LL |     x // B's hidden type is A (opaquely)
+LL | fn muh(x: A) -> B {
-   |     ^ cannot satisfy `A == B`
+   |        ^ cannot satisfy `_ == A`
 
 error: aborting due to 1 previous error
 

tests/ui/impl-trait/two_tait_defining_each_other2.rs

@@ -8,9 +8,9 @@
 trait Foo {}
 
 fn muh(x: A) -> B {
+    //[next]~^ ERROR type annotations needed: cannot satisfy `_ == A`
     x // B's hidden type is A (opaquely)
     //[current]~^ ERROR opaque type's hidden type cannot be another opaque type
-    //[next]~^^ ERROR type annotations needed: cannot satisfy `A == B`
 }
 
 struct Bar;

tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-norm-overflow.rs

@@ -16,6 +16,6 @@ trait Trait {}
 impl<T: Copy> Trait for T {}
 struct LocalTy;
 impl Trait for <LocalTy as Overflow>::Assoc {}
-//~^ ERROR conflicting implementations of trait `Trait` for type `<LocalTy as Overflow>::Assoc`
+//~^ ERROR conflicting implementations of trait `Trait`
 
 fn main() {}

tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-norm-overflow.stderr

@@ -1,11 +1,11 @@
-error[E0119]: conflicting implementations of trait `Trait` for type `<LocalTy as Overflow>::Assoc`
+error[E0119]: conflicting implementations of trait `Trait`
   --> $DIR/trait_ref_is_knowable-norm-overflow.rs:18:1
    |
 LL | impl<T: Copy> Trait for T {}
    | ------------------------- first implementation here
 LL | struct LocalTy;
 LL | impl Trait for <LocalTy as Overflow>::Assoc {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `<LocalTy as Overflow>::Assoc`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
 
 error[E0275]: overflow evaluating the requirement `<T as Overflow>::Assoc: Sized`
   --> $DIR/trait_ref_is_knowable-norm-overflow.rs:10:18

tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-3.rs

@@ -9,7 +9,7 @@ impl<T> Id for T {
 }
 
 
-// Coherence should be able to reason that `(): PartialEq<<T as Id>::Assoc>>`
+// Coherence should be able to reason that `(): PartialEq<<LocalTy as Id>::Assoc>>`
 // does not hold.
 //
 // See https://github.com/rust-lang/trait-system-refactor-initiative/issues/51

tests/ui/traits/next-solver/generalize/generalize-proj-new-universe-index-2.rs

@@ -1,8 +1,8 @@
 //@ compile-flags: -Znext-solver
-//@ known-bug: trait-system-refactor-initiative#60
+//@ check-pass
 
 // Generalizing a projection containing an inference variable
-// which cannot be named by the `root_vid` can result in ambiguity.
+// which cannot be named by the `root_vid` previously resulted in ambiguity.
 //
 // Because we do not decrement the universe index when exiting a forall,
 // this can cause unexpected failures.

tests/ui/traits/next-solver/generalize/generalize-proj-new-universe-index-2.stderr

@@ -1,19 +0,0 @@
-error[E0284]: type annotations needed
-  --> $DIR/generalize-proj-new-universe-index-2.rs:74:5
-   |
-LL |     bound::<<Rigid as IdHigherRankedBound>::Assoc, <Wrapper<Leaf> as Id>::Assoc, _>()
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `V` declared on the function `bound`
-   |
-   = note: cannot satisfy `<<Rigid as IdHigherRankedBound>::Assoc as WithAssoc<<Wrapper<Leaf> as Id>::Assoc>>::Assoc == _`
-note: required by a bound in `bound`
-  --> $DIR/generalize-proj-new-universe-index-2.rs:69:21
-   |
-LL | fn bound<T: ?Sized, U: ?Sized, V: ?Sized>()
-   |    ----- required by a bound in this function
-LL | where
-LL |     T: WithAssoc<U, Assoc = V>,
-   |                     ^^^^^^^^^ required by this bound in `bound`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0284`.

tests/ui/traits/next-solver/generalize/instantiate-canonical-occurs-check-failure.rs

@@ -0,0 +1,29 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+// With #119106 generalization now results in `AliasRelate` if the generalized
+// alias contains an inference variable which is not nameable.
+//
+// We previously proved alias-relate after canonicalization, which does not keep track
+// of universe indices, so all inference vars were nameable inside of `AliasRelate`.
+//
+// If we now have a rigid projection containing an unnameable inference variable,
+// we should emit an alias-relate obligation, which constrains the type of `x` to
+// an alias. This caused us to emit yet another equivalent alias-relate obligation
+// when trying to instantiate the query result, resulting in overflow.
+trait Trait<'a> {
+    type Assoc: Default;
+}
+
+fn takes_alias<'a, T: Trait<'a>>(_: <T as Trait<'a>>::Assoc) {}
+
+fn foo<T: for<'a> Trait<'a>>() {
+    let x = Default::default();
+
+    let _incr_universe: for<'a, 'b> fn(&'a (), &'b ()) =
+        (|&(), &()| ()) as for<'a> fn(&'a (), &'a ());
+
+    takes_alias::<T>(x);
+}
+
+fn main() {}

tests/ui/traits/next-solver/generalize/occurs-check-nested-alias.next.stderr

@@ -1,9 +0,0 @@
-error[E0284]: type annotations needed: cannot satisfy `_ == <<T as Id<_>>::Id as Unnormalizable>::Assoc`
-  --> $DIR/occurs-check-nested-alias.rs:36:9
-   |
-LL |     x = y;
-   |         ^ cannot satisfy `_ == <<T as Id<_>>::Id as Unnormalizable>::Assoc`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0284`.

tests/ui/traits/next-solver/generalize/occurs-check-nested-alias.rs

@@ -1,10 +1,8 @@
 //@ revisions: old next
-//@[old] check-pass
-
-// Currently always fails to generalize the outer alias, even if it
-// is treated as rigid by `alias-relate`.
 //@[next] compile-flags: -Znext-solver
-//@[next] known-bug: trait-system-refactor-initiative#8
+//@ check-pass
+
+// case 3 of https://github.com/rust-lang/trait-system-refactor-initiative/issues/8.
 #![crate_type = "lib"]
 #![allow(unused)]
 trait Unnormalizable {
@@ -14,8 +12,8 @@ trait Unnormalizable {
 trait Id<T> {
     type Id;
 }
-impl<T, U> Id<T> for U {
+impl<T, U> Id<U> for T {
-    type Id = U;
+    type Id = T;
 }
 
 struct Inv<T>(*mut T);
@@ -24,15 +22,23 @@ fn unconstrained<T>() -> T {
     todo!()
 }
 
-fn create<T, U: Unnormalizable>(
+fn create<T: Unnormalizable, U>(
-    x: &U,
+    x: &T,
-) -> (Inv<T>, Inv<<<U as Id<T>>::Id as Unnormalizable>::Assoc>) {
+) -> (Inv<U>, Inv<<<T as Id<U>>::Id as Unnormalizable>::Assoc>) {
     todo!()
 }
 
 fn foo<T: Unnormalizable>() {
-    let q = unconstrained();
+    let t = unconstrained();
-    let (mut x, y) = create::<_, _>(&q);
+    let (mut u, assoc) = create::<_, _>(&t);
-    x = y;
+    u = assoc;
-    drop::<T>(q);
+    // Instantiating `?u` with `<<?t as Id<?u>>::Id as Unnormalizable>::Assoc` would
+    // result in a cyclic type. However, we can still unify these types by first
+    // normalizing the inner associated type. Emitting an error here would be incomplete.
+    drop::<T>(t);
+
+    // FIXME(-Znext-solver): This line is necessary due to an unrelated solver bug
+    // and should get removed in the future.
+    //   https://github.com/rust-lang/trait-system-refactor-initiative/issues/96
+    drop::<Inv<<T as Unnormalizable>::Assoc>>(u);
 }

tests/ui/traits/next-solver/issue-118950-root-region.stderr

@@ -14,13 +14,9 @@ LL | #![feature(lazy_type_alias)]
    = note: `#[warn(incomplete_features)]` on by default
 
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
 WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [ReBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
-WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [RePlaceholder(!1_BoundRegion { var: 0, kind: BrNamed(DefId(0:15 ~ issue_118950_root_region[d54f]::{impl#1}::'a), 'a) }), ?1t], def_id: DefId(0:8 ~ issue_118950_root_region[d54f]::Assoc) }
 error[E0119]: conflicting implementations of trait `Overlap<fn(_)>` for type `fn(_)`
   --> $DIR/issue-118950-root-region.rs:19:1
    |