add next-solver min-specialization region-resolution regression test

tests/ui/specialization/min_specialization/next-solver-region-resolution.rs

@@ -0,0 +1,26 @@
+//@ compile-flags: -Znext-solver=globally
+// Regression test for https://github.com/rust-lang/rust/issues/151327
+
+#![feature(min_specialization)]
+
+trait Foo {
+    type Item;
+}
+
+trait Baz {}
+
+impl<'a, T> Foo for &'a T //~ ERROR not all trait items implemented, missing: `Item`
+//~| ERROR the trait bound `&'a T: Foo` is not satisfied
+where
+    Self::Item: 'a, //~ ERROR the trait bound `&'a T: Foo` is not satisfied
+{
+}
+
+impl<'a, T> Foo for &T //~ ERROR not all trait items implemented, missing: `Item`
+//~| ERROR cannot normalize `<&_ as Foo>::Item: '_`
+where
+    Self::Item: Baz,
+{
+}
+
+fn main() {}

tests/ui/specialization/min_specialization/next-solver-region-resolution.stderr

@@ -0,0 +1,69 @@
+error[E0046]: not all trait items implemented, missing: `Item`
+  --> $DIR/next-solver-region-resolution.rs:12:1
+   |
+LL |       type Item;
+   |       --------- `Item` from trait
+...
+LL | / impl<'a, T> Foo for &'a T
+LL | |
+LL | | where
+LL | |     Self::Item: 'a,
+   | |___________________^ missing `Item` in implementation
+
+error[E0277]: the trait bound `&'a T: Foo` is not satisfied
+  --> $DIR/next-solver-region-resolution.rs:12:21
+   |
+LL | impl<'a, T> Foo for &'a T
+   |                     ^^^^^ the trait `Foo` is not implemented for `&'a T`
+   |
+help: the trait `Foo` is not implemented for `&'a _`
+      but it is implemented for `&_`
+  --> $DIR/next-solver-region-resolution.rs:12:1
+   |
+LL | / impl<'a, T> Foo for &'a T
+LL | |
+LL | | where
+LL | |     Self::Item: 'a,
+   | |___________________^
+
+error[E0277]: the trait bound `&'a T: Foo` is not satisfied
+  --> $DIR/next-solver-region-resolution.rs:15:17
+   |
+LL |     Self::Item: 'a,
+   |                 ^^ the trait `Foo` is not implemented for `&'a T`
+   |
+help: the trait `Foo` is not implemented for `&'a _`
+      but it is implemented for `&_`
+  --> $DIR/next-solver-region-resolution.rs:12:1
+   |
+LL | / impl<'a, T> Foo for &'a T
+LL | |
+LL | | where
+LL | |     Self::Item: 'a,
+   | |___________________^
+
+error[E0046]: not all trait items implemented, missing: `Item`
+  --> $DIR/next-solver-region-resolution.rs:19:1
+   |
+LL |       type Item;
+   |       --------- `Item` from trait
+...
+LL | / impl<'a, T> Foo for &T
+LL | |
+LL | | where
+LL | |     Self::Item: Baz,
+   | |____________________^ missing `Item` in implementation
+
+error: cannot normalize `<&_ as Foo>::Item: '_`
+  --> $DIR/next-solver-region-resolution.rs:19:1
+   |
+LL | / impl<'a, T> Foo for &T
+LL | |
+LL | | where
+LL | |     Self::Item: Baz,
+   | |____________________^
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0046, E0277.
+For more information about an error, try `rustc --explain E0046`.