add regression tests

tests/ui/traits/next-solver/overflow/coherence-alias-hang-with-region.rs

@@ -0,0 +1,30 @@
+//@ check-pass
+//@ revisions: ai ia ii
+//@ compile-flags: -Znext-solver=coherence
+
+// Regression test for nalgebra hang <https://github.com/rust-lang/rust/issues/130056>.
+
+#![feature(lazy_type_alias)]
+#![allow(incomplete_features)]
+
+type Id<T: ?Sized> = T;
+trait NotImplemented {}
+
+struct W<'a, T: ?Sized, U: ?Sized>(&'a (), *const T, *const U);
+trait Trait {
+    type Assoc: ?Sized;
+}
+impl<'a, T: ?Sized + Trait> Trait for W<'a, T, T> {
+    #[cfg(ai)]
+    type Assoc = W<'a, T::Assoc, Id<T::Assoc>>;
+    #[cfg(ia)]
+    type Assoc = W<'a, Id<T::Assoc>, T::Assoc>;
+    #[cfg(ii)]
+    type Assoc = W<'a, Id<T::Assoc>, Id<T::Assoc>>;
+}
+
+trait Overlap<T: ?Sized> {}
+impl<'a, T: ?Sized> Overlap<T> for W<'a, T, T> {}
+impl<T: ?Sized + Trait + NotImplemented> Overlap<T::Assoc> for T {}
+
+fn main() {}

tests/ui/traits/next-solver/overflow/nalgebra-hang.rs

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+//@ check-pass
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+// Regression test for nalgebra hang from
+//     https://github.com/rust-lang/rust/pull/130654#issuecomment-2365465354
+trait HasAlias {}
+
+struct Dummy;
+trait DummyTrait {
+    type DummyType<T: HasAlias>;
+}
+impl DummyTrait for Dummy {
+    type DummyType<T: HasAlias> = T;
+}
+type AliasOf<T> = <Dummy as DummyTrait>::DummyType<T>;
+
+struct Matrix<T, S>(T, S);
+type OMatrix<T> = Matrix<T, AliasOf<T>>;
+
+impl<T: HasAlias> HasAlias for OMatrix<T> {}
+
+trait SimdValue {
+    type Element;
+}
+impl<T: HasAlias + SimdValue<Element: HasAlias>> SimdValue for OMatrix<T> {
+    type Element = OMatrix<T::Element>;
+}
+
+trait Unimplemented {}
+pub trait MyFrom<T> {}
+impl<T: Unimplemented> MyFrom<T> for T {}
+impl<T: SimdValue<Element: HasAlias>> MyFrom<T> for OMatrix<T::Element> {}
+
+fn main() {}