Add test for issue 30472

Author: clubby789

tests/ui/traits/assoc-type-hrtb-normalization-30472.rs

@@ -0,0 +1,32 @@
+//@ check-pass
+//! Tests that associated type projections normalize properly in the presence of HRTBs.
+//! Original issue: <https://github.com/rust-lang/rust/issues/30472>
+
+
+pub trait MyFrom<T> {}
+impl<T> MyFrom<T> for T {}
+
+pub trait MyInto<T> {}
+impl<T, U> MyInto<U> for T where U: MyFrom<T> {}
+
+
+pub trait A<'self_> {
+    type T;
+}
+pub trait B: for<'self_> A<'self_> {
+    // Originally caused the `type U = usize` example below to fail with a type mismatch error
+    type U: for<'self_> MyFrom<<Self as A<'self_>>::T>;
+}
+
+
+pub struct M;
+impl<'self_> A<'self_> for M {
+    type T = usize;
+}
+
+impl B for M {
+    type U = usize;
+}
+
+
+fn main() {}