Add ICE reproduction for issue rust-lang/rust#79590.

Author: rustbot

ices/79590.rs

@@ -0,0 +1,17 @@
+trait Database: Restriction<Inner = u32> {}
+
+trait Restriction {
+    type Inner;
+}
+
+struct Test {}
+
+impl Database for Test {}
+impl Restriction for Test {
+    type Inner = u32;
+}
+
+fn main() {
+    let t = Test {};
+    let x: &Database<Inner = _> = &t;
+}