Add regression test for issue 73899

Adds regression test for #73899

src/test/ui/issues/issue-73899.rs

@@ -0,0 +1,21 @@
+// run-pass
+#![feature(const_evaluatable_checked)]
+#![feature(const_generics)]
+#![allow(incomplete_features)]
+
+trait Foo {}
+
+impl<const N: usize> Foo for [(); N] where Self: FooImpl<{ N == 0 }> {}
+
+trait FooImpl<const IS_ZERO: bool> {}
+
+impl FooImpl<{ 0u8 == 0u8 }> for [(); 0] {}
+
+impl<const N: usize> FooImpl<{ 0u8 != 0u8 }> for [(); N] {}
+
+fn foo<T: Foo>(_v: T) {}
+
+fn main() {
+    foo([]);
+    foo([()]);
+}