polymorphize: constrain unevaluated const handling

This commit constrains the support added for handling unevaluated consts
in polymorphization (introduced in #75260) by:

- Skipping associated constants as this causes cycle errors.
- Skipping promoted constants when they contain `Self` as this ensures
  `T` is used in constants of the form `<Self as Foo<T>>`.

Signed-off-by: David Wood <david@davidtw.co>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/test/ui/polymorphization/promoted-function-3.rs b/src/test/ui/polymorphization/promoted-function-3.rs
new file mode 100644
index 00000000000..1c84df13e10
--- /dev/null
+++ b/src/test/ui/polymorphization/promoted-function-3.rs
@@ -0,0 +1,14 @@
+// run-pass
+// compile-flags: -Zpolymorphize=on -Zmir-opt-level=3
+
+fn caller<T, U>() -> &'static usize {
+    callee::<U>()
+}
+
+fn callee<T>() -> &'static usize {
+    &std::mem::size_of::<T>()
+}
+
+fn main() {
+    assert_eq!(caller::<(), ()>(), &0);
+}