From a03da2bdeb7c7b466b7b4a9b361d1d19c171a589 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Thu, 9 Feb 2023 20:45:01 +0100
Subject: [PATCH] Add test for implementation on projection

---
 .../ui/const-generics/wrong-normalization.rs  | 19 +++++++++++++++++++
 .../const-generics/wrong-normalization.stderr | 11 +++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 tests/ui/const-generics/wrong-normalization.rs
 create mode 100644 tests/ui/const-generics/wrong-normalization.stderr

diff --git a/tests/ui/const-generics/wrong-normalization.rs b/tests/ui/const-generics/wrong-normalization.rs
new file mode 100644
index 0000000000000..f1ce317b3f78b
--- /dev/null
+++ b/tests/ui/const-generics/wrong-normalization.rs
@@ -0,0 +1,19 @@
+// This test ensures that if implementation on projections is supported,
+// it doesn't end in very weird cycle error.
+
+#![crate_type = "lib"]
+
+pub trait Identity {
+    type Identity: ?Sized;
+}
+
+impl<T: ?Sized> Identity for T {
+    type Identity = Self;
+}
+
+pub struct I8<const F: i8>;
+
+impl <I8<{i8::MIN}> as Identity>::Identity {
+//~^ ERROR no nominal type found for inherent implementation
+    pub fn foo(&self) {}
+}
diff --git a/tests/ui/const-generics/wrong-normalization.stderr b/tests/ui/const-generics/wrong-normalization.stderr
new file mode 100644
index 0000000000000..fb806bdb1e747
--- /dev/null
+++ b/tests/ui/const-generics/wrong-normalization.stderr
@@ -0,0 +1,11 @@
+error[E0118]: no nominal type found for inherent implementation
+  --> $DIR/wrong-normalization.rs:16:6
+   |
+LL | impl <I8<{i8::MIN}> as Identity>::Identity {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl requires a nominal type
+   |
+   = note: either implement a trait on it or create a newtype to wrap it instead
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0118`.