From 2f9a240b91f766f158b652f537b828c9909bfdd3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matthias=20Kr=C3=BCger?= <matthias.krueger@famsik.de>
Date: Sat, 23 Mar 2024 12:01:39 +0100
Subject: [PATCH] add test for opaque type with non-universal region substs
 #101852

Fixes #101852
---
 tests/ui/impl-trait/recursive-ice-101862.rs   | 12 ++++++++++
 .../ui/impl-trait/recursive-ice-101862.stderr | 24 +++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 tests/ui/impl-trait/recursive-ice-101862.rs
 create mode 100644 tests/ui/impl-trait/recursive-ice-101862.stderr

diff --git a/tests/ui/impl-trait/recursive-ice-101862.rs b/tests/ui/impl-trait/recursive-ice-101862.rs
new file mode 100644
index 00000000000..02f95fe5604
--- /dev/null
+++ b/tests/ui/impl-trait/recursive-ice-101862.rs
@@ -0,0 +1,12 @@
+// issue: rust-lang/rust#101852
+// ICE opaque type with non-universal region substs
+
+pub fn ice(x: impl AsRef<str>) -> impl IntoIterator<Item = ()> {
+//~^ WARN function cannot return without recursing
+    vec![].append(&mut ice(x.as_ref()));
+    //~^ ERROR expected generic type parameter, found `&str`
+
+    Vec::new()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/recursive-ice-101862.stderr b/tests/ui/impl-trait/recursive-ice-101862.stderr
new file mode 100644
index 00000000000..f4148720c33
--- /dev/null
+++ b/tests/ui/impl-trait/recursive-ice-101862.stderr
@@ -0,0 +1,24 @@
+warning: function cannot return without recursing
+  --> $DIR/recursive-ice-101862.rs:4:1
+   |
+LL | pub fn ice(x: impl AsRef<str>) -> impl IntoIterator<Item = ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
+LL |
+LL |     vec![].append(&mut ice(x.as_ref()));
+   |                        --------------- recursive call site
+   |
+   = help: a `loop` may express intention better if this is on purpose
+   = note: `#[warn(unconditional_recursion)]` on by default
+
+error[E0792]: expected generic type parameter, found `&str`
+  --> $DIR/recursive-ice-101862.rs:6:5
+   |
+LL | pub fn ice(x: impl AsRef<str>) -> impl IntoIterator<Item = ()> {
+   |               --------------- this generic parameter must be used with a generic type parameter
+LL |
+LL |     vec![].append(&mut ice(x.as_ref()));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0792`.